Functional annotation of 433 genes.

Cotton fiber initiation is a critical determinant of yield and quality. To decipher the genetic networks underlying this process, we conducted a time-series transcriptome analysis of a wild-type cotton (142-WT) and its fuzzless-lintless mutant (142-fl) at 0, 1, and 2 days post-anthesis (DPA). Phenotypic characterization confirmed the absence of fiber protrusion in the mutant. Through integrated analysis of differentially expressed genes (DEGs) and weighted gene co-expression network analysis (WGCNA), we identified a key module highly correlated with fiber development. This module is overwhelmingly enriched for lipid metabolism pathways, notably fatty acid elongation. Furthermore, we identified 83 high-connectivity hub genes within this network, including key enzymes like 3-ketoacyl-CoA synthases (KCS) and regulatory transcription factors. Our findings propose a novel model in which the coordinated activation of fatty acid metabolism, particularly the biosynthesis of very-long-chain fatty acids, is essential for the initiation and early development of cotton fibers. This study provides crucial insights and valuable genetic resources for the molecular breeding of cotton with improved fiber traits.棉纤维起始是决定棉花产量与品质的关键环节。为解析该过程背后的遗传调控网络，我们对野生型棉花（142-WT）及其无绒无絮突变体（142-fl）在开花后天数（days post-anthesis, DPA）0、1、2天的样本开展了时序转录组分析。表型鉴定结果证实，该突变体无纤维突起产生。通过整合分析差异表达基因（differentially expressed genes, DEGs）与加权基因共表达网络分析（weighted gene co-expression network analysis, WGCNA），我们筛选得到一个与纤维发育高度相关的关键模块。该模块极显著富集于脂质代谢通路，尤以脂肪酸延伸过程为著。此外，我们在该网络中鉴定出83个高连接度的枢纽基因，包括3-酮脂酰-CoA合酶（3-ketoacyl-CoA synthases, KCS）这类关键酶以及调控转录因子。本研究提出了一个全新的调控模型：脂肪酸代谢的协同激活，尤其是超长链脂肪酸的生物合成，对于棉纤维的起始与早期发育至关重要。本研究为纤维性状改良的棉花分子育种提供了重要的理论参考与宝贵的遗传资源。