Plant innate immunity relies on nucleotide binding leucine-rich repeat receptors (NLRs) that recognize pathogen-derived molecules and activate downstream signaling pathways. We analyzed the variation in NLR gene copy number and identified plants with a low number of NLR genes relative to sister species. We specifically focused on four plants from two distinct lineages, one monocot lineage (Alismatales) and one eudicot lineage (Lentibulariaceae). In these lineages, the loss of NLR genes coincides with loss of the well-known downstream immune signaling complex ENHANCED DISEASE SUSCEPTIBILITY 1 (EDS1)/PHYTOALEXIN DEFICIENT 4 (PAD4). We expanded our analysis across whole proteomes and found that other characterized immune genes were absent only in Lentibulariaceae and Alismatales. Additionally, we identified genes of unknown function that were convergently lost together with EDS1/PAD4 in five plant species. Gene expression analyses in Arabidopsis (Arabidopsis thaliana) and Oryza sativa revealed that several homologs of the candidates are differentially expressed during pathogen infection, drought, and abscisic acid treatment. Our analysis provides evolutionary evidence for the rewiring of plant immunity in some plant lineages, as well as the coevolution of the EDS1/PAD4 pathway and drought responses.

植物先天免疫依赖于核苷酸结合富含亮氨酸的重复受体（NLR），其识别病原体衍生的分子并激活下游信号通路。我们分析了 NLR 基因拷贝数的变化，并鉴定出相对于姐妹物种 NLR 基因数量较少的植物。我们特别关注来自两个不同谱系的四种植物，一种是单子叶植物谱系（泽泻目），一种是双子叶植物谱系（扁豆科）。在这些谱系中，NLR 基因的丢失与众所周知的下游免疫信号复合物增强疾病易感性 1 (EDS1) /植物抗毒素缺陷 4 (PAD4) 的丢失同时发生。我们将分析扩展到整个蛋白质组，发现仅在扁豆科和泽泻目中不存在其他特征性免疫基因。此外，我们还发现了5 个植物物种中与EDS1 / PAD4一起逐渐丢失的功能未知的基因。拟南芥（Arabidopsis thaliana）和稻的基因表达分析表明，候选者的几个同源物在病原体感染、干旱和脱落酸处理期间存在差异表达。我们的分析为某些植物谱系中植物免疫的重新布线以及 EDS1/PAD4 途径和干旱反应的共同进化提供了进化证据。