Lasiojasmonates A–C, three jasmonic acid esters produced by Lasiodiplodia sp., a grapevine pathogen

Abstract

In this study, a strain (BL 101) of a species of Lasiodiplodia, not yet formally described, which was isolated from declining grapevine plants showing wedge-shaped cankers, was investigated for its ability to produce in vitro bioactive secondary metabolites. From culture filtrates of this strain three jasmonic acid esters, named lasiojasmonates A–C and 16-O-acetylbotryosphaerilactones A and C were isolated together with (1R,2R)-jasmonic acid, its methyl ester, botryosphaerilactone A, (3S,4R,5R)-4-hydroxymethyl-3,5-dimethyldihydro-2-furanone and (3R,4S)-botryodiplodin. The structures of lasiojasmonates A–C were established by spectroscopic methods as (1R∗,2R∗,3′S∗,4′R∗,5′R∗)-4-hydroxymethyl-3,5-dimethyldihydro-2-furanone, (1R∗,2R∗,3′S∗,4′R∗,5′R∗,10′R∗,12′R∗,13′R∗,14′S∗) and (1R∗,2R∗,3′S∗,4′R∗,5′R∗,10′S∗,12′R∗,13′R∗,14′S∗)-4-(4-hydroxymethyl-3,5-dimethyltetrahydro-furan-2-yloxymethyl)-3,5-dimethyldihydro-2-furanones jasmonates (1, 4 and 5). The structures of 16-O-acetylbotryosphaerilactones A and C were determined by comparison of their spectral data with those of the corresponding acetyl derivatives obtained by acetylation of botryosphaerilactone A. The metabolites isolated, except 4 and 5, were tested at 1mg/mL on leaves of grapevine cv. Cannonau and cork oak using the leaf puncture assay. They were also tested on detached grapevine leaves at 0.5mg/mL and tomato cuttings at 0.1mg/mL. In all phytotoxic assays only jasmonic acid was found to be active. All metabolites were inactive in the zootoxic assay at 50μg/mL.