甘蓝型油菜湿害胁迫响应性状的全基因组关联分析及候选基因预测

Genome-wide association analysis and candidate genes prediction of waterlogging-responding traits in Brassica napus L.

湿害严重影响油菜的产量和品质,前人在耐湿机制和生理响应等方面已经做了许多研究,但涉及油菜耐湿相关基因的研究相对较少。本研究以248份甘蓝型油菜品种(系)为材料,进行湿害胁迫处理,调查了8个湿害响应的相关性状,基于60K Illumina Infinium SNP芯片基因型数据对各性状耐湿系数进行了全基因组关联分析和湿害响应候选基因预测。结果显示,湿害胁迫较正常灌溉油菜幼苗绿叶数减少,地上部干重和鲜重以及叶片可溶性蛋白含量降低,叶片POD酶活性和MDA含量略有升高。地下部干重和鲜重在多数材料中降低,而在有些材料中升高,变化幅度均较小。经全基因组关联分析共检测到与耐湿系数显著关联的SNP标记36个,可解释表型变异8.28%~12.95%,其中17个所关联的耐湿系数在基因型间具有显著(P<0.05)或极显著(P<0.01)差异,其所在的Blocks共覆盖了71个候选基因,包括Blast到同源拟南芥基因64个,主要编码转录因子(如Transcription initiation factor IIF、bZIP68、myb-like HTH transcriptional regulator family protein)、转运蛋白(如SUC2)、生长抑制子(如ING2)、蛋白磷酸酶(如Protein phosphatase 2C family protein)、DNA/RNA结合蛋白[如bHLH DNA-binding superfamily protein、RNA-binding(RRM/RBD/RNP motifs)family protein]、激素响应蛋白(如ARF8、ADC2、ERD6、NF-YC9)以及氧化胁迫、渗透胁迫、盐胁迫或水分剥夺响应蛋白(如ERD6、NP1、TIR-NBS-LRR、CRT1b)等。本研究可为揭示甘蓝型油菜耐湿机理和培育耐湿新品种奠定基础。

The yield and quality of rapeseed are significantly affected by waterlogging.Many researches on waterlogging of rapeseed mostly aimed at its mechanism and physiological response,but a few of them identified the genes related to waterlogging.In this study,248 Brassica napus L.accessions were planted in flowerpots with treatments of waterlogging and well watering for four weeks when the plants had four true leaves in rain-proof installation,and eight waterlogging-responding traits were investigated.The genome-wide association analysis was carried out based on 60K Illumina Infinium SNP genotype data and the candidate genes associated with waterlogging responses were predicted.Under waterlogging,the number of green leaf,the shoot fresh weight and dry weight,the leaf soluble protein content were lower,and the leaf POD activity,the MDA content were higher than those under well watering.The root fresh weight and dry weight were lower in most accessions and higher in some accessions under waterlogging stress.A total of 36 SNPs were identified associated with waterlogging traits and explained the phenotypic variation of 8.28%–12.95%.There were significant(P<0.05)or extremely significant(P<0.01)differences in the waterlogging resistance index among genotypes of 17 SNPs.The Blocks containing 17 SNPs covered 71 candidate genes.Among them,64 candidate genes were homologous to Arabidopsis genes by blast.They encoded transcription factors(e.g.transcription initiation factor IIF,bZIP68,myb-like HTH transcriptional regulator family protein),transport protein(e.g.SUC2),inhibitor of growth(e.g.ING2),protein phosphatase(e.g.protein phosphatase 2C family protein),DNA/RNA binding proteins[e.g.bHLH DNA-binding superfamily protein,RNA-binding(RRM/RBD/RNP motifs)family protein],hormone response proteins(e.g.ARF8,ADC2,ERD6,NF-YC9),oxidative/osmotic/cold stress or water deprivation response proteins(e.g.ERD6,NP1,TIR-NBS-LRR,CRT1b).These results would be benefit for revealing the waterlogging resistance mechanism and cultivating new varieties with waterlogging resistance in Brassica napus L.