Identification of SSR markers linked to the abscission of cotton boll traits and mining germplasm in Cotton

Background Cotton is an economically important crop.It is crucial to find an effective method to improve cotton yield,and one approach is to decrease the abscission of cotton bolls and buds.However,the lack of knowledge of the genetic and molecular mechanisms underlying cotton boll abscission traits has hindered genetic improvements.Results Pearson’s correlation analysis revealed a significant positive correlation between boll abscission rates 1(AR1)and boll abscission rates 2(AR2).A genome-wide association study was conducted on 145 loci that exhibited high polymorphism and were uniformly distributed across 26 chromosomes(pair).The study revealed 18,46,and 62 markers that were significantly associated with boll abscission,fiber quality,and yield traits(P<0.05),explaining 1.75%–7.13%,1.16%–9.58%,and 1.40%–5.44%of the phenotypic variation,respectively.Notably,the marker MON_SHIN-1584b was associated with the cotton boll abscission trait,whereas MON_CGR5732a was associated with cotton boll abscission and fiber quality traits.Thirteen of the marker loci identified in this study had been previously reported.Based on phenotypic effects,six typical cultivars with elite alleles related to cotton boll abscission,fiber quality,and yield traits were identified.These cultivars hold great promise for widespread utilization in breeding programs.Conclusions These results lay the foundation for understanding the molecular regulatory mechanism of cotton boll abscission and provide data for the future improvement of cotton breeding.

Morphological and cytological assessments reveal pollen degradation causes pollen abortion in cotton cytoplasmic male sterility lines

Background Understanding the mechanism of male sterility is crucial for producing hybrid seeds and developing sterile germplasm resources.However,only a few cytoplasmic male sterility(CMS)lines of cotton have been produced due to several challenges,like inadequate variation of agronomic traits,incomplete sterility,weak resilience of restorer lines,and difficulty in combining strong dominance.Therefore,the morphological and cytological identification of CMS in cotton will facilitate hybrid breeding.Results Two F_(2) segregating populations of cotton were constructed from cytoplasmic male sterile lines(HaA and 01A,maternal)and restorer lines(HaR and 26R,paternal).Genetic analysis of these populations revealed a segregation ratio of 3:1 for fertile to sterile plants.Phenotypic analysis indicated no significant differences in traits of flower bud development between sterile and fertile plants.However,sterile plants exhibited smaller floral organs,shortened filament lengths,and anther atrophy on the flowering day in comparison with the fertile plants.When performed scanning electron microscopy(SEM),the two F_(2) populations revealed morphological variations in the anther epidermis.Cellular analysis showed no significant differences in pollen development before pollen maturation.Interestingly,between the pollen maturation and flowering stages,the tapetum layer of sterile plants degenerated prematurely,resulting in abnormal pollen grains and gradual pollen degradation.Conclusion The results of this study suggest that fertility-restoring genes are controlled by a single dominant gene.Sterile plants exhibit distinctive floral morphology,which is characterized by stamen atrophy and abnormal anthers.Pollen abortion occurs between pollen maturity and flowering,indicating that premature tapetum degradation may be the primary cause of pollen abortion.Overall,our study provides a theoretical basis for utilizing CMS in hybrid breeding and in-depth investigation of the dominant configuration of cotton hybrid combinations,mechanisms of sterility,and the role of sterile and restorer genes.

Correction:Identification of SSR markers linked to the abscission of cotton boll traits and mining germplasm in Cotton

Correction:J Cotton Res 7,20(2024)https://doi.org/10.1186/s42397-024-00180-3 Following publication of the original article(Shui et al.2024),the author found 5 errors in the published article.1.One of the author’s name has been corrected from Gou Chunping to Guo Chunping.2.The reference(Zhao SQ.2016)in Table 2 has been updated to:Zhao SQ.Analysis on the major gene and multigene mixed inheritance and QTL mapping for early maturity traits in upland cotton.Chin Acad Agric Sci.2016.https://doi.org/10.3969/j.issn.201600501.(in Chinese with English abstract).3.In’Results’part,’Phenotype analysis of 238 cotton boll abscission among cotton accessions’paragraph,the phenotype analysis of AR1 ranging from 19.27%–63.79%,which was wrongly written as 19.27%-63.97%.4.The‘2018KRL’is modified to‘2018KEL’in Table 1.

