Background Plant receptors with lysin motifs (LsyM) recognize microbial signals such as fungal chitin and lipo-chitooligosaccharidic Nod factors of nitrogen-fixing rhizobia. It is generally assumed that ligand-induced dimerization of LysM receptors is an essential step in activation of intracellular kinase domains and downstream signaling. Consequently, genes required for plant defense and establishment of symbiosis are expressed. We recently found that three LysM receptor proteins (namely LYK1, LYK4 and LYK5) of Arabidopsis thaliana form a tripartite receptor complex to perceive chitin. However, constitutive and ligand-induced interactions of LysM receptors generally remain difficult to be characterized. Results Interactions between ectodomains of LYK1, LYK4 and LYK5 were investigated by a chimeric receptor approach using hairy roots of the legume Lotus japonicus. Synthetic receptor pairs consisting of a LYK ectodomain and the intracellular domain of a L. japonicus Nod factor receptor (NFR1 and NFR5, respectively) were tested for their capacity to activate expression of the symbiotic NIN (nodule inception) gene. The results indicated constitutive (LYK4ED-LYK4ED, LYK4ED-LYK5ED) and chitin-induced interactions (LYK1ED-LYK1ED, LYK1ED-LYK5ED) of the examined ectodomains. Conclusion We present a method to functionally analyze constitutive and ligand-induced interactions of LysM-type proteins.

中文翻译：

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一种功能测试溶素基序受体蛋白的组成型和配体诱导的相互作用的方法。

背景 具有溶素基序 (LsyM) 的植物受体识别微生物信号，例如固氮根瘤菌的真菌几丁质和脂壳寡糖 Nod 因子。通常认为配体诱导的 LysM 受体二聚化是激活细胞内激酶结构域和下游信号传导的必要步骤。因此，表达了植物防御和建立共生关系所需的基因。我们最近发现拟南芥的三种 LysM 受体蛋白（即 LYK1、LYK4 和 LYK5）形成三联受体复合物来感知几丁质。然而，LysM 受体的组成型和配体诱导的相互作用通常仍然难以表征。结果 LYK1 胞外域之间的相互作用，LYK4 和 LYK5 是通过嵌合受体方法使用豆科植物 Lotus japonicus 的毛根进行研究的。测试了由 LYK 胞外域和 L. japonicus Nod 因子受体（分别为 NFR1 和 NFR5）的胞内域组成的合成受体对激活共生 NIN（结节起始）基因表达的能力。结果表明所检查的胞外域的组成型（LYK4ED-LYK4ED、LYK4ED-LYK5ED）和几丁质诱导的相互作用（LYK1ED-LYK1ED、LYK1ED-LYK5ED）。结论 我们提出了一种功能分析 LysM 型蛋白的组成型和配体诱导的相互作用的方法。分别）测试了它们激活共生 NIN（结节起始）基因表达的能力。结果表明所检查的胞外域的组成型（LYK4ED-LYK4ED、LYK4ED-LYK5ED）和几丁质诱导的相互作用（LYK1ED-LYK1ED、LYK1ED-LYK5ED）。结论 我们提出了一种功能分析 LysM 型蛋白的组成型和配体诱导的相互作用的方法。分别）测试了它们激活共生 NIN（结节起始）基因表达的能力。结果表明所检查的胞外域的组成型（LYK4ED-LYK4ED、LYK4ED-LYK5ED）和几丁质诱导的相互作用（LYK1ED-LYK1ED、LYK1ED-LYK5ED）。结论 我们提出了一种功能分析 LysM 型蛋白的组成型和配体诱导的相互作用的方法。