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[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 ] 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.
[前沿资讯 ] Building resistance one plant at a time——Fred Bourland tracks plant bug resistance in breeding lines of cotton 进入全文
FarmProgress
Fred Bourland has been evaluating tarnished plant bug resistance in cotton breeding lines at the Northeast Research and Extension Center near Keiser, Ark., since before 2003. That’s a lot of cotton and plant bugs. When Bourland says varieties containing the ThryvOn technology “were very impressive” in their performance in his trials at the Northeast Research Center in 2023 and 2024, it’s based on years of experience. ThryvOn varieties But Bourland had a caveat: In 2024, the test had 16 ThryvOn varieties. Twelve of those ranked in the top varieties for boll loads in the tarnished plant bug tests. Of the other four, some were ranked considerably lower in the test. “So ThryvOn is not a silver bullet,” said Bourland. “But some of the varieties have stayed very consistent.” Bourland’s work with developing improved cotton varieties goes back more than the 20 years included in the presentation to include testing them for resistance to both tarnished plant bugs and boll weevils. He remembers the work of researchers including Bill Meredith with USDA’s Agricultural Research Service and Marion L. Laster with Mississippi State University at the Delta Research and Extension Center in Stoneville, Miss., in the 1960s, 70s and 80s. “They would take different lines and put them in large plots, side-by-side, treated and untreated, and see which ones in the untreated would do well,” he said. “Typically, they would use buffers planted with mustard in between those to serve as host plants for plant bugs. Then they would terminate the mustard to force the insects to move to cotton. Related:Supply and demand shifts leave cotton farms grasping for traction “I remember Bill Meredith presenting a paper at the Beltwide Cotton Conferences one year where he talked about being able to really cut the mustard, a reference to this tarnished plant bug work where they encouraged the plant bugs to move to the cotton.” Large plots Using large plots may still be the defining way to identify resistance to tarnished plant bugs, he said. “But how many varieties can you test at a time with these larger plots? With 20 or so entries that’s a big commitment. We’ve averaged looking at close to 100 different varieties or breeding line a year in our small plot work.” In the early days of his research, scientists had to be able to distinguish between insect damage caused by boll weevils and by tarnished plant bugs. “The first two years we used mustard, similar to what they did at Stoneville,” he said. “But mustard is a species that is difficult to manage out in a cotton field. So, we went to an early maturing frego-bract cotton, instead.” Frego bract, a mutant trait where the bracts surrounding the flower buds and bolls are long, narrow, twisted and tend to curl outward, exposing the square or boll, is another bit of cotton history associated with northeast Arkansas. It was discovered by a farmer named Frego, who observed it in a field of Stoneville 2B cotton on his farm about 20 miles from Keiser in the 1940s. He picked the cotton from the boll, ginned it by hand and planted the seed in his garden. The cotton that came up retained the trait, and Mr. Frego grew more of it. He told a county agent about it, and it eventually made its way to USDA researchers at Stoneville. “One thing we’ve learned is you don’t have to encourage the plant bugs in our area to get them to move to the plots,” Bourland noted. “They are there. And, really, the mustard was used back before boll weevil eradication. They were spraying for boll weevils and bollworms and controlling plant bugs with those sprays. They had to do something to encourage them, but we don’t have to do that. “I still plant the buffer of frego-bract – it helps separate the test. We like to plant it and three or four weeks earlier than we plant the plant bug test plots. We typically don’t use any insecticides for tarnished plant bugs. We did make one application this past year because they were just overwhelming our whole test.” Pest control Boll weevil eradication meant that farmers and researchers no longer had to contend with the pest. But it also meant the elimination of some of the boll weevil sprays that had helped control tarnished plant bugs. When Bourland began looking at cotton varieties for resistance solely to tarnished plant bugs in 2003, he started slowly because of the amount of manhours involved in plant sampling and determining boll loads to gauge the impact of the pest. “In 2006, Cotton Incorporated started supporting some of this work, and we expanded to variety tests and regional tests,” he said, “And, over the years, we have looked at a total of 2,724 lines in 102 tests. If you multiply that, that’s over 26,000 plots. So, it has been a large effort. “One lesson we have learned is we don’t have to have large plots. We can separate lines based on their performance in these short one-row plots. And I think that by using boll load ratings we can go to less than eight replications.”