后基因组时代发展抗除草剂作物的机遇及挑战

全球农业正在面临着严峻的挑战,育种技术是种业发展的基础和关键。基因编辑技术是指对目标基因进行定点修饰,实现对特定靶标基片段的删除、插入和替换。利用基因编辑技术可以精准修改目标基因或将某种优良基因引入到作物中产生优良农艺性状,在分子设计育种中具有巨大潜力,对保障粮食安全具有重大意义。杂草危害对作物的产量和品质影响巨大,如何高效、安全、可持续地防治草害一直是研究的热点。目前,全球市场已经出现超过200种的化学除草剂,利用化学方法来防治草害已成为现代化农业的重要组成部分,抗除草剂作物的推广也显著降低了杂草防治成本,但随着抗除草剂作物的大面积推广和长期使用单一除草剂,杂草抗/耐药性和抗性基因逃逸等环境安全问题逐渐被发现。目前,功能基因组学、生物信息学、基因工程技术的发展(特别是基因编辑技术在植物中的广泛应用),为创制抗除草剂作物和新型高效的除草剂系统创造了条件。本文首先介绍抑制植物氨基酸生物合成、植物脂类代谢、植物类胡萝卜素、质体醌和生育酚生物合成途径除草剂的主要作用靶标基因及其作用机制。其次,介绍2种挖掘新型抗除草剂基因与除草剂系统的方法,包括基于CRISPR/Cas系统对作物内源的除草剂抗性基因进行定向突变方法和基于天然产物与生物体在自然界中存在共同进化理论的抗性基因导向方法。同时,介绍3种培育抗除草剂作物方法的研究进展,包括常规育种培育法、转基因育种培育法和基于CRISPR/Cas基因组编辑技术培育法。其中,重点介绍CIRSPR/Cas系统、碱基编辑技术和Prime-editing系统在培育抗除草剂作物中的研究进展。针对抗性杂草的产生及环境安全问题是当前化学防治杂草面临的主要挑战,以及抗除草剂作物所面临的主要挑战是基因逃逸问题。目前,快速发展的基因组编辑技术为后基因组时代发展抗除草剂作物提供了新的解决策略和新的机遇。最后,对除草剂作物的未来进行了展望。

基于黄褐棉导入系群体定位抗黄萎病QTL

【目的】黄萎病(Verticillium wilt)是棉花生产中的最主要病害,且棉花黄萎病的致病机理尚不清楚。通过构建黄褐棉导入系群体定位棉花黄萎病抗性相关的数量性状位点(quantitative trait loci,QTL),为抗黄萎病分子标记开发和辅助育种提供参考。【方法】以陆地棉(Gossypium hirsutum)B0011为轮回亲本、黄褐棉(G.mustelinum)为供体亲本,构建有71个株系的BC_(5)S_(5)群体。利用2 839个单核苷酸多态性(single nucleotide polymorphism,SNP)标记结合表型值进行黄萎病抗性相关QTL定位。【结果】共检测到15个与黄萎病抗性相关的QTL,可解释4.21%~26.77%的表型变异。加性效应分析表明:其中6个QTL的有利等位基因来源于黄褐棉,9个QTL有利等位基因来自B0011。同时,qVW-A01-1、q VW-A02-2和qVW-A07-2在2个及以上环境中被检测到,表型变异解释率分别为15.56%~16.56%、11.95%~24.62%和13.22%~16.73%。利用BC5S5群体黄萎病抗性的最佳线性无偏预测值(best linear unbiased prediction,BLUP)进行QTL定位,共检测到5个QTL,其中qVW-A01-1B、q VW-A02-1B分别与加性效应分析稳定检测到的qVW-A01-1、qVW-A02-2物理位置一致,分别解释23.67%和17.90%的表型变异。【结论】本研究发现2个稳定的QTL即qVW-A01-1和qVW-A02-2,可为抗黄萎病分子标记辅助选择育种及候选基因功能鉴定奠定基础。

