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    25 November 2022, Volume 43 Issue 11 Previous Issue    Next Issue
    Special Topic of Natural Rubber
    Selection of miRNA Reference for Normalization of Quantitative Real-time PCR Analysis in the Bark of Rubber Tree (Hevea brasiliensis Muell. Arg.)
    WU Shaohua, ZHANG Shixin, YANG Shuguang, TIAN Weimin
    2022, 43 (11):  2181-2187.  doi: 10.3969/j.issn.1000-2561.2022.11.001
    Abstract ( 113 )   HTML ( 9 )   PDF (1670KB) ( 38 )  

    Rubber tree is the main source of natural rubber worldwide. Natural rubber is synthesized and stored in laticifer, a tissue composed of laticifer cells. The laticifer cells in the trunk bark are directly associated with natural rubber production and differentiated from the fusiform initials of vascular cambia. As the number of laticifer rings is positively correlated with rubber yield, the differentiation of laticifer from vascular cambia is a major theoretical subject faced to natural rubber industry. Plant miRNAs are a class of small noncoding RNAs about 20?24 nucleotides in length and play a pivotal regulatory role in development, cell differentiation and adversity stress by mediating the the gene silencing. Quantitative Real-time PCR (qPCR) is widely used in the quantitative analysis of the miRNA expression levels, and the selection of appropriate internal reference of miRNA is crucial for accurating the miRNA expression levels. In the present study, the expression stability of three non-coding RNAs (U6 snRNA, 5S rRNA, 18S rRNA) and 6 mature miRNAs (hbr-miR159b, hbr-miR396b, miR169-x, miR172-y, miR535-x, miR894-x) were evaluated on the basis of coronatine-induced secondary laticifer differentiation in the bark of rubber trees using poly (A)-tailed qPCR. According to the analysis of geNorm and NormFinder, hbr-mi396b and miR894-x were the top two stable miRNAs and U6 snRNA was the least stable gene in response to coronatine in the cambium tissue of rubber trees. The results showed that hbr-mi396b and miR894-x could serve as qPCR reference miRNA to analyze the miRNA expression pattern in COR-induced secondary laticifer differentiation. This study will provide a good basis for identification of the differentially expressed miRNAs related to secondary laticifer differentiation.

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    Identification and Expression Analysis of YABBY Gene Family in Hevea brasiliensis
    ZHANG Hongtao, XIAO Xiaohu, YANG Jianghua, QIN Yunxia, LONG Xiangyu, YIN Hongyan, FANG Yongjun
    2022, 43 (11):  2188-2198.  doi: 10.3969/j.issn.1000-2561.2022.11.002
    Abstract ( 68 )   HTML ( 13 )   PDF (8413KB) ( 27 )  

    YABBY genes family is a plant-specific transcription factor, which plays an important role in the development of plant leaves, floral organs and abiotic stress response, but it has not been reported in rubber tree so far. In this study, eleven HbYABBY genes were identified from the genome of Hevea brasiliensis, and the gene structure, promoter regulatory elements, chromosome location and collinearity, phylogeny and gene expression were analyzed. The results showed that the HbYABBY family genes were distributed on nine chromosomes. The length of the encoded protein was between 141 and 233 amino acids, and the molecular weight was ranged from 14.75 to 26.41kDa. The promoter regions contained response elements such as stress response, among which the number of light response elements was the largest. Gene transcriptional analysis showed that HbYABBY had significant tissue-specific expression profile, eight genes were only highly expressed in leaves and flowers but not in latex and roots. During the leaf development, except for HbCRC1, the expression of the other 9 HbYABBY were significantly down-regulated, which indicated that HbYABBY were deeply involved in the regulation of leaf development of rubber trees. Furthermore, both transcriptional and RT-qPCR experiments showed that HbYABBY genes were continuously down-regulated under high temperature treatment, indicating the regulatory roles in high temperature stress responses of rubber trees. In this paper, YABBY genes were firstly reported in H. brasiliensis, the physical and chemical characteristics, expressions and function of the genes were preliminarily studied, which would provide a solid foundation to investigate the functions and evolution of HbYABBY genes.

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    Salt Stress Response and Functional Indentification of HbICEs from Rubber Tree
    LI Yan, YANG Shuguang, SHI Minjing, TIAN Weimin
    2022, 43 (11):  2199-2206.  doi: 10.3969/j.issn.1000-2561.2022.11.003
    Abstract ( 45 )   HTML ( 3 )   PDF (6589KB) ( 17 )  

    ICE (inducer of CBF expression), the MYC (myelocytomatosis)-like bHLH (basic helix-loop-helix) transcription factor, plays an important role in regulating the responses of plants to abiotic stresses such as low temperature, drought, and high salt. In this study, the expression patterns of rubber tree ICE genes were analyzed by qPCR. The expression of five HbICEs were up-regulated in rubber tree seedlings upon salt stress, HbICE2, HbICE3, HbICE4 and HbICE5 were significantly up-regulated under salt stress for 2 h. At 4 h of salt stress, the expression of HbICE4 and HbICE5 reached the maximum with the most up-regulated level of HbICE4. Under salt stress for 4-24 h, HbICE3 was significantly down regulated. The expression of HbICE1 had no obvious change before 4 h of salt stress, but increased significantly after 8 h. Therefore, all five HbICE genes may participate in the salt stress response of rubber tree. Overexpression of HbICEs, especially HbICE4, led to an enhanced salt-tolerance of transgenic Arabidopsis based on survival rate, average fresh and dry weight per plant. Under salt stress, all wild-type Arabidopsis wilted. The survival rate of HbICE4 overexpressing Arabidopsis was 96.29%, the average fresh weight per plant was 0.03 g, and the average dry weight per plant was 0.0035 g, the three growth parameters of HbICE4 overexpressing plants were the highest among the transformed strains of rubber tree HbICE genes. Compared with the physiological indexes before salt stress, the relative conductivity of WT and HbICEs transgenic plants increased significantly under salt stress, and the chlorophyll content and relative water content decreased significantly. Among them, relative conductivity increase of HbICE4 transformed Arabidopsis was the smallest, and the decrease of SPAD value (chlorophyll content) and relative water content was the smallest. Therefore, the enhanced salt-tolerance was associated with lower relative conductivity, a physiological parameter for evaluating membrane system stability, as well as higher chlorophyll content and relative water content in comparison to those of WT. Salt stress leads to the damage of plant cell membrane system, resulting in the decrease of water content, the destruction of chloroplasts and the degradation of chlorophyll. The membrane system of plants overexpressing HbICE4 was slightly damaged under salt stress, delaying the decrease of water content and the degradation of chlorophyll. Rubber tree HbICEs can not only improve the cold and drought tolerance of transgenic plants, but also improve the salt-tolerance of transgenic plants. This study would deepen the understanding of the biological function of rubber tree HbICEs, and provide candidate target genes for improving salt-tolerance of crops.

