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    Omics & Biotechnology
  • Omics & Biotechnology
    PENG Jun, ZENG Fanyun, WANG Yanwei, QI Yanxiang, DING Zhaojian, WANG Shaoling, XIE Yixian, ZHANG Xin
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    Fusarium oxysporum f. sp. cubense (Foc), the causal agent of Fusarium wilt (Panama disease), is one of the most devastating diseases of banana (Musa spp.). The Foc race 4 (Foc4) is currently known as a major concern in global banana production. carS is involved in the biosynthesis of Fusarium carotenoid by regulating downstream car structural genes. In this study, Foc4carS (FOIG_05085) was cloned and identified. Foc4carS had a typical RING-finger protein domain. The fusion fragment of Foc4carS was obtained by using Split-marker PCR, and the pUC-fFuCas9-HTBNLS- hph-Foc4carS gene editing vector containing the sequence of sgRNA591 of Foc4carS was constructed, the PEG- mediated protoplast transformation was used to obtain the knockout mutants, the complement mutants and the gene-editing mutants. The biological characteristics and pathogenicity of the knockout mutants and the complement mutants were analyzed. The results showed that the colony diameter, sporulation and pathogenicity of ΔFoc4carS mutants were not significantly different with wild strain Foc4, but the colony color of ΔFoc4carS mutant was dark orange, deletion of the Foc4carS gene affected the biosynthesis of the secondary metabolite carotenoid, and gene-edited ΔFoc4carS (HDR) mutants showed typical dark orange coloration in both regenerative screening plates and subcultured PDA plates. The results indicated that Foc4carS could be used as an endogenous reporter gene to perform gene plasmid CRISPR/Cas9 editing in F. oxysporum f. sp. cubense Foc4.

  • Omics & Biotechnology
    ZENG Sixian, YU Rangcai, FAN Yanping
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    Oncidium is an important fresh-cut flower in the market because of its unique flower pattern and brilliant color. The petals of Oncidium are highly susceptible to flower diversity. RNA extraction and transcriptome analysis were performed on the lateral petals of O. flexuosum ‘Honey Angel’ and variants with two lateral petals converted into lips to explore the molecular mechanism regulating the labialization of Oncidium lateral petals. A total of 45 525 415 high-quality reads were obtained from the sequencing results and 52 253 unigenes were identified. The seven databases of NR, Swissprot, PFAM, GO, NT, KO and KOG were used to annotate gene functions and annotated to 31 828, 23 174, 21 369, 21 367, 20 830, 10 523, 6465 unigenes. Upon expression comparison,3120 differential genes were obtained between O. flexuosum ‘Honey Angel’ and the mutant. A total of 1537 differentially expressed genes were annotated into three functional groups: biological processes, cellular components and molecular functions. KEGG functional enrichment analysis enriched 690 differentially expressed genes into different metabolic pathways, with the most genes enriched by metabolic pathway. To date, the study of lip formation in orchids has focused more on the MADS-box gene family, not only five significantly differentially expressed MADS-box genes were screened in this transcriptome data, but also other transcription factor such as NAC, TCP, MYB and WRKY that may be related to the lip formation in Oncidium were also discovered. RT-qPCR was used to verify the expression of key genes, and the quantitative results were consistent with RNA-seq data, most of the genes were highly expressed in the lip-like lateral petals, indicating that the genes may positively regulate the development of the lip of Oncidium. In summary, this study excavated a large number of key transcription factors involved in the variation of labialization in Oncidium, which would provide a certain reference for the study of the molecular mechanism and regulatory network of lip formation of orchid.

  • Omics & Biotechnology
    ZHENG Yujiao, CHANG Lili, ZHAO Yongguo, ZENG Changying, ZOU Zhi
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    Tigernut (Cyperus esculentus L.), which belongs to the Cyperaceae family within Poales, is a novel herbaceous oil crop producing high amounts of oil in underground tubers. Like other tuber and tuberous root crops, water accounts for approximately 85% of immature tubers, implying a crucial role of water balance for tuber development in tigernut. Plasma membrane intrinsic proteins (PIPs), which include two groups (i.e. PIP1 and PIP2) typically localized to the cell membrane, constitute a subfamily of aquaporin facilitating the passive transport of water. Based on one PIP identified in the proteomes of tigernut tubers, its coding gene CePIP1;1 was cloned using the RT-PCR technique, followed by analyzing the exon-intron structure, sequence features, evolutionary relationships, expression profiles, and protein subcellular localization. CePIP1;1 was shown to contain three introns with a coding sequence of 867 bp, putatively encoding 288 amino acids with the theoretical molecular weight of 30.76 kDa, the isoelectric point of 8.82, the instability index of 32.95, the grand average of hydropathicity of 0.384, and the aliphatic index of 95.28, implying that it is stable, basic, and hydrophobic. The protein was predicted to harbor one conserved MIP (major intrinsic protein) domain, including six transmembrane helices, two half helices, and dual NPA motifs located at the N-termini of two half helices. Sequence alignment and phylogenetic analysis revealed that CePIP1;1 clustered with Oryza sativa PIP1s and possesses an extended N-terminus but a short C-terminus relative to Spinacia oleracea PIP2;1, supporting its classification. Transient over-expression in Nicotiana benthamiana leaves supported the plasma membrane localization of CePIP1;1, which is consistent with the bioinformatics prediction. Further expression analysis showed that CePIP1;1 was constitutively expressed in all tissues examined in this study. During tuber development, CePIP1;1 exhibited a typical bell-shaped expression pattern, which is consistent with that of the moisture content. These results lay a solid foundation for further functional analysis and genetic improvement in tigernut.

