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[学术文献 ] Rhizospheric Bacillus isolates control Fusarium wilt on cotton and enhance plant biomass and root development 进入全文
FRONTIERS IN MICROBIOLOGY
Cotton is a globally significant crop, serving as a source of natural fiber for the textile industry and contributing to various other products. Its economic importance is substantial, impacting livelihoods and international trade. However, cotton production faces numerous challenges, including Fusarium wilt caused by Fusarium oxysporum f. sp. vasinfectum (Fov), which can lead to significant yield and fiber quality losses. Plants alter their root exudate profiles in response to pathogens, often selectively enriching for beneficial rhizobacteria with antagonistic activity and plant growth-promoting traits. This study thus aims to characterize bacteria isolated from the rhizosphere of diseased cotton plants. The antifungal activity of 43 isolates was assessed against Fov in vitro. Eight of these inhibited Fov growth by 68.4 to 76.9%. 16S rRNA sequencing confirmed these isolates as Bacillus species. These eight Bacillus strains were further examined for their different modes of action in vitro, and their effect on cotton plants in greenhouse experiments challenged with Fov. All eight strains produced chitinases and pectinases, seven demonstrated cellulase and three protease activity, six produced urease, and five siderophores. Only B. subtilis SC11 exhibited phosphate solubilization activity. Seed treatments revealed that B. subtilis SC10 and B. subtilis SC11 were the standout treatments reducing Fov-caused symptoms by similar to 83% compared to Fov-inoculated control plants and most significantly improved plant growth and antioxidant activity. In detail, B. subtilis SC11 increased shoot and root dry weight by 160 and 250%, respectively. B. subtilis SC10 increased peroxidase activity by similar to 143% and ascorbate peroxidase activity by similar to 60%, while in B. subtilis SC11 treated plants superoxide dismutase activity increased by similar to 100%. Bacillus treatments effectively mitigated lipid peroxidation, achieving up to 91.4% reduction (B. subtilis SC10, B. halotolerans SC15), and decreased H2O2 accumulation by up to 58.4% (B. halotolerans SC32) compared to the Fov control. Principle component analysis revealed that regarding plant growth parameters, the treatments, and controls were distributed differentially across PC1 and PC2, with 60.30 and 15.62% data variance, respectively, showing the effectiveness of Bacillus isolates in greenhouse experiments. The findings of this study will contribute to the development of sustainable biocontrol strategies for managing Fusarium wilt in cotton.
[学术文献 ] Advancing cotton fiber research with variable-pressure scanning electron microscopy 进入全文
FRONTIERS IN PLANT SCIENCE
Cotton fibers, as highly extended, thickened epidermal seed structures, are a crucial renewable resource in textile production. Cotton plants produce two main types of fiber cells: wide, hemisphere-shaped fibers and narrow, tapered fibers. Both types stabilize through secondary cell wall development, with the mature narrow fibers being particularly valued for spinning into fine, strong yarns, suitable for premium cotton fabrics. Traditional methods for studying fiber development and cell types, such as scanning electron microscopy (SEM), are often time-intensive and costly. SEM preparation steps, including fixation, dehydration, and sputter coating, can cause shrinkage and other image distortions, limiting the accuracy of observations. Variable-pressure scanning electron microscopy (VP-SEM) offers an alternative approach, operating under low pressure rather than a high-vacuum environment, which can be advantageous for imaging live samples with minimal sample preparation. In this study, we applied VP-SEM to observe fiber cell initiation and early elongation in the conventional upland cotton cultivar UGA 230 at 0 and 1-day post-anthesis. Two SEM detectors, the ultra-variable-pressure detector and backscattered electrons, were used to capture detailed images. Optimal imaging conditions were identified with a 15 keV accelerating voltage and a 50 Pa pressure setting, enabling clear visualization of early fiber development without the need for extensive preparation. This VP-SEM protocol not only facilitates high-resolution imaging of cotton fibers at early developmental stages but also reduces time and expense, minimizing sample damage. Additionally, this optimized approach can be adapted for other fresh biological samples, making it a versatile tool for real-time imaging across various studies in plant biology and beyond.
[学术文献 ] Development of Gossypium hirsutum-Gossypium raimondii introgression lines and their use in QTL mapping of agricultural traits 进入全文
JOURNAL OF INTEGRATIVE AGRICULTURE
Gossypium raimondii (2n=2x=26, D5), an untapped wild species, is the putative progenitor of the D-subgenome of G. hirsutum (2n=4x=52, AD1), an extensively cultivated species. Here, we developed a G. hirsutum (recipient)-G. raimondii (donor) introgression population to exploit the favorable QTLs/genes and mapped potential quantitative trait loci (QTLs) from wild cotton species. The introgression population consisted of 256 lines with an introgression rate of 52.33% for the G. raimondii genome. The introgression segment length range was 0.03-19.12 Mb, with an average of 1.22 Mb. The coverage of total introgression fragments from G. raimondii was 386.98 Mb. Further genome-wide association analysis (Q+K+MLM) and QTL mapping (RSTEP-LRT) identified 59 common QTLs, including 14 stable QTLs and six common QTL (co-QTL) clusters, and one hotspot of micronaire (MIC). The common QTLs for seed index all showed positive additive effects, while the common QTLs for boll weight all had negative additive effects, indicating that the linkage between seed index and boll weight could be broken. QTLs for lint percentage showed positive effects and could be beneficial for improving cotton yield. Most QTLs for fiber quality had negative additive effects, implying these QTLs were domesticated/improved in G. hirsutum. A few fiber quality QTLs showed positive additive effects, so they could be used to improve cotton fiber quality. The introgression lines developed could be useful for molecular marker-assisted breeding and mapping QTLs precisely for mining desirable genes from the wild species G. raimondii. Such genes can improve cultivated cotton in the future through a design-breeding approach.