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    Quantification and Characterization of Rubber from Primary Laticifers of Hevea brasiliensis
    YAO Xingcheng, TU Hanqi, ZHOU Jun, CHEN Xianhong, CHEN Qing, LIN Weifu, WANG Jun
    2022, 43 (11):  2207-2214.  doi: 10.3969/j.issn.1000-2561.2022.11.004
    Abstract ( 46 )   HTML ( 2 )   PDF (1126KB) ( 29 )  

    Hevea brasiliensis contains two types of laticifers, primary and secondary. The former distributes in the leaf and bark of stems with primary growth, and the latter distributes in the bark of stems with secondary growth. The commercial rubber is extracted from the latex of secondary laticifers and much is known to this rubber. However, little is known to the rubber in primary laticifers as it has not been exploited. This study focused on the rubber from primary laticifers from young shoots of grafted plants. We evaluated the rubber yield-related factors, including shoot biomass, biomass partitioning, and rubber content, to determine rubber yield potential. In addition, we characterized the physical and chemical properties and vulcanization behavior of raw rubbers. Results showed that clones could affect shoot biomass, biomass partitioning, and rubber content. On average, biomass partitioning value for the leaf, bark and wood was 55.5%, 10.5%, and 34.0%, respectively. Rubber content in the leaf and bark was 13.7 and 35.6 mg/g dry weight, respectively. The rubber particle average size of the latex from primary laticifers was 0.36 μm, smaller than that from secondary laticifers. Rubber from primary laticifers had a smaller molecular weight than that from conventionally tapped mature trees. The nitrogen content of rubber from primary laticifers was 0.56%, higher than that of conventional rubber (0.50%). The plasticity retention index (PRI) of rubber from primary laticifers was 89%, higher than that of conventional rubber (80%). However, the Mooney viscosity and initial plasticity (P0) of the rubber from primary laticifers was 66 and 26, respectively, lower than that of conventional rubber (101 and 50, respectively). The volatile matter content and the ash content of rubber from primary laticifers was 0.50% and 0.38%, respectively, the same as that of conventional rubber. The scorching T10 and optimal vulcanization T90 times of the rubber from primary laticifers was 2.00 and 19.12 min, respectively, which was lower than conventional rubber (2.47 and 25.08 min, respectively). Comparing to conventional rubber, rubber from primary laticifers exhibited a lower minimum torque (ML) value (0.22 dN·m), but a higher maximum torque (MH) value (8.25 dN·m). By analyzing three clones, the results suggest that the rubber yield from primary laticifers from young shoots could be affected by shoot biomass, biomass partitioning and rubber contents. This rubber yield related results would provide a foundation for future work on breeding, germplasm development and cultivation practices. The results on rubber property showed that the rubber from primary laticifers was comparable to conventional rubber except for Mooney viscosity and P0, suggesting that the rubber from primary laticifers could not be used as standard rubber but general rubber material.

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    Molecular Simulation on Miscibility of NR/BR Blends
    YUAN Xiaoqin, CAO Xianchao, MA Yanbin, YU Rentong, ZHAO Yanfang, CHEN Yongping, LIAO Jianhe
    2022, 43 (11):  2215-2223.  doi: 10.3969/j.issn.1000-2561.2022.11.005
    Abstract ( 41 )   HTML ( 4 )   PDF (2627KB) ( 25 )  

    Natural rubber (NR) is widely used in various fields for its excellent comprehensive properties, however its poor heat resistance and aging resistance have great influence on the service life of NR products. The blending of natural rubber and cis-butadiene rubber (BR) could not only improve the tensile strength, wear resistance and tear resistance of the product, but also improve the service life and cold resistance of the product, and the NR/BR blends are widely used in tire manufacturing. When NR and BR are blended, the miscibility between NR and BR has an important influence on the phase structure and properties of the blends. In this study, Material Studio software was used to build the models required for the simulation, and molecular dynamics (MD) and dissipative particle dynamics (DPD) simulation methods were performed to investigate the miscibility of NR/BR blends from the molecular and mesoscopic scales at room temperature. The MD simulation results showed that the minimum repeating units of NR and BR in the NR/BR blend models were both 20; Models of NR/BR blends with mass ratios of 10/90, 30/70, 50/50, 70/30, 90/10 were constructed by Material Studio, by calculating the interaction parameter χ of each NR/BR blends, it was found that the interaction parameters of NR-BR in NR/BR blends (χNR/BR) were always smaller than the critical interaction parameter χC; The radial distribution function between molecules of NR/BR blends with different mass ratios were analyzed, and it was found that the radial distribution function ginter (r) between NR and BR molecules were always higher than that between NR and NR, BR and BR molecules of the same species, which showed that the interaction between different species (NR-BR) in the blends is stronger than the interaction between the same species (NR-NR, BR-BR). In addition, DPD simulations results calculated from the NR/BR blends with different mass ratios showed that the domain size of the dispersed phase of the blends increased with the increase of the dispersed phase content while macroscopic phase separation had always not been detected. Furthermore, the samples of NR/BR blends were prepared, and the miscibility of each blending system was confirmed with the results of dynamic mechanical analysis (DMA). The simulation results show that when NR and BR are blended with different mass ratios at room temperature, they always show good compatibility, and the experimental results are consistent with the results of molecular simulation.For this reason, molecular simulation will be of significance to study and predict the miscibility of polymer blend, and it will provide much more reliable guidance for experiment.

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    Protective Effect of Two Hindered Phenolic Antioxidants Against Thermal and Oxygen Aging of Natural Rubber by Multi-scale Molecular Simulation and Experimental
    CAO Xianchao, YUAN Xiaoqin, MA Yanbin, YU Rentong, ZHAO Yanfang, CHEN Yongping, LIAO Jianhe
    2022, 43 (11):  2224-2234.  doi: 10.3969/j.issn.1000-2561.2022.11.006
    Abstract ( 28 )   HTML ( 2 )   PDF (3012KB) ( 15 )  

    The anti-oxidative effect of two types of hindered phenolic antioxidants, i.e., 2,2'-methylenebis (6-tert-butyl-4-methylphenol) (AOA2246) and 2,2'-methylenebis (6-tert-butyl-4-ethylphenol) (AOA425) on natural rubber (NR) was investigated by means of multiscale molecular simulation and experimental validation. According to the quantum mechanical simulation, it was found that the changes in Gibbs free energy (ΔG) of dissociation of O-H bonds of the two anti-oxidative agents were lower than that of dissociation of C-H bonds of NR when heated. In addition, the ΔG of the O-H bonds cleavage in AOA425 (the weakest position h) was calculated to be as low as 250.08 kcal/mol. Besides, the energy barrier (Ebarrier) for the reaction between AOA425 and CH3OO was found to be only 5.31 kcal/mol, which was the lowest by searching and comparing all the transition states between the reactant (AOA2246, AOA425 or NR) and CH3OO·. As a result, AOA425 was supposed to be effective in suppressing the oxidation reaction of NR in consideration of the distinguished ability of scavenging free radicals. Consequently, the protection mechanism of the hindered phenolic antioxidants was interpreted by chemical reaction mechanism. In addition, the solubility parameter of AOA425 was calculated to be close to that of NR according to the molecular dynamics simulation. The low oxygen diffusion coefficient in NR indicated that AOA425 would play a long-term role. The oxygen permeability coefficients calculated via Monte Carlo simulation can be sequenced as PNR>PNR/2246>PNR/425. Therefore, AOA425 was found to be beneficial to shielding oxygen in the light of physical protection mechanism. Furthermore, the anti-oxidative influence of AOA425 and AOA2246 on NR was validated with the results of mechanical measurements, Shore A hardness testing, Fourier transform infrared spectra (FT-IR), and accelerated thermal oxygen aging experiments. The mechanical properties of NR were slightly decreased with the incorporation of AOA425. The infrared spectra also demonstrated that AOA425 exhibited better thermal oxygen aging resistance for NR in consideration of the molar ratio of carbon to oxygen. The experimental data showed a good agreement with the results of molecular simulation and multiscale molecular simulation would be of significance to predict the anti-oxidative performance of materials.