  • Germplasm Resources, Genetics & Breeding
  • Germplasm Resources, Genetics & Breeding
    MA Liang, CHEN Xinyan, FU Houhua, LIU Mingzhu, CHEN Wenwei, CHEN Shipin
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    Fujian is rich in mountains, special landforms and plant diversity. Many investigations of the plants in Fujian have been carried out, but the plant diversity status of the whole province has not been fully understood. Four angiosperm plants were newly found during the survey on native wild plants in Fujian, and were identified as Cyrtosia septentrionalis, Conchidium rhomboidale, Trichosanthes laceribractea, Viburnum betulifolium referring to specimen and literature. Cyrtosia is a new record genus. The morphological characteristics of the four species were described and the corresponding characteristic photos were provided, and the differences between the morphological characteristics of the four species and the original similar species in Fujian were analyzed. The discovery of the four new records of angiosperms has enriched the plant diversity of Fujian province, and would provide new data for the protection and utilization of plant diversity in Fujian. All the voucher specimens were preserved in the Herbarium of College of Forestry, Fujian Agriculture and Forestry University (FJFC).

  • Germplasm Resources, Genetics & Breeding
    GUO Hui, CHEN Can, ZHANG Zongqiong, YANG Xinghai, LIANG Shuhui, ZHANG Xiaoli, XU Zhijian, NONG Baoxuan, LI Danting, XIA Xiuzhong, FENG Rui
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    Oryza officinalis Wall. ex G. Watt has excellent characteristics such as disease and insect resistance, stress tolerance, high biological yield and high light efficiency, and contains many excellent genes. In this study, 199 representative resources collected from all Oryza officinalis distribution sites in Guangxi were used to analyze the genetic diversity and principal components for five important agronomic traits, including heading stage, anther length, grain width, grain length and grain weight. The results showed that O. officinalis from Guangxi had rich genetic diversity, with coefficients of variation of 9.12%, 11.90%, 3.39%, 4.64% and 6.24% for heading stage, anther length, grain width, grain length and grain weight, respectively, and diversity index was 1.4878, 2.0453, 1.7727, 1.1567 and 2.0379, respectively. Principal component analysis showed that the first and second principal components were mainly related to yield traits, with a cumulative contribution rate of 63.759%. The third and fourth principal components had a cumulative contribution rate 16.306% and 15.542%, respectively. The heading stage and anther length were the influential determinants, mainly reflecting the plant growth characteristics. According to the genetic diversity, the seven geographic populations are ranked as follows: Wuzhou (1.6731)>Yulin (1.5784)>Guigang (1.5070)>Nanning (1.3325)>Laibin (1.2131)> Hezhou (0.9629)>Qinzhou (0.3819), and Wuzhou had the highest diversity index, indicating that Wuzhou was the phenotypic diversity center of Oryza officinalis in Guangxi.

  • Germplasm Resources, Genetics & Breeding
    HU Yifan, GAO Xiaoyu, SU Junyu, AN Mei, YANG Linxia, YANG Shaobing, TIAN Yang, FAN Yuanhong
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    Amomum tsao-ko (AT) is a medicinal and food homologous crop rich in polyphenols and flavonoids. The germplasm of AT is relatively mixed, and it is urgent to carry out research on AT germplasm resources and screening of high-quality AT seed sources. This study aimed to screen and evaluate the content of polyphenols and flavonoids and antioxidant activities of laxative active components of AT resources, and to explore the possible factors of component accumulation. In this study, a total of 57 samples were collected in Laos, Myanmar, Sichuan, Guangxi and Yunnan in China, and the polyphenol content and flavonoid content of AT aqueous extract were determined by forinphenol method and NaNO2-Al(NO3)3-NaOH colorimetric method, and the DPPH radical scavenging ability of AT aqueous extract was detected. The correlation between polyphenol and flavonoid content, DPPH radical scavenging capacity and geographic factors was analyzed. The results showed that the content of polyphenols and flavonoids in spindle-shaped AT resources was higher than that of oval fruit and round fruit, and the content of flavonoids in AT resources abroad and Nujiang was higher than that in other regions (outside the province, western Yunnan, southwest Yunnan, Wenshan and Honghe). The content of AT polyphenols and flavonoids was significantly positively correlated with DPPH radical scavenging capacity and altitude (P<0.05), and negatively correlated with longitude (P<0.05) and latitude (P>0.05), so it was speculated that the accumulation of AT polyphenols and flavonoids may be related to temperature, light, ultraviolet rays and soil moisture. Finally, according to polyphenols, flavonoids, the classification standards were formulated, and the AT resources were divided into three grades, which would provide an analysis method for the establishment of the AT quality grade evaluation system. The excellent AT resources were screened by this method as Nujiang samples GS-3 and GS-10 and foreign samples MDL-1 and MGK-2. This study would provide a scientific basis for the investigation and collection of AT, as well as the study of origin and evolution, and also lay a solid foundation for the utilization of AT resources and the development of industry in the future.

