Congratulations to Jinge Gu for publishing their work in Developmental Cell!
Abstract: As sessile organisms, plants are highly sensitive to environmental stresses. In response to stresses, globally repressed translation initiation leads to stress granule (SG) formation. Protein liquid-liquid phase separation (LLPS) contributes to SG formation, but a direct link between protein LLPS and stress resistance has not yet been found in plants. Here, we report that two RNA-binding proteins, RBGD2 and RBGD4, function redundantly to improve heat resistance in Arabidopsis. RBGD2 and RBGD4 undergo LLPS in vitro and condense into heat-induced SGs in vivo via tyrosine residue array (TRA). Importantly, disrupting LLPS by mutating TRA abolishes RBGD2/4 condensation in SGs and impairs their protective function against heat stress (HS). Further study found that upon HS, the RBGD2/4 interaction network expands with additional SG proteins and heat-responsive mRNA. Our work shows a mechanistic basis that underlies protein LLPS in HS response in plants and suggests manipulation of protein LLPS as a general strategy to improve plant stress resistance.