Jasmonate signaling controls negative and positive effectors of salt stress tolerance in rice

Simon Ndecky, Trang Hieu Nguyen, Elisabeth Eiche, Valérie Cognat, David Pflieger, Nitin Pawar, Ferdinand Betting, Somidh Saha, Antony Champion, Michael Riemann, Thierry Heitz

J Exp Bot.; 2023 May 19; 74(10):3220-3239. doi: 10.1093/jxb/erad086.

Figure: Effects of salt stress on the phenotype of the wild type (WT) and JA biosynthesis mutants. (A) Ten-day-old rice seedlings were subjected to salt stress at a high concentration (285mM NaCl) for 24h. (B) The second leaf of 10-day-old rice seedlings which were subjected to a 100mM NaCl solution for 3 d. (C) The third leaf of 10-day-old rice seedlings which were subjected to a 100mM NaCl solution for 3 d. Arrows indicate the salt-treated leaves. Scale bar=10mm. (Hazman et al. 2015)

Abstract

Plant responses to salt exposure involve large reconfigurations of hormonal pathways that orchestrate physiological changes towards tolerance. Jasmonate (JA) hormones are essential to withstand biotic and abiotic assaults, but their roles in salt tolerance remain unclear. Here we describe the dynamics of JA metabolism and signaling in root and leaf tissue of rice, a plant species that is highly exposed and sensitive to salt. Roots activate the JA pathway in an early pulse, while the second leaf displays a biphasic JA response with peaks at 1 h and 3 d post-exposure. Based on higher salt tolerance of a rice JA-deficient mutant (aoc), we examined, through kinetic transcriptome and physiological analysis, the salt-triggered processes that are under JA control. Profound genotype-differential features emerged that could underlie the observed phenotypes. Abscisic acid (ABA) content and ABA-dependent water deprivation responses were impaired in aoc shoots. Moreover, aoc accumulated more Na+ in roots, and less in leaves, with reduced ion translocation correlating with root derepression of the HAK4 Na+ transporter gene. Distinct reactive oxygen species scavengers were also stronger in aoc leaves, along with reduced senescence and chlorophyll catabolism markers. Collectively, our results identify contrasted contributions of JA signaling to different sectors of the salt stress response in rice.

See https://pubmed.ncbi.nlm.nih.gov/36879437/