Feng Liuchun, Chen Yu, Xu Min, Yang Ying, Yue Haoran, Su Qiao, Zhou Chenhui, Feng Guoli, Ai Nijiang, Wang Ningshan, Zhou Baoliang
State Key Laboratory of Crop Genetics & Germplasm Enhancement, Jiangsu Collaborative Innovation Center for Modern Crop Production, Nanjing Agricultural University, Nanjing, China.
Shihezi Agricultural Science Research Institute, Shihezi, China.
Front Plant Sci. 2021 Aug 2;12:719371. doi: 10.3389/fpls.2021.719371. eCollection 2021.
(2=2=26, A), the putative progenitor of the A-subgenome of (2=4=52, AD), is a repository of genes of interesting that have been eliminated during evolution/domestication of . However, its valuable genes remain untapped so far due to species isolation. Here, using a synthetic amphiploid (AADDAA) previously reported, we developed a set of 289 chromosome segment introgression lines (ILs) in by expanding the backcrossing population and through precise marker-assisted selection (MAS) although complex chromosomal structural variations existed between parents which severely hindered introgression. Our results showed the total coverage length of introgressed segments was 1,116.29 Mb, representing 78.48% of the A-subgenome in the background, with an average segment-length of 8.69 Mb. A total of 81 co- quantitative trait loci (QTLs) for yield and fiber quality were identified by both the RSTEP-ADD-based QTL mapping and the genome-wide association study (GWAS) analysis, with 1.01-24.78% of the phenotypic variance explained. Most QTLs for boll traits showed negative additive effects, but still has the potential to improve boll-number traits in . Most QTLs for fiber quality showed negative additive effects, implying these QTLs were domesticated in compared with and, a small quantity of fiber quality QTLs showing positive additive effects, conversely; however, indicates that has the underlying genes of enhancing fiber quality of . This study provides new insights into the breeding genetic potential of , lays the foundation for further mining favorable genes of interest, and provides guidance for inter-ploidy gene transference from relatives into cultivated crops.
（2n = 2x = 26，A）是（2n = 4x = 52，AD）A 亚基因组的假定祖先，是在进化/驯化过程中被淘汰的有趣基因的储存库。然而，由于物种隔离，其有价值的基因至今尚未被开发利用。在此，我们利用先前报道的一个合成双二倍体（AADDAA），通过扩大回交群体并借助精确的分子标记辅助选择（MAS），尽管亲本之间存在复杂的染色体结构变异严重阻碍了基因渗入，但仍在陆地棉中培育出了一套 289 个染色体片段渗入系（ILs）。我们的结果表明，渗入片段的总覆盖长度为 1116.29 Mb，占陆地棉背景下 A 亚基因组的 78.48%，平均片段长度为 8.69 Mb。通过基于 RSTEP - ADD 的 QTL 定位和全基因组关联研究（GWAS）分析，共鉴定出 81 个与产量和纤维品质相关的数量性状位点（QTL），可解释 1.01% - 24.78%的表型变异。大多数棉铃性状的 QTL 表现出负向加性效应，但陆地棉仍有提高棉铃数性状的潜力。大多数纤维品质 QTL 表现出负向加性效应，这意味着与海岛棉相比，这些 QTL 在陆地棉中已被驯化，相反，少量纤维品质 QTL 表现出正向加性效应；然而，这表明海岛棉具有提高陆地棉纤维品质的潜在基因。本研究为海岛棉的育种遗传潜力提供了新的见解，为进一步挖掘有利基因奠定了基础，并为从亲缘种向栽培作物进行倍性间基因转移提供了指导。
