• Junwen ZHENG , Xiaohua LU , Yuheng LI , Baochang NONG , Yujian GE , Yajie WANG , Yuan YAO , Mengting GENG
    Chinese Journal of Tropical Crops. 2026, 47(3): 579 -587.

    Granule-bound starch synthase I (MeGBSSI) is the key enzyme for amylose synthesis in cassava, primarily responsible for catalyzing the formation of amylose through α-1,4-glucosidic linkages on the surface of starch granules. However, how MeGBSSI cooperates with other starch-synthetic enzymes to orchestrate starch biosynthesis remains unclear. In the previous stage of this research group, through yeast two-hybrid technology, it was hypothesized that the soluble starch synthase MeSSV was a potential binding protein of MeGBSSI. In this study, the MeGBSSI and MeSSV genes were cloned using the main cultivated variety of cassava, Huanshan 8 (SC8), as the material. Yeast two-hybrid vectors pGBKT7-MeGBSSI and pGADT7-MeSSV were constructed. Through yeast two-hybrid point-to-point experiments, the interaction relationship between MeGBSSI and MeSSV was preliminarily verified. The luciferase complementation (LCA) and double-molecule fluorescence complementation (BiFC) techniques were used to further clarify the direct protein interaction between the two. The results showed that the protein sequences encoded by the MeGBSSI and MeSSV genes, compared with the sequenced variety AM560, respectively, had 4 and 2 amino acid substitutions; the MeGBSSI protein was non-toxic to yeast cells and had no self-activation activity; this protein interacted with the soluble starch synthase MeSSV in yeast; the LCA experiment showed that the chemical signals significantly enhanced after co-expression of MeGBSSI and MeSSV; the BiFC experiment further proved that the two could form a complex in plant cells, and the interaction signal was located in the chloroplast. The findings would provide new insight into the synergistic regulation among cassava starch-synthetic enzymes.

  • nanxi XU-QU , Yujie WANG , Shuying CHEN , Lilian HE , Fusheng LI
    Chinese Journal of Tropical Crops. 2026, 47(3): 553 -566.

    The PYR/PYL/RCAR (PYL) gene family (Pyrabactin Resistance 1/PYR1-Like/Regulatory Component of ABA Receptor), as core receptors of abscisic acid (ABA), play a pivotal regulatory role in the signaling pathways of plant responses to abiotic stresses such as drought. Saccharum spontaneum L. (wild sugarcane), an important wild relative for sugarcane stress-resistant breeding, harbors abundant drought-tolerant genetic resources. However, systematic identification and functional analysis of its PYL gene family remain unreported to date. Based on the S. spontaneum genome data (Saccharum spontaneum Np-X2021), the study identified members of the SsPYL gene family using bioinformatics approaches, and systematically analyzed the physicochemical properties, chromosomal localization, phylogenetic relationships, gene structures, conserved motifs, and cis-acting elements in promoters. Additionally, quantitative real-time PCR (qRT-PCR) was employed to investigate the expression patterns of core members under drought stress. The results showed that 32 SsPYL genes, designated as SsPYL1 to SsPYL32, were identified in the S. spontaneum genome. The encoded proteins ranged in length from 149 to 385 amino acids, with most being acidic and hydrophilic proteins primarily localized in the cytoplasm. The secondary structure was dominated by α-helices and random coils. Furthermore, SsPYLs exhibited uneven distribution across chromosomes, and segmental duplication was the dominant mechanism driving family expansion. A total of 54 pairs of syntenic genes were identified between SsPYLs and rice OsPYL genes, reflecting the evolutionary conservation of this family among monocotyledonous plants. Phylogenetic analysis clustered the 32 SsPYLs into three subfamilies, with members of the same subfamily sharing similar conserved motif compositions and gene structures. All SsPYL proteins contained the signature PYR_PYL_RCAR_like domain. The promoter regions of SsPYL genes were enriched in hormone-responsive and abiotic stress-related cis-acting elements, such as ABRE (ABA-responsive element), ARE (anaerobic responsive element), and LTR (low-temperature responsive element). Under drought stress, the expression levels of eight SsPYL genes (SsPYL1, SsPYL3, SsPYL4, SsPYL6, SsPYL8, SsPYL14, SsPYL19 and SsPYL24) were extremely significantly upregulated (P<0.01), among which SsPYL8, SsPYL14 and SsPYL19 showed more than 5-fold upregulation. The genes are thus speculated to be key candidate genes regulating drought tolerance in S. spontaneum. The study represents the first systematic characterization of the molecular features and drought-responsive patterns of the SsPYL gene family in S. spontaneum. It would provide a theoretical basis for further exploring the functional mechanisms in ABA-mediated drought stress signaling pathways and offer important gene targets for the genetic improvement of drought tolerance in sugarcane.

