Wang Nan, Yin Zhiyuan, Zhao Yaning, Li Zhengpeng, Dou Daolong, Wei Lihui
Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Nanjing, China.
College of Plant Protection, China Agricultural University, Beijing, China.
Front Plant Sci. 2022 Aug 15;13:968562. doi: 10.3389/fpls.2022.968562. eCollection 2022.
The allotetraploid Solanaceae plant contains two closely related receptor-like proteins (RLPs), NbEIX2 and NbRXEG1, which regulate the recognition of VdEIX3 and PsXEG1, respectively. VdEIX3, PsXEG1, and their homologs represent two types of microbe-associated molecular patterns (MAMPs) that are widespread in diverse pathogens. Here, we report that NbRXEG1 also participates in VdEIX3 recognition. Both and single mutants exhibited significantly impaired but not abolished ability to mediate VdEIX3-triggered immune responses, which are nearly abolished in double mutants. Moreover, a dominant negative mutant of that contains a 60 bp deletion failed to respond to VdEIX3 and could suppress VdEIX3-induced cell death in the wild-type . Further phylogenetic analyses showed that NbEIX2 and NbRXEG1 are obtained from different diploid ancestors by hybridization. These results demonstrate that the allotetraploid recognizes two types of MAMPs by two homologous but diverged RLPs, which provides a model in which an allopolyploid plant probably exhibits defense hybrid vigor by acquiring divergent immune receptors from different ancestors.
异源四倍体茄科植物含有两种密切相关的类受体蛋白（RLPs），即NbEIX2和NbRXEG1，它们分别调节对VdEIX3和PsXEG1的识别。VdEIX3、PsXEG1及其同源物代表了两种在多种病原体中广泛存在的微生物相关分子模式（MAMPs）。在此，我们报道NbRXEG1也参与VdEIX3的识别。单突变体和双突变体介导VdEIX3触发的免疫反应的能力均显著受损但未完全丧失，而双突变体中这种能力几乎完全丧失。此外，一个含有60 bp缺失的NbRXEG1显性负突变体对VdEIX3无反应，并且能够抑制野生型中VdEIX3诱导的细胞死亡。进一步的系统发育分析表明，NbEIX2和NbRXEG1是通过杂交从不同的二倍体祖先获得的。这些结果表明，异源四倍体通过两种同源但不同的RLPs识别两种类型的MAMPs，这提供了一个模型，即异源多倍体植物可能通过从不同祖先获得不同的免疫受体而表现出防御杂种优势。
