Internode length is a key factor determining sugarcane plant height, and appropriate promotion of sugarcane internode elongation can increase unit yield. The gibberellin insensitive dwarf (GID) gene is a core receptor in the gibberellin (GA) signaling pathway. Previous studies have shown that sugarcane GID1 is highly expressed during the vigorous internode elongation stage, and its overexpression can enhance GA signaling to promote internode elongation. In this study, using the sugarcane variety Guitang 42, Xintaitang 22, Guifu 98-296 as the material, the coding sequence (CDS) of ScGID2 (gibberellin receptor protein) was cloned and subjected to bioinformatics analysis. Besides, quantitative real-time PCR (qRT-PCR) was used to analyze the expression patterns of the gene in different tissues, different genotypic varieties, and under gibberellin (GA3) treatment. Result showed that the cloned ScGID2 gene had a full-length CDS of 720 bp, encoding 239 amino acids, containing a conserved F-box domain. It shared high homology (>88.75%) with GID2 from gramineous plants such as sorghum and maize, and was mainly localized in the nucleus. Expression pattern analysis revealed that ScGID2 had the highest expression level in the shoot apex at the non-elongation stage, followed by the +2 internode at the vigorous elongation stage. There were differences in the expression patterns of ScGID2 among different sugarcane varieties. The expression of ScGID2 in Xintaitang 22, Guifu 98-296, and Guitang 43 showed a trend of first increasing, then decreasing, then increasing again, and then decreasing again. The expression level of ScGID2 in Guitang 43 was much higher than that in Xintaitang 22 and Guifu 98-296. The expression level of ScGID2 in Guitang 42 increased gradually, reaching the peak at 30 days. The expression peak of ScGID2 in long-internode varieties was significantly higher than that in short-internode varieties and lasted longer. After GA3 treatment, the expression peak of ScGID2 in the short-internode variety Guitang 14-818 appeared earlier than that in the long-internode variety Guifu 98-296. Taken together, the present study provides a theoretical basis for elucidating the molecular mechanism of gibberellin-mediated sugarcane internode elongation, and ScGID2 could serve as a potential molecular target for sugarcane plant height improvement, since the expression of ScGID2 is induced by gibberellin and positively correlated with the internode elongation rate.
The glyoxalase system, comprising glyoxalase I (GLYI) and glyoxalase II (GLYⅡ), serves as a key mechanism for detoxifying excess methylglyoxal (MG) in plants and plays an important role in responses to abiotic stress and pathogen infection. To date, genome-wide identification and expression analysis of GLY gene family have not been reported in sugarcane. In this study, we identified 50 SsGLYI genes and 52 SsGLYⅡ genes from the wild sugarcane Saccharum spontaneum, and systematically analyzed the physicochemical properties, gene structures, promoter cis-acting elements, and expression patterns. SsGLY genes were randomly distributed across 30 chromosomes. All 43 SsGLYI members contained a conserved Motif1 (PF00903), while all SsGLYII proteins possessed a conserved Motif1 (PF00753). A total of 39 SsGLYI proteins contained four metal-binding sites (H/Q, L, H, E), except SsGLYII8.1-8.4 from subfamily IV, which were Zn2+-dependent, the remaining SsGLYI proteins were Ni2+-dependent. Only 26 SsGLYI proteins contained both the THxHxDH metal-binding domain and the C/GHT active site. Collinearity analysis identified 41 pairs of collinear genes, among which 39 pairs had Ka/Ks values less than 1, indicating that the SsGLY gene family has undergone predominant purifying selection during evolution. The expression levels of SsGLYI subfamily V and SsGLYⅡ subfamily Ⅲ were higher than those of the other four subfamilies under infection by Sporisorium scitamineum. Notably, the expression of SsGLYI3.4 showed differences in its expression patterns between the resistant genotype YT93-159 and the susceptible genotype ROC22. Furthermore, we cloned the homologous gene ScGLYI-1 of SsGLYI3.4 from YT93-159, which was constitutively expressed and primarily localized to the chloroplast. Meanwhile, the expression of ScGLYI-1 could be up-regulated by exogenous salicylic acid (SA) and smut pathogen stress, indicating that this gene may play a crucial role in response to pathogen stress in sugarcane. This study would provide a theoretical foundation for further elucidating the function of glyoxalase genes in sugarcane.
Phytochrome-interacting factors (PIFs) are key transcription factors that regulate plant photomorphogenesis and play important roles in plant growth, development, and responses to environmental stresses. To date, PIF gene family have been identified in many plant species; however, systematic identification and analysis of the PIF gene family in Saccharum spontaneum L., a wild relative of sugarcane, have not yet been reported. In this study, the PIF gene family in S. spontaneum (SsPIF) was identified, and comprehensive analyses were conducted on the physicochemical properties of the encoded proteins,chromosomal localization, intra- and interspecific synteny relationships, and cis-acting elements in promoter regions. In addition, quantitative real-time PCR (qRT-PCR) was used to analyze the expression patterns of SsPIF genes in different tissues of sugarcane and under three plant hormone treatments. The results showed that 12 SsPIF gene were identified from the S. spontaneum genome. These genes encode proteins ranging from 435 to 765 amino acids in length, with molecular weights between48.14‒83.91 kDa. The predicted isoelectric points (pI) ranged from 5.59 to 6.97; most SsPIF proteins had pI values close to neutral, while a few tended to be acidic or basic. Subcellular localization analysis indicated that all SsPIF proteins are localized in the nucleus. Chromosomal mapping revealed that the SsPIF genes are unevenly distributed across 10 chromosomes. Multiple sequence alignment demonstrated that all SsPIF family members contain conserved basic helix-loop-helix (bHLH) and APB domains, while members of the SsPIF3 subgroup possess a unique APA domain. Comparative synteny analysis showed that fourteen orthologous gene pairs exist between S. spontaneum and rice. Promoter analysis revealed that SsPIF genes are enriched in cis-acting elements related to light responsiveness, hormone signaling, and stress responses. The expression profiles of SsPIF genes exhibited clear tissue specificity, indicating their involvement in the growth and development of S. spontaneum. Furthermore, qRT-PCR analysis revealed distinct expression patterns of the twelve SsPIF genes in response to methyl jasmonate, gibberellin, and auxin treatments. Overall, these findings provide a solid foundation for further functional characterization of the SsPIF gene family and for elucidating their roles in regulating growth, development, and signal transduction pathways in S. spontaneum.