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    Omics & Biotechnology
    Cloning of an FsANT Gene in Fusarium sacchari and Analysis on Its Expression Pattern During Infection Process
    WANG Caixia, HUANG Zhen, LI Huixue, ZHOU Yuming, DUAN Zhenzhen, BAO Yixue, ZHANG Muqing, YAO Wei
    2022, 43 (11):  2235-2242.  doi: 10.3969/j.issn.1000-2561.2022.11.007
    Abstract ( 45 )   HTML ( 4 )   PDF (2688KB) ( 31 )  

    Sugarcane is the main sugar crop in China and the most important raw material for sugar production. The threat of diseases and insect pests in sugarcane production has caused serious losses to the sugar industry. Tip rot caused by Fusarium sacchari is a fungal disease that seriously affects sugarcane crop production. It is of great significance to study the pathogenic genes of F. sacchari. Adenine nucleotide translocase (ANT) mediates the exchange of ADP/ATP between mitochondria and cytoplasmic matrix, which plays an important role in eukaryotic cell energy metabolism and is closely related to cell growth, development and apoptosis. In this study, a 936 bp ANT gene sequence of F. sacchari with a complete open reading frame (ORF) was cloned, tentatively named FsANT, encoding 311 amino acids. FsANT protein of F. sacchari was found to cluster with ANT protein of other pathogens, indicating that FsANT may had the similar function. Softwares analysis showed that the protein encoded by this gene was a stable hydrophobic protein, containing five transmembrane structures. In addition, ANT has three homologous and repeated MCF motifs in one ADP/ATP transporter domain, which conforms to the basic structural characteristics of Mitochondrial carrier family (MCF). The software predicted that the gene might target mitochondria. qRT-PCR results showed that FsANT gene expression was relatively stable during mycelia growth period without significant difference. In the process of interaction with sugarcane, the expression pattern of this gene began to be up-regulated 12 h after inoculation, and increased significantly 24 h after inoculation, and reached its peak at 72 h. It is speculated that the expression of FsANT gene was not only related to the growth of F. sacchari cells, but also maight participate in the interaction between F. sacchari and sugarcane, and mainly played a role in the later stage of infection. The study of pathogenic growth conserved genes would provide a new idea for sugarcane breeding against pokkah boeng disease.

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    Characterization and Expression Analysis of a MiAGL80 Gene in Mango
    ZENG Xuemei, HE Xinhua, YU Haixia, HUANG Xing, LU Tingting, ZHANG Yili, ZHU Jiawei, LUO Cong
    2022, 43 (11):  2243-2248.  doi: 10.3969/j.issn.1000-2561.2022.11.008
    Abstract ( 39 )   HTML ( 2 )   PDF (2016KB) ( 19 )  

    AGL80/FEM111 belong to the Type I class of the MADS-box gene family and regulate the development of central cells and endosperm in Arabidopsis thaliana AGL80 has been rarely reported in woody plants at present. In this study, an AGL80 gene was obtained from mango transcriptome data. Bioinformatics analysis showed that MiAGL80 was located on chromosome 1, the ORF length of MiAGL80 was 897 bp, and there was no intron in the DNA sequence. MiAGL80 encoded 299 amino acids with an isoelectric point and molecular weights of 4.95 and 73.19 kDa, respectively. The amino acid sequence contained a conserved MADS_SRF_like domain. Phylogenetic tree analysis showed that MiAGL80 was closest to PvAGL80 and had the highest homology, with an amino acid similarity of 64.29%. Promoter sequence analysis revealed that the mango MiAGL80 gene promoter contained light response elements, adversity response elements, transcription factor-binding sites and hormone response elements. There were more light response components than other components, which contained not only light regulating elements but also circadian rhythm elements. Hormone response elements included gibberellin response elements, auxin response elements and ethylene response elements, and the stress response elements were mainly drought response elements. The expression of MiAGL80 decreased in the pulp with fruit development and increased first and then decreased during the development of the embryo, but the expression level was very low in the pulp and embryo at 100 days fruit and mature fruit. At the stage of embryo germination, the expression level of MiAGL80 increased significantly with seed germination. MiAGL80 was mainly expressed in leaves, and the expression level decreased at flowering induction period, then significantly upregulated during floral organ development, and last decreased again during the flowering period. MiAGL80 was not expressed in buds during the vegetative period but was also upregulated in floral buds and flowers. However, the expression level was extremely low in the stem. The results suggest that MiAGL80 may play an important role in mango fruit development, seed embryo development and germination, as well as in flower regulation. The results provide a reference for further study of the function of the MiAGL80 gene.

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    Estimation Ploidy and Genome Size of 27 Dendrobium Species by Flow Cytometry
    XIONG Wenyan, PU Ran, LIU Yunli, CHEN Junwen, ZHANG Jingli
    2022, 43 (11):  2249-2257.  doi: 10.3969/j.issn.1000-2561.2022.11.009
    Abstract ( 32 )   HTML ( 4 )   PDF (1254KB) ( 15 )  

    Dendrobium is a large genus within Orchidaceae, and there are 76 species recorded in China, mainly distributed in Hainan, southwest China, and Guangdong, Guangxi. Dendrobium species are highly ornamental because of the wide variety, bright, colorful flowers and long flowering period. At present, Dendrobium plant resources in the field are facing the dilemma of extinction, self-incompatibility, rare ornamental species and lack of good breeding parents. In order to protect the existing varieties, cultivate new species and establish a gene molecular library, the nuclear suspension was prepared by MGb dissociation solution from the young leaves of Dendrobium speceis, and maize (Zeamays, ‘B73’) and tomato (Lycopersicone culentum) were used as internal standard. At the same time, to establish a method for determining the ploidy and genome size of Dendrobium species based on flow cytometry, the ploidy and genome size of 27 Dendrobium species in Orchidaceae were determined by flow cytometry. The results show that it is better differentiation by using maize as internal standard, clear and concentrated which can accurately estimate the ploidy and genome size of Dendrobium species. Among 27 Dendrobium species, 19 species were diploid, 5 species were triploid and 3 species were tetraploid. The 27 Dendrobium species belong to 8 sections, including 1 species of sect. Grastidium, 2 species of sect. Chrysotoxae, 16 species of sect. Dendrobium, 1 species of sect. Breviflores, 1 species of sect. Stuposa, 1 species of sect. Pedilonum, 4 species of sect. Stachyobium and 1 species of sect. Crumenata. The estimated genome size of 27 Dendrobium species ranged from 0.98 pg to 2.41 pg, and the estimated average genome size was 1.44 pg. The estimated genome size of 27 dendrobium species were all greater than 0.7 pg, mainly between 0.7-1.4 pg. The estimated genome size of Dendrobium compactum was the largest, and that of Dendrobium strongylanthum was the smallest, and the difference between them was nearly 2.5 times; the genomes of 27 Dendrobium species can be classified as minimal genome or small genome. This study provides convenience for artificial cross pollination configuration, cross breeding and polyploid induction of Dendrobium species, lays a foundation for the establishment of gene molecular library, genetic variation, evolutionary biology and whole genome sequencing for Dendrobium species.