  • Huanli ZHU , Jiawen LI , Wengang YU , Rizhi WU , Ji LI , Quannan ZHOU
    Chinese Journal of Tropical Crops. 2026, 47(3): 814 -823.

    As an important resource plant in tropical regions, Daemonorops jenkinsiana has significant value in the fields of ecology, economy and medicine. This study investigated the community structure of D. jenkinsiana in the secondary forest of Fanjia Provincial Nature Reserve, Hainan. Through sample plot investigation and analysis, the secondary forest in the Fanjia Provincial Nature Reserve of Hainan served as the research object in this study, revealing its community structure characteristics in detail and providing a theoretical foundation for resource protection and artificial cultivation of D. jenkinsiana., providing theoretical insights for the conservation and sustainable utilization of D. jenkinsiana resources. The D. jenkinsiana community was rich in species composition, encompassing a total of 161 plant species belonging to 134 genera and 69 families. In dominant taxa, the dominant families included Fabaceae, Rubiaceae and Arecaceae, accounting for 47.83% of the total species; the dominant genera were Ficus, Ardisia and Calamus, contributing to 13.66% of the total species. Tropical elements dominated both the families and genera of the plants. Among them, there were 47 tropical families, representing 77.05% of the total families, and 108 tropical genera, accounting for 85.71% of the total genera. The dominant species in the arbor layer were Ficus microcarpa, Heptapleurum heptaphyllum, Phoebe sheareri, Cryptocarya concinna, Quercus glauca, Aporosa dioica, Lannea coromandelica, Camphora officinarum, Zanthoxylum nitidum, Engelhardia roxburghiana. The dominant species in the shrub layer included D. jenkinsiana, Rhapis excelsa, Desmos chinensis, Calamus tetradactylus, Maesa japonica, Calamus egregius, Dypsis lutescens, Psychotria rubra, Ancistrocladus tectorius and Dalbergia hupeana. The dominant species in the herb layer were Rhapis excelsa, Alpinia japonica, D. jenkinsiana, Psychotria rubra, Dalbergia hancei, Maesa japonica, Desmos chinensis, Schima superba, Ardisia crenata and Tetracera asiatica. Species diversity was the highest in the shrub layer and lowest in the herb layer. The D. jenkinsiana community not only serves as a valuable natural subject and sample source for regional biodiversity studies but also supports population regeneration and the long-term maintenance of habitats. Furthermore, it represents a vital natural germplasm repository. By establishing sample banks (e.g., seeds, seedlings, tissue samples from mature plants) and digital information databases (documenting provenance, growth environment parameters, morphological traits, and genetic characteristics), the provenance information for D. jenkinsiana across different species and growth stages can be systematically enriched. The effort holds significant importance for the sustainable management of both cultivated D. jenkinsiana plantations and natural liana communities.

  • Xiaolan ZHENG , Lei LUO , Kexian YI , Weihuai WU , Yanqiong LIANG , Shibei TAN
    Chinese Journal of Tropical Crops. 2026, 47(3): 717 -730.