Sugarcane family evaluation is a key technical method for screening excellent sugarcane hybrid combinations and assessing the breeding value of parents. In this study, 86 sugarcane hybrid combinations were used as the materials for family evaluation. Over consecutive years, investigations were carried out on yield-related traits (plant height, tillering and clump mass), sugar-content traits (brix), and disease/pest resistance traits (smut, top rot, and dead heart seedlings). Subsequently, key evaluation indicators for each trait, including heritability, combining ability, breeding value, and coefficient of variation, were calculated. By employing correlation analysis, principal component analysis, cluster analysis, and economic breeding value estimation, the field performance of each hybrid combination and the genetic contributions of the parents were comprehensively evaluated from multiple dimensions. For yield-related traits, cluster weight had an extremely significant positive correlation with both plant height and tiller number (P<0.01). Through principal component analysis, 5 high-yield hybrid combinations (Guitang 04-1545×Zhongtang 12-02) were screened out. Meanwhile, parents including female parent Q208 and male parent XTT22 exhibited outstanding GCA and possessed excellent genetic transmission capacity for yield. For disease and pest resistance traits, the incidence rates of smut and pokkah boeng disease showed an increasing trend year by year with the observation period, while the incidence rate of dead heart seedlings decreased annually. Among them, 5 hybrid combinations (Yuetang 03-373× CP84-1198) exhibited strong comprehensive disease resistance. For sugar-related traits, 5 hybrid combinations (Yunzhe 05-51×Guitang 00-122) performed excellently in brix value and specific combining ability (SCA). Additionally, parents including female parent Yunrui 15-90 and male parent Guitang 04-1001 showed significant high-sugar genetic characteristics, making them excellent parent materials for breeding high-sugar varieties. In the comprehensive trait evaluation, the results of principal component analysis and cluster analysis mutually verified each other. Finally, hybrid combinations with excellent comprehensive performance (LCP85-384×Yuetang 94-128) and core parents with outstanding comprehensive traits (including female parent Guitang 04-1545 and male parent XTT22) were screened out. The results of the study could provide important references for the directional breeding of specialized sugarcane varieties with high yield, high sugar content and disease resistance, as well as the scientific selection and matching of parents in hybrid breeding.
A systematic multi-trait assessment was conducted using principal component analysis, membership function method, and cluster analysis to comprehensively evaluate the agronomic performances of 15 Yunzhe-type innovative sugarcane germplasm lines in Kaiyuan, Yunnan and identify superior parents for high-yield and high-sugar breeding. The main cultivated variety Yunzhe 05-51 was used as the control. Nine key agronomic traits, plant height (PH), stalk diameter (SD), single stalk weight (SSW), millable stalk number per hectare (MSPH), cane yield (CY), fiber content (FC), juice extraction rate (JE), apparent purity (AP), and sucrose content in cane (SC) were measured under both plant cane and first ratoon conditions. The results showed that the coefficients of variation for the traits ranged from 4.81% to 21.02%, with single stalk weight and cane yield exhibiting the greatest variation. Correlation analysis indicated that plant height, stalk diameter, and single stalk weight were significantly positively correlated with cane yield. Principal component analysis extracted three principal components, which together accounted for 82.436% of the total variance, representing yield structure, sugar quality, and stalk population characteristics, respectively. Based on the comprehensive evaluation D-values derived from the membership function method, there were 11 materials higher than the control. They were ranked as follows from high to low, Yunzhe 2018-124>Yunzhe 2018-95>Yunzhe 2018-120>Yunzhe 2017-121>Yunzhe 2018-92>Yunzhe 2016-166>Yunzhe 2017-131>Yunzhe 2016-145>Yunzhe 2014-170>Yunzhe 2014- 224>Yunzhe 2014-222>Yunzhe 05-51. Cluster analysis classified the germplasm into three groups. Group Ⅰ was identified as the high-yield type, and Group Ⅲ as the high-sugar type. Further screening identified the germplasm with outstanding single traits. High-yield types included Yunzhe 2017-121, Yunzhe 2018-124, and Yunzhe 2018-95. High-sugar types included Yunzhe 2014-222, Yunzhe 2016-145, and Yunzhe 2017-152. High-fiber types included Yunzhe 2017-152 and Yunzhe 2018-120, which are suitable as the parents for breeding mechanization-adapted varieties. Both Yunzhe 2018-124 and Yunzhe 2018-95 demonstrated excellent performances in yield and quality related traits, indicating a high potential as core parents for high-yield and high-sugar sugarcane breeding. The materials could provide valuable germplasm support for sugarcane variety selection in Yunnan and other ecologically similar regions.
Sugarcane (Saccharum spp.) is the most significant global sugar crop, contributing approximately 80% of total sugar production worldwide. Developing high-yielding and high-sugar-content varieties is critical for enhancing sugar industry sustainability. To support this goal and optimize hybrid breeding strategies, this study evaluated 71 sugarcane hybrid combinations derived from 75 parental lines, using six key agronomic traits: plant height, stalk diameter, brix (juice sugar content), number of effective stalks, cane yield and sugar yield. The main objective was to assess general combining ability (GCA) and specific combining ability (SCA), to identify superior parental lines and hybrid combinations for sugarcane breeding programs. The GCA/SCA analyses were performed using the R software. Clustering analyses were conducted based on combining ability values to classify parental materials and hybrid combinations into distinct genetic performance groups. Results showed substantial genetic variation across hybrids, particularly in yield-related traits, with coefficients of variation exceeding 39.00% for effective stalks, cane yield and sugar yield, highlighting significant breeding potential. Conversely, brix exhibited the lowest variation (8.05%), indicating high genetic stability for sugar content traits. Notably, HoCP05-902, GT96-211, YT93-124, YT93-159, GT00-122 and YR05-704 were identified as elite male parents, while GT94-119, CP72-1210 and Eros were outstanding female lines. Two combinations, CP72-1210×GT96-211 and GT94-119×YT93-159, exhibited superior GCA and SCA values, achieving excellent performance in both yield and sugar content. Additionally, GCA/SCA ratio analysis revealed that cane yield exhibited significant additive effects primarily inherited from the male parent. In conclusion, this research provides valuable theoretical guidance and genetic resources for sugarcane breeding, highlighting key parental lines and hybrid combinations that can serve as core materials in developing next-generation high-yield, high-sugar sugarcane cultivars.
