CHARACTERIZATION OF NATIVE PHOSPHATE SOLUBILIZING BACTERIA Pseudomonas spp. AND EFFECT OF THEIR INOCULATION ON PLANTS OF AGRICULTURAL INTEREST IN MICROCOSM ASSAY

ANZUAY, M.S., BERNARDI, P., INTELANGELO, A., LUDUEÑA, L., ANGELINI, J.G., TAURIAN, T.

Chapadmalal

Congreso; XVIII Congreso de la Sociedad Argentino de Microbiología General; 2023

SAMIGE

In Argentinian agricultural areas, deficiency of nutrients is one of the most importantfactors that limit crop production. Within soil bacteria, some of them are capable ofexercising beneficial effects on plant growth designated as plant growth promoting bacteria(PGPB). These bacteria can enhance plant growth and protect plants from disease andabiotic stresses. Bacteria belonging to genus Pseudomonas spp. have been extensivelyanalyzed and present numerous plant growth promoting properties. The formulation andfield application of biological inoculants is of great importance in sustainable agriculture andthe use of native PGPB constitutes an alternative to replace or reduce the use ofagrochemicals.The aim of this study was to characterize native bacteria belonging to genusPseudomonas spp. and analyze the effect of its inoculation on peanut and maize plants inmicrocosm assay.Properties associated with plant growth promotion in native phosphate solubilizingbacteria Pseudomonas sp. SA-S-7 and Pseudomonas sp. LC-ER-4 were determined: N2fixing capacity, siderophores and hydrocyanic acid (HCN) production, synthesis of indoleacetic acid (IAA) and activity of 1-aminocyclopropane-1-carboxylic acid deaminase (ACCdeaminase). For microcosm assays, peanut and maize seedlings grown in individual pots,containing non-sterile soil as a support with low P content, were inoculated withPseudomonas sp. SA-S-7 or Pseudomonas sp. LC-ER-4. Uninoculated peanut and maizeplants and plants inoculated with the commercial strain Pseudomonas fluorescens PMT1(RIZOFOS-RIZOBACTER) recommended for maize and wheat plants in Argentina, wereused as controls. Plants were grown under controlled environmental conditions, wateredregularly with water and nutrient solution. Peanut and maize plants were harvested at 45and 60 days, respectively and aerial and root length, shoot and root dry weight and aerialP content were determined.Results indicated that Pseudomonas sp. SA-S-7 and Pseudomonas sp. LC-ER-4 haveN2 fixing capacity, are able to produce IAA and express ACC deaminase activity. In addition,the SA-S-7 strain presented siderophore production. Neither of the native strains presentedHCN production.Results showed significant increases of shoot dry weight in peanut plants inoculated withLC-ER-4 strain, compared to control plants. Peanut plants inoculated with the SA-S-7 strainsignificantly increased aerial P content with respect to the plants without inoculation. Inaddition, maize plants inoculated with this strain showed significant increases in aerial androot length and in root dry weight compared to uninoculated plants.The native strain Pseudomonas sp. SA-S-7 could be employed in the formulation ofbiofertilizers for peanut and maize crops. These preliminary results are encouraging sincestudies of Pseudomonas spp. associated with growth promotion on peanut plants arescarce