Zhang Sujun, Liu Cunjing, Tang Liyuan, Li Xinghe, Cai Xiao, Wang Haitao, Zhang Jinfa, Zhang Jianhong
Institute of Cotton, Hebei Academy of Agricultural and Forestry Sciences/Key Laboratory of Biology and Genetic Improvement of Cotton in Huanghuaihai Semiarid Area, Ministry of Agriculture and Rural Affairs, Shijiazhuang, 050051, Hebei, China.
Department of Plant and Environmental Sciences, New Mexico State University, Las Cruces, NM, USA.
Theor Appl Genet. 2025 Jun 4;138(7):134. doi: 10.1007/s00122-025-04922-y.
GhPAP was identified as a candidate gene associated with cotton fiber development via genetic mapping and transcriptomic analysis. GhPAP increases fiber strength by modulating cell wall thickness and fiber helix formation. Cotton fiber strength (FS), length (FL), and fineness are economically important quality-related traits. Although many genes related to fiber quality were identified recently, the molecular mechanism controlling fiber quality remains largely unknown. In this study, an FS/FL-related stable QTL was mapped to a 2.92 Mb region containing 81 putative coding genes on chromosome D06 by combining SLAF-BSA-seq and InDel analyses of a bi-parental recombinant inbred line (RIL) population. Five genes in the QTL region were differentially expressed between two near-isogenic RILs, A (with long and strong fibers) and A (with short and weak fibers), during fiber development. GhPAP (Ghi_D06G06106) was subsequently identified as the most likely candidate gene according to its sequence variations and annotation information. The functional validation of GhPAP revealed an association between reduced FS and decreased GhPAP expression in plants due to virus-induced gene silencing (VIGS), leading to a significant decrease in GhPAP-VIGS fiber helix formation and thickness. GhPAP expression positively affected FS in four cotton lines with distinct breeding histories. Additionally, GhPAP overexpression in Arabidopsis thaliana resulted in slower elongation and thicker cell walls in roots and stems (compared with the control). Moreover, SNPs in the GhPAP promoter region were significantly correlated with FS and FL. Notably, a KASP marker was developed for selecting cotton genotypes according to FS and FL. This study identified a new and important gene and developed a KASP marker applicable for future molecular breeding of high-quality cotton.
通过遗传定位和转录组分析，GhPAP被鉴定为与棉花纤维发育相关的候选基因。GhPAP通过调节细胞壁厚度和纤维螺旋形成来提高纤维强度。棉花纤维强度（FS）、长度（FL）和细度是经济上重要的与品质相关的性状。尽管最近鉴定出了许多与纤维品质相关的基因，但控制纤维品质的分子机制仍 largely未知。在本研究中，通过对一个双亲重组自交系（RIL）群体进行SLAF-BSA测序和InDel分析，将一个与FS/FL相关的稳定QTL定位到D06染色体上一个2.92 Mb的区域，该区域包含81个推定的编码基因。在纤维发育过程中，QTL区域的5个基因在两个近等基因RIL，即A（纤维长且强）和A（纤维短且弱）之间差异表达。随后，根据其序列变异和注释信息，GhPAP（Ghi_D06G06106）被确定为最有可能的候选基因。GhPAP的功能验证表明，由于病毒诱导的基因沉默（VIGS）导致植物中GhPAP表达降低与FS降低之间存在关联，从而导致GhPAP-VIGS纤维螺旋形成和厚度显著降低。GhPAP表达对四个具有不同育种历史的棉花品系的FS有积极影响。此外，拟南芥中GhPAP的过表达导致根和茎的伸长变慢且细胞壁变厚（与对照相比）。此外，GhPAP启动子区域的单核苷酸多态性与FS和FL显著相关。值得注意的是，开发了一种KASP标记，用于根据FS和FL选择棉花基因型。本研究鉴定了一个新的重要基因，并开发了一种适用于未来高品质棉花分子育种的KASP标记。
