Arsenic mitigation in spinach using Pseudomonas putida NBRI-RC5.2: Integrating functional traits with genomic insights

Abstract

Arsenic (As) mitigation recently gained prominence due to its escalating environmental risks. Vegetables, collected from affected areas, showed As accumulation ranging from 644 to 12,043 μg kg⁻¹. Among all tested vegetable crops, spinach showed the highest accumulation of As (874–12,043 μg kg⁻¹). Various arsenic-tolerant bacterial strains (∼763), along with plant growth-promoting traits, have been isolated from the rhizospheric and endophytic origins of these vegetables. Pseudomonas putida NBRI-RC5.2 (RC5.2), which possesses arsenate reductase and plant growth-promoting traits, was able to reduce the total As content in spinach leaves by ∼88%. Genes related to As resistance, plant growth promotion, and defense regulation have been identified through whole-genome analysis of RC5.2. The upregulated expression of arsR, arsB, arsA, arsK, arsJ, aqp, arsH and arsC genes in RC5.2 justifies its arsenic detoxification potential. The present study identified RC5.2 with a proven ability to tolerate and mitigate As uptake in spinach leaves. Development of RC5.2-based biofertilizer may be a promising candidate for sustainable As mitigation.