Background:

Mycorrhiza-induced defense has been widely reported, in which, oxylipins pathway participation has been suggested, mainly jasmonic acid (JA), although the involvement of methyl-jasmonate (MeJA) is still controversial.

Objetives:

To evaluate the effect of Rhizophagus irregularis colonization and the exogenous MeJA treatment in the susceptibility to Sclerotinia sclerotiorum in common beans Azufrasin variety, as well as in the relative expression of the PvLOX2 and PvLOX6 genes in response to infection to the pathogen.

Methods:

Leaflets from non-mycorrhizal (NM) and R. irregularis mycorrhizal-colonized common bean plants (M) were treated with 50 µM MeJA, and infected with S. sclerotiorum. The extension of infected tissue by the pathogen was determined 24 h after the infection, as well as, the relative expression ofPvLOX2 and PvLOX6 genes by qPCR.

Results and conclusion:

Treatment with exogenous MeJA increased defense response in leaflets of NM plants (NM-MeJA) to a similar level than M plants, defense response was significanlty increased in leaflets M-MeJA, suggesting an additive effect of the mycorrhiza condition and exogenous MeJA treatment. The overexpression of genes, PvLOX2 and PvLOX6, in the treatment where both conditions were combined (M-MeJA), suggests the participation of jasmonates and other oxylipins in the induction of the defense.

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