Association mapping and domestication analysis to dissect genetic improvement process of upland cotton yield-related traits in China

Background: Cotton fiber yield is a complex trait,which can be influenced by multiple agronomic traits.Unravelling the genetic basis of cotton fiber yield-related traits contributes to genetic improvement of cotton.Results: In this study,503 upland cotton varieties covering the four breeding stages(BS1–BS4,1911–2011)in China were used for association mapping and domestication analysis.One hundred and forty SSR markers significantly associated with ten fiber yield-related traits were identified,among which,29 markers showed an increasing trend contribution to cotton yield-related traits from BS1 to BS4,and 26 markers showed decreased trend effect.Four favorable alleles of 9 major loci(R^(2)≥3)were strongly selected during the breeding stages,and the candidate genes of the four strongly selected alleles were predicated according to the gene function annotation and tissue expression data.Conclusions :The study not only uncovers the genetic basis of 10 cotton yield-related traits but also provides genetic evidence for cotton improvement during the cotton breeding process in China.

Advances and prospects of genetic mapping of Verticillium wilt resistance in cotton

Verticillium wilt is one of the most important diseases affecting cotton production in China.The fungus,Verticillium dahliae,has a wide host range and a high degree of genetic variability.No resistance resources have been found in the available planting resources,thus presenting difficulties and challenges for our study.The long-term production practice shows that selection of disease-resistant varieties is the most economical and effective measure to control Verticillium wilt of cotton to reduce the yield loss and quality decline of cotton.In this paper,we summarized the genetic mapping population,the analysis method of genetic localization,the discovery,mining and cloning of disease-resistant quantitative trait loci/markers,and the analysis of their genetic functions,so as to provide information for the molecular breeding approach of disease-resistant cotton.

Identification of candidate genes controlling fiber quality traits in upland cotton through integration of meta-QTL,significant SNP and transcriptomic data

Background:Meta-analysis of quantitative trait locus(QTL)is a computational technique to identify consensus QTL and refine QTL positions on the consensus map from multiple mapping studies.The combination of meta-QTL intervals,significant SNPs and transcriptome analysis has been widely used to identify candidate genes in various plants.Results:In our study,884 QTLs associated with cotton fiber quality traits from 12 studies were used for meta-QTL analysis based on reference genome TM-1,as a result,74 meta-QTLs were identified,including 19 meta-QTLs for fiber length;18 meta-QTLs for fiber strength;11 meta-QTLs for fiber uniformity;11 meta-QTLs for fiber elongation;and 15 meta-QTLs for micronaire.Combined with 8589 significant single nucleotide polymorphisms associated with fiber quality traits collected from 15 studies,297 candidate genes were identified in the meta-QTL intervals,20 of which showed high expression levels specifically in the developing fibers.According to the function annotations,some of the 20 key candidate genes are associated with the fiber development.Conclusions:This study provides not only stable QTLs used for marker-assisted selection,but also candidate genes to uncover the molecular mechanisms for cotton fiber development.

Research on various factors influencing the moisture absorption property of sodium polyacrylate

Sodium polyacrylate was synthesized with acrylic acid as the monomer, and sodium bisulfate and ammonium persulfate as the initiator, by means of aqueous solution polymerization. The factors influencing the properties of moisture absorption, such as monomer concentration, dosage of initiator, and reaction temperature were systematically investigated. The experimental results indicate that the moisture-absorbing property of this polymer was better than other traditional material, such as silica gel, and molecular sieve. The best reaction condition and formula are based on the orthogonal experiment design. The optimum moisture absorbency of sodium polyacrylate reaches 1.01 g/g. The mathematical correlation of this polymer with various factors and moisture absorbency is obtained based on the multiple regression analysis. The moisture content intuitive analysis table shows that neutralization degree has the most significant influence on moisture absorbency, followed by monomer concentration and reaction temperature, while other factors have less influence.