The study aimed to investigate the physiological responses of intergeneric hybrid Erianthus arundinaceus× Saccharum spontaneum L offspring at the seedling stage under drought stress, to identify novel sugarcane germplasm resources with better drought stress tolerance. The results would provide a theoretical basis for breeding and utilizing drought-tolerant new sugarcane varieties. Thirteen hybrid progenies and the sugarcane variety ROC22 were used as the experimental materials in a barrel experiment. The contents of malondialdehyde (MDA), soluble sugars (SS), soluble protein (SP), proline (PRO), and the activities of peroxidase (POD) and superoxide dismutase (SOD), were measured in sugarcane seedling leaves under mild and severe drought stress, and control (normal watering). A comprehensive evaluation of drought tolerance in thirteen progenies and ROC22 was conducted based on drought resistance coefficients, membership function values, and the comprehensive drought tolerance evaluation index (D value), to screen and identify drought-tolerant sugarcane germplasm resources. Under different drought treatments, the content of SS, SP, PRO, MDA, and the activities of SOD and POD were elevated in the seedling leaves of hybrid progenies. Notably, under severe drought stress, the physiological indicators of AS08-2-28 were significantly higher than those of ROC22. Based on the D value, seven progenies exhibiting greater drought tolerance than ROC22 at the seedling stage were identified, ranked as follows: AS08-2-28>AS11-1-101>AS11-4-44>AS11-75-1>AS12-A6-21>AS12-A6-5>AS12-176-5. This study evaluated the drought tolerance of the hybrid progenies at the seedling stage and successfully screened seven sugarcane germplasm resources with strong drought resistance. The findings would provide a foundational basis for the future mining of drought-related genes and offer scientific guidance and experimental support for the effective utilization of intergeneric hybrid complex offspring in breeding new sugarcane varieties with enhanced drought tolerance.
Sugarcane is a globally important cash crop and bioenergy crop, playing a critical role in promoting economic development in sugarcane-producing countries. Phosphorus is an essential nutrient for plants, and low phosphorus availability in soil often constrains the quality and yield of sugarcane in China. S. officinarum serves as an important genetic foundation for modern sugarcane varieties. Elucidating the low-phosphorus tolerance mechanisms in phosphorus-efficient genotypes of S. officinarum is of significant theoretical and practical importance for screening and breeding phosphorus-efficient sugarcane varieties, improving phosphorus fertilizer utilization efficiency, and promoting the development of the sugarcane industry. The study was aimed to explore the response characteristics of different S. officinarum genotypes under low-phosphorus stress from the perspectives of root morphology and physiological adaptations, identify key factors affecting phosphorus absorption, and provide a theoretical basis for improving nutrient utilization efficiency in sugarcane through root plasticity modification. Phosphorus-efficient S. officinarum genotypes (48 Mouna and Loether) and phosphorus-inefficient genotypes (NC20 and Badila) were used in the study. Under two phosphorus supply conditions, low phosphorus (0.2 μmol/L KH2PO4) and normal phosphorus (1000 μmol/L KH2PO4), comparative analyses were conducted on root morphological indices, low-phosphorus tolerance indices, root activity, acid phosphatase activity, and other physiological characteristics of each variety. The results indicated that low-phosphorus stress could inhibit the growth and development of various sugarcane tropical varieties to different degrees. Among them, the phosphorus-efficient variety Loether was the least affected by low-phosphorus stress in terms of plant height, stem dry weight, and whole-plant biomass, while its root dry weight and root-to-shoot ratio significantly increased. Low-phosphorus stress promoted increases in total root length, total root surface area, and total root volume in both Loether and 48 Mouna, with Loether exhibiting the most pronounced increase. The specific root length, specific root surface area, and specific root volume of most varieties decreased, with NC20 showing the greatest reduction. Additionally, all varieties exhibited root thinning. Furthermore, under low-phosphorus stress, 48 Mouna and Loether demonstrated higher root low-phosphorus tolerance indices, root activity, and phosphorus acquisition capacity. In conclusion, this study reveals that the phosphorus-efficient tropical varieties 48 Mouna and Loether can better optimize root architecture, enhance phosphorus absorption interfaces, maintain strong root activity and enzymatic adaptability, effectively improve phosphorus absorption and utilization efficiency, and exhibit strong adaptability to low-phosphorus stress.
Lodging resistance is an important trait in sugarcane breeding. Accurate evaluation of the lodging resistance of germplasm resources is of great significance for breeding lodging-resistant varieties. This study investigated the effects of agronomic traits and stalk fiber components on lodging resistance using 16 sugarcane germplasm materials. The key traits affecting lodging resistance were identified by grey correlation analysis, and the comprehensive evaluation was carried out by using membership function method and cluster analysis method to screen excellent lodging resistance germplasm and its key traits, so as to provide germplasm resources and theoretical reference for sugarcane lodging resistance breeding. The results showed that the sugarcane germplasm materials with the strongest lodging resistance were Yunzhe 17501, Guiliu 05136 and Yuetang 93159. Among them, stem diameter, effective stem number, plant height and cellulose content were the key factors affecting the lodging resistance of sugarcane.