  • Germplasm Resources, Genetics & Breeding
    JIANG Suhua, WU Yuxin, LUO Jinrong, YE Yuejuan, LIN Jinshui, YU Huiwen, LU Luanmei
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    Curcuma alsimatifolia is a perennial bulbous herb of the genus Curcuma in the Gingeraceae.family The inflorescence of C. alismatifolia resembles tulips and enjoys the reputation of “tropical tulips”. C. alsimatifolia was introduced into China from Thailand and it is acclaimed by an ever-increasing number of consumers. The varieties of C. alismatifolia are relying on import in China today. The lack of new varieties with proprietary intellectual property rights limits the development of C. alismatifolia industry in China. Three different cross combinations of 327 hybrid offspring were constructed using the Siam TM Sitrone variety of C. alismatifolia as the female parent to breed new varieties of C. alismatifolia with independent intellectual property rights and increase the variety diversity. Eleven pairs of SSR primers were selected to analyze the hybrid F1 generation of the three cross combinations and the parents, and five pairs of specific SSR primers were selected for each cross combination to identify the authenticity of the hybrid F1 generation. The genetic segregation pattern and genetic diversity and genetic relationship of the parental and hybrid F1 generation populations were also analyzed. The results showed that the eleven pairs of SSR markers had high resolution and good amplification polymorphism for the three parental materials, and each parent had its specific SSR markers, which could effectively identify the genetic authenticity of the hybrid offspring. True hybridization rates of 91.8%, 90.8% and 93.4% were identified in 327 F1 individuals The SSR molecular marker primers had high polymorphism and could be directly used for C. alismatifolia genetic diversity analysis, hybrid identification and other related studies, providing efficient and reliable SSR marker selection for future identification of hybrid progeny, while the identified true C. alismatifolia progeny population could provide germplasm for genetic studies of superior traits. The identification of authentic C. alismatifolia progeny could provide germplasm materials for genetic research on superior traits and provide scientific basis for the selection of new varieties.

  • Plant Cultivation, Physiology & Biochemistry
  • Plant Cultivation, Physiology & Biochemistry
    XU Yunlong, ZHOU You, WANG Jun, GUO Lijia, HUANG Junsheng, YANG Laying
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    A nitrogen fixing bacteria strain named BWLY3X-6 was isolated from the rhizosphere soil of wild banana (Musa nana Lour. sp) in Hainan, China using Ashby nitrogen free medium, and.its morphological characteristics, physiological and biochemical characteristics, 16S rRNA and gyrB sequence analysis, nitrogen fixation characteristics and growth promoting ability to different banana varieties were studied. The strain was identified as an azotobacter Klebsiella variicola, and its extracellular ammonia nitrogen content was (17.98±1.88)μg/mL, nitrogenase activity was (220.51±8.21)ng/L. The results of the growth promoting test of the strain on different banana varieties showed that, compared with the blank control and 0.5% urea treatment, after inoculation with BWLY3X-6, under the inoculation concentration of 106 CFU/mL and 108 CFU/mL, there were significant changes in various biomass of M. acuminata AAA Cavendish cv. Nantianhuang and M. acuminata AAA Cavendish cv. Baxi (P<0.05), with more significant changes in root length, with the increase ratio of 43.5% and 54.6% respectively. In this study, nitrogen fixing bacteria with good nitrogen fixing ability were screened, and this strain had a good promoting effect on banana growth, wihich would provide a theoretical basis for its subsequent practical application in agricultural production.

  • Plant Cultivation, Physiology & Biochemistry
    GAO Xiang, YANG Yongzhi, LI Juan, CHEN Siru, RUAN Yunze, GAO Wei
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    Phosphorus (P) is an essential macro-element for crop growth and is involved in critical physiological and biochemical processes in plants. Pitaya is an important economic crop in tropical and subtropical regions. High fruit P concentration and huge yield require high P demand for pitaya growth. However, the P absorption characteristics of pitaya and the relationship of root morpho-physiological processes and P uptake are still unclear. In this study, pitaya variety Soft Dahong, which is the most popular cultivar in China, was used. Five P gradients of 0, 0.01, 0.1, 0.5 and 1.0 mmol/L were set by hydroponic experiment to explore the changes of root morphology and physiological process of pitaya under different P application rates. At the same time, the content of phosphorus and other nutrient elements in the aboveground part were analyzed to clarify the mechanism of root morphological and physiological traits for efficient P use and the effect of P supply on other nutrients uptake in pitaya. The results showed that compared with no P, P fertilizer application did not affect the accumulation of aboveground biomass. P uptake and P concentration of shoot increased with the P application rates. The total root length and the number of fine roots with diameter≤0.05 mm in low P treatment (0.1 mmol/L) were significantly higher than those of other treatments. High P supply inhibited root growth, showing that the total root length was the shortest, and the number of coarse roots with diameter≥2 mm was higher than that of other treatments. Low P (0.01 mmol/L) treatment had the highest total organic acid content and higher root CEC content. Compared with no P, the organic acid secretion rate and root CEC content decreased under high P supply (1.0 mmol/L). In terms of the absorption of other nutrient elements, the absorption concentration of iron in the mother branch and the primary branch decreased gradually with the increase of P rate. The contents of nitrogen, calcium, magnesium, manganese and zinc in the second order branches decreased gradually with the increase of P rate, showing a significant negative correlation. This study showed that low P and moderate P supply (0.01 mmol/L or 0.1 mmol/L) could promote root growth, root organic acid secretion and ion absorption capacity of pitaya, while excessive P supply (1.0 mmol/L) significantly inhibited root growth and significantly reduced the absorption of trace elements accumulation in shoots. Therefore, rational application of P fertilizer is of great significance for pitaya to maximize its root biological potential and improve the P use efficiency, and also plays a key role in the balance of trace elements uptake in plants.

