In vivo and in silico evaluation of the phytoalexin-eliciting activity in common bean (Phaseolus vulgaris L.) of jasmonoyl-l-isoleucine analogs having a pyrazolidin-3-one ring

Jasmonates are phytohormones derived from jasmonic acid that regulate metabolic processes involved in the chemical response of plants to biotic and abiotic stress. As part of this response, some species synthesize de novo compounds with biological activity against some pathogens. In this work, nine analogs of jasmonoyl-l-isoleucine containing a pyrazolidin-3-one core were tested in their activity to elicit the production of phytoalexins (daidzein, genistein, coumestrol, and phaseollin) in common bean (Phaseolus vulgaris L.) cultivars when added exogenously. Some variations in selected parts of the analogs, such as the side chain, the linker, or the conjugated amino acid, allowed the establishment of qualitative relations with the observed activity. The analogs were tested at two levels of concentration, and the observed activity was, in most cases, higher than the observed for methyl jasmonate at 0.5 mM, even at the lower level. Seedlings treated with most heterocyclic compounds exhibited significantly higher amounts of phaseollin than untreated seedlings. Jasmonoyl-l-isoleucine analogs having a pyrazolidin-3-one ring trigger the production of phytoalexins and can be used for crop protection. Additionally, the protein-complex receptor involved in the jasmonate signaling mechanism was modeled by homology for P. vulgaris, using that for Arabidopsis thaliana as a template. After being modeled, it was assessed and used to qualitatively correlate the observed activity values and the vina scores from the docking of the tested analogs.