Table_5_Genome-wide characterization of trichome birefringence-like genes provides insights into fiber yield improvement.xlsx

Cotton is an important fiber crop. The cotton fiber is an extremely long trichome that develops from the epidermis of an ovule. The trichome is a general and multi-function plant organ, and trichome birefringence-like (TBL) genes are related to trichome development. At the genome-wide scale, we identified TBLs in four cotton species, comprising two cultivated tetraploids (Gossypium hirsutum and G. barbadense) and two ancestral diploids (G. arboreum and G. raimondii). Phylogenetic analysis showed that the TBL genes clustered into six groups. We focused on GH_D02G1759 in group IV because it was located in a lint percentage-related quantitative trait locus. In addition, we used transcriptome profiling to characterize the role of TBLs in group IV in fiber development. The overexpression of GH_D02G1759 in Arabidopsis thaliana resulted in more trichomes on the stems, thereby confirming its function in fiber development. Moreover, the potential interaction network was constructed based on the co-expression network, and it was found that GH_D02G1759 may interact with several genes to regulate fiber development. These findings expand our knowledge of TBL family members and provide new insights for cotton molecular breeding.

棉花是重要的纤维作物。棉花纤维是一类由胚珠表皮发育而来的超长毛状体（trichome）。毛状体是一类广泛存在且具有多种功能的植物器官，而毛状体双折射样（trichome birefringence-like, TBL）基因与毛状体发育密切相关。本研究在全基因组范围内，对4个棉属物种中的TBL基因家族成员进行了鉴定，这4个物种包含2个栽培异源四倍体棉种（陆地棉Gossypium hirsutum与海岛棉G. barbadense）以及2个祖先二倍体棉种（亚洲棉G. arboreum和雷蒙德氏棉G. raimondii）。系统发育分析显示，TBL基因可聚类为6个进化组。我们重点关注第IV组中的GH_D02G1759基因，因其坐落于与衣分相关的数量性状位点（quantitative trait locus）内。此外，我们通过转录组分析，解析了第IV组TBL基因在纤维发育中的功能。将GH_D02G1759基因在拟南芥（Arabidopsis thaliana）中过表达后，转基因植株茎秆上的表皮毛数量显著增多，由此验证了该基因在纤维发育中的功能。进一步基于共表达网络构建了潜在的基因互作网络，发现GH_D02G1759可能通过与多个基因互作来调控纤维发育。上述研究结果拓展了学界对TBL基因家族的认知，同时为棉花分子育种提供了全新的研究思路。