  • Plant Cultivation, Physiology & Biochemistry
    LU Zhixia, TAN Chunlin, CHEN Huiping
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    Rice (Oryza sativa L.) is an important food crop, and the normal germination of rice seeds is related to the growth and yield of the plant in the later period. The germination begins with water absorption by dry seeds and ends with cotyl elongation. Water transport within and between cells is highly selectively regulated by aquaporins (AQPs). The seeds of cereal are rich in starch. And the endogenous gibberellin can induce the synthesis of hydrolase such as α-amylase in the embryo and secrete them into the starchy endosperm to degrade starch into small molecules for seed germination. Studies have shown that only α-amylase can complete the degradation of starch in rice seeds. Nitric oxide (NO) is a signaling molecule that forms a variety of active nitrogen substances. It also participated in the signaling process of seed dormancy removal. NO donor plays a role in seed germination by enhancing amylase activity. NO donor can promote seed germination by improving the activity of amylase. Rice hybrid seeds of ‘BoⅡ you 767’ were used as experimental materials to investigate the effects of aquaporins (AQPs) and nitric oxide (NO) on the germination of rice seeds. In this study, NO synthesis inhibitors N-(G)-nitro-L-arginine methyl ester (L-NAME) and sodium tungstate (ST), sodium nitroprusside (SNP), an exogenous donor of NO, and mercury chloride (HgCl2), an activity inhibitor of AQPs, were used to treat rice seeds. The changes of water absorption capacity, amylase activity and starch degradation rate during germination of rice seeds were determined in virtue of apparent analysis and index detection. The results showed that the water absorption capacity, amylase activity and germination rate decreased in the rice seeds treated with 90 mg/L HgCl2, while the starch content remained high, and the growth of radicle and germ was inhibited. However, NO exogenous donor SNP could reverse the effect of HgCl2. And the effect of NO synthesis inhibitors L-NAME (15 mmol/L) and ST (80 µmol/L) on the germination of rice seeds was similar to that of HgCl2. The results indicated that AQPs could induce water uptake, stimulate amylase, accelerate starch degradation and promote seed germination in the early germinating stage of rice seeds through NO. The study would lay a theoretical foundation for improving rice yield.

  • Plant Cultivation, Physiology & Biochemistry
    LIN Mingliang, CHEN Renli, WANG Chunsheng, CHEN Jinhui, ZENG Jie, LIN Peiqun
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    Pterocarpus santalinus is one of the most famous rosewood (Hongmu) species in the world. Its large-scale development is restricted due to limited seed production in China. A grafted clone seed orchard was established recently using suprior tree materials by Experiment Station of Research Institute of Tropical Forestry, Chinese Academy of Forestry in Jianfengling, Hainan Island, and most trees in the orchard have flowered and fruited. The differences in seed quality among superior trees in the introduction garden and the grafted clones need to be studied. Here the morphological traits were measured, and germination tests were conducted for the seeds of P. santalinus collected from six superior trees in the introduction garden and the grafted clones in the seed orchard at the experiment station. The coefficients of variance for the seed morphological traits were much lower than those for seedling growth traits among superior trees or the grafted clones, and the coefficients of variance was the lowest for the weight of 1000-grain seeds, indicating that the variations of seedling growth were more abundant than those of seed morphorlogy Seed length was significantly different at 0.05 level among the superior trees with No. 7 performing the best, and seed length, width and thickness differed remarkably among the grafted clones, in which No. 9# performed the best in seed length and width, and No. 7# did the best in seed thickness. The germination rate and potential differed significantly among superior trees (No. 3 and No. 9 performed the best, respectively) or the clones (No. 5# did the best), and significant difference occurred in the length of epicotyl, hypocotyl, radicle and total seedling among the superior trees (No. 3 did the best), and in the length of radicle and total seedling among the grafted clones (No. 7# did the best), demonstrating that abundant variation in seed germination and seedling growth existed among superior trees and among the grafted clones. Significance of difference between each superior tree and its clone varied with gene type, and clones performed as a whole, better than relevant superior trees in seed length and width, seed germination and seedling growth. It was indicated from relationship analysis that seed weight was significantly correlated with germination rate at 0.01 level, the germination rate of the plumper seeds was higher. In conclusion, seeds from the grafted clone seed orchard performed better in the seed morphorlogy and germination than those from the superior trees in the introduction garden, and significant difference was absent in seed weight among the superior trees or the grafted clones, and between each superior tree and its clone (P≥0.05), the seeds developed fully in the seed orchard with 1000-grain weight near 100 g, more than that for scattered individuals early grafted (92.9 g). The findings would provide scientific evidences for elite variety selection, seed orchard establishment and robust seedling cultivation.

  • Plant Cultivation, Physiology & Biochemistry
    LIU Chao, TIAN Xuelian, TANG Shixiang, YANG Caijing, HAN Lihong
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    Cordyceps chanhua is an important Chinese traditional medicine and food, that has important application value in the development of green functional food and new resource drugs. Taking one wild fungi Chanhua collected from Qujing of Yunnan province as the experimental material, the biological characteristics and artificial cultivation conditions were studied for the purpose of domestication and cultivation. Based on the morphological anatomy and molecular phylogenetic analysis, a wild ascomycetes was identified as C. chanhua. The biological characteristics and domestication of C. chanhua strain were studied by single factor experiments and orthogonal tests. The result showed that the branch stalk of C. chanhua was orange yellow or yellow white, (8.0-28.0)mm×(1.5-3.0)mm, and the conidia was oblong, (4.0-8.5)µm×(1.5-3.5)µm. The optimum temperature for the mycelial growth was 24 ℃, the optimum pH value was 6, the carbon source, nitrogen source and mineral salt was sucrose, yeast powder and magnesium sulfate respectively. The results of orthogonal test based on three factors under the optimum pH value and temperature showed that carbon source had the greatest impact on the mycelial growth, followed by nitrogen source and mineral salt, with range 1.21, 0.39 and 0.13 respectively. Therefore, the optimal combination of factors for the mycelial growth of C. chanhua was sucrose 20 g/L, yeast powder 2 g/L and magnesium sulfate 2 g/L. The artificial cultivation of C. chanhua utilized the 1∶1 mixed medium of wheat and rice, and the harvest cycle of fruiting body was about 40-45 days, and the average dry weight of each cultivated Chanhua was about 9.56 g. The external morphological characteristics of artificially harvested C. chanhua were significantly different from those of wild fruiting body. The fruiting body was yellowish to light yellow, with few branches, 1.5-5.0 cm in length, 0.3-0.8 cm in width and 0.1-0.2 cm in depth. The sporangium bundles were covered with dirty white flocculent or powdery conidia. The screening of excellent strains and optimal culture conditions of C. chanhua would provide a theoretical basis for its study on the diversity of germplasm resources, protection and utilization.