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    Expression Pattern Analysis and Prokaryotic Expression of MaUBC-C Gene in Mulberry
    ZHAO Xinru, MO Yingxi, LI Jieqiu, MENG Jiaorong
    2022, 43 (11):  2258-2267.  doi: 10.3969/j.issn.1000-2561.2022.11.010
    Abstract ( 27 )   HTML ( 3 )   PDF (1890KB) ( 14 )  

    Ubiquitin-conjugating enzyme (E2) plays an important role in plants and participates in physiological activities such as plant growth and development, stress, immune response and so on. In previous research, we profiled the transcriptome of ‘Guisangyou 62’ which infested with mulberry vein binding-associated virus (MVBaV) to obtain the up-regulated expression gene MaUBC-C. In order to explore the function of MaUBC-C, the CDS sequence of MaUBC-C was cloned from mulberry for bioinformatics and expression pattern analysis, and MaUBC-C was obtained by prokaryotic expression. The results showed that the coding region of MaUBC-C was 567 bp, coding 188 amino acids, and it was predicted to target the nuclear. MaUBC-C was 21.03 KDa and belonged to hydrophilic, acidic and unstable protein with a conserved UBC domain. Multiple sequence alignment and phylogenetic analysis of UBC in Morus atropurpurea and other species showed that MaUBC-C had the highest similarity with the homologous MnUBC from M. notabilis, which was 98.40%. The real-time fluorescence quantitative PCR data showed that MaUBC-C was expressed in roots, stems and leaves, and the highest expression was in roots, which were 1.24 and 1.71 times higher than those in stems and leaves, respectively. And we found MaUBC-C responded to differently to different (ABA, GA, MeJA, SA) and abiotic stress (low temperature, high temperature, high salt, drought). Among them, MaUBC-C was significantly up-regulated after treatment with ABA and MeJA, as the expression at 24 h was 29.55 and 9.05 times of the normal level, respectively. It is speculated that MaUBC-C may extensively regulate the growth and development of mulberry, participating in the hormonal signal transduction and defense responses to abiotic stresses. The prokaryotic expression vector pET-30a-MaUBC-C was constructed and transformed into E. coli BL21 to induce the expression of MaUBC-C with 0.5 mmol/L IPTG at 37℃. SDS-PAGE gel showed that a band with a size of about 25 kDa appeared from 2 h, the size was basically consistent with the expectation. And Western-blot showed that it could react specifically with His-tag monoclonal antibody indicating that MaUBC-C was successfully expressed, which provided basic materials for functional research of MaUBC-C. The results of this study would provide a theoretical basis for further exploring the mechanism of action of the ubiquitin proteasome pathway in mulberry.

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    Germplasm Resources, Genetics & Breeding
    Newly Recorded Species of Hypoxylaceae (Ascomycota) from Medog in China
    ZHU Anhong, GAO Yue, TANG Ke, SONG Zikun, YANG Zhanen, MA Haixia
    2022, 43 (11):  2268-2274.  doi: 10.3969/j.issn.1000-2561.2022.11.011
    Abstract ( 74 )   HTML ( 4 )   PDF (2136KB) ( 21 )  

    A preliminary account of Hypoxylaceae species (Ascomycota) by now widely unexplored forests of Medog county, southeast Tibet of China is surveyed. Three newly recorded species to China and seven species new to Tibet, are documented based on morphological and molecular phylogeny. The newly recorded species of China are: Annulohypoxylon leptascum, Daldinia bambusicola and Hypoxylon sublenormandii, and the morphological descriptions and illustrations in details are provided in the paper. Seven newly recorded species in Tibet, A. bovei, D. childiae, H. howeanum, H. investiens, H. perforatum, H. trugodes and Jackrogersella multiformis are listed including the type location, distribution, habitat and simple characteristics. The discovery of newly distributed fungi is of great significance for exploring the species diversity and attributing the regionalization of Hypoxylaceae from Medog in China.

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    Phenotypic Diversity Analysis and Comprehensive Evaluation of Weedy Rice Germplasm
    CAI Haibin, HAN Guangyu, TU Min, GUAN Xin, WANG Zhi, FU Yongwei, WANG Yunyue, LU Baorong
    2022, 43 (11):  2275-2285.  doi: 10.3969/j.issn.1000-2561.2022.11.012
    Abstract ( 28 )   HTML ( 4 )   PDF (2360KB) ( 25 )  

    Weedy rice is a weed similar to cultivated rice in growth form, but does not meet the requirements of cultivated rice production in rice quality, grain setting and dormancy. Jiangsu province is one of the provinces with the most serious damage to weedy rice in China. Many studies have focused on the origin, characters and control of weedy rice. There has no systematic study on weedy rice population as germplasm resources for cultivar improvement. Rich genetic diversity and excellent germplasm resources are the most important material basis for cultivated rice breeding and variety improvement. In the study, 21 weedy rice populations in different regions of Jiangsu Province, six cultivated rice varieties and two weedy rice populations as the control were planted in a Hainan homogeneous garden, and the diversity of 18 phenotypic traits was analyzed. Correlation analysis, principal component analysis, cluster analysis and comprehensive evaluation analysis were performed. The full panicle stage and flowering stage of weedy rice were significantly earlier than that of cultivated rice, and the rice grain number and total grain number of the weedy rice were relatively better than that of the cultivated rice. The phenotypic traits variation coefficient of the weedy rice resources group was 2.99%?196.29%, and the diversity index was 0.27?2.06, with the highest diversity index for seed setting rate, followed by solid grain number, sword leaf length/width, and total grain number. The beginning stage of heading and flowering had extremely significant positive relation with plant height, spike length, sword leaf aspect ratio, total grain number, actual grain number, 1000 grain weight and tillering number. 1000 grain weight had extremely significant positive relation with tiller number, spike length, sword leaf aspect ratio, tillering number, beginning stage of heading and flowering. Cumulative contribution 70.57% was from six principal components, including first heading stage, first flowering stage, full heading stage, full flowering stage, total grain number and full grain number. The 23 weedy rice populations were divided into five categories when the Euclidean distance was 5. There were three populations with D value >0.68 in the comprehensive evaluation of the18 indicators, with the D value of WJ-NJ1 from Rugao, Nantong the highest (0.715), followed by WJ-CZ1 from Jintan, Changzhou (0.698) and WJ-YC2 from Yancheng Municipal District (0.682). This study would provide an important theoretical basis for weedy rice germplasm resources in future assisted breeding and improvement of cultivated rice varieties.

