Li Pengtao, Chen Yu, Yang Rui, Sun Zhihao, Ge Qun, Xiao Xianghui, Yang Shuhan, Li Yanfang, Liu Qiankun, Zhang Aiming, Xing Baoguang, Wu Bei, Du Xue, Liu Xiaoyan, Tang Baomeng, Gong Juwu, Lu Quanwei, Shi Yuzhen, Yuan Youlu, Peng Renhai, Shang Haihong
School of Biotechnology and Food Engineering, Anyang Institute of Technology, Anyang 455000, China.
National Key Laboratory of Cotton Bio-Breeding and Integrated Utilization, Institute of Cotton Research of Chinese Academy of Agricultural Sciences, Anyang 455000, China.
Plants (Basel). 2024 Aug 19;13(16):2308. doi: 10.3390/plants13162308.
Fiber length (FL) and strength (FS) are the core indicators for evaluating cotton fiber quality. The corresponding stages of fiber elongation and secondary wall thickening are of great significance in determining FL and FS formation, respectively. QTL mapping and high-throughput sequencing technology have been applied to dissect the molecular mechanism of fiber development. In this study, 15 cotton chromosome segment substitution lines (CSSLs) with significant differences in FL and FS, together with their recurrent parental line CCRI45 and donor parent line Hai1, were chosen to conduct RNA-seq on developing fiber samples at 10 days post anthesis (DPA) and 20 DPA. Differentially expressed genes (DEGs) were obtained via pairwise comparisons among all 24 samples (each one with three biological repeats). A total of 969 DEGs related to FL-high, 1285 DEGs to FS-high, and 997 DEGs to FQ-high were identified. The functional enrichment analyses of them indicated that the GO terms of cell wall structure and ROS, carbohydrate, and phenylpropanoid metabolism were significantly enriched, while the GO terms of glucose and polysaccharide biosynthesis, and brassinosteroid and glycosylphosphatidylinositol metabolism could make great contributions to FL and FS formation, respectively. Weighted gene co-expressed network analyses (WGCNA) were separately conducted for analyzing FL and FS traits, and their corresponding hub DEGs were screened in significantly correlated expression modules, such as , , and in the fiber elongation and WRKY, TDT, and RAC-like 2 during secondary wall thickening. An integrated analysis of these hub DEGs with previous QTL identification results successfully identified a total of 33 candidate introgressive DEGs with non-synonymous mutations between the and species. A common DEG encoding receptor-like protein kinase 1 was reported to likely participate in fiber secondary cell thickening regulation by brassionsteroid signaling. Such valuable information was conducive to enlightening the developing mechanism of cotton fiber and also provided an abundant gene pool for further molecular breeding.
纤维长度（FL）和强度（FS）是评估棉纤维品质的核心指标。纤维伸长和次生壁加厚的相应阶段分别对于确定FL和FS的形成具有重要意义。数量性状基因座（QTL）定位和高通量测序技术已被应用于剖析纤维发育的分子机制。在本研究中，选择了15个在FL和FS上有显著差异的棉花染色体片段代换系（CSSLs），连同它们的轮回亲本系CCRI45和供体亲本系海1，对开花后10天（DPA）和20 DPA的发育中的纤维样本进行RNA测序。通过对所有24个样本（每个样本有三个生物学重复）进行两两比较获得差异表达基因（DEGs）。共鉴定出969个与高FL相关的DEGs、1285个与高FS相关的DEGs和997个与高纤维品质（FQ）相关的DEGs。对它们的功能富集分析表明，细胞壁结构以及活性氧、碳水化合物和苯丙烷代谢的基因本体（GO）术语显著富集，而葡萄糖和多糖生物合成以及油菜素类固醇和糖基磷脂酰肌醇代谢的GO术语可能分别对FL和FS的形成有很大贡献。分别进行加权基因共表达网络分析（WGCNA）以分析FL和FS性状，并在显著相关的表达模块中筛选它们相应的枢纽DEGs，例如在纤维伸长过程中的 、 和 以及次生壁加厚过程中的WRKY、TDT和RAC样2。将这些枢纽DEGs与先前的QTL鉴定结果进行综合分析，成功鉴定出总共33个在 和 物种之间具有非同义突变的候选渐渗DEGs。据报道，一个编码类受体蛋白激酶1的共同DEG可能通过油菜素类固醇信号传导参与纤维次生细胞壁加厚调控。这些有价值的信息有助于阐明棉纤维的发育机制，也为进一步的分子育种提供了丰富的基因库。
