Jarin-1, an inhibitor of JA-Ile biosynthesis in Arabidopsis thaliana, acts differently in other plant species

ABSTRACT

Jasmonates (JAs), including jasmonic acid (JA) and its biologically active derivative JA-Ile, are lipid-derived plant signaling molecules. They govern plant responses to stresses, such as wounding and insect herbivory. Wounding elicits a rapid increase of JA and JA-Ile levels as well as the expression of JAR1, coding for the enzyme involved in JA-Ile biosynthesis. Endogenous increase and application of JAs, such as MeJA, a JA methylester, result in increased defense levels, often accompanied by diminished growth. A JA-Ile biosynthesis inhibitor, jarin-1, was shown to exclusively inhibit the JA-conjugating enzyme JAR1 in Arabidopsis thaliana. To investigate whether jarin-1 does function similarly in other plants, we tested this in Medicago truncatula, Solanum lycopersicum, and Brassica nigra seedlings in a root growth inhibition assay. Application of jarin-1 alleviated the inhibition of root growth after MeJA application in M. truncatula seedlings, proving that jarin-1 is biologically active in M. truncatula. Jarin-1 did not show, however, a similar effect in S. lycopersicum and B. nigra seedlings treated with MeJA. Even JA-Ile levels were not affected by application of jarin-1 in wounded leaf disks from S. lycopersicum. Based on these results, we conclude that the effect of jarin-1 is highly species-specific. Researchers intending to use jarin-1 for studying the function of JAR1 or JA-Ile in their model plants, must test its functionality before use.

KEYWORDS:

• Jarin-1
• root length
• jasmonic acid methyl ester (MeJA)
• jasmonic acid isoleucine (JA-Ile)

Acknowledgments

This research was supported by iDiv funded by the German Research Foundation (DFG–FZT 118, 202548816). We gratefully acknowledge Ainhoa Martínez-Medina for reading a previous version of this manuscript. We gratefully acknowledge Jessil Ann Pajar for providing tomato and Brassica seeds.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Author contributions

MZ designed and performed the experiments and wrote the first version of this manuscript. BH and NMvD took the lead of revising this manuscript. All authors contributed to the final version of this manuscript.

Data availability statement

Data are available from the corresponding authors upon reasonable request.

Additional information

Funding

The work was supported by the Deutsches Zentrum für integrative Biodiversitätsforschung Halle-Jena-Leipzig [DFG–FZT 118, 202548816].