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    Plant Cultivation, Physiology & Biochemistry
    Effects of Aqueous Extracts from Continuous Cropping Rhizosphere Soil of Coffee on Development of Seedling Roots
    TAN Jun, WANG Rui, LIN Xingjun, SHI Zhonghai, DONG Yunping, ZHANG Ang
    2022, 43 (11):  2286-2293.  doi: 10.3969/j.issn.1000-2561.2022.11.013
    Abstract ( 84 )   HTML ( 3 )   PDF (1394KB) ( 20 )  

    Coffee with rich nutritional value and high economic value is one of the three major beverages in the world, and is deeply welcome by consumers all over the world. Coffee is an important perennial cash crop in hot areas, and the long-term continuous cropping of which has produced serious continuous cropping obstacles, which has become a serious problem affecting the income of coffee farmers and restricting the sustainable development of the industry. Therefore, it needs to be solved urgently. In order to clarify the mechanism of coffee continuous cropping obstacle and provide scientific and experimental basis for overcoming it, the rhizosphere soil of diseased coffee plants was collected, and the indoor pot experiment was carried out to study the response of root growth and development of coffee seedlings to four concentrations of which water extracts (0, 0.50, 1.00 and 2.00 g/mL, recorded as CK, T1, T2 and T3, respectively) in this study. The rhizosphere soil aqueous extracts of diseased coffee plants caused the epidermal cells of coffee seedlings to become smaller and arranged more closely. With the increase of its concentration, the root cell wall and intimal system were gradually destroyed and formed a cavity. The lignification degree of primary xylem cells increased gradually as well. Root fresh weight, dry weight, total root length, root volume, root tip number, total root surface area and root activity decreased with the rhizosphere soil aqueous extracts of diseased coffee plants. Compared with CK, those from T2 decreased to a significant different level (P<0.05), and those from T3 decreased to a very significant different level (P<0.01). The lignin content and relative conductivity of roots increased gradually with the rhizosphere soil aqueous extracts. Compared with CK, the lignin content of T1 increased by 29.53%, reaching a significant different level, and the lignin of T2 and T3 increased by 42.38% and 66.52% respectively, reaching a very significant different level. The root relative conductivity of T2 and T3 increased by 34.40% and 58.30%, respectively. With the aqueous extracts concentration rising up, the soluble protein content of roots increased, 61.75% higher of T2 than that of CK. Although subsequently the amount decreased, but which was significantly different according to the data recorded before. MDA content, and the activities of SOD, POD and CAT increased with the increase of the aqueous extracts concentration. Compared with CK, the activity of SOD in T3 increased by 56.77%, reaching a significant different level, POD activity increased by 96.28%, reaching a very significant different level. In conclusion, there are autotoxic substances in the aqueous extract of rhizosphere soil of diseased coffee plants, which destroy the root structure of coffee seedlings and affect the growth and development of roots.

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    Effect of Different Fertilizer Models on the Growth, Development, Yield and Quality of Pineapple in Tropics
    LIANG Zhenghao, ZHANG Hanying, JIN Xin, ZHAI Pengfei, ZHAO Yan, LI Changjiang, RUAN Yunze, WANG Chaobi, WANG Tingzhong
    2022, 43 (11):  2294-2303.  doi: 10.3969/j.issn.1000-2561.2022.11.014
    Abstract ( 40 )   HTML ( 3 )   PDF (1618KB) ( 42 )  

    This experiment investigated the effects of different fertilization patterns on the growth and development, nutrient uptake and yield quality of pineapple (Ananas comosus), with the aim of screening out a high yield, high quality and efficient fertilization program. The variety ‘Tainong 17’ was subjected to a field plot experiment with five treatments: no fertilizer (CK), conventional fertilizer (NPK), reduced fertilizer (INF), organic and inorganic fertilizer (INF+M) and organic and inorganic slow-release fertilizer (INF+M+S). Each group was repeated three times, to compare the differences in leaf number, dry matter accumulation, yield quality and N, P and K accumulation and distribution of pineapples under different fertilization patterns. After the rapid growth period, the number of leaves in NPK treatment was higher than that in other treatments, about 84 leaves. INF+M and INF+M+S treatments increased dry matter accumulation at harvest by 20.28% and 23.16%, while there was no significant difference between INF and NPK treatments. The INF+M+S treatment increased N and P accumulation by 8.33% and 2.77% respectively compared to the NPK treatment, with no significant difference in K accumulation, while the INF and INF+M treatments had no significant effect on N accumulation, but reduced P and K accumulation. In addition, the INF+M+S treatment significantly increased N, P and K transport by 62.32%, 189.83% and 30.79%, respectively. The transport volume of N, P and K also increased in the INF+M treatment, while the INF treatment reduced P and K transport. Compared with the CK treatment, the fertilization treatment significantly reduced the nutrient distribution rate of the crown buds. Compared with the NPK treatment, the three reduced fertilization treatment increased the nutrient distribution rate of the pineapple fruit during the harvest period and reduced the nutrient distribution rate of the leaves and other nutrient organs. Among them, the distribution rate of N, P and K in the fruit under the INF+M+S treatment increased by 131.43%, 66.60% and 147.33%, respectively, compared with the NPK treatment. The INF, INF+M and INF+M+S treatments increased yield by 1.64%, 19.35% and 37.09%, respectively, compared to the NPK treatment, and INF+M+S was significantly higher than that of the other treatments. Compared with CK, fertilization treatment significantly increased the content of soluble sugar but reduced the content of titratable acid and vitamin C. However, there were no significant differences in soluble sugar, titratable acid and vitamin C content between fertilizer treatments. In summary, pineapple yield was the highest under INF+M+S treatment, and it increased nutrient accumulation, nutrient translocation and fruit nutrient distribution rate, making it the optimal fertilization mode for pineapple.

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    Metabolomics and Its Difference of Chinese Olive Fruit of Different Varieties (lines) During the Ripening Period
    CAI Jingrong, WANG Jie, ZHAO Junyue, PAN Tengfei, GUO Zhixiong, SHE Wenqin
    2022, 43 (11):  2304-2315.  doi: 10.3969/j.issn.1000-2561.2022.11.015
    Abstract ( 1448 )   HTML ( 4 )   PDF (3326KB) ( 37 )  

