Phenolic acid-induced phase separation and translation inhibition mediate plant interspecific competition

Phenolic acids (PAs) secreted by donor plants suppress the growth of their susceptible plant neighbours. However, how structurally diverse ensembles of PAs are perceived by plants to mediate interspecific competition remains a mystery. Here, we show that a plant stress granule (SG) marker, RNA-BINDING PROTEIN 47B (RBP47B), is a sensor of PAs in Arabidopsis. PAs including salicylic acid (SA), 4-hydroxybenzoic acid, protocatechuic acid, etc. directly bind RBP47B, promote its phase separation and trigger SG formation accompanied by global translation inhibition. SA-induced global translation inhibition depends on RBP47 family members. RBP47s regulate the proteome rather than the absolute quantity of SG. The rbp47 quadruple mutant shows a reduced sensitivity to the inhibitory effect of the PA mixture as well as to that of PA-rich rice when tested in a co-culturing ecosystem. Our study discovers RBP47B as the long sought-after PA sensor and unveils PA-induced SG formation and translation inhibition as one of the PA perception mechanisms.