草铵膦胁迫下油菜苗期叶片药害相关性状的全基因组关联分析

Genome-wide Association Analysis of Some Phytotoxicity Related Traits at Seedling Stage in Rapeseed under Glufosinate Stress

随着油菜大面积种植和田间草害的日益严重,草铵膦近年来被尝试性地用于田间除草,但草铵膦在杀除杂草的同时或轻或重会对油菜产生药害,影响其正常生理活动,甚至影响其产量。本研究通过比较,选取最能体现油菜苗期耐药性差异的200 mg L–1作为胁迫浓度。以506份具有代表性的甘蓝型油菜品种(系)为材料,利用芸薹属60k Illumina Infinium SNP芯片分析其基因型,对油菜种质苗期的单位叶面积干重耐除草剂系数(CLW)、叶绿素含量耐除草剂系数(CCC)和综合药害指数(CPC)进行全基因组关联分析,从基因组水平分析油菜在草铵膦胁迫下的生理和形态反应。关联分析中,扫描到与单位叶面积干重耐除草剂系数显著相关的SNP位点6个,表型贡献率在6.53%～10.04%之间;与叶绿素含量耐除草剂系数相关的SNP位点共22个,表型贡献率在4.97%～6.20%之间;与综合药害指数相关的SNP位点98个,覆盖了A、C基因组,贡献率在3.25%～18.66%之间。通过对显著SNP位点对应的LD区间基因序列的分析,共获得18个与草铵膦的灭生机制相关的候选基因。在叶绿素含量耐除草剂系数关联位点的LD区域发现11个候选基因,其中9个参与酰基转移酶活性的调控,2个与乙酰CoA转移酶活性有关。在与综合药害指数关联位点的LD区域发现7个候选基因,其中1个与谷氨酰胺转移酶活性有关,参与谷氨酰胺代谢,其余6个和乙酰CoA转移酶活性有关。这些基因调控的生理生化过程均与叶片干重、叶绿素含量的变化及草铵膦的灭生机制有关。这些关联位点和候选基因的挖掘,将为油菜在草铵膦逆境胁迫下的生理生态反应的基因调控机制研究提供参考。

With planting rape in large area and weeds growing seriously in the field,glufosinate has been used in controlling field weeds tentatively.However glufosinate also produced phytotoxicity to the main cultivated rapeseed more or less,affecting the normal physiological and morphological activities,even yield.In this study,glufosinate of 200 mg L–1 was used at stress concentration 506 representative Brassica napus varieties(lines)were genotyped using the Brassica 60k Illumina Infinium SNP array by genome-wide association studies of herbicide resistance coefficient of dry weight per unit leaf area(CLW),herbicide resistance coefficient of chlorophyll content(CCC)and comprehensive phytotoxicity coefficient(CPC).A total of 16 SNP sites related to the killing mechanism of glufosinate were detected.Six SNP sites associated with CLW were detected,with phenotypic contribution rate ranging from 6.53%to 10.04%,and 22 SNP sites associated with CCC,with the phenotypic from 4.97%to 6.20%,98 SNP sites associated with CPC over A subgenome and C subgenome,with the rate range from 3.25%to 18.66%.After analysising the genes in the linkage disequilibrium(LD)interval of significant SNP,we found 18 glufosinate tolerance related candidate genes.Eleven candidate genes were found in the LD interval of SNPs related to CCC,among them nine were involved in acyltransferase activity,two were involved in acetyl-CoA transferase activity,seven candidate genes were found in the LD interval of SNPs related to CPC,one of them was associated with glutamine transferase activity,participating in glutamine metabolism,and other six genes were involved in acetyl CoA transferase activity.The physiological and biochemical process regulated by these genes related to the changes of leaf dry weight,chlorophyll content and the killing mechanism of glufosinate.Mining association sites and candidate genes provides a reference for the research of gene regulation mechanism in the physiological and morphological process under glufosinate stress.