Rhizosphere associated bacteria trigger accumulation of terpenes in leaves of Vitis vinifera L. cv. Malbec that protect cells against reactive oxygen species

REBECA PURPORA; MARIAVICTORIA SALOMON; PATRICIA PICCOLI; RUBEN BOTTINI

PLANT PHYSIOLOGY AND BIOCHEMISTRY

ELSEVIER FRANCE-EDITIONS SCIENTIFIQUES MEDICALES ELSEVIER

Lugar: Paris; Año: 2016 vol. 106 p. 295 - 304

0981-9428

It has been proposed that plant growth promoting rhizobacteria (PGPR)stimulate plant growth and development by inducing the biosynthesis ofsecondary metabolites, like terpenes, which reduce stress incidence. Threebacteria previously isolated from grapevine roots and adjacent soil (Microbacterium imperiale Rz19M10, Kocuriaerythromyxa Rt5M10 and Terribacillussaccharophilus Rt17M10) were tested as PGPR. After 30 days since rootinoculation of in vitro grown Vitisvinifera cv. Malbec plants, the monoterpenes α-pinene, terpinoleneand 4-carene, and the sesquiterpene nerolidol were detected only inbacterized-plant leaves. Also, the concentrations of the diterpenes α andγ-tocopherol, and the sterols sitosterol and lupeol were significantly enhancedcompared to controls. The leaf extracts of bacterized plants showedphotoprotective properties since they decreased the oxygen consumption (that isphoto-oxidation) of the amino acid tryptophan in a sensitized solution, thusindicating an increment of the antioxidant capacity of the tissues. In addition, experiments with α-pinene and nerolidol standardsshowed the capability to intercept reactive oxygen species in the sensitizedsolution. Moreover, bacterized plants infected with the pathogen Botrytiscinerea showed a reduction in the lesion diameter compared withnon-bacterized plants. The results suggestthat M. imperial, K. erythromyxa and mainly T.saccharophilus are able to induce a systemic response thattrigger increases on monoterpenes, sesquiterpenes, tocopherols and membranesterols. These compounds enhance the antioxidant capacity in leaf tissues thatmay help grapevine to cope with stresses.