The study systematically investigated the long-term regulatory effects of returning sugarcane organic materials to the field on soil physicochemical properties, microbial communities, and sugarcane growth to solve the problems of soil acidification, organic matter attenuation and structural degradation in sugarcane fields on dry slopes in China. Through a three-year barrel planting experiment (including one new planting season and two-year ratoon season), four types of sugarcane organic materials were returned to the field, including filter mud (T1), sugarcane bagasse ash (T2), sugarcane leaves (T3), sugarcane bagasse (T4), along with control (without organic amendment). Soil nutrients, physical structure, microbial diversity, root morphology, yield and sugar content were measured. The four sugarcane organic materials returned to the field reduced soil bulk density and improved soil mechanical properties and pore structure, but significant difference were observed in the effects of different materials. T1 and T2 significantly increased soil pH, total organic carbon (TOC), alkali-hydrolyzable nitrogen (AN) and available phosphorus (AP). T1 consistently optimized deep soil structure, and T2 had a significant effect on improving available potassium (AK) and water retention. T3 and T4 mainly increased soil TOC content, but T4 aggravated soil acidification during the new planting season. T3 and T4 promoted the formation of highly stable large aggregates, with significant short-term effect. Although T1 and T2 promoted the formation of mechanically stable large aggregates, the water stability was poor. T1 and T2 had significant and long-lasting effects on improving the diversity and richness of soil bacteria and fungi, T3 promoted microbial activity in the early stage but inhibited it in the later stages, and T4 significantly restored microbial diversity in the later stages. T1 had the most significant effect on increasing yield and sugar content, T2 had an outstanding effect on promoting root development and had significantly effects on increasing yield and sugar content. T3 had a certain yield-increasing effect in the later stages. T4 led to a yield reduction and was not conducive to sugar accumulation. Overall, the effects of returning different sugarcane organic materials to the field varied significantly. Filter mud (T1) proved to be the optimal material, combining long-term soil improvement, enhanced microbial diversity, and increased yield and sugar content. Sugarcane bagasse ash (T2) was suitable for short-term water retention and root growth, but the risk of deep soil compaction must be controlled. Sugarcane leaves (T3) should be accompanied by nitrogen fertilizer. Sugarcane bagasse (T4) returning to field requires decomposition pretreatment. This study could provides theoretical support for the precise return of sugarcane organic materials to the field and the sustainable management of cultivated land in red soil areas.
The study conducted a two-year field experiment to explore the effects of pesticide application via under-mulch drip irrigation on the control efficacy of major pests and comprehensive benefits in the field propagation of disease-free sugarcane original seedlings. With no pesticide application as the control (CK), four treatments were simultaneously set up, two drip irrigation pesticide application treatments (T1 and T2: applying 40% chlorantraniliprole·thiamethoxam WG via drip irrigation 3 times and 2 times, respectively), one unmanned aerial vehicle (UAV) spraying treatment (T3: spraying 40% chlorantraniliprole·thiamethoxam WG 2 times), and one conventional root application treatment (T4: applying 4% imidacloprid·bisultap GR 2 times). A comprehensive comparative analysis was performed on indicators such as the control efficacy against sugarcane borers, thrips, and aphids, as well as the propagation efficiency and economic benefits of disease-free sugarcane original seedlings, aiming to provide a theoretical basis for scientifically guiding sugarcane elite seed propagation bases to utilize existing under-mulch drip irrigation systems for efficient and economical control of major pests. In the early stage of seedling propagation, the two drip irrigation treatments (T1 and T2) exhibited the best control efficacy against the rate of borer-induced dead heart seedlings, reaching over 76.00%, with the dead heart seedling rate controlled below 1.20%, which was significantly lower than that of other pesticide treatments. In the middle and late stages of propagation, UAV spraying T3 showed the highest control efficacy against the rate of borer-damaged plants, reaching 72.00%, followed by the two drip irrigation treatments T1 and T2 with control efficacy ranging from 61.00% to 66.00%. Specifically, except that the rate of borer-damaged plants of T3 was significantly lower than that of T2 in the 2023 experiment, there was no significant difference in the rate of borer-damaged plants between T3 and T1, T2. Conventional root application T4 had the lowest control efficacy, and the rate of borer-damaged plants was significantly lower than that of other pesticide treatments. In terms of the rates of borer-damaged internodes and borer-damaged buds, drip irrigation treatment T1 (applied 3 times) showed the highest control efficacy, both reaching over 82.00%, with the rates of borer-damaged internodes and buds controlled below 0.73% and 0.28%, respectively, which were significantly lower than those of other pesticide treatments. For the two foliar pests (thrips and aphids), UAV spraying T3 showed better control efficacy than other treatments, reaching over 70.00%, but there was no significant difference compared with the two drip irrigation treatments. In terms of seedling propagation efficiency, drip irrigation treatments T1 and T2 had the highest number of effective buds, reaching 138.71×104, 136.53×104 buds per hectare, respectively, which was more than 6.12% higher than that of conventional root application T4, but there was no significant difference compared with UAV spraying T3. In terms of comprehensive propagation benefits, compared with CK, drip irrigation treatments T1 and T2 had the highest increase in net income, reaching 31 300, 30 400 yuan/hm2, respectively, with an input-output ratio of above 1∶30, which was much higher than the input-output ratio of approximately 1∶21 for UAV spraying T3 and conventional root application T4. Comprehensively, applying 40% chlorantraniliprole·thiamethoxam WG via drip irrigation 3 times can sustainably and efficiently control borers, thrips and aphids, balances propagation efficiency and benefits, and has the lowest rate of borer-damaged internodes in seed canes. Thus, it can be used as the optimal scheme for controlling above-ground pests in the field propagation of disease-free sugarcane original seedlings.
