Phytophthora is a major threat to agriculture. However, the molecular interaction of these severe pathogens with plant hosts is poorly understood. Here, we report that the Phytophthora Suppressor of RNA Silencing 1 (PSR1) effectively promotes infection in Arabidopsis thaliana by directly targeting an essential protein containing a aspartate–glutamate–alanine–histidine-box RNA helicase domain. This PSR1-Interacting Protein 1 (PINP1) is required for the accumulation of distinct classes of endogenous small RNAs and acts as a positive regulator of plant immunity. Silencing of PINP1 impaired the assembly of microRNA-processing complexes in the nucleus, leading to defects in development and immunity. This study revealed a conserved RNA helicase as a regulator of RNA silencing and provides mechanistic insight into Phytophthora pathogenesis.
Via Kamoun Lab @ TSL