    Chinese olive fruit has a unique flavor and polyphenols, flavonoids, amino acids and other physiologically active substances, which are closely related to its flavor quality. At present, there are few reports on the systematic study of Chinese olive fruit metabolites. The main metabolic components of the olive fruit of three varieties (lines) having different quality types (‘Changying’, ‘Tanxiang’, ‘Lingfeng’) were assayed to provide a theoretical basis for the study of Chinese olive fruit quality formation and select fine varieties. In the experiment, the widely targeted metabolome technology based on ultra performance liquid chromatography and tandem mass spectrometry (UPLC-MS/MS) was used to determine the fruit metabolites of the three varieties (lines) at maturity, and combined with the multivariate statistical analysis method and the data of total phenols, total flavonoids and lignin in the fruits of the three varieties (lines). ‘Tanxiang’ had the highest content of total phenols and flavonoids, and ‘Lingfeng’ had the lowest content of total phenols and flavonoids. The total lignin content of ‘Changying’ was very high, which was consistent with the characteristics of hard poor mastication. A total of 13 categories and 524 metabolites including flavonoids, phenolic acids, amino acids and derivatives, organic acids, lipids, nucleotides and derivatives, tannins, saccharides and alcohols, lignin and coumarins were detected by the extensive targeted metabolomics technology. Among them, the number of flavonoids metabolites was the largest, mainly quercetin derivatives, luteolin derivatives and kaempferol derivatives. The metabolites of the varieties (lines) were significantly different, and the main differential metabolites were flavonoids, phenolic acids and amino acids and derivatives. There were 161 different metabolites in ‘Changying’ compared with ‘Tanxiang’ (116 up-regulated metabolites and 45 down-regulated metabolites). There were 164 differential metabolites in ‘Tanxiang’ compared with ‘Lingfeng’ (51 up-regulated metabolites and 113 down-regulated metabolites). There were 146 differential metabolites (51 up-regulated metabolites and 95 down-regulated metabolites) in ‘Changying’ compared with ‘Lingfeng’. The KEGG pathway enrichment analysis of differential metabolites found that among the varieties (lines), ‘Tanxiang’ had the most active flavonoid metabolism and amino acid metabolism, accumulating more flavonoids and amino acids such as quercetin derivatives, luteolin derivatives, kaempferol derivatives, alanine, serine, histidine, phenylalanine, tyrosine and etc. The flavonoid metabolism of ‘Lingfeng’ was relatively weaker than that of ‘Changying’, and the accumulation of flavonoids was relatively less, while ‘Changying’ had high lignin content, which might be one of the reasons for the stronger flavor of ‘Tanxiang’, and the sweeter flavor of ‘Lingfeng’.

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    Effects of Double Cropping in Summer and Autumn on Yield and Quality of Different Sweet Maize Varieties
    FANG Siyang, ZHANG Xiaomei, AN Tongxin, ZHOU Feng, YANG Youqiong, WU Bozhi
    2022, 43 (11):  2316-2323.  doi: 10.3969/j.issn.1000-2561.2022.11.016
    Abstract ( 28 )   HTML ( 6 )   PDF (902KB) ( 17 )  

    In previous studies on fresh maize planting in tropics, there are few studies on selecting suitable varieties for different multiple cropping seasons. A summer-autumn replanting trial of sweet maize was conducted in Mangshi, Yunnan using the local main sweet maize varieties ‘Kupula’ (T1), ‘Jinzhongyu’ (T2), ‘Gaoyuanwangzi’ (T3), and ‘Ruijiatian-1’ (T4) to meet the diversified production needs of fresh maize.. The differences between the two seasons of each variety were analyzed and compared. The test results showed that the differences of agronomic traits of each variety in both seasons reached a highly significant level (P<0.01), the plant height and stem thickness of T2 and T4 were higher than those of T1 and T3, the average stem thickness and leaf area index of autumn sowing increased by 8.78% and 16.67% respectively compared with summer sowing, the leaf area index of summer sowing T2 increased by 94.73% compared with T1, and the plant height of autumn sowing T4 increased by 71.76% compared with T1. The difference in forage quality indexes of each variety in both seasons reached a highly significant level (P<0.01), and the overall forage quality of T2 and T4 was better, the crude protein and ether extract content of T2 increased by 5.52% and 8.93% respectively in summer sowing, and the acid detergent fiber content effectively decreased by 5.21%, and the crude ash content of T4 decreased by 40.83% compared with T1 in autumn sowing. The difference in yield production value of each variety in both seasons reached a highly significant level (P<0.01), T1 and T3 yield production values were lower than those of T2 and T4 in both seasons, and the average yield of autumn sowing increased by 24.68% compared with summer sowing, and the average total yield increased by 57.83% (about 33 200 RMB per hectare), among which T2 summer sowing and T4 autumn sowing could achieve a total annual cob yield of 47.2 t/hm2, total stem and leaf yield of 42.4 t/hm2, and total production value of 113 500 RMB. T2 is more suitable for summer sowing, T1, T3 and T4 are more suitable for autumn sowing. Among them, the comprehensive performance of the three varieties of autumn sowing is in the order of T4>T3>T1, and T2 summer sowing, T4 autumn planting can achieve the maximum benefit.

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    Comparison of Nutritional Components and Correlation Analysis in Different Purple Rice Varieties
    SHI Jiang, LI Qian, LI Weifeng, CHEN Yunlan, HUANG Yanli, LIU Xingyong
    2022, 43 (11):  2324-2333.  doi: 10.3969/j.issn.1000-2561.2022.11.017
    Abstract ( 1459 )   HTML ( 3 )   PDF (5319KB) ( 35 )  

    In this study, four purple rice from Mojiang County (MJ), Xinhua County (HN), Hunan, Liping County (GZ), Guizhou and Hanzhong County (SX), Shaanxi were selected to evaluate the differences in starch, fat, anthocyanins, polyphenols, amino acids and elements between different origins, to determine the relationship among nutrient components, and to compare with red rice and black rice. The nutritional characteristics of the purple rice of different origins were different. Purple rice from HN had the lowest starch content (68.13%), highest fat, Fe, K, Mg, Mn, Na, P and Zn elements content, among which Mn (80.37 mg/kg) and Na (10.75 mg/kg) were significantly higher than other origins (P<0.05). Anthocyanins (533.03 mg/kg, 412.54 mg/kg), polyphenols (340.55 mg/100 g, 387.91 mg/100 g) content in purple rice from MJ and SX were significantly higher than those from the other origins (P<0.05), while anthocyanins (156.55 mg/kg) and polyphenols (239.23 mg/100 g) in purple rice from GZ were significantly lower (P<0.05) than those from the other origins. SX purple rice had the highest content of total amino acids (74.37 g/kg) and total essential amino acids (ΣEAA, 26.09 g/kg), which was not significantly different from other purple rice. Correlation analysis between the components of purple rice showed that anthocyanins was positively correlated with polyphenols (0.625), and both were negatively correlated with Ca (-0.571, -0.549), respectively. Asp and Gly were significantly positively correlated with Fe and Ca, respectively, and among most of each elements was significantly positively correlated. Among colored rice, red rice had the highest starch content (74.73%), but the lowes content of anthocyanins (9.05 mg/kg), total amino acids (55.94 g/kg), ΣEAA (19.78 g/kg), Fe (6.51 mg/kg), Mg (609.41 mg/kg), and P (1746.72 mg/kg), which were significantly different with purple rice and black rice (P<0.05). The contents of anthocyanin (533.03 mg/kg) and polyphenols (453.53 mg/100g) of black rice were significantly higher (P<0.05) than that of other colored rice. The difference in amino acid content between black rice and purple rice was not significant (P>0.05), but significantly higher than that of red rice (P<0.05).. The ratio of ΣEAA/ΣNEA was about 0.54 among colored rice. Principal component analysis (PCA) divided the three colored rice into two groups. red rice, purple and black rice. The first three principal components could explain 91% of the total variance. The contribution of the first principal component (PC1) was 67.5%, which represented mineral elements, indicating that the origin was the main reason for the difference in the composition of colored rice. The second principal component (PC2) accounted for 18.2% of the total variance, mainly including total anthocyanin and amino acids.This study could provide some reference for nutritional evaluation of purple rice.