The primary bottleneck restricting sugarcane harvesting mechanization in Chinaʼs hilly regions is fragmented terrain combined with narrow-row, high-density planting. This study was aimed to systematically analyze the effects of a two-step mechanical harvesting model on production efficiency, raw material quality, and farmer’ income, thereby clarifying its application potential and promotion strategies in these regions. During the 2023/2024 and 2024/2025 harvesting seasons in Gengma, field experiments and cost-benefit analyses were conducted to compare four harvesting models, Combine Harvesting, Traditional Manual, Commissioned Processing, and Raw Cane Sale. Statistical methods, including ANOVA, were employed to analyze the effects of sugarcane growth stages and major cultivars on the impurity rate of raw materials. The Commissioned Processing model increased farmerʼs net income to 365.00 yuan/t over the Traditional Manual model (farmerʼs net income 318.00 yuan/t), an increase of 14.80%, while reducing harvesting costs 42.06%. The income was comparable to the Combine Harvesting model but effectively avoided the severe damage to sugarcane ratoons caused by the latter. Regarding raw material quality, genetic differences among cultivars had no significant effect on the impurity rate, whereas harvest time was the dominant factor. As the harvest period was extended from December to the following April, the net cane rate under Traditional Manual model significantly increased from 75.76% to 84.90%. Correspondingly, the impurity rate of two-step mechanized harvesting decreased from 6.42% to 4.52%, indicating that scheduling operations within the full maturity window after January effectively controls raw material impurities. The study also revealed a misalignment between the commercial impurity deduction standards of sugar mills and field-measured impurity rates. This discrepancy, characterized by significant inter-varietal differences, could hinder the fair promotion of this new technology. The two-step mechanical harvesting model is an optimal choice for Chinaʼs hilly regions, balancing economic benefits with ecological sustainability. Its promotion strategy should prioritize establishing a precise operational timetable based on sugarcane growth stages rather than developing differentiated harvesting systems for existing cultivars. This model would provide a quantifiable and scalable solution for mechanization in hilly sugarcane areas, holding significant practical value and strategic importance for enhancing the competitiveness of national sugar industry and ensuring sugar security.
Raffinose family oligosaccharides (RFOs) are the most widely distributed oligosaccharides containing galactose (-Gol) in higher plants. Raffinose (Raf) and stachyose (Sta) are the main members of this family, which are used as osmotic agents or active oxygen scavengers in many plants to maintain cell integrity. Glycosyl hydrolase 36 family (GH36) is a kind of α-galactosidase, which can catalyze oligosaccharides containing -Gol to produce RFOs. Hevea brasiliensis is an important plant for synthesizing natural rubber. After tapping and stimulation by exogenous ethylene, glycosyl hydrolases accumulate in latex and play an important role in maintaining latex stability. Eight genes (HbGH36-1-8) of glycosyl hydrolase 36 family (HbGH36) were successfully identified to search for functional hydrolases in the latex of H. brasiliensis. QRT-PCR analysis showed that five genes (HbGH36-1, HbGH36-4, HbGH36-6, HbGH36-7, HbGH36-8) were obviously expressed in latex. Among the five genes, HbGH36-4, HbGH36-6, HbGH36-7 and HbGH36-8 were highly expressed in response to tapping stimulation, and the expression levels of HbGH36-4 and HbGH36-7 changed more obviously. HbGH36-1, HbGH36-4, HbGH36-6 and HbGH36-7 expressed at high levels in response to exogenous ethylene stimulation, and HbGH36-6 expressed at high levels for a relatively long time after ethylene stimulation. Western blot of different components of H. brasiliensis latex confirmed that HbGH36-1 and HbGH36-8 were expressed in C-serum component of latex. The results indicate that H. brasiliensis HbGH36s may be involved in the regulation of latex stability and latex physiological metabolism in response to tapping and ethylene stimulation.
The induction of adventitious roots (AR) is a key step for successful clonal propagation in plants. Previous studies have shown that the auxin polar transport carrier MiPIN1 plays an important role in AR formation from mango cotyledon segments, yet its upstream regulatory mechanisms remain unclear. In this study, a 2 112 bp promoter sequence of MiPIN1 isolated using FPNI-PCR. Bioinformatic analysis revealed that the promoter region contained various cis-acting elements, including those involved in light response, MYB binding, abscisic acid response, and low-temperature stress. A bait vector, pAbAi-MiPIN1, was constructed, and the minimal concentration of Aureobasidin A (AbA) required to suppress autoactivation in the yeast system was determined to be 500 ng/mL. Furthermore, a yeast cDNA library was constructed from mango cotyledon segments during AR formation. Using the yeast one-hybrid (Y1H) system, 62 upstream proteins that potentially bind to the MiPIN1 promoter were identified, including auxin-binding protein ABP19a-like, zinc finger protein CCCH, MYB308, 8-hydroxygeraniol dehydrogenase, and chlorophyll a-b binding protein LHCII. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses indicated that the proteins were mainly involved in biological processes such as cellular processes, metabolism, response to stimuli, and biological regulation. They were also enriched in metabolic pathways related to secondary metabolite biosynthesis, energy metabolism, and the metabolism of amino acids, lipids, and carbohydrates. The findings would lay a foundation for unraveling the molecular regulatory network underlying adventitious root formation in mango.
Calcium-dependent protein kinases (CPKs) are a class of plant-specific key signal transduction factors. In pineapple, an important tropical economic crop, the identification, classification, and functional characterization of the CPKs gene family are still in their infancy, and the molecular mechanisms by which they participate in stress responses remain unclear, which limits their application in the improvement of stress-resistant pineapple varieties. In this study, we systematically investigated the AcoCPKs gene family in pineapple by integrating genomic analysis, chromosomal localization, bioinformatic prediction, and qRT-PCR-based molecular approaches. A total of 18 AcoCPKs family members were identified at the whole-genome level in pineapple. Chromosomal mapping showed that these AcoCPKs genes are unevenly distributed across the nine chromosomes of pineapple. Bioinformatic analysis revealed that all AcoCPKs sproteins share similar conserved motifs and domain architectures. qRT-PCR expression profiling further demonstrated that the 18 AcoCPKs genes are expressed in multiple tissues, including fruits, leaves, fruit peduncles, and flower buds, with distinct tissue-specific expression patterns; moreover, the transcription levels of several AcoCPKs genes were markedly up-regulated under high-temperature, low-temperature, and NaCl salt stress treatments.Taken together, this study systematically elucidates the physicochemical properties, genetic characteristics, and stress-responsive expression patterns of members of the AcoCPKs gene family in pineapple. These findings not only provide an important theoretical basis for further dissecting the molecular mechanisms underlying AcoCPKs-mediated stress responses in pineapple, but also lay a solid foundation for the targeted improvement of stress tolerance and the breeding of high-quality, stress-resistant pineapple cultivars through gene editing, transgenic approaches, and other modern molecular breeding technologies.