    Konjac (Amorphophallus spp.) is an important medicine and food economic crop in China, but its industrial development has long been threatened by soft rot disease, known as the konjac 'cancer'. Hainan is an emerging konjac producing area, but the current epidemiological pattern of konjac soft rot disease and pathogenic bacteria population structure is not clarified. The study was aimed to carry out soft rot disease investigation, pathogen isolation and identification, and to provide a scientific basis for the control of the disease. The survey of konjac soft rot disease in six cities and counties in Hainan showed that the highest incidence rate (46.01%) was found in the third team of Danzhou Experimental Farm, while that of Wenchang planting base is low (8.25%). Combining morphology, molecular biology (16S rDNA, proA, gapA and mdh multigene phylogenetic analysis) identifications and distribution information of pathogens, Dickeya fangzhongdai (88.64% of the total), Pectobacterium aroidearum (6.82%) and P. colocasium (4.54%), were the cause of the disease. Pathogenicity assay showed that D. fangzhongdai was high pathogenicity, and indoor screening showed that 0.3% tetramycin had the best inhibitory effect on D. fangzhongdai, with the lowest inhibitory concentration (MIC) of 1.825 μg/mL, followed by 80% ethacrynicin (MIC of 25 μg/mL) and 25% bromoxynil (MIC of 125 μg/mL). The dynamic changes of defence antioxidant enzymes and malondialdehyde in konjac in response to D. fangzhongdai infestation were determined by pot inoculation experiment. The results showed that the activity of superoxide dismutase (SOD) and peroxidase (POD) reached 182.57 U/g and 300.33 U/g, respectively, after 72 h of infestation, which was 2.27-fold and 7.03-fold higher than that of the control, while the activity of catalase (CAT) peaked at 24 h (1093.67 U/g) and decreased to 658.01 U/g in the later period (72 h). Malondialdehyde (MDA) content increased incrementally with infestation time and increased by 30.51% at 72 h compared to the control, and β-galactosidase (β-GAL) activity continued to rise [97 nmol/(min·g)] and increased by 36.86% compared to the control.

  • Ximeng ZHENG , Xiao YANG , Shiqing ZHANG , Zijun XIONG , Shuai MA , Xiaolong HUANG , Zhikai GUO
    Chinese Journal of Tropical Crops. 2026, 47(3): 731 -743.

    Xisha Islands are located in a low-latitude area that straddles the boundary between the Indian and eastern Asian monsoon systems. The unique and diverse ecosystem provides habitats for numerous microorganisms, generating exceptionally rich microbial resources. Due to the remote geographical locations of most islands and the fact that the coastal vegetation is in the vanguard stage of oligotrophic conditions, the microbial communities may differ from those of islands with complex vegetation. In this study, through the research on the fungal diversity of coastal coral sandy soil in Xisha Islands, two new species of Aspergillus, namely A. paraflavipes and A. ganquanensis, were isolated from the local coral sandy soil samples using potato-dextrose agar. Identifications of new species were carried out based on various methods such as detection of growth rate in plate culture, observation of colony morphology in plate growth, microscopic morphological comparison, and multi-gene combined phylogenetic analysis (ITS-BenA-CaM-RPB2). The results showed that the species exhibiedt taxonomic status and morphological characteristics that are different from those of existing species. By integrating various detection methods and comparison results, they could be regarded as new taxonomic units. A. paraflavipes and A. ganquanensis belonged to the genus Aspergillus, subgen. Circumdati in sect. Flavipedes and sect. Circumdati, respectively. According to the results of the combined phylogenetic analysis of multiple genes, A. paraflavipes in sect. Flavipedes was a separate lineage parallel to the ser. Flavipedes. According to its microscopic morphological structure, it is shown that the conidiomata of A. paraflavipes was very special, and the size of its stipes and vesicles was much smaller than that of other species in the sect. Flavipedes. According to the growth rate detection results, A. paraflavipes could grow at a relatively fast rate (21-24 mm, 7 days) on Czapek yeast autolysate (CYA) at 40 ℃. Among the ser. Flavipedes similar to A. paraflavipes, only A. ardalensis (growth rate ≤2 mm, 7 days) and A. templicola (4-8 mm, 7 days) could grow on CYA at 40 ℃. And its growth rate was extremely slow, and none of the other species grow. Based on the results of phylogenetic analysis, microscopic morphological observation and growth rate comparison, it is believed that A. paraflavipes is located in an undiscovered series in sect. Flavipedes. Therefore, we propose to establish a new strain, ser. Paraflavipedes, to accommodate A. paraflavipes. The detailed morphological comparison and the description of the identification results were described in the article. Multi-gene combined phylogenetic analysis showed A. ganquanensis presented a unique branch in the sect. Circumdati, ser. Sclerotiorum, showing similar morphology to those of the species in this series. This study isolated and documented two new species of Aspergillus originated from the Xisha Islands, expanding our understanding of the fungal diversity of the Xisha Islands. Moreover, it is particularly important to record the biodiversity of the ecosystem before human activities affecting it.

  • Shiying LIU , Mengzhuo ZHANG , Xingdie XU , Yamei CHEN , Lanhuan MENG
    Chinese Journal of Tropical Crops. 2026, 47(3): 603 -612.

