Kurya Benjamin, Mia Md Sultan, Liu Hui, Yan Guijun
UWA School of Agriculture and Environment, The University of Western Australia, Perth, WA, Australia.
The UWA Institute of Agriculture, The University of Western Australia, Perth, WA, Australia.
Front Plant Sci. 2022 May 19;13:842191. doi: 10.3389/fpls.2022.842191. eCollection 2022.
Understanding the genetics of metribuzin (a group C herbicide) tolerance in wheat is vital in developing tolerant cultivars to improve wheat productivity in dryland farming systems. This study investigated metribuzin tolerance in wheat by conducting a Genome-wide Association Studies (GWAS) with a panel of 150 wheat genotypes of diverse genetic backgrounds and genotyped them with the wheat 90 K SNP genotyping assay. The phenotyping was conducted in a temperature-controlled glasshouse at the University of Western Australia (UWA). Genotypes were sprayed with a metribuzin dose of 400 grams of active ingredient (g. a.i.) ha as pre-emergent in a specialized spraying cabinet and transferred to the glasshouse where the tolerance level of the genotypes was assessed by measuring the relative reduction in chlorophyll content of the leaves. The decrease in chlorophyll content of the treated plants compared to the control was regarded as the phytotoxic effects of metribuzin. GWAS analysis following a mixed linear model revealed 19 genomic regions with significant marker-trait associations (MTAs), including ten on chromosome 6A, three on chromosome 2B, and one on chromosomes 3A, 5B, 6B 6D, 7A, and 7B, respectively. Sequences of the significant markers were blasted against the wheat genome, IWGSC RefSeq V1.0, and candidate genes having annotations related to herbicide tolerance in wheat, especially in pathways reported to be involved in metribuzin tolerance, such as cytochrome P450 pathways and ATP Binding Cassette (ABC) superfamilies, were identified in these genomic regions. These included These genomic regions were validated on 30 top tolerant and 30 most susceptible genotypes using the five closest SSR makers to the flanked SNPs. Sufficient polymorphism was detected on two markers ( and ) that were found to differentiate between the susceptible and tolerant alleles and a t-test analysis of the phenotypic data shows a significant (value of < 0.001) difference suggesting that these markers can be used for marker-assisted selection (MAS) in metribuzin studies and wheat breeding programs.
了解小麦对嗪草酮（一种C组除草剂）的耐受性遗传机制对于培育耐受性品种以提高旱地农业系统中的小麦产量至关重要。本研究通过对一组具有不同遗传背景的150个小麦基因型进行全基因组关联研究（GWAS）来调查小麦对嗪草酮的耐受性，并使用小麦90K SNP基因分型检测对它们进行基因分型。表型分析在西澳大利亚大学（UWA）的一个温度控制温室中进行。在一个专门的喷雾柜中，对基因型喷施400克活性成分（g.a.i.）/公顷的嗪草酮剂量作为芽前处理，然后转移到温室中，通过测量叶片叶绿素含量的相对降低来评估基因型的耐受水平。与对照相比，处理植物叶绿素含量的降低被视为嗪草酮的植物毒性效应。采用混合线性模型进行的GWAS分析揭示了19个具有显著标记-性状关联（MTA）的基因组区域，分别包括6A染色体上的10个、2B染色体上的3个以及3A、5B、6B、6D、7A和7B染色体上各1个。将显著标记的序列与小麦基因组IWGSC RefSeq V1.0进行比对，在这些基因组区域中鉴定出了具有与小麦除草剂耐受性相关注释的候选基因，特别是在据报道参与嗪草酮耐受性的途径中，如细胞色素P450途径和ATP结合盒（ABC）超家族。使用与侧翼SNP最近的五个SSR标记，在30个耐受性最强和30个最敏感的基因型上对这些基因组区域进行了验证。在两个标记（和）上检测到足够的多态性，发现它们能够区分敏感等位基因和耐受等位基因，对表型数据的t检验分析显示存在显著差异（值<0.001），这表明这些标记可用于嗪草酮研究和小麦育种计划中的标记辅助选择（MAS）。