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    Plant Protection & Bio-safety
    Resources of Arbuscular Mycorrhizal Fungi in the Rhizosphere Soil of Mango Trees in Baise, Guangxi, China
    LI Han, JIANG Shangtao, PENG Haiying, GAO Rifang, ZHANG Jinlian, LI Dongping, JIANG Rou, DONG Caixia, CHEN Tingsu
    2022, 43 (11):  2334-2344.  doi: 10.3969/j.issn.1000-2561.2022.11.018
    Abstract ( 65 )   HTML ( 3 )   PDF (2407KB) ( 15 )  

    In order to find out the distribution of AM fungi in the mango rhizosphere soil in Baise City, Guangxi, AM fungi were isolated from the rhizosphere soil and root samples from the main mango producing areas with both main application of organic fertilizers and main application of chemical fertilizer in Baise, Guangxi, and the species and infection of AM fungi under different fertilization regimes were compared. The rhizosphere soils of 5 mango orchards with the main application of organic fertilizer (OT) and 5 mango orchards with the main application of chemical fertilizer (CT) were collected. The AM fungi spores in the soil were isolated by the wet sieve decantation method, and the AM fungi in them were purified by enrichment and induction culture. The spores were identified molecularly and morphologically. The root samples were stained by the ink-vinegar solution staining method and the infection rate of endophytic fungi was determined. Six spore species of AM fungi were identified in the soil samples. Three AM fungal spores including one Acaulospora, one Claroideoglomus and one Paraglomus were identified in OT-treated soil samples. Three AM fungal spores including two Acaulospora, one Claroideoglomus were identified in CT-treated soil samples. Few species of AM fungi were isolated from the two fertilization systems, and the isolated species of AM fungi were relatively common, with no endemic species. Root staining showed that OT treatment had more hyphae, AM fungal structures were abundant, arbuscular and vesicle structures could be clearly observed, and a small amount of dark septate endophytes (DSE) were also found. CT treatment had relatively few hyphae, with less vesicular structures and arbuscules, and relatively more DSE. Analysis of variance (ANOVA) revealed that the colonization rate of extraradical hyphae, vesicle structure and spore density were affected by fertilization regime, mango variety and tree ages to a different extent. OT treatment had higher rates of extraradical hyphae and vesicle structure than those of CT treatment. In summary, the AM fungi isolated in this study enriched the AM fungal strain library in China, which would provide a basis for selecting high-efficiency AM fungal inoculants for fruit trees and a new direction for orchard management.

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    Identification and Biological Analysis of Fusarium lateritium Causing Leaf Blight Disease on Coffea canephora
    WANG Qian, WU Weihuai, HE Chunping, LIANG Yanqiong, LU Ying, YI Kexian
    2022, 43 (11):  2345-2355.  doi: 10.3969/j.issn.1000-2561.2022.11.019
    Abstract ( 38 )   HTML ( 3 )   PDF (6935KB) ( 17 )  

    An unknown disease on Coffea canephora which caused the leaves to become brick-red and withered in a farm of Baisha County, Hainan Province was studied. Two pure cultures 21BS02-1 and 21BS02-2 were isolated. The isolates were inoculated into the leaves and the symptoms were observed. It was found that the symptoms of 21BS02-1 were similar to the field symptoms, and the re-isolate was also consistent with the original pathogen. Therefore, strain 21BS02-1 was determined to be the pathogen. The colony of strain 21BS02-1 was mainly white, felt, dense hyphae, and the color of the center colony was rose. Its mycelia were slender, and some mycelia were septate mycelium. The two ends of macroconidia were slightly curved and shaped like a sickle, with a size of (56.26-175.76)μm × (12.93-19.78)μm, and there were 3-7 partitions. There were few microconidium, which were mainly elliptical and with 0-1 partition. According to the morphological characteristics, the pathogen was preliminarily identified as Fusarium sp. Then through internal transcribed spacer (ITS), β-tubulin and TEF genes to identify the pathogen, BLAST indicated that the homology with Fusarium lateritium of each gene sequence was 99.56% (MN686293), 100% (KJ00154), 99.68% (KF918550), respectively. The three single gene cluster trees based on ITS, β- tubulin, and TEF gene sequence showed that 21BS02-1 belonged to F. lateritium. The determination of biological characteristics showed that the most suitable medium for 21BS02-1 was OMA and CMA medium. The most suitable carbon source was sucrose, and the utilization rate was the highest. Beef extract was the most suitable nitrogen source. The mycelia growth was the fastest under the condition of alternating light and dark for 12 h, and pH value 7-9. This is the first detailed report of F. lateritium infecting C. canephora.

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    Post-harvest Treatment & Quality Safety
    Analysis of Metabolites of Three Different Cassava Varieties
    WU Jinshan, WANG Siqi, GENG Mengting, SONG Jiming, HUANG Jiaquan, JIA Yingxue, ZHANG Yijie, ZHANG Xiaofei, CHEN Yinhua
    2022, 43 (11):  2356-2365.  doi: 10.3969/j.issn.1000-2561.2022.11.020
    Abstract ( 34 )   HTML ( 3 )   PDF (3376KB) ( 22 )  

    In this study, the root tubers of three cassava varieties (‘KU50’‘SC205’ and ‘SC9’) were used as the experimental materials. The metabolites of 8-month-old cassava tubers were analyzed by chromatography-mass spectrometry with non targeted metabolomics. A total of 77 differential metabolites were obtained through identification, mainly involving sugar and its derivatives, amino acids, organic acids, etc.. The dominant metabolites (relative content > 15%) of ‘KU50’ and ‘SC205’ were sucrose, and the contents were basically the same. The dominant metabolites for ‘SC9’ were sucrose and fructose. The relative contents of sucrose and citric acid in ‘SC9’ were significantly lower than those of ‘KU50’ and ‘SC205’, but the contents of fructose, galactose and glucose were higher than those of ‘KU50’ and ‘SC205’. Principal component analysis (PCA) found that there were significant differences in the composition and structure of root metabolites among the three cassava varieties. Among the 33 metabolites, there were mainly five categories, including sugars and the derivatives, organic acids and the derivatives, alkaloids, nucleotides and the derivatives, amino acids and the derivatives. A total of 14 metabolic pathways with significant differences were annotated through GO, KEGG and pathway enrichment analysis, of which 16 metabolites were enriched in aminoacyl tRNA biosynthesis pathway, nine in arginine and proline metabolism pathway and three in cyano amino acid metabolism pathway. By analyzing the types, relative contents, main metabolites and significantly different metabolites of root tubers of the varieties, this paper would enrich the material basis of starch quality formation of different cassava varieties and provide a reference for cassava variety improvement, variety breeding and cassava food processing in the later stage.

