Constitutive expression of <i>JASMONATE RESISTANT 1</i> induces molecular changes that prime the plants to better withstand drought
Sakil Mahmud, Chhana Ullah, Annika Kortz, Sabarna Bhattacharyya, Peng Yu, Jonathan Gershenzon, Ute C. Vothknecht
Abstract
Abstract In this study, we investigated Arabidopsis thaliana plants with altered levels of the enzyme JASMONATE RESISTANT 1 ( JAR1 ), which converts jasmonic acid (JA) to jasmonoyl‐ l ‐isoleucine (JA‐Ile). Analysis of a newly generated overexpression line (35S::JAR1) revealed that constitutively increased JA‐Ile production in 35S::JAR1 alters plant development, resulting in stunted growth and delayed flowering. Under drought‐stress conditions, 35S::JAR1 plants showed reduced wilting and recovered better from desiccation than the wild type. By contrast, jar1‐11 plants with a strong reduction in JA‐Ile content were hypersensitive to drought. RNA‐sequencing analysis and hormonal profiling of plants under normal and drought conditions provided insights into the molecular reprogramming caused by the alteration in JA‐Ile content. Especially 35S::JAR1 plants displayed changes in expression of developmental genes related to growth and flowering. Further transcriptional differences pertained to drought‐related adaptive systems, including stomatal density and aperture, but also reactive oxygen species production and detoxification. Analysis of wild type and jar1‐11 plants carrying the roGFP‐Orp1 sensor support a role of JA‐Ile in the alleviation of methyl viologen‐induced H 2 O 2 production. Our data substantiate a role of JA‐Ile in abiotic stress response and suggest that JAR1‐mediated increase in JA‐Ile content primes Arabidopsis towards improved drought stress tolerance.