EFFECTS OF INOCULATION WITH DROUGHT TOLERANT PHOSPHATE SOLUBILIZING BACTERIA ON PEANUT PLANTS GROWN UNDER PHOSPHORUS AND WATER DEFICIT CONDITIONS

LOPEZ, AGUSTIN; FURLAN, ANA LAURA; LOSER, URSULA ANA; TAURIAN, TANIA; ANZUAY, SOLEDAD

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

In Argentina´s semiarid pampas region, peanut ( L.) crop is challenged by low values of phosphorus (P). Also, in this region frequent and unpredictable drought stress periods were detected. Plant growth promoting bacteria (PGPB) can enhance plant growth and protect plants from abiotic stress. PGPB have some mechanisms to alleviate phosphorus deficit and drought stress as phosphorus solubilization and production of phytohormones and activity of 1-aminocyclopropane-1-carboxylic acid deaminase, respectively. The aim of thisstudy was to analyze the beneficial effect of inoculation with water stress tolerant phosphate solubilizing bacteria on the growth and nutritional status of peanut plants exposed to P deficiency and drought in a microcosm assay. Three phosphate solubilizing bacteria, Pseudomonas sp. SA-S-7, Pseudomonas sp. NVAM24 and Enterobacter sp. J49, were selected because of their ability to tolerate water stress and produce indol acetic acid (IAA) and ACC deaminase. Peanut plants were grown in individual pots containing 1,5 kg of nonsterile soil with low level of P (5 ppm) and were inoculated with Pseudomonas sp. SA-S-7, Pseudomonas sp. NVAM24 or Enterobacter sp. J49. All plants were inoculated with the nitrogen fixing microsymbiont of peanut Bradyrhizobium sp. SEMIA 6144. The treatments analyzed were: plants grown under available P conditions (AP), plants grown under P deficiency (PD), and within that half were irrigated (I) and the other half were exposed to drought stress (DS) where the irrigation was suspended in R1. The plants were harvested when the plants of DS treatments presented wilting symptoms. The parameters determined on plants were: relative water content (RWC), shoot and root dry weight, aerial P, N andchlorophyll content, nodule number, nodule dry weight and normalized-nodule weight. Results indicated significant increases in RWC, shoot and root dry weight on plants grown under P deficiency and drought (PD-DS) and inoculated with Pseudomonas sp. SA-S-7, compared with uninoculated plants. Also, the inoculation with this strain produced the highest content of chlorophyll in plants grown under P deficiency and irrigation (PD-I). Plants inoculated with Pseudomonas sp. NVAM24 presented significant increases in nodule number, nodule dry weight and P content, compared with uninoculated plants in control irrigation (I). In conclusion, the inoculation of peanut plants with drought tolerant phosphate solubilizing bacteria enhances their growth. Pseudomonas sp. SA-S-7 inoculation promoted growth and nutritional status of peanut plants in P deficiency and drought stress. Field experiments could confirm the results observed in this assay at this scale.