OLATION AND STUDY OF Pseudomonas putida STRAINS ADAPTED TO SALINE STRESS

COSTA GUTIERREZ, SB; LAMI, MARÍA JESÚS; ANA M. ZENOFF; CARAM DI SANTO, CAROLINA; PAULA A. VINCENT; ESPINOSA URGEL, M; DE CRISTÓBAL, RICARDO

Congreso; LI Reunión Anual Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2015

In this work we used a "fast selection" method to obtain good root-colonizing and salt tolerant bacteria, by successive and alternating rounds of growth in saline conditions of corn plants inoculated with the wild type strain Pseudomonas putida KT2440. We isolate two bacteria adapted to saline conditions (C2 and C3) after 7 cycles in corn. To evaluate salt tolerance of these bacteria, we performed growth curves in saline and non-saline conditions. We observed greater tolerance of C2 and C3 strain, compared to the WT strain, after 8 hours of growth (68% and 74% of higher growth for strains C2 and C3, respectively). In addition, the two adapted bacteria showed better growth promotion effect both on corn and soybean plants in saline conditions (70-90 mM NaCl), comparing with the parental strain, both in vitro and in vivo assays. When corn plants were inoculated with C2 and C3 strains and grown in saline conditions showed 61% and 51% longer roots length, respectively, compared with plants inoculated with the WT strain. In soybean inoculated with C3 strain (in vitro), 48% longer roots were obtained, whereas in in vivo assays 45% higher plants were obtained with C2 strain. This work shows an interesting method to get adapted bacteria without the need for genetic tools. A hopeful solution to the cultivation in saline soils could be proposed by using these adapted bacteria.