[学术文献 ] Breeding triple-advantage cottonseed with higher yield, enhanced nutrition, and reduced toxicity by redirecting terpenoid metabolism to astaxanthin 进入全文
PLANT BIOTECHNOLOGY JOURNAL
Cottonseed is a valuable source of edible oil and protein, but its utilization is limited by high gossypol content. In this study, we engineered cotton (Gossypium hirsutum) to biosynthesize astaxanthin through both single-gene (CrBKT) and multi-gene (CrBKT, ZmPSY1, PaCrtI, HpCrtZ) expression strategies. Transgenic cotton plants exhibited significant astaxanthin accumulation across multiple tissues, with distinct red pigmentation observed in leaves, stems, reproductive organs, and cottonseeds. While single CrBKT expression was sufficient to redirect metabolic flux toward astaxanthin biosynthesis, multi-gene transformation did not necessarily lead to higher astaxanthin levels, suggesting that BKT is the key determinant of astaxanthin accumulation in cotton. Additionally, BKT-overexpressing plants produced larger cottonseeds, with increased seed weight and size, indicating a possible link between carotenoid metabolism and seed development. Importantly, gossypol content was significantly reduced in transgenic cottonseeds, likely due to the redistribution of terpene metabolism. The qRT-PCR analyses confirmed that the expression of key gossypol biosynthetic genes was downregulated, supporting a metabolic trade-off between astaxanthin and gossypol biosynthesis. These results demonstrate that cotton can serve as a biofactory for astaxanthin production, providing a scalable and cost-effective alternative to traditional sources. Furthermore, the dual benefits of enhanced nutrition and reduced toxicity significantly expand the potential applications of cottonseed in human food, animal feed, and functional ingredient markets.
[学术文献 ] The PAP Gene Family in Cotton: Impact of Genome-Wide Identification on Fiber Secondary Wall Synthesis 进入全文
INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
Cotton is a crucial cash crop widely valued for its fiber. It is an important source of natural fiber and has diverse applications. Improving fiber quality is of significant economic and agricultural importance. Purple acid phosphatases (PAPs) are multifunctional enzymes critical for plant cell wall biosynthesis, root architecture modulation, low-phosphorus stress adaptation, and salt/ROS stress tolerance. In this study, a comprehensive genome-wide analysis of the PAP gene family was performed for four cotton species (G. hirsutum, G. barbadense, G. raimondii, and G. arboreum) to explore its potential role in improving fiber quality. A total of 193 PAP genes were identified in these species, revealing several conserved domains that contribute to their functional diversity. Phylogenetic analysis showed that the cotton PAP2 genes exhibited high homology with NtPAP12, a cell wall synthesis-related gene. Using cotton varieties with contrasting fiber thickness (EZ60, micronaire 4.5 vs. CCRI127, micronaire 3.5), qRT-PCR analysis demonstrated significantly higher expression levels of GhPAP2.2, GhPAP2.6, GhPAP2.8, and GhPAP2.9 in EZ60 fibers during 20-25 DPA compared to CCRI127. These results highlight the potential influence of PAP genes on cotton fiber development and provide valuable insights for improving fiber quality in cotton breeding.
[学术文献 ] Role of Molecular Breeding Tools in Enhancing the Breeding of Drought-Resilient Cotton Genotypes: An Updated Review 进入全文
Water
Drought stress is an inevitable factor that disturbs the production of plants by altering morphological, physiological, biochemical, and molecular functions. Breeding for drought tolerance requires a complete understanding of the molecular factors controlling stress-responsive pathways. The plant responds to drought stress by adopting four mechanisms: avoidance, escape, tolerance, and recovery. Traditional plant-breeding tools have been employed to increase tolerance in cotton, but the complexity of drought tolerance has limited the use of these breeding methods. The plant adopts several key strategies against drought stress, such as activating the signaling network and activating molecular factors. Cotton breeders have been engaged in elucidating the molecular mechanisms of drought tolerance in cotton using significant molecular tools such as quantitative trait loci (QTL) mapping, transcription factor (TFs) analysis, transcriptome analysis, genome-wide association studies (GWAS), genetic engineering, and CRISPR/Cas9. Breeders have studied the functional description of genes and the interacting pathways accountable for controlling drought tolerance in cotton. Hundreds of genes/QTL have been identified, and many have been cloned for drought tolerance in cotton; however, a complete understanding of these traits still needs more study. This review presents a detailed overview of molecular tools, their application for improving drought tolerance in cotton, and their prospects. This review will help future researchers to conduct further studies to develop drought-tolerant cotton genotypes that can thrive under conditions of water scarcity.
