Genome-wide association analysis of seed germination percentage and germination index in Brassica napus L. under salt and drought stresses

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• 作者：Min Tan ; Fang Liao ; Lintao Hou ; Jia Wang ; Lijuan Wei ; Hongju Jian ; Xinfu Xu…
• 关键词：Brassica napus L. ; GWAS ; Germination percentage ; Germination index ; Salt stress ; Drought stress
• 刊名：Euphytica
• 出版年：2017
• 出版时间：February 2017
• 年：2017
• 卷：213
• 期：2
• 全文大小：
• 刊物类别：Biomedical and Life Sciences
• 刊物主题：Plant Sciences; Plant Genetics & Genomics; Plant Pathology; Plant Physiology; Biotechnology;
• 出版者：Springer Netherlands
• ISSN：1573-5060
• 卷排序：213

文摘

Identifying genetic loci and possible candidate genes related to salt and drought stresses would be an economical, feasible and efficient way to accelerate the progress of abiotic tolerance breeding in rapeseed. In this study, a seed germination experiment using distilled water, salt and drought stresses was carried out with 520 B. napus germplasm resources. The rapeseed accessions showed large variation in the seed germination percentage (GP) and germination index (GI), with GP ranging from 26 to 100%, 0 to 100% and 0 to 100% and GI from 3.05 to 53.92, 0 to 24.50 and 0 to 25.00 in distilled water, under salt stress and drought stress, respectively. The coefficients of GP and GI were 0.72, 0.97 and 0.96 in distilled water, under salt stress and drought stress, respectively. A genome-wide association analysis of the 520 accessions was performed using the Q+K model and 31,839 single-nucleotide polymorphism (SNP) sites, revealing 23 SNPs associated with GP and 20 SNPs associated with GI under salt and drought stresses. The significant loci rs32406 and rs9466 on chromosome C08 and A04 were mapped to sites 3.32 and 2.20 kb from the salt- and drought-responsive gene BnaC08g41070 and drought-responsive gene BnaA04g02620D, respectively. BnaC06g01910D, a drought-responsive gene on chromosome C06, was found to overlap with the significant locus rs44427. In addition, 37 candidate genes associated with GP and GI under salt and drought stresses were detected. Most of these candidate genes regulate signal transduction and proline biosynthesis or encode a ubiquitin ligase E3; some have unknown biological functions and may respond to salt and drought stresses together as a complex network.