Organic soil-derived Saccharopolyspora thermophila for enhancing plant growth and controlling Fusarium wilt disease in tomato

This study investigated the effects of Saccharopolyspora thermophila, a plant growth-promoting actinomycete (PGPA), on tomato plants (Suvarna 22) and its potential to mitigate Fusarium wilt disease. Saccharopolyspora thermophila was isolated from organic farm soil and molecularly identified through 16S rRNA sequencing. Seed treatment with S. thermophila significantly enhanced germination rates (83% vs 59% in control) and seedling vigor (625 vs 192 in control). Treated plants exhibited improved growth parameters, including increased plant height (83.3%), chlorophyll content (88.2%), and fruit yield (66.7%). Under pathogen challenge, S. thermophila-treated plants showed reduced disease incidence (37% vs 92% in untreated plants). Biochemical analyses revealed that S. thermophila treatment enhanced antioxidant enzyme activities (CAT, SOD, APX, POD) and maintained higher chlorophyll content under pathogen stress. The treatment also moderated pathogen-induced increases in lipid peroxidation and proline levels, indicating improved stress tolerance. Interestingly, S. thermophila treatment counteracted pathogen-induced starch depletion and moderated sucrose accumulation, suggesting a complex interplay in plant metabolism regulation. These findings demonstrated the potential of S. thermophila as a PGPA to enhance tomato plant growth, productivity, and resilience against Fusarium wilt disease. The study provides insights into the physiological and biochemical mechanisms underlying PGPA-mediated plant growth promotion and disease resistance, offering promising avenues for sustainable agricultural practices.