STUDY OF Pseudomonas putida KT2440 AS PLANT GROWTH PROMOTING RHIZOBACTERIA (PGPR) AND THE IMPORTANCE OF LIPOPOLYSACCHARIDE (LPS) UNDER SALINITY CONDITIONS

COSTA GUTIERREZ SB ; CARAM DI SANTO MC; ,ZENOFF AM,; VINCENT PA; DE CRISTOBAL, RE

Buenos Aires

Congreso; Reunión conjunta de Sociedades de Biociencia; 2017

Sociedad Argentina de Investigación en Bioquímica y Biología Molecular

Abstract: The role of Pseudomonas putida KT2440 as PGPR under salinity conditions was evaluated. Also, a mutant (Mut11) with low salinity tolerance was evaluated, this mutation affects it in the LPS synthesis activity; and this, could help us to shed light in some mechanisms of action of P. putida KT2440 in salinity. To achieve this, the bacteria`s growth promoting properties, such as indol acetic acid, phosphate-solubilization and siderophore synthesis of P. putida KT2440 wild type and the mutant were evaluated, under saline (0.5 M NaCl) and non saline conditions. Additionally, in vitro seed germination and growth promotion of soybean and corn in saline soils were assayed.The strain P. putida KT2440 and the Mut11 mutant exhibited plant growth promoting properties. When IAA production was determinate no statistical differences were observed between the strains and the conditions. The wild type and the Mut 11 mutant showed similar activities in phosphate solubilization for both conditions, seeming not to be affected in presence of saline conditions. Nevertheless, the synthesis of siderophore was significantly affected under salinity conditions; and no synthesis was detected in the mutant, contrary for the wild type strain which exhibited a small halo.The plant growth promoting effect under salinity conditions of the P. putida KT2440 strain was highlighted and the negative effect of the mutant Mut11, especially under saline conditions, evidence the effect of the mutation, which apparently is not only important for salinity tolerance of the bacterium, but also reduce the effect of salinity stress for soybean and corn plants.These studies showed that P. putida KT2440 strain is a useful PGPR bacterium for salinity conditions and also suggest that LPS are relevant to reduce salinity stress, these data provides new information on the KT2440 strain adaptation in response to those kind of environments.