Plant growth-promoting effects of native Pseudomonas strains on Mentha piperita (peppermint): an in vitro study.

SANTORO, M., CAPPELLARI, L., GIORDANO, W. AND BANCHIO, E.

PLANT BIOLOGY

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2015 p. 1 - 9

1435-8603

Plant growth-promoting rhizobacteria (PGPR) affect growth of host plants throughvarious direct and indirect mechanisms. Three native PGPR (Pseudomonas putida)strains isolated from rhizospheric soil of a Mentha piperita (peppermint) crop fieldnear Cordoba, Argentina, were characterised and screened in vitro for plant growth promoting characteristics, such as indole-3-acetic acid (IAA) production, phosphatesolubilisation and siderophore production, effects of direct inoculation on plantgrowth parameters (shoot fresh weight, root dry weight, leaf number, node number)and accumulation and composition of essential oils. Each of the three native strainswas capable of phosphate solubilisation and IAA production. Only strain SJ04 produced siderophores. Plants directly inoculated with the native PGPR strains showed increased shoot fresh weight, glandular trichome number, ramification number and root dry weight in comparison with controls. The inoculated plants had increasedessential oil yield (without alteration of essential oil composition) and biosynthesis of major essential oil components. Native strains of P. putida and other PGPR have clear potential as bio-inoculants for improving productivity of aromatic crop plants. There have been no comparative studies on the role of inoculation with native strains on plant growth and secondary metabolite production (specially monoterpenes). Native bacterial isolates are generally preferable for inoculation of crop plants because they are already adapted to the environment and have a competitive advantage over nonnative strains.