The combined effects of drought stress and phosphorus deficiency on peanut (Arachis hypogaea L.) plants are mitigated by drought tolerant phosphate-solubilizing bacteria

Abstract

Abiotic stresses negatively impact legume crop production. Peanut (Arachis hypogaea L.) yield is affected, among other factors, by drought stress and phosphorus (P) soil deficiency. To address this, the use of inputs based on soil phosphate-solubilizing bacteria (PSB) that can leave soluble phosphorus accessible to plants and possess properties that help alleviate drought stress is a sustainable strategy. This study aimed to evaluate the drought tolerance of native peanut-associated PSB and to assess their effects on the water condition, growth, and nutritional status of this legume under combined drought and P deficiency. Five PSB native strains, Pseudomonas sp. SAS7, Pseudomonas sp. NVAM24, Pseudomonas sp. LCER4, Enterobacter sp. J49, and Serratia sp. S119 were assessed for viability and phosphate solubilization under osmotic stress using PEG-6000. The strains Pseudomonas sp. SAS7, Pseudomonas sp. NVAM24 and Enterobacter sp. J49 maintained their viability and phosphate-solubilizing ability under this stress condition. Those PSB identified as drought tolerant were inoculated on peanut plants in a microcosm assay subjected to drought stress (DS) and phosphorus deficiency (PD). Peanut plants inoculated with Pseudomonas sp. SAS7 and Enterobacter sp. J49 showed the highest root dry weight and number of root nodules under combined DS-PD conditions. Additionally, plants inoculated with Pseudomonas sp. SAS7 exhibited 20% higher shoot dry biomass compared to uninoculated plants under DS conditions. In conclusion, native drought-tolerant PSB offer promising biofertilizer potential by enhancing peanut resilience and growth under combined drought and phosphorus deficiency stresses, supporting sustainable agriculture in challenging environments.