Wei Lijuan, Jian Hongju, Lu Kun, Yin Nengwen, Wang Jia, Duan Xiujian, Li Wei, Liu Liezhao, Xu Xinfu, Wang Rui, Paterson Andrew H, Li Jiana
Chongqing Engineering Research Center for Rapeseed, College of Agronomy and Biotechnology, Southwest University, Chongqing, 400716, China.
Plant Genome Mapping Laboratory, University of Georgia, Athens, 30605, GA, USA.
Theor Appl Genet. 2017 Sep;130(9):1961-1973. doi: 10.1007/s00122-017-2937-x. Epub 2017 Jun 20.
Candidate genes associated with lignin and lodging traits were identified by combining phenotypic, genotypic, and gene expression data in B. napus. Brassica napus is one of the world's most important oilseed crops, but its yield can be dramatically reduced by lodging, bending, and falling of its vertical stems. Lignin has been shown to contribute to stem mechanical strength. In this study, we found that the syringyl/guaiacyl (S/G) monolignol ratio exhibits a significant negative correlation with disease and lodging resistance. A total of 92 and 50 SNP and SSR loci, respectively, were found to be significantly associated with five traits, breaking force, breaking strength, lodging coefficient, acid detergent lignin content, and the S/G monolignol ratio using GWAS. To identify novel genes involved in lignin biosynthesis, transcriptome sequencing of high- (H) and low (L)-ADL content accessions was performed. The up-regulated genes were mainly involved in glycoside catabolic processes (especially glucosinolate catabolism) and cell wall biogenesis, while down-regulated genes were involved in glucosinolate biosynthesis, indicating that crosstalk exists between glucosinolate metabolic processes and lignin biosynthesis. Integrating this differential expression with the GWAS analysis, we identified four candidate genes regulating lignin, including glycosyl hydrolase (BnaA01g00480D), CYT1 (BnaA04g22820D), and two encoding transcription factors, SHINE1 (ERF family) and DAR6 (LIM family). This study provides insight into the genetic control of lodging and lignin in B. napus.
通过整合甘蓝型油菜的表型、基因型和基因表达数据，鉴定了与木质素和倒伏性状相关的候选基因。甘蓝型油菜是世界上最重要的油料作物之一，但其产量会因直立茎的倒伏、弯曲和折断而显著降低。研究表明木质素有助于提高茎的机械强度。在本研究中，我们发现紫丁香基/愈创木基（S/G）单木酚比例与抗病性和抗倒伏性呈显著负相关。利用全基因组关联研究（GWAS）发现，分别有92个和50个单核苷酸多态性（SNP）和简单序列重复（SSR）位点与五个性状显著相关，这五个性状分别是折断力、抗折强度、倒伏系数、酸性洗涤木质素含量和S/G单木酚比例。为了鉴定参与木质素生物合成的新基因，对高（H）和低（L）酸性洗涤木质素含量的材料进行了转录组测序。上调基因主要参与糖苷分解代谢过程（尤其是硫代葡萄糖苷分解代谢）和细胞壁生物合成，而下调基因参与硫代葡萄糖苷生物合成，这表明硫代葡萄糖苷代谢过程与木质素生物合成之间存在相互作用。将这种差异表达与GWAS分析相结合，我们鉴定出四个调控木质素的候选基因，包括糖基水解酶（BnaA01g00480D）、CYT1（BnaA04g22820D）以及两个编码转录因子的基因，即SHINE1（ERF家族）和DAR6（LIM家族）。本研究为甘蓝型油菜倒伏和木质素的遗传控制提供了见解。