Plants are prone to low inorganic phosphorus (Pi) abiotic stress, which has adverse effects on the growth, development and physiological metabolic processes. Camellia hainanica, a local variety in Hainan, mostly grows in low-phosphorus environments. C. hainanica has unique genetic characteristics that distinguish it from C. oleifera. In this study, a tropical cultivar Haida Oil-tea 4 (H4) was used as the research object to screen reference genes suitable for quantitative real-time polymerase chain reaction (qRT-PCR) analysis of C. hainanica under low Pi stress. The expression levels of six candidate reference genes, EF1α1, GAPDH, Actin, UBQ, ETIF3H and TUB2, were detected by qRT-PCR. The stability of each reference gene was comprehensively evaluated using ΔCt, geNorm, NormFinder, BestKeeper software and RefFinder online analysis tools, and ETIF3H was identified as the optimal reference gene. Using ETIF3H as the reference gene, we validated the expression levels of three low Pi responsive genes. The results showed that the target genes were differentially expressed in response to low Pi, indicating that ETIF3H is suitable as a reference gene for detecting gene differential expression under low Pi stress conditions. This work would provide appropriate reference genes for transcript normalization in H4 under low Pi stress, which will facilitate subsequent study of phosphorus signal-response gene expression in C. hainanica.
Dalbergia odorifera is a rare perennial plant valued for both its medicinal and aromatic properties. However, its long growth cycle and slow maturation to meet traditional medicinal standards are major constraints for its rational utilization and development. To investigate the active components in its roots and facilitate the use, this study utilized aeroponic cultivation to rapidly obtain a substantial quantity of high-quality roots from one-year-old seedlings. Comparative transcriptome analysis between soil-cultivated roots and aeroponic roots was conducted using high-throughput sequencing to identify key genes and pathways involved in root secondary metabolite biosynthesis. The results revealed 7731 significantly differentially expressed genes (DEGs) between the two groups, with 4447 upregulated and 3284 downregulated. GO, KEGG and GSEA enrichment analyses indicated that the DEGs were primarily associated with defense signal transduction, amino acid metabolism, and the biosynthesis of secondary metabolites. Specifically, sesquiterpene and triterpene biosynthesis pathways and defense signal transduction pathways were highly expressed in soil-cultivated roots, whereas amino acid metabolism and flavonoid biosynthesis pathways were upregulated in aeroponic roots. Further analysis identified candidate key DEGs related to secondary metabolite synthesis: evm.TU.scaffold_100.907, MSTRG.3788, evm.TU.scaffold_233.200, evm.TU.scaffold_111.78 and evm.TU.scaffold_5.71 in the flavonoid pathway, and evm.TU.scaffold_36.788, MSTRG.8652, evm.TU.scaffold_40.382, MSTRG.27285 and MSTRG.28295 in the sesquiterpene pathway. This study preliminarily elucidates the differences in gene expression between soil-cultivated roots and aeroponic roots, uncovering genes and pathways regulating secondary metabolite synthesis. The findings would provide valuable data and references for the further development and utilization of D. odorifera root resources.
Long-term subculture preservation significantly impacts somatic embryogenesis (SE) in various plant species. Studies on its effects in litchi (Litchi chinensis Sonn.) remain scarce. This study aimed to investigate the effects of subculture times on SE in litchi embryogenic callus (EC) and to uncover the metabolic basis for its decline, thereby providing a theoretical foundation for improving SE efficiency. Using 'Feizixiao' litchi EC materials from different subculture times (denoted as J11, J22, J48, J65 and J86). Somatic embryo induction rate, phenotypic characteristics, and dynamic changes in soluble sugars, organic acids, free amino acids, and energy-related substances were measured. The results showed that subcultures times significantly influenced SE in litchi EC. The embryo induction rate initially increased and then decreased with increasing subculture times, while the yield of normal somatic embryos (monocotyledonous, dicotyledonous, and polycotyledonous embryos) was also significantly affected. Among the five groups, J22 exhibited the highest induction rate (257.33%) and the greatest number of milky-white embryos. Sucrose content showed a significant positive correlation with SE, highlighting its role as the key carbon source for litchi SE. Fluctuations in soluble sugar content were primarily attributed to variations in sucrose. Low-subculture materials (J11 and J22) showed significant decreases in citric acid, succinic acid, and malic acid during the middle-late SE induction stages, indicating a stronger tricarboxylic acid (TCA) cycle flux compared to high-subculture materials (J48, J65, J86). The total amino acid content in EC initially increased and then stabilized during SE induction, with low-subculture materials maintaining higher overall amino acid levels. The contents of two major amino acids (glutamine and alanine) were significantly more abundant in low-subculture materials. Furthermore, the contents of adenosine triphosphate (ATP), adenosine diphosphate (ADP), and adenosine monophosphate (AMP) initially increased and then decreased, with AMP being the most abundant. Low-subculture materials maintained significantly higher AMP levels during the first 49 days of SE induction, particularly in J22. The results demonstrate that subculture times is a critical factor influencing SE in litchi EC. Long-term subculture induces embryogenic decline by impacting energy supply and amino acid metabolism.
