Raman Rosy, Warren Annie, Krysinska-Kaczmarek Marzena, Rohan Maheswaran, Sharma Niharika, Dron Nicole, Davidson Jenny, Moore Kevin, Hobson Kristy
NSW Department of Primary Industries, Wagga Wagga Agricultural Institute, Wagga Wagga, NSW, Australia.
NSW Department of Primary Industries, Tamworth Agricultural Institute, Tamworth, NSW, Australia.
Front Plant Sci. 2022 May 18;13:877266. doi: 10.3389/fpls.2022.877266. eCollection 2022.
Ascochyta blight (AB), caused by a necrotrophic fungus, (syn. ) has the potential to destroy the chickpea industry worldwide, due to limited sources of genetic resistance in the cultivated gene pool, high evolutionary potential of the pathogen and challenges with integrated disease management. Therefore, the deployment of stable genetic resistance in new cultivars could provide an effective disease control strategy. To investigate the genetic basis of AB resistance, genotyping-by-sequencing based DArTseq-single nucleotide polymorphism (SNP) marker data along with phenotypic data of 251 advanced breeding lines and chickpea cultivars were used to perform genome-wide association (GWAS) analysis. Host resistance was evaluated seven weeks after sowing using two highly aggressive single spore isolates (F17191-1 and TR9571) of GWAS analyses based on single-locus and multi-locus mixed models and haplotyping trend regression identified twenty-six genomic regions on Ca1, Ca4, and Ca6 that showed significant association with resistance to AB. Two haplotype blocks (HB) on chromosome Ca1; HB5 (992178-1108145 bp), and HB8 (1886221-1976301 bp) were associated with resistance against both isolates. Nine HB on the chromosome, Ca4, spanning a large genomic region (14.9-56.6 Mbp) were also associated with resistance, confirming the role of this chromosome in providing resistance to AB. Furthermore, trait-marker associations in two F derived populations for resistance to TR9571 isolate at the seedling stage under glasshouse conditions were also validated. Eighty-nine significantly associated SNPs were located within candidate genes, including genes encoding for serine/threonine-protein kinase, Myb protein, quinone oxidoreductase, and calmodulin-binding protein all of which are implicated in disease resistance. Taken together, this study identifies valuable sources of genetic resistance, SNP markers and candidate genes underlying genomic regions associated with AB resistance which may enable chickpea breeding programs to make genetic gains marker-assisted/genomic selection strategies.
由一种坏死营养型真菌引起的Ascochyta叶枯病（AB），（同义词： ）有可能摧毁全球的鹰嘴豆产业，原因是栽培基因库中遗传抗性来源有限、病原体进化潜力高以及综合病害管理面临挑战。因此，在新品种中部署稳定的遗传抗性可以提供一种有效的病害控制策略。为了研究AB抗性的遗传基础，利用基于测序的基因分型DArTseq单核苷酸多态性（SNP）标记数据以及251个高级育种系和鹰嘴豆品种的表型数据进行全基因组关联（GWAS）分析。播种七周后，使用两种高度致病的单孢分离株（F17191-1和TR9571）评估宿主抗性。基于单基因座和多基因座混合模型的GWAS分析以及单倍型趋势回归确定了Ca1、Ca4和Ca6上的26个基因组区域，这些区域与AB抗性显著相关。Ca1染色体上的两个单倍型块（HB）；HB5（992178-1108145 bp）和HB8（1886221-1976301 bp）与对两种分离株的抗性相关。Ca4染色体上的9个HB跨越一个大的基因组区域（14.9-56.6 Mbp）也与抗性相关，证实了该染色体在提供AB抗性方面的作用。此外，还验证了两个F衍生群体在温室条件下苗期对TR9571分离株抗性的性状-标记关联。89个显著相关的SNP位于候选基因内，包括编码丝氨酸/苏氨酸蛋白激酶、Myb蛋白、醌氧化还原酶和钙调蛋白结合蛋白的基因，所有这些基因都与抗病性有关。综上所述，本研究确定了与AB抗性相关的基因组区域潜在的宝贵遗传抗性来源、SNP标记和候选基因，这可能使鹰嘴豆育种计划能够通过标记辅助/基因组选择策略实现遗传增益。