    Tomato ripening involves the coordinated regulation of key agronomic traits such as color transformation, texture softening, and flavor compound accumulation. Elucidating its molecular mechanisms is not only a central goal in postharvest biology but also crucial for improving fruit quality and achieving precise control of storage duration. In this study, the functions of SlBEL1, SlBEL2 and SlBEL11, members of the BEL family of transcription factors in tomato, were systematically investigated through multi-dimensional experiments. Phylogenetic and amino acid sequence alignment analyses revealed that SlBEL1, SlBEL2 and SlBEL11 possessed highly conserved protein domains, suggesting potential functional similarities. Spatiotemporal expression profiling showed that the genes were synchronously highly expressed during critical stages of fruit ripening, from the breaker to the full ripening stage. Using CRISPR-Cas9 technology, single-gene and triple-gene editing lines of SlBEL1, SlBEL2 and SlBEL11 were generated. The single-gene editing lines CR-SlBEL1, CR-SlBEL2 and CR-SlBEL11 all exhibited a delayed fruit ripening phenotype, while the triple editing line resulted in impaired reproductive development, failing to proceed to flowering and fruit setting. Furthermore, reverse transcription quantitative real-time PCR (qRT-PCR) analysis revealed that SlBEL1/2/11 modulated the expression of multiple ripening-related genes in tomato. Collectively, the results demonstrate that SlBEL1/2/11 functioned redundantly to coordinately control the fruit ripening process. This study identified novel targets for the genetic improvement of tomato fruit ripening.

  • Hua XIAO , Yunke ZHENG , Jianbin ZHANG , Lili CHANG , Zuxiang SU , Xinguo LI , Juhua2 LIU
    Chinese Journal of Tropical Crops. 2026, 47(3): 754 -762.

    Banana has high nutritional and economic value. However, banana is easy to decay after harvest, making preservation difficult. Banana quality is significantly affected by external conditions. Temperature is a key factor in regulating the post-harvest banana ripening quality. Zhongre No. 1 is a new variety resistant to Fusarium wilt with high yield and good quality, which is independently cultivated by our research group. However, its optimal storage temperature has not been clearly defined. Therefore, investigating the effect of different temperature on the post-harvest quality of Zhongre No. 1 is of great significance for the industrialization of the variety. In the study, freshly harvested Zhongre No. 1 banana was ripened at 14 ℃, 16 ℃, 18 ℃, 20 ℃, 22 ℃ and 25 ℃, respectively. Aimed at determining the optimal preservation temperature, the ripening characteristics and starch degradation dynamics were systematically observed, and indicators such as weight loss rate, peel color difference, ethylene release amount, firmness, and starch and sugar content were measured to analyze the effect of storage temperature on the quality indicators. The results showed that higher temperature led to faster fruit color change, weight loss, bunch separation, ethylene release, softening, and starch degradation. Different temperature had little effect on fructose and glucose content but significantly affected sucrose content, with the sucrose content in 22 ℃ and 25 ℃ being significantly higher than that at 14 ℃ and 18 ℃, among which 22 ℃ had the highest sucrose content and 14 ℃ had the lowest. Banana stored at 14 ℃ had the strongest storability, with stable color after turning yellow, making them suitable for long-term storage and transportation. Banana at 22 ℃ ripened quickly and had high sweetness but poor color. Banana at 18 ℃ ripened relatively quickly with golden and plump fruit color, making it more suitable for rapid shelf placement and sales. Banana at 25 ℃ failed to normally lose green color, was easy to bunch separation, and lost commercial value.

  • Jie LI , Guangying YE , Bin LI , Xinyu WEI , Yizhi OU , Fengxi YANG
    Chinese Journal of Tropical Crops. 2026, 47(3): 676 -684.