The study was aimed to explore the effects of reducing chemical fertilizer application combined with microbial fertilizer on the quality of cempedak [Artocarpus champeden (Lour.) Spreng.] and soil nutrients. 7-year-old Duoyi No.1 cempedak was used as the material and 6 treatments, 100% compound fertilizer treatment (CK, 2 kg), 20% reduction in compound fertilizer + 20% microbial fertilizer (T1), 40% reduction in compound fertilizer + 40% microbial fertilizer (T2), 60% reduction in compound fertilizer + 60% microbial fertilizer (T3), 80% reduction in compound fertilizer + 80% microbial fertilizer (T4), and 100% microbial fertilizer treatment (T5, 5 kg) were set up. The effects of different fertilization treatments on cempedak quality, the effects of soil nutrients, and the correlation between cempedak quality index and soil nutrient index were analyzed. Compared with CK and T5 treatments, other treatments increased the fruit weight, edible rate, single aril pit weight, single aril weight, and soluble solids content of cempedak, reduced the fruit wall thickness. The T3 and T4 treatments significantly increased the single fruit weight and single aril weight of cempedak. The combined application of microbial fertilizer had a certain promoting effect on soil nutrients. The T4 treatment significantly enhanced soil total nitrogen, available phosphorus, available potassium, organic matter, and pH, while also increasing the levels of six metal elements in the soil: Ca, Mg, Fe, Mn, Cu, and Zn. The T3 treatment was second only to T4 treatment. Correlation analysis showed that the combined application of microbial fertilizer improved the single fruit weight and single aril weight of cempedak mainly by increasing available phosphorus, available potassium, Fe and Mn in the soil. In conclusion, the treatments of T3 and T4 not only improved the yield and quality of cempedak, but also improved the soil environment and ecological benefits, which are the optimal combined application modes for green and efficient cultivation of cempedak.
Phosphorus (P), a crucial nutrient, has a significant impact on the growth, development, and productivity of sweetpotato. Establishing an evaluation system for low-phosphorus tolerance in sweetpotato and screening for low-phosphorus tolerant sweetpotato varieties can provide essential foundational support for the further development, breeding, and utilization of low-phosphorus tolerant sweet potato resources. In this study, 30 sweet potato varieties were selected. Field experiments with phosphorus deficiency were conducted, involving two phosphorus treatment conditions, no phosphorus application (0 kg/hm2) and normal phosphorus supply (110 kg/hm2). At the harvest stage, 14 characteristic traits were measured, including fibrous root fresh weight, lateral root of storage root fresh weight, single storage root fresh weight, storage root fresh weight per plant, storage root number per plant, fibrous root dry weight, lateral root of storage root dry weight, storage root dry weight, leaf fresh weight, stem fresh weight, leaf dry weight, stem dry weight, relative chlorophyll content and root/shoot ratio. The low-phosphorus tolerance coefficient for each index was calculated. Principal component analysis, correlation analysis, and cluster analysis were performed using the comprehensive membership function method to evaluate the low-phosphorus tolerance of each sweet potato cultivar. Principal component analysis showed that the cumulative variance contribution rate of the five principal components reached 80.36%, indicating these indicators fully reflected the low-phosphorus tolerance of sweetpotato varieties. The comprehensive low-phosphorus tolerance evaluation value (D) was calculated via the membership function method, with D values ranging from 0.30 to 0.79. The varieties were classified into four grades, high tolerance, medium tolerance, low tolerance, and non-tolerance. Through systematic cluster analysis, Qiongshu4 was identified as a high-tolerance variety, Silky, Fushu8, and Shanchuanzi were classified as medium-tolerance varieties, Yanshu25, Taishu14, and Xuzishu8 were low-tolerance varieties, and Annayu, Jinshu17, and Xinxiang were low phosphorus-sensitive varieties. The key evaluation indicators for low-phosphorus tolerance in sweet potato at harvest stage were determined to be the yield per plant (storage root fresh weight per plant), fibrous root fresh weight, lateral root of storage root fresh weight, fibrous root dry weight, leaf fresh weight, stem fresh weight, leaf dry weight, and stem dry weight. This study would provide a theoretical basis for breeding and utilizing new low-phosphorus-tolerant sweetpotato varieties.
The heavy texture, acidification, compaction and water-air imbalance of red soils constrain crop yield enhancement. To investigate the combined effects of aerated irrigation and nitrogen application on maize yield and water-nitrogen use efficiency in red soil regions, this study employed a four-year (2021—2024) field-based design using Huiyu Sweet 3 corn as the test variety. Four treatments were established: no nitrogen application (CK), low nitrogen (N1, 150 kg/hm²), medium nitrogen (N2, 300 kg/hm²), and high nitrogen (N3, 450 kg/hm²) treatments. The study measured the effects of aerated irrigation technology on soil physicochemical properties, maize nitrogen use efficiency, and yield under different nitrogen fertilizer levels. Results indicated that aerated irrigation combined with nitrogen fertilization significantly improved soil bulk density in the plow layer (0-40 cm), with N2 and N3 treatments showing superior effects. Average soil bulk density decreased significantly by 3.87% and 5.23% compared to CK, respectively, while total soil porosity increased significantly by 5.40% and 6.27%, respectively. Under the N2 treatment, soil water storage capacity significantly increased compared to CK. Nitrogen application elevated soil organic carbon and total nitrogen content in the plow layer. The soil carbon-to-nitrogen ratio decreased with increasing nitrogen application rates, effectively promoting soil microbial growth, particularly bacterial biomass accumulation, with N2 treatment yielding the best results. Under aerated irrigation conditions, nitrogen fertilization improved maize yield traits, with N2 yielding the best results, achieving a significant average yield increase of 63.7% compared to CK. Fitting the relationship between maize yield and nitrogen application rate under aerated irrigation revealed that grain yield peaked at nitrogen application rates of 250-350 kg/hm². The agronomic efficiency (4.50-25.10 kg/kg) and nitrogen use efficiency (30.1%-41.9%) were higher under N1 and N2 treatments. In summary, considering nitrogen fertilizer reduction, corn yield maximization, and efficient nitrogen utilization, applying 250-350 kg/hm² of pure nitrogen improves soil physicochemical properties and enhances water retention capacity under aerated irrigation in Guangdong's red soil regions, effectively boosting corn yield and nitrogen utilization. These findings provide theoretical support and practical pathways for improving the aeration of clayey red soils in southern China.
