Liu Xueying, Hou Juan, Chen Li, Li Qingqing, Fang Xiaomei, Wang Jinxia, Hao Yongshui, Yang Peng, Wang Wenwen, Zhang Dishen, Liu Dexin, Guo Kai, Teng Zhonghua, Liu Dajun, Zhang Zhengsheng
Engineering Research Center of South Upland Agriculture, Ministry of Education, Southwest University, Chongqing, 400716, China.
Theor Appl Genet. 2022 Oct;135(10):3661-3672. doi: 10.1007/s00122-022-04209-6. Epub 2022 Sep 9.
qSI07.1, a major QTL for seed index in cotton, was fine-mapped to a 17.45-kb region, and the candidate gene GhSI7 was verified in transgenic plants. Improving production to meet human needs is a vital objective in cotton breeding. The yield-related trait seed index is a complex quantitative trait, but few candidate genes for seed index have been characterized. Here, a major QTL for seed index qSI07.1 was fine-mapped to a 17.45-kb region by linkage analysis and substitutional mapping. Only GhSI7, encoding the transcriptional regulator STERILE APETALA, was contained in the candidate region. Association test and genetic analysis indicated that an 845-bp-deletion in its intron was responsible for the seed index variation. Origin analysis revealed that this variation was unique in Gossypium hirsutum and originated from race accessions. Overexpression of GhSI7 (haplotype 2) significantly increased the seed index and organ size in cotton plants. Our findings provided a diagnostic marker for breeding and selecting cotton varieties with high seed index, and laid a foundation for further studies to understand the molecular mechanism of cotton seed morphogenesis.
qSI07.1是棉花籽指的一个主要数量性状基因座，被精细定位到一个17.45千碱基的区域，并在转基因植株中验证了候选基因GhSI7。提高产量以满足人类需求是棉花育种的一个重要目标。与产量相关的性状籽指是一个复杂的数量性状，但很少有籽指的候选基因被鉴定出来。在此，通过连锁分析和代换作图将籽指的一个主要数量性状基因座qSI07.1精细定位到一个17.45千碱基的区域。候选区域仅包含编码转录调节因子不育花被的GhSI7。关联测试和遗传分析表明，其内含子中的一个845碱基对的缺失导致了籽指的变异。起源分析表明，这种变异在陆地棉中是独特的，起源于种族种质。GhSI7（单倍型2）的过表达显著增加了棉花植株的籽指和器官大小。我们的研究结果为选育高籽指棉花品种提供了一个诊断标记，并为进一步研究棉花种子形态发生的分子机制奠定了基础。
