Phytophthora sojae leucine-rich repeat receptor-like kinases: diverse and essential roles in development and pathogenicity

Abstract

Leucine-rich repeat receptor-like kinases (LRR-RLKs) are critical signal receptors in plant development and defense. Like plants, oomycete pathogen genomes also harbor LRR-RLKs, but their functions remain largely unknown. Here, we systematically characterize all the 24 <i>LRR-RLK</i> genes (<i>PsRLKs</i>) from <i>Phytophthora sojae</i>, which is a model of oomycete pathogens. Although none of them was required for vegetative growth, the specific PsRLKs are important for stress responses, zoospore production, zoospores chemotaxis, and pathogenicity. Interestingly, the Gα subunit PsGPA1 interacts with the five chemotaxis-related PsRLKs via their intracellular kinase domains, and expression of <i>PsGPA1</i> gene is downregulated in the three mutants (Δ<i>PsRLK17/22/24</i>). Moreover, we generated the PsRLK-PsRLK interaction network of <i>P. sojae</i> and found that PsRLK21, together with PsRLK10 or PsRLK17, regulate virulence by direct association. Taken together, our results reveal the diverse roles of LRR-RLKs in modulating <i>P. sojae</i> development, interaction with soybean, and responses to diverse environmental factors.