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    Identification of P-type ATPase Gene Family and Analysis of Expression Pattern in Response to Antagonistic N-1 During Postharvest Storage in Litchi
    WANG Xin, SHAO Yuanzhi, TANG Yue, LI Wen
    2022, 43 (11):  2366-2374.  doi: 10.3969/j.issn.1000-2561.2022.11.021
    Abstract ( 33 )   HTML ( 3 )   PDF (7550KB) ( 14 )  

    P-type ATPase is an important membrane transporter in plants. It plays a significant role in plant energy metabolism and acid metabolism. In addition, the enzyme is widely involved in plant ion transport, stress resistance, cell signal transduction and other life activities. However, p-type ATPase gene family has not been comprehensively analyzed in litchi or other sapindaceae plants. In this study, based on the transcriptome data of ‘Feizixiao’ litchi, 28 p-type ATPase genes were identified through physiological and biochemical analysis, bioinformatics analysis and expression analysis, to explore the potential function of P-type ATPase during postharvest storage of litchi. The structure and phylogenetic analysis showed that the gene could be divided into 5 subfamilies, the genes in the same subfamily had similar gene structure and motifs. The secondary structure of protein was mainly consisted of α -helix, and the N-terminal domain of LcPAs was more conserved than the C-terminal domain. Subcellular localization prediction analysis showed that LcPAs were mostly located in mitochondria (21/28). According to transcriptome analysis, the up-regulated genes of P type ATPase family genes in litchi were significantly higher than the down-regulated genes during postharst storage, which suggesting that they may play a positive role in the resistance of quality deterioration of litchi after harvest. As a safe and healthy preservation technology, the mechanism of antagonistic biological control is very complex. Results showed that the antagonistic N-1 treatment could effectively inhibit the browning and disease occurrence of litchi fruits after harvest. Combined with RT-qPCR results, it was found that antagonistic N-1 treatment could induce up-regulated expression of LcPA1, LcPA7, LcPA8 and LcPA19 during the whole storage process, which further indicating that P-type ATPase family genes would play an important role in the antagonistic N-1 inhibition of litchi lesions. This study would provide a reference for understanding the evolution and biological function analysis of p-type ATPase gene family in litchi, it also provide new evidence for further understanding the molecular regulation mechanism of antagonistic N-1 preservation mechanism.

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    Characteristics of Lactic Acid Bacteria Colony Change and Organic Acid Metabolism During Inoculation and Spontaneous Fermentation of Banana Fruit Wine
    YANG Ying, DAN Xia, GUAN Jingxi, LI Jiemin, HE Xuemei, YE Dongqing, SUN Jian
    2022, 43 (11):  2375-2382.  doi: 10.3969/j.issn.1000-2561.2022.11.022
    Abstract ( 29 )   HTML ( 3 )   PDF (1223KB) ( 13 )  

    Bananas, rich in nutritional and bioactive ingredients, can be used as remarkable raw materials for deep processing products in food industry. Banana wine is one of the important deep-processing products. During the fermentation process, high sugar and low acidity of banana juice is suitable for microorganisms growth, especially for lactic acid bacteria (LAB) growth which is closely related to the production of organic acids. The change of LAB community easily produces excessive volatile acid content during the fermentation process, leading to low-quality banana wine. Therefore, this study was to investigate the growth and reproduction pattern of naturally existing LAB, as well as to evaluate the effect of LAB on the organic acid metabolism during banana wine fermentation. The findings of this research could provide theoretical references for accurately managing fermentation process to promote banana wine quality. In this study, the commercial yeast K1 inoculated fermentation and the banana juice spontaneous fermentation (SF) were used as the fermentation processes. The colony changes of yeast and LAB in the fermentation processes were monitored by real-time PCR, and the changes of organic acid content in fermentation processes were also detected by high performance liquid chromatography (HPLC). The organic acid metabolism characteristics of LAB in the processes were comparatively studied as well. The results showed that the growth of yeast and LAB differed significantly in the fermentation processes. In the fermentation process using K1 yeast, the number of LAB community was significantly inhibited, and the maximum growth amount of LAB was only 4.0×106 CFU/mL and the biomass of yeast was 1.2×107 CFU/mL. In the banana juice spontaneous fermentation process, the growth cycles of LAB and yeast were not affected mutually, and the biomass of LAB and yeast was 1.0×107 CFU/mL and 1.6×107 CFU/mL, respectively. Both fermentation processes demonstrated that there was a competitive relationship between yeast and LAB in banana wine fermentation. Additionally, organic acid metabolism was mainly related to the number of LAB community, and the contents of different organic acids had the similar change trends in this study. During the fermentation processes, lactic acid content was increased, and acetic acid content was increased firstly and then decreased. However, the total lactic acid and acetic acid contents in the spontaneous fermentation were higher than those in the yeast K1 inoculated fermentation. The citric acid, malic acid and tartaric acid contents showed a decreasing trend during the two kinds of fermentation process.

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    Changes of Main Biochemical Components and Expression of Related Enzyme Genes of Qilan Autumn Black Tea During Processing
    LIU Jinxian, LU Li, FU Xianyu, SHI Lingshan, WU Guangheng
    2022, 43 (11):  2383-2393.  doi: 10.3969/j.issn.1000-2561.2022.11.023
    Abstract ( 26 )   HTML ( 3 )   PDF (1337KB) ( 14 )  

    In order to provide reference for the quality improvement and process improvement of black tea in autumn, the fresh leaves of tea cultivars Qilan were processed to black tea in autumn, and the change law of content of main biochemical components, polyphenol oxidase (PPO) activity, and related enzyme gene expression was analyzed during processing process. The tea polyphenols, catechins, water extracts, and caffeine decreased from fresh leaves (XY) to the end of fermentation (FJ8) by 6.13%, 15.66%, 10.64%, and 0.10% respectively, and flavonoids, theaflavins, thearubigins, theabrownins, and free amino acids increased by 4.98 mg/g, 7.45 mg/g, 2.03%, 5.58%, and 0.14% respectively, among which the change range of caffeine was the smallest. Theaflavins, thearubigins, theabrownins and catechins showed a very significant negative correlation, and the correlation coefficient was -0.991, -0.969, -0.972 respectively. PPO enzyme activity fluctuated, increased first and then decreased in the withering stage, reached a peak value of 458.83 U/g during rolling, about 1.67 times that of XY, finally decreased rapidly in the fermentation stage, which was significantly lower than that of XY, and was about 0.89 times that of XY. The expression of polyphenol oxidase genes CsPPO1 and CsPPO2 both increased first and then decreased from rolling, and the highest relative expression appeared at 15 h of withering (WD15), 11.2 and 12.8 times that of XY, respectively. There was no significant difference between the CsPPOs expression in fermentation stage and fresh leaves. The expression of catechins metabolism related enzyme genes PAL, CHS, C4H, CHI, F3H, F3°5°H, FLS, DFR, LAR, and ANR was inhibited in varying degrees during processing, and significantly lower than that of XY. Except for the negative correlation with CG (Catechin Gallate), the genes were positively correlated with other components of catechins, and the correlation coefficient was 0.130-0.750.

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