Song Xiaohui, Zhu Guozhong, Su Xiujuan, Yu Yujia, Duan Yujia, Wang Haitang, Shang Xiaoguang, Xu Haijiang, Chen Quanjia, Guo Wangzhen
State Key Laboratory of Crop Genetics and Germplasm Enhancement and Utilization, Nanjing Agricultural University, Nanjing 210095, China.
Engineering Research Center of Ministry of Education for Cotton Germplasm Enhancement and Application, Nanjing Agricultural University, Nanjing 210095, China.
Plant Physiol. 2024 Jun 28;195(3):2158-2175. doi: 10.1093/plphys/kiae175.
Gossypium barbadense, which is one of several species of cotton, is well known for its superior fiber quality. However, the genetic basis of its high-quality fiber remains largely unexplored. Here, we resequenced 269 G. barbadense accessions. Phylogenetic structure analysis showed that the set of accessions was clustered into 3 groups: G1 and G2 mainly included modern cultivars from Xinjiang, China, and G3 was related to widely introduced accessions in different regions worldwide. A genome-wide association study of 5 fiber quality traits across multiple field environments identified a total of 512 qtls (main-effect QTLs) and 94 qtlEs (QTL-by-environment interactions) related to fiber quality, of which 292 qtls and 57 qtlEs colocated with previous studies. We extracted the genes located in these loci and performed expression comparison, local association analysis, and introgression segment identification. The results showed that high expression of hormone-related genes during fiber development, introgressions from Gossypium hirsutum, and the recombination of domesticated elite allelic variation were 3 major contributors to improve the fiber quality of G. barbadense. In total, 839 candidate genes with encoding region variations associated with elite fiber quality were mined. We confirmed that haplotype GB_D03G0092H traced to G. hirsutum introgression, with a 1-bp deletion leading to a frameshift mutation compared with GB_D03G0092B, significantly improved fiber quality. GB_D03G0092H is localized in the plasma membrane, while GB_D03G0092B is in both the nucleus and plasma membrane. Overexpression of GB_D03G0092H in Arabidopsis (Arabidopsis thaliana) significantly improved the elongation of longitudinal cells. Our study systematically reveals the genetic basis of the superior fiber quality of G. barbadense and provides elite segments and gene resources for breeding high-quality cotton cultivars.
海岛棉是棉花的几个品种之一，以其优异的纤维品质而闻名。然而，其高品质纤维的遗传基础在很大程度上仍未被探索。在此，我们对269份海岛棉种质进行了重测序。系统发育结构分析表明，这些种质被聚类为3组：G1和G2主要包括来自中国新疆的现代品种，G3与全球不同地区广泛引进的种质有关。在多个田间环境中对5个纤维品质性状进行全基因组关联研究，共鉴定出512个qtls（主效QTL）和94个qtlEs（QTL与环境互作）与纤维品质相关，其中292个qtls和57个qtlEs与先前研究共定位。我们提取了位于这些位点的基因，并进行了表达比较、局部关联分析和渐渗片段鉴定。结果表明，纤维发育过程中激素相关基因的高表达、陆地棉的渐渗以及驯化优良等位变异的重组是提高海岛棉纤维品质的3个主要因素。总共挖掘出839个与优良纤维品质相关的编码区变异候选基因。我们证实，单倍型GB_D03G0092H追溯到陆地棉渐渗，与GB_D03G0092B相比，1个碱基的缺失导致移码突变，显著提高了纤维品质。GB_D03G0092H定位于质膜，而GB_D03G0092B同时存在于细胞核和质膜中。在拟南芥中过表达GB_D03G0092H显著提高了纵向细胞的伸长。我们的研究系统地揭示了海岛棉优良纤维品质的遗传基础，并为培育高品质棉花品种提供了优良片段和基因资源。