  • Plant Protection & Bio-safety
  • Plant Protection & Bio-safety
    SHI Chunlan, QIN Deqiang, QIN Xiaoping, LIU Quanjun, HE Mingchuan, GAO Xi, TANG Ping, WU Guoxing
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    Anthracnose is a common disease of coffee, which causes serious loss to the yield and quality of coffee fruit. The research on pathogenicity and biological characteristics of the pathogenic bacteria causing coffee anthracnose and screening of effective antagonists would provide reference for the biological control of coffee anthracnose. Four coffee anthracnose pathogens Wyq1 (Colletotrichum siamense), Yyq1 (C. fructicola), Xbd1 (C. gloeosporioides) and Hb1 (C. theobromicola) were isolated and tested for pathogenicity by spore suspension, and the most virulent strains were selected for further experiments. The biological characteristics of the pathogenic bacteria were studied by the plate culture method. Screening of antagonistic bacteria was done by the plate confrontation method. Xbd1 strain could infect healthy coffee leaves, and its virulence was the strongest among the four strains. The most suitable medium for the vegetative growth was PDA. The optimal nitrogen source was tryptone. The most suitable carbon source was glucose. The optimum temperature was 28 ℃. The optimal pH was 7. The difference of vegetative growth was not significant under different light conditions. Bacillus subtilis MC4-2, B. tequilensis D5-8, B. velezensis MC2-1 and B. flexus ZLSY3 and B. amyloliticus GJ7 showed good antagonistic effect in indoor screening. B. subtilis MC4-2 had the best antagonistic effect, with an inhibitory rate of 57.8%. The study would lay the foundation for the control of anthrax and the development of biocontrol agents.

  • Plant Protection & Bio-safety
    ZHOU Yunying, SAUBAN Musa Jibril, WANG Ling, ZHU Xishen, WANG Yi, ZHANG Limin, LI Chengyun
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    Gypsophila paniculata L. is one of the most popular and bestselling cut flowers in the world. Stem rot is among the common disease of G. paniculata L. causing plant withering and death in serious cases, affecting the ornamental and utilization value of the flowers and causing certain economic losses. In March 2021, a severe wilt due to stem rot was observed on G. paniculata L. in Haikou town, Kunming, Yunnan, China. The disease mainly affected the stem base which was manifested by rot on stem base and wilting. In order to identify the pathogenic microorganism, we isolated and identified the pathogen associated with the stem of G. paniculata L.. Koch’s postulates proved that the isolate caused similar symptom on tissue culture and potted seedlings of G. paniculata L., and the isolate had similar morphology with initially isolated from with the naturally infected seedlings in the field. Through morphological identification, the isolate produced a large number of dense aerial hyphae with color ranging from white to light orange or yellow with dark red pigment deposition on the back of the colony. The conidia of the isolate was sickle-shaped with flat ventral side, the dorsal side was arched, with three to six septation. The macroconidia was in the range (21.1‒57.9)µm×(2.7‒5.1)µm (n=100), no microconidia were observed. The morphology was similar to that of Fusarium pathogenic fungi. Through the identification of ITS gene sequence and morphology, the isolate was initially identified as F. graminearum species complex (FGSC). In order to further identify the subspecies, the TEF-1α sequence was used for sequencing. It was found that the isolate was 100% homologous with F. meridionale. Therefore, combined with morphological and molecular biological characteristics, the pathogen of the stem rot of G. paniculata L. was identified as F. meridionale. This is the first report on the stem rot of G. paniculata L. in China, which would provide an important basis for the prevention and control of the disease.

  • Post-harvest Treatment & Quality Safety
  • Post-harvest Treatment & Quality Safety
    JIANG Shikuan, LI Juan, ZHANG Guimei, XU Rong, DING Li
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    The adsorption and desorption rates of nine cationic exchange resins on ergothioneine (EGT) were investigated to screen out the ion exchange resin suitable for the separation and purification of EGT from natural rubber serum (NRS) and determine the optimum process parameters. The results showed that the SA-2 cation exchange resin was the most suitable for the separation and purification of EGT from NRS, and the optimum parameters were as follows: pH of sample loading 3.0‒4.0, sample loading flow rate 2 BV/h, and eluted with 0.5% ammonium hydroxide at the flow rate of 1 BV/h. Furthermore, a higher sample loading concentration was more conducive to the adsorption capacity of resin. Under the conditions, the EGT elution rate could reach 97.83%. This research indicated that the SA-2 cation exchange resin is an ideal medium for the separation and purification of EGT from NRS, which would lay a theoretical foundation for the industrial production of EGT.

