ICARDA引进小麦种质苗期的抗旱性鉴定及SNP关联分析

Drought resistance identification and SNP association analysis of wheat germ-plasm introduced by ICARDA at seedling stage

以引进国际干旱地区农业研究中心(ICARDA)的159份小麦为研究对象,在苗期用20%PEG-6000模拟干旱条件进行处理,以正常营养液作为对照,分析干旱环境对7个苗期相关生理性状(丙二醛含量、超氧化物歧化酶活性、相对电导率、过氧化物酶活性、可溶性糖含量、脯氨酸含量和叶绿素含量)的影响,进行相关性分析,并结合55K SNP芯片对159份小麦的苗期抗旱相关生理性状进行关联分析。研究结果表明,干旱处理后,其体内脯氨酸含量和可溶性糖含量均呈现上升趋势,其余性状则并未表现出一致的上升或下降。相关性分析表明,在正常处理条件下,丙二醛含量与过氧化物酶活性呈显著正相关,和脯氨酸含量呈极显著负相关;过氧化物酶活性和可溶性糖含量呈极显著负相关。在干旱胁迫处理条件下,可溶性糖含量与丙二醛含量呈极显著正相关,与相对电导率呈显著正相关;叶绿素含量与可溶性糖含量呈极显著正相关,与脯氨酸含量呈显著负相关。关联分析结果显示,利用24,151个SNP标记位点结合苗期相关生理性状在P≤0.001水平下共定位到311个抗旱相关标记,分布于小麦的21条染色体上,贡献率为7.13%~21.11%。2种处理下检测到8个稳定位点,分别位于1B、2B和6A染色体上,贡献率为7.85%~14.58%。检测到1个多效应位点,同时关联了超氧化物歧化酶活性和可溶性糖含量2个性状,位于3D染色体上,贡献率为7.95%~8.69%。检测到4个显著位点与相对电导率、过氧化物酶活性、叶绿素含量的抗旱系数和干旱处理下的相对电导率、过氧化物酶活性、脯氨酸含量和超氧化物歧化酶活性等性状相关联,分别位于2D、3A和4A染色体上,贡献率为7.61%~14.74%。

A total of 159 wheat samples imported from the International Center for Agricultural Research in the Arid Areas(ICARDA)were used as the research subjects.To simulate drought conditions during the seedling stage,20%PEG-6000 was applied,while a normal nutrient solution served as the control.The effects of drought on seven physiological traits related to the seedling stage(malondialdehyde content,superoxide dismutase activity,relative conductivity,peroxidase activity,soluble sugar content,proline content,and chlorophyll content)were analyzed.Correlation analysis of drought resistance-related physiological traits in the 159 wheat samples was conducted using a 55K SNP chip.The results indicated that,following drought treatment,the levels of proline and soluble sugars increased,whereas other traits did not show consistent trends.Under normal conditions,malondialdehyde content was significantly positively correlated with peroxidase activity and highly significantly negatively correlated with proline content;peroxidase activity was highly significantly negatively correlated with soluble sugar content.Under drought stress,soluble sugar content was significantly positively correlated with malondialdehyde content and relative conducti-vity,while chlorophyll content was highly significantly positively correlated with soluble sugar content and significantly nega-tively correlated with proline content.Association analysis identified 311 drought resistance-related markers(P≤0.001)across 24,151 SNP loci,distributed on all 21 wheat chromosomes,with contribution rates of 7.13%-21.11%.Eight stable loci were de-tected under both treatments,located on chromosomes 1B,2B,and 6A,with contribution rates of 7.85%-14.58%.Additionally,a multiple effector locus associated with both superoxide dismutase activity and soluble sugar content was found on chromosome 3D,with a contribution rate of 7.95%-8.69%.Four significant loci associated with the drought resistance coefficient of relative conductivity,peroxidase activity,chlorophyll content,and traits such as relative conductivity,peroxidase activity,proline content,and superoxide dismutase activity under drought treatment were detected on chromosomes 2D,3A,and 4A,with a contribution rate of 7.61%-14.74%.