Abstract：
Knowledge of plant recognition of insects is largely limited to a few resistance (R) genes against sap-sucking insects. Hypersensitive response (HR) characterizes monogenic plant traits relying on R genes in several pathosystems. HR-like cell death can be triggered by eggs of cabbage white butterflies (Pieris spp.), pests of cabbage crops (Brassica spp.), reducing egg survival and representing an effective plant resistance trait before feeding damage occurs. Here, we performed genetic mapping of HR-like cell death induced by Pieris brassicae eggs in the black mustard Brassica nigra (B. nigra). We show that HR-like cell death segregates as a Mendelian trait and identified a single dominant locus on chromosome B3, named PEK (Pieris egg- killing). Eleven genes are located in an approximately 50 kb region, including a cluster of genes encoding intracellular TIR-NBS-LRR (TNL) receptor proteins. The PEK locus is highly polymorphic between the parental accessions of our mapping populations and among B. nigra reference genomes. Our study is the first one to identify a single locus potentially involved in HR-like cell death induced by insect eggs in B. nigra. Further fine-mapping, comparative genomics and validation of the PEK locus will shed light on the role of these TNL receptors in egg-killing HR.
摘要：
对昆虫的植物识别的知识在很大程度上限于针对吸汁昆虫的一些抗性（R）基因。超敏反应（HR）表征了几种病理性系统中依赖于R基因的单基因植物性状。类似HR的细胞死亡可以由卷心菜白蝴蝶的卵触发（Pierisspp。),卷心菜作物的害虫（芸苔属。),在摄食损害发生之前，降低卵的存活率并代表有效的植物抗性性状。这里,我们对黑芥菜中的菜青虫卵诱导的HR样细胞死亡进行了遗传定位（B.nigra).我们表明，HR样细胞死亡分离为孟德尔性状，并在B3号染色体上确定了一个显性基因座，称为PEK（Pieriseg-killing）。11个基因位于大约50kb的区域,包括编码细胞内TIR-NBS-LRR(TNL)受体蛋白的基因簇。PEK基因座在我们作图种群的亲本种质之间以及黑芽孢杆菌参考基因组之间具有高度多态性。我们的研究是第一个鉴定出可能参与黑芽孢杆菌昆虫卵诱导的HR样细胞死亡的单个基因座的研究。进一步精细映射，比较基因组学和PEK基因座的验证将揭示这些TNL受体在杀卵HR中的作用。
