Metabolism of airborne methyl salicylate in adjacent plants.

Salicylic acid (SA) and methyl salicylate (MeSA) are synthesized in many plants and are crucial components that establish their disease responses. The metabolism of airborne MeSA to SA has been previously reported. In this report, it was found that SA glucose ester (SAGE), ether (SAG), and salicyloyl-L-aspartic acid (SA-Asp) are metabolites of airborne MeSA. Furthermore, it was found that airborne MeSA was able to increase the endogenous amount of rosmarinic acid in Perilla frutescens, which is known as one of the functional components that contributes to the maintenance of human health.

Jasmonic acid is not a biosynthetic intermediate to produce the pyrethrolone moiety in pyrethrin II.

Pyrethrum (Tanacetum cinerariifolium) produces insecticidal compounds known as pyrethrins. Pyrethrins are esters; the acid moiety is either trans-chrysanthemic acid or pyrethric acid and the alcohol moiety of pyrethrins is either pyrethrolone, cinerolone, or jasmolone. It was generally accepted that cis-jasmone was biosynthetic intermediate to produce the alcohol moieties of pyrethrin, and the biosynthetic origin of the cis-jasmone was postulated to be jasmonic acid. However, there was no direct evidence to prove this hypothesis. In order to uncover the origin of pyrethrolone moiety in pyrethrin II, feeding experiments were performed employing deuterium- and 13C-labeled compounds as substrates, and the expected labeled compounds were analyzed using UPLC MS/MS system. It was found that the pyrethrolone moiety in pyrethrin II was derived from 12-oxo-phytodienoic acid (OPDA), iso-OPDA and cis-jasmone but not from methyl jasmonate and 3-oxo-2-(2'-[Z]-pentenyl)-cyclopentane-1-hexanoic acid. The results supported that the biosynthesis of the pyrethrolone moiety in pyrethrin II partially used part of the jasmonic acid biosynthetic pathway, but not whole.

12OHJA, 12OGlcJA, and JA-L-Val as airborne MeJA metabolites.

It has been reported that airborne methyl jasmonate (MeJA) was metabolized into jasmonic acid (JA) and jasmonoyl isoleucine (JA-L-Ile). In this report, jasmonoyl valine (JA-L-Val), 12-hydroxy JA (12OHJA), and 12-glucosyloxy JA (12OGlcJA) were identified as metabolites originating from airborne MeJA using tomato (Solanum lycopersicum). Furthermore, the preferable conversion of (-)-MeJA (natural form) into 12OHJA, 12OGlcJA, JA-L-Ile, and JA-L-Val was observed.

Ability of plant pathogenic fungi Gibberella fujikuroi and Fusarium commune to react with airborne methyl jasmonate.

The pathogenic fungi Gibberella fujikuroi and Fusarium commune produce jasmonic acid. The application of volatile deuterium-labeled methyl jasmonate increased the amount of nonlabeled JA present in G. fujikuroi and F. commune. These results indicate that the fungi have the ability to react with airborne methyl jasmonate in a manner similar to a plant.