Critical role for the LRR receptor kinase PcLRR-RK2 in the physiology and pathogenesis of Phytophthora capsici

Plants contain many proteins known as Leucine-rich repeat receptor-like kinases (LRR-RLKs). These proteins aided in the transmission of signals within cells, which are important for development, growth, and defense against biotic and abiotic threats. Although oomycetes also include LRR-RLKs, not much is known about their function in these organisms. In this research, PcLRR-RK2 in Phytophthora capsici was investigated for its contribution to growth, pathogenicity, and reproduction of P. capsici. Corresponding results obtained showed that PcLRR-RK2 is necessary for optimal vegetative growth of P. capsici, and silencing of PcLRR-RK2 resulted in reduced vegetative growth. This study also demonstrated that silencing PcLRR-RK2 causes defective zoosporogenesis, resulting in impaired sporangia production. Investigation further revealed that silencing PcLRR-RK2, which reduces the ability of zoospores to germinate and penetrate plant tissues, prevents the production of necrotic lesions indicative of disease establishment. Similarly, the mycelium of silenced P. capsici exhibited a deteriorated ability to cause infection and was unable to invade plant tissues extensively. In summary, our study suggested that PcLRR-RK2 is necessary for regulating vegetative growth, thereby facilitating the penetration and infection of host leaf tissues by zoospores.