EFFECT OF INOCULATION OF PGPR NATIVE TO MENDOZA ON ARABIDOPSIS THALIANA PLANTS UNDER IRRIGATION AND DROUGHT CONDITIONS.

JOFRÉ, MARÍA FLORENCIA; GÓMEZ, FEDERICO ; LÓPEZ APPIOLAZA, MARTÍN; SILVA, MARÍA FERNANDA; COHEN, ANA CARMEN

on-line

Simposio; SIMPOSIO SAIB-SAMIGE 2021; 2021

Sociedad Argentina de Microbiología y Soc. Argentina de Bioquímica

EFFECT OF INOCULATION OF PGPR NATIVE TO MENDOZA ON ARABIDOPSIS THALIANA PLANTS UNDER IRRIGATION AND DROUGHT CONDITIONS.María Florencia Jofre; Federico C. Gomez; Martín Lopez; María Fernanda Silva; Ana Carmen CohenInstituto de Biología Agrícola de Mendoza - Facultad de Ciencias Agrarias (CONICET-Universidad Nacional de Cuyo), Chacras de Coria, Mendoza, Argentina.E-mail: florjofre@gmail.comPromoting Growth Plant Rhizobacteria (PGPR) are bacteria that colonize plant roots and promote their growth. These bacteria are present in the rhizosphere, rhizoplane or spaces between the root cortex cells and others exist within the cells roots. The PGPRs increase plant?s yield by various mechanisms that include secreting phytohormones, fixing atmospheric nitrogen, solubilizing insoluble phosphates among others. The inoculation with PGPR on stressed plants (drought, high temperature, salinity, etc.) reduces negative symptoms from stress. Native strains with PGPR characteristics have been isolated in the Cuyo region. PGPRs produce phytohormones like auxin, abscisic acid, ethylene, cytokinins, gibberellins that enhance the plant´s growth (root growth, tissue differentiation, cell elongation, plant growth promotion). Melatonin (MT) is a hormone of great interest for its wide variety of functions. In stress conditions such as cold, heat, drought and salinity MT decrease the negative effects in plants, eg., acts as a scavenger of reactive oxygen and reactive nitrogen species (ROS/SNS). In plants it has been widely studied, but the study of its role in bacteria is limited and even more so in rhizobacteria. The aim of this study was determinate the effect of inoculation with the Enterobacter 64S1 and Pseudomonas 42P4 strains in Arabidopsis thaliana plants under conditions of drought stress and irrigation at field capacity. The plants were grown in a greenhouse for 5 weeks. A randomized design of 4 treatments with 12 plants each was established. To verify the effect of inoculation, strains 64S1 and 42P4 were used. In addition, a treatment was carried out with the application of MT. The treatments were: 1) control, 2) MT, 3) strain 42P4 and 4) strain 64S1. Morphological, physiological and biochemical variables were evaluated and the concentration of MT in the rosettes was determined. The data were analyzed by means of analysis of variance. The inoculated plants under drought stress, presented a greater foliar area, stomatal conductance, concentration of photosynthetic and photoprotective pigments. Furthermore, for the first time, an increase in MT levels was observed due to inoculation with these PGPRs. These results show a new mechanism by which PGPR attenuates the effects of drought stress.