Isolation and characterization of potential PGPR bacteria from the rhizosphere of regional crops

MICHAVILA G, ADLER C, CARAM DI SANTO MC, POMARES MF, DE CRISTOBAL RE, LOPEZ FE, VINCENT PA

Buenos Aires

Encuentro; Reunión anual Sociedad Argentina de Bioquímica y Biología molecular; 2013

Sociedad Argentina de Bioquímica y Biología molecular

The bacteria that inhabit the rhizosphere and have ability to cause a positive effect on plants are called plant growth promoting Rhizobacteria (PGPR). In general, biological control mechanisms and plant growth promotion by rhizospheric bacteria are based on microbial metabolites that adversely affect the pathogen or induce systemic resistance in the plant. Our laboratory addressed a screening for rhizospheric bacteria featuring plant promoting traits and antibiotic action against plant pathogens. Pseudomonas and Enterobacter bacterial genera were isolated from soy rhizosphere and Bacillus, Burkholderia, Rhizobium, Pantoea, from sugar cane rhizosphere. We studied biochemical markers associated with growth promotion i.e. siderophore production, synthesis of indole acetic acid and phosphate solubilization. We found that three isolates from sugar cane showed antibiotic activity against the pathogen Acidoborax avenae. Moreover, one Pseudomonas strain from soy inhibited Xanthomonas campestri pv. campestri. Preliminary in vivo assays using soy plants showed a protective effect of the Pseudomonas strain against the causal agent of ringspot disease in soy (Corynespora casiicola). However, no antibiotic activity was observed in vitro. These results indicate a promising role of this Pseudomonas strain as a biocontrol agent for plant diseases through the induction of the plant defense response.