  • Post-harvest Treatment & Quality Safety
    ZHAI Huinan, YU Fei, TANG Yumei, DONG Wenjiang, LI Ya’nan, HU Rongsuo
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    The main taste components of six different coffee beans from various regions in Hainan, including Xinglong coffee beans (XL), Fushan coffee beans (FS), Qionghai coffee beans (QH), YSL coffee beans from Baisha Yushiling (YSL), MS1 coffee beans from Mushan No.1 (MS1), and MS2 coffee beans from Mushan No.2 (MS2) were studied. Differences in taste composition and component content of the roasted coffee beans from different regions were compared. Based on the chemical characterization of the beans using the fingerprinting of the main taste components, the influence of the origin on the taste characteristics components of coffee beans was investigated and the roasted beans were distinguished. The levels of eight chlorogenic acids, caffeine, trigonelline and eight organic acids in the roasted beans were measured using ultra-high performance liquid chromatography (UPLC), while the composition and content of monosaccharides in the coffee samples were determined using pulsed amperometry by ion exchange chromatography (HPAEC-PAD) and the composition and content of amino acids were determined using an automatic amino acid analyser. The results showed significant differences in the content of taste components among the roasted beans, with the highest content of caffeine and trigonelline found in MS2 beans and the lowest in MS1 beans. The highest content of amino acids was found in QH beans, while the lowest content of chlorogenic acids and monosaccharides was found in QH beans. The content of chlorogenic acids in the roasted beans was as follows: caffeoylquinic acids (CQAs)>feruloylquinic acids (FQAs)>dicaffeoylquinic acids (diCQAs). Only eight monosaccharide components were detected in the six varieties, with the highest content of galactose. Based on principal component analysis (PCA) and partial least squares discriminant analysis (PLS-DA), the six coffees beans were successfully discriminated, with high similarity between the XL coffee beans, YSL and MS2 coffees beans, indicating that the major chemical taste components can be used to distinguish coffee beans from different regions of Hainan. The results show that the fingerprinting of key taste components can effectively distinguish coffee beans from different regions. This study would provide information on the chemical composition and quality characteristics of coffee beans from different regions and provide a theoretical basis for improving coffee flavour quality, which is important for the screening and differentiation of high-quality coffee samples.

  • Agricultural Ecology & Environmental Protection
  • Agricultural Ecology & Environmental Protection
    LUO Hongxia, DAI Shengpei, LI Maofen, LI Hailiang, HU Yingying, ZHENG Qian, YU Xuan
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    Coconut is an important economic crop in tropics. The area of coconut palm in Hainan Island accounts for 90% of the total production area in China. Up-to-date maps of coconut palm are essential for the industrial planning of tropical agriculture. In this study, an object-oriented image analysis method was used for mapping coconut palms based on high spatial resolution imagery of Gaofen-2. Dongjiao town in Wenchang was selected as the study area. An optimal segmentation scale of Gaofen-2 imagery was obtained using the fractal evolution approach. Then, a combined layer of four original bands, five vegetation indices and 32 gray-level co-occurrence (GLCM) texture indices were used as input features. Four different sets of features (including only original bands, original bands and textures indices, original bands and vegetation indices, and all features) were applied in object-based classification. The overall accuracy (OA) and user’s accuracy (UA) of pixel-based method achieved 87.05% and 85.21%, respectively. Compared with the pixel-based method, the object-based approaches significantly increased overall accuracy (OA) between 5.51%-8.72%. The OA and user’s accuracy (UA) reached 95.77% and 97.15% respectively, which was the optimal classification result, when the combination of original bands and textural features were used in coconut palms classifying. In addition, the combination of original bands and vegetation indexes achieved a satisfactory accuracy (OA=94.88% and UA=94.42%). While the combination of original bands, vegetation indexes and textural indexes performed a lower accuracy (OA=94.67% and UA=94.17%) in comparison with that of above two combination. Generally, our researches indicate that Gaofen-2 imagery has a good potential for coconut palms classification in complex tropical regions, and the textural indexes are very useful for identifying coconut palms at object-based level. The results would provide a reference framework for tropical agriculture decision management.

  • Agricultural Ecology & Environmental Protection
    YUN Yingying, FAN Qiuyun, SHI Youhai
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    Rhododendron hainanense Merr. has high ornamental and ecological value. It is of great significance for the protection and application of this plant through the study of ecological requirement and applicable range. In this paper, MaxEnt model and ArcGIS were used to simulate the potential geographical distribution of R. hainanense in China, based on the existing geographic distribution information, climate factors of this plant. And the key environmental factors, affecting the potential distribution of R. hainanense and suitable thresholds are analyzed. The results showed that under the contemporary climate scenario (1970—2000), the maximum entropy model (MaxEnt) can predict the suitable area of R. hainanense with high accuracy. The temperature and precipitation have a great influence on R. hainanense. The main factors affecting the potential distribution of R. hainanense are precipitation of warmest quarter (bio18) and mean diurnal range (bio2). When the precipitation of warmest quarter (bio18) is between 610-3990 mm and the mean diurnal range (bio2) is 5-7 ℃, the climate environment is suitable for the growth of R. hainanense. In a certain range, the probability of presence of R. hainanense will increase with the increase of precipitation. In China, the suitable habitat area of R. hainanense is mainly distributed in Hainan, Guangxi, Guangdong, Taiwan, eastern Sichuan, Chongqing and Guizhou. The total suitable habitat area of R. hainanense under contemporary climate scenarios is 132.36×104 km2. The purpose of this paper is to provide a scientific basis for the protection and application for the species.

