Constitutive expression of JASMONATE RESISTANT 1 induces molecular changes that prime the plants to better withstand drought

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 droughtstress 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.

Metabolite modification in oxidative stress responses: A case study of two defense hormones

“…JAR1 is a well characterized aminotransferase competent for this reaction [9]. The level of JAR1 expression has recently been shown to affect drought resistance [57] and a double cat2 jar1 mutant presented an enhanced lesion phenotype compared to cat2 [29]. However, no consistent up-regulation of this gene was observed in our experiments.…”

The sex determination gene of Populus deltoides, PdFERR, interacts with ERF96 to promote the development of female flower organs

“…Among these candidates, two genes, AtERF96 and AtJAR1 , are annotated to be involved in flower development. AtJAR1 was reported to alter plant development, causing stunted growth and delayed flowering (Mahmud et al, 2022). AtERF96 belongs to the AP2/ERF gene family, which is involved in modulating gynoecium development (Durán‐Medina et al, 2017).…”

Photo‐oxidative stress leading to oxylipin accumulation may trigger drought‐induced leaf abscission in olive trees

“…The ratio JA‐Ile/JA also increased in water‐stressed petioles, thus suggesting an activation of the enzyme JAR1 and that the metabolic pathway of jasmonates was probably directed towards the formation of JA‐Ile (Staswick & Tiryaki, 2004; Wasternack & Hause, 2013). It has been previously shown that exposure to drought induces jasmonate biosynthesis in various species (de Ollas et al, 2015), and a recent study suggested a drought stress tolerance priming effect of jasmonates via JAR‐1 mediated accumulation of JA‐Ile in Arabidopsis (Mahmud et al, 2022). Therefore, it appears that jasmonates, and more specifically the bioactive form JA‐Ile, play a major role in drought stress tolerance, particularly in conditioning the tissue (petiole 2) containing the AZ for leaf abscission induced by mechanical stress to occur.…”

“…shown that exposure to drought induces jasmonate biosynthesis in various species (de Ollas et al, 2015), and a recent study suggested a drought stress tolerance priming effect of jasmonates via JAR-1 mediated accumulation of JA-Ile in Arabidopsis (Mahmud et al, 2022).…”