[学术文献 ] Identification of favorable alleles from exotic Upland cotton lines for fiber quality improvement using multiple association models 进入全文
Frontiers in Plant Science
Upland cotton (Gossypium hirsutum) faces the challenge of limited genetic diversity in the elite or improved gene pool. To address this issue, we explored alleles contributed by five ‘converted’ exotic lines sampling most of the undomesticated botanical races of G. hirsutum, in BC1F2 and F3 populations. Joint analysis of all populations along with population-specific analyses identified 38 unique QTL for six different fiber quality traits. At 15 of these loci, DES56 or the elite allele improved upon all the exotics. For another 15, only a single of the five exotics improved upon the elite allele, suggesting the rare alleles that may not have been sampled in the cotton domestication or improvement. At the remaining 8 QTL, multiple exotic lines contributed the superior allele, suggesting that DES56 (and by extension the elite gene pool) has chronically poor alleles at these loci. Converted strains T1046, T326, and T063 showed the highest potential for contributions to cotton fiber quality breeding programs. Upper Half Mean Length and Fiber Strength showed multiple QTL regions affecting both traits simultaneously, while the Uniformity Index showed the smallest heritability values. The estimation of pairwise genetic distances for six parental lines indicates that DES56 has a higher genetic similarity with each exotic line than the exotic lines have with each other. Most of the detected QTL were ‘minor’ (explaining less than 10% of variance) supporting the implementation of genomic selection techniques to utilize the cumulative effects of most of these QTL distributed genome-wide. Finally, some regions were consistently unfavorable for exotic introgression such as on chromosomes A13 and D09, indicating the possible genome-wide haplotypes that may combine the benefits of a history of scientific breeding of the elite gene pool.
[学术文献 ] Differences in homologous and heterologous nucleocytoplasmic interactions of cytoplasmic male sterility lines in Gossypium barbadense 进入全文
scientific reports
The utilization of crop hybrids plays an important role in crop breeding and production, and the innovation of the male sterile germplasm is the basis for this utilization. Cotton has a very clear hybrid advantage, and the hybrid advantage in yield and quality has been widely utilized in cotton breeding. However, the exploitation of heterosis in cotton is currently dominated by cytoplasmic male sterility (CMS) lines. These CMS lines are found only in Harknessi cotton. They have a single cytoplasmic origin. Additionally, they exhibit a significant negative effect of cytoplasmic-nuclear interactions. To minimize this effect, it is necessary to select and breed CMS lines. In these CMS lines, both the cytoplasm and nucleus should originate from the same variety. However, no homologous cytoplasmic-nuclear CMS germplasm has been created, and its mechanism of occurrence has not been determined. In this study, two homologous cytoplasmic-nuclear CMS lines and two heterologous cytoplasmic-nuclear CMS lines were utilized, and the heterologous cytoplasmic-nuclear CMS lines were aborted at a relatively early stage. The physiological indexes related to reactive oxygen species ROS-mediated metabolic processes in the heterologous cytoplasmic-nuclear CMS lines were lower than those of the homologous cytoplasmic-nuclear CMS lines, including the enzyme activities of POD and CAT from tetrad to mature pollen grain, and the metabolite content of malondialdehyde (MDA) was inversely correlated with the enzyme activities of the heterologous cytoplasmic-nuclear CMS lines. Resequencing analysis of four cotton mitochondrial genomes (mt genomes) revealed that the heterologous cytoplasmic-nuclear CMS lines were more complex than the homologous cytoplasmic-nuclear CMS lines, and the homologous CMS lines showed a higher degree of collinearity with the maintainer lines. This indicates that heterologous cytoplasmic-nuclear interactions are more likely to lead to mtDNA structural variation. Taken together, the results showed that the cytoplasmic-nuclear homologous system was less affected by the cytoplasmic-nuclear interaction and was the best combination for the study of male sterility.