Rubber is a globally significant strategic raw material, playing an irreplaceable role in national defense, transportation, aerospace and medical equipment industries. However, pests such as the rubber tree leaf mite frequently occur in tropical rubber plantations, especially under conditions of high temperature and drought, where they are prone to large-scale outbreaks. Infestations result in symptoms such as leaf chlorosis, yellowing and premature defoliation, which severely compromise tree vitality and substantially reduce latex yield. Traditional pest and disease monitoring relies primarily on manual field surveys, which are time-consuming, labor-intensive, and limited in spatial scope. The constraints make it increasingly difficult to meet the needs of modern rubber plantations for rapid early warning and precise pest management. Remote sensing technology has demonstrated significant advantages in the monitoring of agricultural pests and diseases. It enables large-scale, rapid, non-contact and dynamic monitoring across multiple temporal scales. To address the limitations of conventional monitoring methods, such as low efficiency and inadequate accuracy, this study proposes a multi-source remote sensing approach that integrates ground-based ASD (Analytical Spectral Devices) hyperspectral data, proximal multispectral imagery, and field survey data to achieve rapid and accurate detection of rubber tree mite infestations. The study was conducted based on spectral reflectance data of rubber leaves collected in 2024 from the experimental station of Rubber Research Institute, Chinese Academy of Tropical Agricultural Sciences in Danzhou, Hainan province, along with UAV-based multispectral imagery. The raw spectral data were preprocessed using Multiplicative Scatter Correction (MSC), Savitzky-Golay (SG) smoothing and first-order derivative transformation. Four types of spectral feature variables were derived, including vegetation indices (VIs), hyperspectral features, continuum removal (CR) parameters and wavelet coefficients. Sensitive features were selected through a combination of the Least Absolute Shrinkage and Selection Operator (LASSO) and Pearson correlation coefficient analysis. Based on the selected features, three regression models, Multiple Linear Regression (MLR), Random Forest (RF) and Back Propagation Neural Network (BPNN), were developed to model rubber tree mite infestations levels. Results indicated that the ASD hyperspectral data yielded the best performance across all models, with the RF and BPNN models performing particularly well. Among them, the RF model achieved the highest coefficient of determination (R²) of 0.8361 and the lowest root mean square error (RMSE) of 0.6353 on the validation dataset, demonstrating a strong capacity for accurate infestation severity prediction. In conclusion, the integration of ASD hyperspectral data with the RF model enables the construction of a high-accuracy, strongly interpretable monitoring model for rubber tree mite infestations. This approach effectively supports early detection and quantitative classification of infestation levels in rubber tree mite infestations, and would provide essential technical guidance and theoretical support for precision plantation management and integrated pest control.
To address the limitation of conventional rubber plantation suitability assessments that overlook geographical environmental heterogeneity, this study proposes a suitability evaluation approach based on geographical zoning modeling. Eight key indicators were selected from three dimensions, topographic conditions, hydrothermal conditions, and cold damage risk, to construct the evaluation index system. The weight of these indicators was determined by integrating the Analytic Hierarchy Process (AHP) with the GeoDetector method. Using the Ailao Mountains ridge as a geographical demarcation, the rubber plantation area in Yunnan province was divided into western and eastern zones, for which region-specific factor suitability grading standards were established and applied for factor reclassification. Subsequently, the reclassified factors were integrated through linear weighting to produce a comprehensive suitability evaluation, classifying the results into four categories, unsuitable, marginally suitable, moderately suitable, and highly suitable. Among the six prefecture-level regions engaged in rubber cultivation, highly suitable areas accounted for approximately 4.29% of the total land area, moderately suitable areas for 2.79%, and marginally suitable areas for 5.06%, totaling about 12.14%. These areas are mainly concentrated in Xishuangbanna, Pu’er and Honghe. Overlay analysis with 2024 rubber plantation distribution data revealed that about 47.80% of existing plantations in highly suitable zones, 22.09% in moderately suitable zones, and 19.29% in marginally suitable zones, accounting for a combined 89.18%. This distribution shows a high degree of spatial consistency with the actual planting patterns. The evaluation results, with a spatial resolution of 10 m, are capable of reflecting fine-scale variations in Yunnan’s mountainous environments, and can thus provide valuable references for rubber plantation planning and adjustment in Yunnan province.
Mango is one of the most widely cultivated and economically significant fruit trees in tropical regions of China, playing a vital role in optimizing agricultural structure and promoting rural revitalization. Scientifically delineating suitable planting zones for mango is essential for precise resource allocation and the high-quality development of the industry. However, most existing studies focus on climatic and topographic factors, with insufficient systematic consideration of soil physicochemical properties. In addition, current suitability evaluations often suffer from strong subjectivity in indicator selection and low integration of evaluation methods. To address these gaps, this study took Sanya city as the research area and developed a comprehensive evaluation model for mango planting suitability. First, the MaxEnt model was employed to identify key environmental factors and extract response curves for constructing membership functions. Second, an improved three-scale Analytic Hierarchy Process (3-scale AHP) and the entropy weight method were applied to determine subjective and objective weights, respectively, which were then integrated using a game theory-based weighting approach. Finally, the study area was classified into three planting suitability zones based on a comprehensive suitability index, and field surveys were conducted for validation. Bulk density, pH, cation exchange capacity (CEC), silt content, total potassium, soil type, slope, elevation, sunshine hours during the fruit maturity and harvest period, and annual maximum temperature were the ten dominant factors, with soil-related variables playing a critical role in the model. The suitable area covered 117 939 hm2, accounting for 61% of Sanya’s total area, with the most advantageous zones concentrated in southern Yazhou and southern Tianya. Advantageous zones were characterized by “low elevation-slightly acidic-potassium-rich-high permeability-high sunshine” conditions, which are conducive to high and stable mango yields with premium quality. The “factor selection-membership function construction-game theory-based weighting-suitability zoning” evaluation framework proposed in this study would provide both theoretical and methodological support for precision planting of tropical fruit trees and the optimization of regional agricultural spatial layouts.
