Effects of inoculation of plant growth-promoting rhizobacteria and jasmonic acid application on growth parameters and essential oil production in Mentha piperita L.

CAPPELLARI, L., GIORDANO, W., BANCHIO, E.

Simposio; 32nd New Phytologist Symposium. Plant interactions with other organisms: molecules, ecology and evolution.; 2013

Numerous species of bacteria, most of which are associated with the plant rhizosphere, have been shown to have beneficial effects on plant growth and on crop yield and quality. The effects of inoculation of two strains of Pseudomonas spp. isolated from the rhizosphere of mint (SJ04 and SJ25) and P. fluorescens WCS417r (wild type) on plant growth parameters were evaluated in mint plants. Shoot length and fresh weight, leaf number, node number, root length and dry weight were measured. Shoot length and fresh weight were significantly higher in P. fluorescens WCS417r and Pseudomonas spp. SJ25 inoculated plants than in control and Pseudomonas spp. SJ04 inoculated plants. The effect of inoculation of PGPR strains and jasmonic acid 1 mM (JA) application on EO yield was also evaluated. EO yield increased 100% in inoculated and JA treated plants in comparison with control (non-inoculated) plants, without altering EO composition. Levels of the major EO components analysed (á-pinene, limonene, menthone, menthol, and pulegone) also showed significant differences in all treatments evaluated. JA treatment caused an increase of two folds in the content of pulegone and menthol. In view of the economic importance of monoterpenes for a variety of applications in industry, P. fluorescens have clear potential for improving the productivity of cultivated of aromatic plants.