Yang X, Wang Y, Zhang G, Wang X, Wu L, Ke H, Liu H, Ma Z
North China Key Laboratory for Crop Germplasm Resources of Education Ministry, Key Laboratory of Crop Germplasm Resources of Hebei, Hebei Agricultural University, No. 2596 Lekai South St, 071001, Baoding, People's Republic of China.
Mol Genet Genomics. 2016 Aug;291(4):1625-38. doi: 10.1007/s00438-016-1206-z. Epub 2016 Apr 27.
Fiber strength is an essential trait of fiber property in cotton, and it is quantitatively inherited. Identification of stable quantitative trait loci (QTL) contributing to fiber strength would provide the key basis for marker-assisted selection (MAS) in cotton breeding. In this study, four interspecific hybridization populations were established with a common G. barbadense parent Pima 90-53 and two G. hirsutum parents (CCRI 8 and Handan 208), each of which had fiber strength characteristic. Based on the phenotypic data of fiber strength from seven environments, a stable QTL, qFS-c9-1, was detected and validated on c9 in a marker interval between SSR markers NAU2395 and NAU1092. The QTL explaining 14.4-17.9 % of the phenotypic variation was firstly detected in two populations (CCRI 8 × Pima 90-53, BC1F1 and BC1F2) and its derived lines in four environments. And it accounting for 12.1-14.8 % of the phenotypic variation was further confirmed in two populations (Handan 208 × Pima 90-53, BC1F1, and F2) under one environment. In silico mapping using three sequenced cotton genomes indicated that homologous genes, anchored by NAU2395 and NAU1092, were aligned to the G. arboreum genome within a physical distance between 81.10 Mbps and 87.07 Mbps. In that interval, several genes were confirmed in literatures to associate with fiber development. Among these genes, seven genes were further selected for an expression analysis through fiber development transcriptome database, revealing unique expression patterns across different stages of fiber development between CCRI 8 and Pima 90-53. The genes underlying qFS-c9-1 were favorable to fine mapping and cloning. The current study results provided valuable evidence for mapping stable QTL of fiber strength utilizing multiple populations and environments, as well as map-based cloning the candidate gene underlying the QTL for future prospective research directions.
纤维强度是棉花纤维品质的一个重要性状，且其受数量遗传。鉴定出有助于纤维强度的稳定数量性状位点（QTL）将为棉花育种中的分子标记辅助选择（MAS）提供关键依据。在本研究中，以一个常见的海岛棉亲本Pima 90 - 53和两个陆地棉亲本（中棉所8号和邯郸208）构建了四个种间杂交群体，每个亲本都具有纤维强度特性。基于七个环境下的纤维强度表型数据，在c9染色体上SSR标记NAU2395和NAU1092之间的标记区间检测并验证了一个稳定的QTL，qFS - c9 - 1。该QTL解释了14.4 - 17.9%的表型变异，首先在两个群体（中棉所8号×Pima 90 - 53，BC1F1和BC1F2）及其四个环境中的衍生系中被检测到。并且在一个环境下，它在另外两个群体（邯郸208×Pima 90 - 53，BC1F1和F2）中进一步得到确认，解释了12.1 - 14.8%的表型变异。利用三个已测序的棉花基因组进行电子定位表明，由NAU2395和NAU1092定位的同源基因在亚洲棉基因组中物理距离81.10 Mbps至87.07 Mbps之间比对。在该区间内，文献中证实有几个基因与纤维发育相关。在这些基因中，通过纤维发育转录组数据库进一步选择了七个基因进行表达分析，揭示了中棉所8号和Pima 90 - 53在纤维发育不同阶段独特的表达模式。qFS - c9 - 1位点的基因有利于精细定位和克隆。当前的研究结果为利用多个群体和环境定位纤维强度稳定QTL以及基于图谱克隆该QTL的候选基因提供了有价值的证据，为未来的前瞻性研究方向奠定了基础。
