Bacteria isolated from roots and rhizosphere of Vitis vinifera retard water losses, induce abscisic acid accumulation and synthesis of defense-related terpenes in in vitro cultured grapevine

MARIAVICTORIA SALOMON ; RUBEN BOTTINI; GONÇALO APOLINARIO DE SOUZA FILHO; ANA CARMEN COHEN; DANIELA MORENO; MARIANA GIL; PATRICIA PICCOLI

PHYSIOLOGIA PLANTARUM

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2014 vol. 151 p. 111 - 126

0031-9317

Elevenbacterial strains were isolated at different soil depths from roots and rhizosphereof grapevines from a commercial vineyard. By 16S rRNA gene sequencing 10different genera and 8 possible at species level were identified. From them, Bacillus licheniformis Rt4M10 and Pseudomonas fluorescens Rt6M10 wereselected according to their characteristics as plant growth promotingrhizobacteria (PGPR). Both produced abscisic acid (ABA), indole- AQ1 3-aceticacid (IAA) and the gibberellins A1 and A3 in chemically-defined medium. Theyalso colonized roots of in vitro grown Vitisvinifera cv. Malbec plants. As result of bacterization ABA levels in 45days-old in vitro plants were increased 76-fold by B. licheniformis and 40-fold by P.fluorescens as compared to controls. Both bacteria diminished plants waterloss rate in correlation with increments of ABA. Twenty and 30 days postbacterization the plants incremented terpenes. The monoterpenes á-pinene,terpinolene, 4-carene, limonene, eucalyptol and lilac aldehyde A, and thesesquiterpenes á-bergamotene, á-farnesene, nerolidol and farnesolwere assessed by gas chromatography-electron impact mass spectrometry analysis.á-Pinene and nerolidol were the most abundant (ìg per g of tissue inplants bacterized with P. fluorescens).Only á-pinene, eucalyptol and farnesol were identified at lowconcentration in non-bacterized plants treated with ABA, while no terpenes weredetected in controls. The results obtained along with others from literaturesuggest that B. licheniformis and P. fluorescens act as stress alleviatorsby inducing ABA synthesis so diminishing water losses. Thesenbacteria alsoelicit synthesis of compounds of plant defense via an ABA independentmechanism.