State Key Laboratory of Cotton Biology, Institute of Cotton Research of the Chinese Academy of Agricultural Sciences, Anyang, 455000, China.
Hainan Yazhou Bay Seed Laboratory, Sanya, Hainan, 572000, China.
BMC Genomics. 2023 Sep 7;24(1):531. doi: 10.1186/s12864-023-09640-7.
Due to the influence of extreme weather, the environment in China's main cotton-producing areas is prone to drought stress conditions, which affect the growth and development of cotton and lead to a decrease in cotton yield.
In this study, 188 upland cotton germplasm resources were phenotyped for data of 8 traits (including 3 major yield traits) under drought conditions in three environments for two consecutive years. Correlation analysis revealed significant positive correlations between the three yield traits. Genetic analysis showed that the estimated heritability of the seed cotton index (SC) under drought conditions was the highest (80.81%), followed by that of boll weight (BW) (80.64%) and the lint cotton index (LC) (70.49%) With genome-wide association study (GWAS) analysis, a total of 75 quantitative trait loci (QTLs) were identified, including two highly credible new QTL hotspots. Three candidate genes (Gh_D09G064400, Gh_D10G261000 and Gh_D10G254000) located in the two new QTL hotspots, QTL51 and QTL55, were highly expressed in the early stage of fiber development and showed significant correlations with SC, LC and BW. The expression of three candidate genes in two extreme materials after drought stress was analyzed by qRT-PCR, and the expression of these two materials in fibers at 15, 20 and 25 DPA. The expression of these three candidate genes was significantly upregulated after drought stress and was significantly higher in drought-tolerant materials than in drought-sensitive materials. In addition, the expression levels of the three candidate genes were higher in the early stage of fiber development (15 DPA), and the expression levels in drought-tolerant germplasm were higher than those in drought-sensitive germplasm. These three candidate genes may play an important role in determining cotton yield under drought conditions.
This study is helpful for understanding the regulatory genes affecting cotton yield under drought conditions and provides germplasm and candidate gene resources for breeding high-yield cotton varieties under these conditions.
由于极端天气的影响，中国主要棉花产区的环境容易出现干旱胁迫条件，影响棉花的生长发育，导致棉花产量下降。
本研究在三年两季三个环境下对 188 份陆地棉种质资源进行了数据为 8 个性状（包括 3 个主要产量性状）的表型鉴定。相关分析表明，三个产量性状之间存在显著的正相关。遗传分析表明，干旱条件下籽棉指数（SC）的估计遗传力最高（80.81%），其次是铃重（BW）（80.64%）和衣分（LC）（70.49%）。通过全基因组关联研究（GWAS）分析，共鉴定到 75 个数量性状位点（QTLs），包括两个高度可信的新 QTL 热点。位于两个新 QTL 热点 QTL51 和 QTL55 中的三个候选基因（Gh_D09G064400、Gh_D10G261000 和 Gh_D10G254000）在纤维发育早期高表达，与 SC、LC 和 BW 呈显著相关。通过 qRT-PCR 分析干旱胁迫后两个极端材料中三个候选基因的表达情况，以及两个材料在 15、20 和 25 DPA 时纤维中的表达情况。这三个候选基因在干旱胁迫后表达明显上调，且在耐旱材料中表达明显高于敏感材料。此外，三个候选基因在纤维发育早期（15 DPA）的表达水平较高，耐旱种质的表达水平高于敏感种质。这三个候选基因可能在决定棉花在干旱条件下的产量方面发挥重要作用。
本研究有助于了解影响棉花在干旱条件下产量的调控基因，为培育这些条件下的高产棉花品种提供了种质和候选基因资源。
