The combination of plant growth promoting rhizobacteria and methyl jasmonate produce positive and synergetic effects on phytochemical and morphological changes in Mentha x piperita L.

CAPPELLARI L; CHIAPPERO JULITA; GIORDANO W; BANCHIO, E.

foz iguazu

Congreso; 32nd Annual Meeting of the International Society of Chemical Ecology and 4th Congress of the Latin American Association of Chemical Ecology. 1st Joint Meeting ISCE/ALAEQ; 2016

Peppermint is one of the most important crops cultivated worldwide for fresh or driedleaves, and essential oils (EOs). The EOs are produced inepidermal structuresknown asglandular hairs.Numerous species of bacteria associated with the plant rhizosphere, haveshown beneficial effects on plant growth, yield and quality of crops. Such bacteria arecollectively ?plant growth- -promoting rhizobacteria? (PGPR).M. piperitashootswereinoculated with PGPR strains Bacillus subtilisGB03, Pseudomonas fluorescensWCS417ror P. putidaSJ04. The inoculated plants were sprayed with methyl jasmonate (MeJA) atdifferent concentration. At 7 and 14 days after the treatmentwith MeJA shoot biomass,EOs yield, major essential-oil components, total phenolics content, and peltate glandulartrichome density were evaluated.Treated plants (inoculated with PGPR orMeJAsprayedin different concentrations) showed a similar increases in all parametersevaluated except MeJA treated plants exhibit a slight decrese in shoot biomas.Total EOscontent in inoculated plantswas 2-3 folds higher than the control.Exogenous applicationof MeJA increase the total phenolics content.The combined (PGPR + MeJA)treatmentexhibit an increases in total EO yield and marked quantitative changes inmonoterpene content; total phenolic and trichome density much higher than that observedin the individual treatments. Aproximately was2-fold higher in the different parametersevaluated. The exogenous application of MeJA in combination with rhizobacteria causesan increase on secondary metabolites content and the number of peltate trichomes in M.piperitahigher than individual treatments. As might be suggested that both rhizobacteriaand the methylated derivative of JA trigger the activation of defense responses in theplant, involving stimulation of the biosynthesis of secondary metabolites. Improvedknowledge of factors that affect biosynthesis of secondary metabolites will lead tostrategies for improved cultivation and productivity of aromatic plants and otheragricultural crops without the use of chemical fertilizers