  • Agricultural Ecology & Environmental Protection
    XIAO Jian, YANG Shangdong, LIANG Tian, LU Wen, TAN Hongwei
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    To develop sustainable sugarcane production and scientific use of nitrogen fertilizer, the effect of long-term application of nitrogen fertilizer on the soil and endophytic fungal compositions in the rhizosphere and roots were explored. The soil and endophytic fungal compositions in the rhizospheres and roots of sugarcanes under long-term application of nitrogen fertilizers were analyzed. 0, 96, 482, 964 kg/hm2 nitrogen fertilizer application (CK, L, M, H) were set in the same sugarcanes field, and based on the high-throughput sequencing techniques, the soil and endophytic fungal compositions in the rhizospheres and roots of sugarcanes were analyzed. In comparison with CK, although the richness of soil fungi in the rhizospheres of sugarcanes was significantly increased by different nitrogen application levels (P<0.05), particularly, L, M and H treatments increased by 39.58%, 24.04% and 35.33%, respectively; the diversity was not significantly different. Meanwhile, there were not significantly different in the diversity and richness of the endophytic fungi in the sugarcane roots under different nitrogen application treatments. Moreover, the soil fungi in the rhizospheres of sugarcanes, the relative abundances of Saitozyma, Trichoderma, unclassified_p__Ascomycota and Fusarium increased under nitrogen application. On the contrary, the relative abundances of Talaromyces, unclassified_f__Herpotrichiellaceae, Coniosporium, Penicillium, Chaetosphaeria, Chaetomium, unclassified_o__Hypocreales decressed under nitrogen application. In addition, the endophytic fungi in sugarcane roots, unclassified_k__Fungi and unclassified_p__Ascomycota increased, and Talaromyces, Chaetomium, unclassified_f__Strophariaceae decreased under different nitrogen application treatments. The results showed that the enrichment of single soil fungal communities in the rhizospheres or roots, and the potential risk of decreasing cane resistance could be induced by long-term nitrogen fertilizer application only. Meanwhile, in view of maintaining the soil health in the rhizospheres of sugarcanes, the optimal nitrogen application rate for sugarcane was 96 kg/hm2.

  • Agricultural Ecology & Environmental Protection
    LIU Junjie, HUANG Yuanyuan, LEI Xiao, GE Liangfa
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    Anthocyanins, also called anthocyans, are a group of plant secondary metabolites of flavonoid derivatives. Anthocyanins play an important role in mediating plant stress responses. However, whether anthocyanins are also involved in regulating phyllosphere bacterial communities remains unknown. To evaluate the differences of phyllosphere bacterial communities in plants with different anthocyanin contents, this study analyzed the phyllosphere bacterial communities of two cultivars of elephant grass with contrasting anthocyanins content, Pennisetum purpureum cv. Purple (Purple) with a high amount of anthocyanins and P. purpureum cv. Mott (Mott) with relatively low anthocyanins. The anthocyanins content determination results showed that the anthocyanins content in Purple leaves was nearly 20 times of that in Mott leaves. High throughput sequencing of 16S rRNA and analysis of the microbiome community indicated that though alpha diversity was not significantly changed, the bacterial communities of Purple was significantly different from that of Mott. In Purple, the relative abundance of endopphytic Proteobacteria and Bacteroidetes, and epiphytic Deinococus-Thermus were significantly increased, whereas epiphytic Bacteroidetes and Firmicutes were significantly decreased. The composition of microbiomes (ANCOM) at the OTU level, the relative abundance analysis at the genus level and correlation analysis between epiphytes and anthocyanins showed that the relative abundance of Methylobacterium, Unclassified Methylobacteriaceae and Deinococcus, which showed a significant positive correlation with anthocyanins content, were significantly increased in the episphere of Purple. In summary, the phyllosphere bacterial communities were significantly different between Purple and Mott. The findings from this work would provide new insights into the understanding of the superior forage value of P. purpureum cv. Purple, and lay a foundation to further investigate the mechanism of how plant secondary metabolism products regulate phylloshpere microorganisms.

  • Agricultural Ecology & Environmental Protection
    LI Si, WANG Deli, XU Shitao, ZHANG Mengzhen, LI Huiting
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    In this experiment, we analyzed the rhizosphere fungal populations of Aquilaria sinensis (Lour.) Spreng. in different planting areas, and understood the change pattern of the rhizosphere microorganisms before and after agarwood induction, providing a reference basis for the formulation of reasonable cultivation measures for A. sinensis. High-throughput sequencing and bioinformatics methods were used to analyze the diversity and community structure of the rhizosphere soil and fungi of A. sinensis in three sample sites of Hainan province (Wenshan in Haikou, Dongguang in Lingao, and Baolun in Ledong) before and after agarwood induction, the correlation between soil physicochemical properties and fungal communities before and after agarwood induction was also clarified by redundancy analysis. The results indicated that a total of 3 697 288 ITS sequences belonging to 1 kingdom, 2 Phylum, 12 classes, 9 orders, 24 families, 55 genera, 62 species were obtained from the three planting areas. There was little variability in the fungal communities and diversity before and after agarwood induction in the sample plot, but there was significant differences in the abundance of dominant population. The Shannon diversity index of the rhizosphere soil fungi of A. sinensis before and after agarwood induction ranged from high to low: LDWJX>LDJX>LGJX>LGWJX>WSWJX>WSJX. The fungal species composition of the rhizosphere soil samples of A. sinensis was rich. There were differences in the soil fungal community composition, the relative abundance of taxonomic units and the dominant taxonomic units in the rhizosphere of A. sinensis before and after Agarwood induction in different planting areas. In terms of community structure, there were differences in the dominant populations among the three planting areas; at the Phylum level, the common dominant Phyla in the three cultivation areas were Ascomycota and Basidiomycota; at the Class level, the dominant Class in Wenshan was Dothideomycetes, In Lingao the dominant Class was Sordariomycete, In Ledong the dominant Class was Ascomycetes; at the genus level, the dominant genus in Wenshan was p__Ascomycota, in Lingao was Myrothecium, and in Ledong was c__Dothideomycetes. By correlating the physicochemical properties of the inter-rhizosphere soil with the major genera of inter-rhizosphere fungi of A. sinensis in three growing areas, it was found that soil pH, organic matter, alkaline nitrogen, total nitrogen, total phosphorus, effective phosphorus had significant effects on most of the major fungi in the inter-rhizosphere soil of A. sinensis. The results of this study are of guiding significance for the improvement of soil at the fungal level and the evaluation of soil quality of A. sinensis, and also provide a reference basis for the future fertilization strategies of A. sinensis planting areas in Hainan province.

