Biocontrol and PGPR Features in Native Strains Isolated from Saline Soils of Argentina

摘要

A bacterial collection of approximately one thousand native strains, isolated from saline soils of Cordoba province (Argentina), was established. From this collection, a screening to identify those strains showing plant growth promotion and biocontrol activities, as well as salt tolerance, was performed. Eight native strains tolerant to 1 M NaCl and displaying plant growth promotion and/or biocontrol features were selected for further characterization. Strains MEP2 18, MRP2 26, MEP2 11a, MEP3 1, and MEP3 3b significantly increased the growth of maize seedlings under normal and saline conditions, whereas isolates ARP2 3, AEP1 5, and ARP2 6 were able to increase the root dry weight of agropyre under saline conditions. On the other hand, strains MEP2 18 and ARP2 3 showed antagonistic activity against phytopathogenic fungi belonging to Sclerotinia and Fusarium genus. Antifungal activity was found in cell-free supernatants, and it was heat and protease resistant. Strains MEP218 and ARP23 were identified as Bacillus sp. and strains MEP211a and MEP33b as Ochrobactrum sp. according to the sequence analysis of 16S rRNA gene.