Shrestha Swati, Fu Yuqing, Michael Vincent Njung'e, Meru Geoffrey
Horticultural Sciences Department and the Tropical Research and Education Center, University of Florida, Homestead, FL, United States.
Front Plant Sci. 2022 May 19;13:848631. doi: 10.3389/fpls.2022.848631. eCollection 2022.
Squash () is among the most important cucurbit crops grown worldwide. Plant pathogen, Papaya ringspot virus W (PRSV-W) causes significant yield loss in commercial squash production globally. The development of virus-resistant cultivars can complement integrated disease management and mitigate losses due to viral infections. However, the genetic loci and molecular markers linked to PRSV-W resistance that could facilitate marker-assisted selection (MAS) for accelerated cultivar development are unknown. In this study, quantitative trait loci (QTL), molecular markers, and candidate genes associated with PRSV-W resistance in squash were identified in an F population ( = 118) derived from a cross between Nigerian Local accession (resistant) and Butterbush cultivar (susceptible). Whole genome re-sequencing-based bulked segregant analysis (QTLseq method; = 10 for each bulk) and non-parametric interval mapping were used to identify a major QTL associated with PRSV-W resistance on chromosome 9 () ( < 0.05) of . extended from 785,532 to 5,093,314 bp and harbored 12,245 SNPs among which 94 were high-effect variants. To validate , 13 SNP markers were assayed as Kompetitive allele-specific PCR (KASP) markers in the F population and tested for the association with PRSV-W resistance. Among these, two KASP markers (Ch09_2080834 and Ch09_5023865-1) showed significant association with PRSV-W resistance ( < 0.05). The two SNPs were located within exons of putative disease-resistant genes encoding the clathrin assembly family and actin cytoskeleton-regulatory complex proteins, which are implicated in disease resistance across plant species. The findings of this study will facilitate MAS for PRSV-W resistance in squash and allow further understanding of the functional mechanisms underlying potyvirus resistance in species.
南瓜（）是全球种植的最重要的葫芦科作物之一。植物病原体番木瓜环斑病毒W（PRSV-W）在全球商业南瓜生产中导致显著的产量损失。抗病毒品种的开发可以补充综合病害管理并减轻病毒感染造成的损失。然而，与PRSV-W抗性相关的遗传位点和分子标记尚不清楚，而这些标记有助于进行标记辅助选择（MAS）以加速品种开发。在本研究中，在一个由尼日利亚地方种质（抗性）与巴特布什品种（易感）杂交产生的F群体（ = 118）中，鉴定了与南瓜PRSV-W抗性相关的数量性状位点（QTL）、分子标记和候选基因。基于全基因组重测序的混合分组分析法（QTLseq方法；每个混合池 = 10）和非参数区间作图法被用于在的第9号染色体（）上鉴定一个与PRSV-W抗性相关的主要QTL（ < 0.05）。该QTL从785,532延伸至5,093,314 bp，包含12,245个单核苷酸多态性（SNP），其中94个是高效变体。为了验证该QTL，在F群体中检测了13个SNP标记作为竞争性等位基因特异性PCR（KASP）标记，并测试其与PRSV-W抗性的关联。其中，两个KASP标记（Ch09_2080834和Ch09_5023865-1）与PRSV-W抗性显示出显著关联（ < 0.05）。这两个SNP位于推定的抗病基因的外显子内，这些基因编码网格蛋白组装家族和肌动蛋白细胞骨架调节复合体蛋白，它们与多种植物物种的抗病性有关。本研究结果将有助于南瓜PRSV-W抗性的MAS，并进一步了解物种中马铃薯Y病毒抗性的功能机制。
