Peptide ligand-mediated trade-off between plant growth and stress response

The decision of whether to grow or to divert energy to stress response is a key physiological trade-off for plants seeking to survive under fluctuating environments. However, the cell-to-cell communication underlying this decision is largely unknown. Here we show that three orphan leucine-rich repeat receptor kinases (LRR-RKs) act as direct ligand-perceiving receptors for PSY-family peptides and play a key role in local switching between two opposing pathways. In contrast to the known LRR-RKs which activate signaling upon ligand binding, PSY receptor (PSYR) signaling, which intrinsically induces a stress response, usually is repressed by ligands to permit growth. Conversely, PSYRs activate the expression of various genes encoding stress response transcription factors upon depletion of the ligands. Loss of PSYRs resulted in defects in the plant’s tolerance to both biotic and abiotic stresses. This ligand-deprivation-dependent activation system enables plants to exert exquisitely tuned regulation of stress responses in the tissues proximal to metabolically dysfunctional damaged sites where ligand production is impaired. Genome-wide transcriptome analysis in roots of tpst-1 mutant, tpst/psyr1,2,3 quadruple mutant and PSY5 treated tpst-1 mutant. Transcriptome analysis in shoots of WT, tpst-1 mutant, psyr1,2,3 triple mutant, tpst/psyr1,2,3 quadruple mutant and PSY5 treated tpst-1 mutant.