Brassinosteroid receptor BRL3 triggers systemic plant adaptation to elevated temperature from the phloem cells

Abstract

Understanding plant receptor signaling is crucial to mitigate climate change impact on agriculture. BRs bind to membrane receptor-kinase BR-INSENSITIVE 1 (BRI1) in most plant cells that is essential to promote growth and stress responses, while the roles of vascular BRI1-LIKE1 and 3 (BRL3) receptors were considered redundant. While going unnoticed for twenty years, our study unveils that brl3 mutants show conditional phenotypes to climate stress factors such as elevated temperatures, water deprivation and rising CO2 levels. In response to adverse climate conditions such as elevated temperature, BRL3 signaling at the phloem-companion cells can promote growth by activating BRI1-EMS-SUPPRESSOR1 (BES1) effector, hormonal homeostasis, and central carbon metabolism. This study shifts the paradigm for our present understanding of BR signaling and opens innovative strategies to develop climate-smart crops. One sentence summaryPhloem-specific BRL3 receptor pathway controls plant adaption to elevated temperature.