PGPR ability and stress tolerance of native Pseudomonas

FISCHER, S; CORDERO, P; BUENO, M.; MORI, G

Los Cocos, còrdoba

Conferencia; XXIII Reunión de la Asociación Latinoamericana de Rizobiología; 2007

ALAR

Pseudomonas spp. SF4C and Pseudomonas spp. SF10b are native strains isolated from rhizosphere wheat of Cordoba province. Previously, we demonstrated that these strains promote the wheat and tomato growth under greenhouse conditions. Pseudomonas spp. SF10b produces siderophores and IAA-like substances and solubilize phosphate while Pseudomonas spp. SF4C is siderophores and proteases producer. Both strains secrete an antibacterial compound that is active against other Pseudomonas. On the other hand, strains SF10b inhibit in vitro the phytopathogenic fungi Rhizoctonia solani and SF4C inhibit the formation of sclerotia of Sclerotinia minor. We studied the tolerance of Pseudomonas to saline and pH stress. The viability of SF4c is similar at pH 7 and pH 5.5 while 88% and 60% of cells survival a pH 4.5 and pH 4, respectively, during 12 hs of incubation under stress. On the other hand, SF10b survival a 91% in 0.75 M and 55% in 1M NaCl while SF4c survival an 89% and 65% in 0.75M and 1M NaCl, respectively. We are carrying out experiments with maize, other important crops of the pampa region