Evolution of Lipochitooligosaccharide Binding to a LysM-RLK for Nodulation in Medicago truncatula
Evolution of Lipochitooligosaccharide Binding to a LysM-RLK for Nodulation in Medicago truncatula
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DOI：
10.1093/pcp/pcad033
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发表时间：
2023-06-01
影响因子：
4.9
通讯作者：
Lefebvre, Benoit
中科院分区：
文献类型：
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作者：
Cullimore, Julie;Fliegmann, Judith;Lefebvre, Benoit
溶素基序受体样激酶 (LysM-RLK) 参与植物中壳寡糖 (CO) 和相关脂壳寡糖 (LCO) 的感知。进化过程中基因家族的扩展和分化导致了共生和防御中的各种作用。通过研究禾本科 LysM-RLK 的 LYR-IA 亚类蛋白质，我们在此表明它们是高亲和力的 LCO 结合蛋白，对 CO 的亲和力较低，这与在 LCO 感知中建立丛枝菌根 (AM) 的作用一致。在蝶形花豆科植物中，全基因组复制在蒺藜苜蓿中产生了两个 LYR-IA 旁系同源物：MtLYR1 和 MtNFP，其中 MtNFP 在根瘤与固氮根瘤菌的共生中发挥着重要作用。我们证明 MtLYR1 保留了祖先的 LCO 结合特征，并且对于 AM 来说是可有可无的。 MtNFP 和 MtLYR1 的三个 LysM 之间的结构域交换以及 MtLYR1 中的诱变表明 MtLYR1 LCO 结合位点位于第二个 LysM 上，并且 MtNFP 中的分歧导致更好的结瘤，但令人惊讶的是 LCO 结合减少。这些结果表明，LCO 结合位点的分歧对于 MtNFP 在根瘤菌结瘤中的作用的进化非常重要。
Lysin motif receptor-like kinases (LysM-RLKs) are involved in the perception of chitooligosaccharides (COs) and related lipochitooligosaccharides (LCOs) in plants. Expansion and divergence of the gene family during evolution have led to various roles in symbiosis and defense. By studying proteins of the LYR-IA subclass of LysM-RLKs of the Poaceae, we show here that they are high-affinity LCO-binding proteins with a lower affinity for COs, consistent with a role in LCO perception to establish arbuscular mycorrhiza (AM). In Papilionoid legumes, whole-genome duplication has resulted in two LYR-IA paralogs, MtLYR1 and MtNFP in Medicago truncatula, with MtNFP playing an essential role in root nodule symbiosis with nitrogen-fixing rhizobia. We show that MtLYR1 has retained the ancestral LCO-binding characteristic and is dispensable for AM. Domain swapping between the three LysMs of MtNFP and MtLYR1 and mutagenesis in MtLYR1 suggest that the MtLYR1 LCO-binding site is on the second LysM and that divergence in MtNFP led to better nodulation, but surprisingly with decreased LCO binding. These results suggest that divergence of the LCO-binding site has been important for the evolution of a role of MtNFP in nodulation with rhizobia.