    To enhance the flower quantity and flowering quality of Phalaenopsis, this study investigated the regulatory effects of spraying 6-BA or multi-stem inducer before and after flower stalk emergence on the flowering traits and lateral branch development of different cultivars. The experiment employed one large-flowered cultivar and six small-flowered cultivars. Treatments included spraying 400 mg/L 6-BA or multi-stem inducer (200×dilution) before stalk emergence and 200 mg/L 6-BA after stalk emergence. Flowering indices such as stalk emergence time, double-stalk rate, multiple-stalk rate, stalk length, flower number, number of lateral branches on the stalk, and bud abortion count were measured. Spraying 6-BA or the multi-stem inducer before stalk emergence significantly promoted stalk emergence in small-flowered cultivars, increasing the double-stalk and multiple-stalk rates (e.g., the multiple-stalk rate of 'Jinbian linglong' reached 100%). However, it reduced the number of lateral branches on the stalk in some cultivars. The large-flowered cultivar 'Daliajiao' was insensitive to multi-stalk induction, with a double-stalk rate of only 3.3%, but its stalk emergence time was advanced by 20 days compared to the control after pre-emergence 6-BA treatment. Although spraying 6-BA after stalk emergence delayed flowering, it significantly increased the inflorescence length, flower number, number of lateral branches on the stalk, and the length of the longest lateral branch in small-flowered cultivars. It also induced varying degrees of bud abortion, with 'Jinbian kafei' being the most severely affected, showing a bud abortion rate as high as 59.2%. In conclusion, the effects of 6-BA on Phalaenopsis flowering exhibit significant cultivar differences and are dependent on the application timing. Treatment before stalk emergence is conducive to inducing multiple stalks in small-flowered cultivars and improving emergence uniformity, with the multi-stem inducer showing similar effects to 6-BA. Treatment after stalk emergence can optimize the inflorescence structure of small-flowered cultivars but requires attention to the risk of bud abortion. In production, the appropriate treatment timing should be selected based on cultivar characteristics and cultivation objectives.

  • Fangfang LI , Jianwei ZHENG , Mingjuan ZHENG , Ning ZHANG , Wei HU , Haiquan FU , Jie LI
    Chinese Journal of Tropical Crops. 2026, 47(3): 685 -693.

    Phoenix dactylifera L. (Date Palm), with a cultivation history of over 7000 years, ranks among the world's most ancient fruit trees. Renowned for its exceptional tolerance to drought, high temperatures, and salinity, it has become a highly valuable economic crop in arid regions. Advances in agricultural technology and growing awareness of ecological conservation underscore the strategic importance of developing efficient date palm cultivation technologies for food security, ecological protection, and enhanced regional economic benefits. This paper systematically explored the key technologies for high-quality and high-yield date palm cultivation under the synergistic framework of intelligent cultivation and green control. It comprehensively reviewed strategies for optimizing the growth environment, including soil adaptation, water regulation, and light & temperature management. Core high-yield cultivation techniques-such as soil preparation, planting density, precision fertilization, tree pruning, water-saving irrigation, and intercropping models were systematically integrated and summarized. The application status and potential of intelligent technologies, including the Internet of Things (IoT), big data, artificial intelligence (AI), and unmanned aerial vehicles (UAVs), in precision date palm cultivation were discussed. Research progress and optimization directions for propagation techniques, notably offshoot propagation and tissue culture, were analyzed. Furthermore, an Integrated Pest Management (IPM) strategy centered on biological control was proposed as a green pest and disease control approach. The paper would provide prospects for the date palm industry from four key perspectives, ecological environment, cultivation technology innovation, industrial integration, and international cooperation, aiming to offer a solid scientific basis and technical support for the high-quality, efficient, and sustainable development of the date palm industry.

  • Peng ZHANG , Chaohua ZHANG , Guiping WU , Fenglin GU , Weicheng HU , Lingjun ZHENG , Fan XIE , Meifang HOU , Jae Youl CHO
    Chinese Journal of Tropical Crops. 2026, 47(3): 777 -787.

    To address the issues of low added value in traditional pepper processing, poor fluidity of pepper oleoresin, and the incomplete extraction and emulsification techniques for freeze-dried green pepper oleoresin, this study used freeze-dried green pepper as raw material to prepare pepper oleoresin through ultrasonic-microwave assisted extraction. The volatile components were analyzed by gas chromatography-mass spectrometry (with cyclohexanone as the internal standard), and a mixed emulsi-system of Tween 80 and Span 80 was selected to investigate the effects of pH, ionic strength, and water content on the of the emulsion. The results showed that a total of 37 volatile compounds were detected in the pepper oleoresin, mainly monoterpenes and sesquiterpenes, among which β-caryophyllene (210.83 mg/mL) had a relatively high content. The ideal value of the mixed emulsifier was approximately 11. Under the conditions of pH 8.0-9.0, without adding NaCl, and a water content of 95%, the emulsion had a lower particle size and stable physicochemical properties. This study optimized the extraction and emulsification process of freeze-dried green pepper oleoresin, providing technical support for its development and utilization as well as the upgrading of the pepper industry's deep processing.

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