Reciprocal regulation of nitrate and jasmonate signaling by JASMONATE ZIM DOMAIN PROTEIN 1 coordinates plant growth and defense.

Abstract

Nitrate (NO3 -) and jasmonates (JAs) are essential signaling molecules that regulate plant growth and defense responses, respectively. However, the molecular mechanism underlying their crosstalk remains to be elucidated. Here, we uncovered the reciprocal regulation between NO3 - and JAs through the key integrator JASMONATE ZIM DOMAIN PROTEIN 1 (JAZ1). We found that NIN-LIKE PROTEIN 7, a central transcription factor in NO3 - signaling, directly activates JAZ1 expression by binding to its promoter, thereby suppressing JA-mediated defense responses under high NO3 - conditions. Conversely, JA signaling inhibited NO3 --promoted growth via CORONATINE-INSENSITIVE 1-mediated degradation of JAZ1, which releases transcriptional repressors LATERAL ORGAN BOUNDARY DOMAIN37/38 (LBD37/38) to downregulate NO3 --responsive genes. Our findings underscore the dynamic interplay between nutrient availability and hormone signaling in shaping plant development and defense, which could offer potential strategies for improving crop resilience.