摘要：

向日葵是我国重要的油料作物,具有较强的耐盐性,但主产区盐渍化加重制约了向日葵的生产。为揭示向日葵苗期耐盐相关性状的耐盐机制,挖掘与向日葵苗期耐盐性显著相关的SNP位点及候选基因,以124份向日葵种质资源为材料,在250 mmol/L NaCl胁迫条件下,对株高、叶面积、地上部分鲜质量、地下部分鲜质量、SPAD值5个性状进行全基因组关联分析及耐盐位点/基因的挖掘。结果表明:在盐胁迫14 d时,苗期相对株高、相对叶面积、相对地上部分鲜质量、相对地下部分鲜质量和相对SPAD值5个性状指标均发生了显著变异,呈正态分布,影响最明显的为相对地下部分鲜质量和相对叶面积(变异系数46.57%以上);利用全基因组关联分析获得18个显著关联的SNP位点,其中Chr35448-18789497在多个耐盐相关性状中均被检测到;在上下游各80 kb进行基因搜索,筛选到45个相关候选基因;通过对关联位点区间进行扫描和基因注释分析,发掘出4个可能与向日葵苗期耐盐性状相关的候选基因。通过对向日葵进行苗期耐盐性状的全基因组关联分析,获得了与苗期耐盐性状显著关联的SNP位点,发掘出耐盐性相关的候选基因,为后续开展耐盐基因的验证奠定了基础。

关键词: 向日葵, 种质资源, 苗期耐盐性, 全基因组关联分析, 基因

Abstract:

Sunflower is an important oil crop with strong salt tolerance in China.However,the production of sunflower is severely restricted by the intensification of salinization in main producing areas.To understand the salt tolerance mechanism of salt tolerance-related traits at the seedling stage of sunflower,and to identify SNP loci and candidate genes significantly associated with salt tolerance at the seedling stage of sunflower,124 sunflower germplasm accessions were used as materials.Under the stress of 250 mmol/L NaCl,genome-wide association analysis and mining of salt-tolerance loci/genes were performed based on 5 traits including plant height,leaf area,aboveground fresh weight,underground fresh weight,and SPAD value.The results showed that after 14 days of salt stress,the five trait indexes of relative plant height,relative leaf area,relative fresh weight of the above-ground part,relative fresh weight of the underground part and relative SPAD value at seedling stage had significant variations and normal distributions,and the most obvious influences were the relative fresh weight of the underground part and relative leaf area (with a coefficient of variation of over 46.57%).Eighteen significantly-associated SNP loci were obtained by genome-wide association analysis,among which Chr35448-18789497 was detected in several salt-tolerant traits;gene searches were conducted at 80 kb each in the upstream and downstream of associated loci,45 related candidate genes were screened out.Through scanning and gene annotation analysis of the associated locus intervals,four candidate genes that might be related to the salt tolerance trait of sunflower seedlings were discovered.A genome-wide association analysis was conducted using the phenotypes of salt tolerance identification at the seedling stage and genomic SNP data for sunflower germplasm accessions.SNP loci significantly associated with salt tolerance at the seedling stage were detected,and candidate genes related to salt tolerance at the seedling stage of sunflower were selected,which laid the foundation for the subsequent verification of salt-tolerant genes.

Key words: Sunflower, Germplasm resource, Salt tolerance at seedling stage, Genome-wide association study(GWAS), Gene

中图分类号: 

• S565.5

• Q943.2植物基因工程