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

LÓPEZ, A., FURLAN, A.L., LOSER, U.A., TAURIAN, T., ANZUAY, M.S.

Chapadmalal

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

SAMIGE

In Argentina´s semiarid pampas region, peanut ( L.) crop is challenged by low values ofphosphorus (P). Also, in this region frequent and unpredictable drought stress periods weredetected. Plant growth promoting bacteria (PGPB) can enhance plant growth and protectplants from abiotic stress. PGPB have some mechanisms to alleviate phosphorus deficitand drought stress as phosphorus solubilization and production of phytohormones andactivity of 1-aminocyclopropane-1-carboxylic acid deaminase, respectively. The aim of thisstudy was to analyze the beneficial effect of inoculation with water stress tolerant phosphatesolubilizing bacteria on the growth and nutritional status of peanut plants exposed to Pdeficiency and drought in a microcosm assay. Three phosphate solubilizing bacteria,Pseudomonas sp. SA-S-7, Pseudomonas sp. NVAM24 and Enterobacter sp. J49, wereselected 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 thenitrogen fixing microsymbiont of peanut Bradyrhizobium sp. SEMIA 6144. The treatmentsanalyzed were: plants grown under available P conditions (AP), plants grown under Pdeficiency (PD), and within that half were irrigated (I) and the other half were exposed todrought stress (DS) where the irrigation was suspended in R1. The plants were harvestedwhen the plants of DS treatments presented wilting symptoms. The parameters determinedon 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 grownunder 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 thehighest content of chlorophyll in plants grown under P deficiency and irrigation (PD-I). Plantsinoculated with Pseudomonas sp. NVAM24 presented significant increases in nodulenumber, nodule dry weight and P content, compared with uninoculated plants in controlirrigation (I). In conclusion, the inoculation of peanut plants with drought tolerant phosphatesolubilizing bacteria enhances their growth. Pseudomonas sp. SA-S-7 inoculation promotedgrowth and nutritional status of peanut plants in P deficiency and drought stress. Fieldexperiments could confirm the results observed in this assay at this scale.