Data from: Mapping resistance to Alternaria cucumerina in Cucumis melo

Infection with Alternaria cucumerina causes Alternaria leaf blight (ALB), a disease characterized by lesion formation on leaves, leading to substantial yield and quality losses in Cucumis melo (melon). While fungicides are effective against ALB, reduction in the frequency of application would be economically and environmentally beneficial. Resistant melon lines have been identified but the genetic basis of this resistance has not been determined. A saturated melon genetic map was constructed with markers developed through genotyping-by sequencing of an MR-1 (resistant) by Ananas Yokneum (susceptible Israeli cultivar) a recombinant inbred line (RIL) population (F6-F10; N=82) derived from single seed descent of a F2 population from a cross between the ALB resistant parent MR-1 and the ALB susceptible parent Ananas Yokneum. The population was evaluated for A. cucumerina resistance with an augmented block greenhouse study using inoculation with the wounded-leaf method. Multiple quantitative trait loci (QTL) mapping identified two QTL that explained 33.9% of variation in lesion area. Several candidate genes within range of these QTL were identified using the C. melo v3.5 genome. Markers linked to these QTL will be used to accelerate efforts to breed melon cultivars resistant to ALB.

瓜链格孢（Alternaria cucumerina）侵染会引发链格孢叶枯病（Alternaria leaf blight, ALB），该病害以叶片产生病斑为特征，会导致甜瓜（Cucumis melo）大幅减产并降低品质。尽管杀菌剂对ALB防治有效，但减少施药频次在经济与环境层面均具有积极意义。目前已筛选出抗病甜瓜材料，但该抗病性的遗传基础尚未明确。本研究通过对抗病亲本MR-1与感病以色列栽培品种Ananas Yokneum杂交获得的F2群体经单粒传法培育得到的F6-F10代重组自交系（RIL）群体（样本量N=82）进行测序分型（genotyping-by sequencing）开发分子标记，进而构建了一张高密度甜瓜遗传图谱。本研究采用伤叶接种法开展温室增广区组试验，对该群体的瓜链格孢抗性进行表型鉴定。多数量性状位点（QTL）定位分析共鉴定到2个QTL，可解释病斑面积33.9%的表型变异。基于甜瓜v3.5版本参考基因组，在上述QTL的侧翼区间内筛选得到多个候选基因。与上述QTL连锁的分子标记将用于加速抗ALB甜瓜品种的育种进程。