Li Zhonghua, Wang Pengcheng, You Chunyuan, Yu Jiwen, Zhang Xiangnan, Yan Feilin, Ye Zhengxiu, Shen Chao, Li Baoqi, Guo Kai, Liu Nian, Thyssen Gregory N, Fang David D, Lindsey Keith, Zhang Xianlong, Wang Maojun, Tu Lili
National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, 430070, Hubei, China.
Cotton Research Institute, Shihezi Academy of Agriculture Science, Shihezi, 832000, Xinjiang, China.
New Phytol. 2020 Jun;226(6):1738-1752. doi: 10.1111/nph.16468. Epub 2020 Feb 29.
The cotton fibre serves as a valuable experimental system to study cell wall synthesis in plants, but our understanding of the genetic regulation of this process during fibre development remains limited. We performed a genome-wide association study (GWAS) and identified 28 genetic loci associated with fibre quality in allotetraploid cotton. To investigate the regulatory roles of these loci, we sequenced fibre transcriptomes of 251 cotton accessions and identified 15 330 expression quantitative trait loci (eQTL). Analysis of local eQTL and GWAS data prioritised 13 likely causal genes for differential fibre quality in a transcriptome-wide association study (TWAS). Characterisation of distal eQTL revealed unequal genetic regulation patterns between two subgenomes, highlighted by an eQTL hotspot (Hot216) that established a genome-wide genetic network regulating the expression of 962 genes. The primary regulatory role of Hot216, and specifically the gene encoding a KIP-related protein, was found to be the transcriptional regulation of genes responsible for cell wall synthesis, which contributes to fibre length by modulating the developmental transition from rapid cell elongation to secondary cell wall synthesis. This study uncovered the genetic regulation of fibre-cell development and revealed the molecular basis of the temporal modulation of secondary cell wall synthesis during plant cell elongation.
棉纤维是研究植物细胞壁合成的重要实验系统，但我们对纤维发育过程中该过程的遗传调控的了解仍然有限。我们进行了全基因组关联研究（GWAS），并在异源四倍体棉花中鉴定出28个与纤维品质相关的基因座。为了研究这些基因座的调控作用，我们对251份棉花材料的纤维转录组进行了测序，鉴定出15330个表达数量性状基因座（eQTL）。在全转录组关联研究（TWAS）中，通过对局部eQTL和GWAS数据的分析，确定了13个可能导致纤维品质差异的因果基因。对远端eQTL的表征揭示了两个亚基因组之间不同的遗传调控模式，一个eQTL热点（Hot216）突出了这种差异，该热点建立了一个全基因组遗传网络，调控962个基因的表达。发现Hot216的主要调控作用，特别是编码KIP相关蛋白的基因，是对负责细胞壁合成的基因进行转录调控，通过调节从快速细胞伸长到次生细胞壁合成的发育转变来影响纤维长度。这项研究揭示了纤维细胞发育的遗传调控，并揭示了植物细胞伸长过程中次生细胞壁合成时间调控的分子基础。