  • Agricultural Ecology & Environmental Protection
    ZHANG Mingfu, WANG Song, LI Jiayuan, WANG Xuebin, LI Meng, YA Fengshuo, HUANG Danni, HE Bing, GU Minghua, WANG Xueli, WEI Yanyan
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    The effects of water management and foliar spraying of exogenous plant hormone ethylene (ETH) on the accumulation of rhizosphere iron membrane, cadmium (Cd) and health risk index of rice were studied. Through the potting test, two concentrations (50 μmol/L and 100 μmol/L) ethylene (ETH) were sprayed three times at the jointing stage, the flowering stage and the grouting stage, and the water management modes of continuous flooding (CF) and interval flooding (IF) were adopted. Compared with the IF water management mode, the storage morphology of Cd in the soil was changed in the CF water management mode, and the soluble Cd was reduced from 36% to 30%, and the reducing state Cd was increased from 30% to 40%. Compared with the IF water management mode, the Fe and Cd content in the rice root surface iron film were significantly increased in the CF water management mode, and the exogenous spraying of ETH also significantly increased the Fe and Cd content in the iron film under the two water management modes, up to 50.59% and 58.06%. Compared with the IF water management mode, the Cd content in rice roots, leaves, brown rice and polished rice decreased significantly under the CF water management mode. The external spraying of ETH was also conducive to reducing the cadmium content of rice under the two water management modes, among which the Cd content in polished rice under CF+50ETH treatment was the lowest, and the Cd content in polished rice decreased from 0.68 mg/kg to 0.45 mg/kg, a decrease of 33.82% compared with CF treatment. Exogenous spraying of ETH significantly reduced the transport coefficients of Cd from rhizome and stem-grain under the two water management modes, and the transport coefficients were the lowest under CF+50ETH treatment, which was reduced by 55.17% and 23.81% respectively compared with CF treatment. CF water management mode and spray ETH treatment have a good effect on reducing the health risk index of rice Cd. It can be seen that CF water management mode and exogenous spraying of ETH have certain application prospects for reducing the accumulation of Cd in rice.

  • Agricultural Ecology & Environmental Protection
    FENG Jihong, HE Ji, WU Chuanmei, LI Longgui, ZU Gang, LUO Xue, SONG Lihong
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    The effect of composite passivators on the in-situ Cd contaminated soil and its absorption and accumulation of Cd in cabbage were explored, which would provide a scientific basis for the treatment and restoration of medium and mild Cd contaminated farmland. Field experiments were carried out in Cd polluted farmland soil with five passivator combinations: red mud + lime + phosphate rock powder (T1), red mud + lime + biochar (T2), lime + humic acid + sepiolite (T3), sepiolite + biochar + red mud (T4), sepiolite + biochar + phosphate rock powder (T5), in order to study the effects of the five passivating agent combinations on the content of various forms of Cd, enzyme activity, microbial carbon (MBC), microbial nitrogen (MBN) and the absorption and accumulation of Cd in various parts of Chinese cabbage in the cultivated layered soil. The five compound passivating agents could improve soil pH and reduce the availability of Cd in the soil in different degrees. Soil pH in T3, T4 and T5 treatments was significantly higher than that in CK, and soil available Cd content in T2, T3, T4 and T5 treatments was significantly lower than that in CK. In each form of Cd, in T5 treatment, the content of Cd in weak acid extraction state and reducible state was significantly higher than that in CK, while the content of Cd in residue state was significantly lower than that in CK. Compared with CK, T1, T3, T4 and T5 treatments significantly increased soil sucrase and acid phosphatase activities by 42.06%-152.46% and 15.95%-26.48%, respectively. Treatments T1, T2, T3 and T4 significantly increased urease activity by 18.43%-35.19%, treatments T3 and T4 significantly increased catalase activity by 18.78%-19.01%, treatments T1, T2 and T3 significantly increased soil MBC content by 31.83%-53.19%. T2, T3 and T4 treatments significantly increased soil MBN content by 19.14%-59.89%. Different treatments had different effects on Cd absorption and accumulation in different parts of Chinese cabbage. Compared with CK, T4 and T5 treatments significantly reduced Cd content in roots, T1, T4 and T5 treatments significantly reduced Cd content in stems, and the five treatments significantly reduced Cd content in leaves, and the enrichment and transport capacity of Cd in leaves of Chinese cabbage was greater than that in stems and roots. In terms of comprehensive passivation effect, T4 and T5 treatments, namely sepiolite + biochar + red mud (3∶5∶3), sepiolite + biochar + phosphate powder (3∶5∶3), had better passivation effect in the field soil mildly polluted by Cd during in-situ passivation restoration, which could effectively reduce the absorption of heavy metal Cd in soil by plants.