SACCHAROPOLYSPORA THERMOPHILA-MEDIATED INDUCTION OF RESISTANCE AND GROWTH PROMOTION IN PLANT UNDER FUSARIUM WILT STRESS

Abstract

This study investigates the role of plant growth-promoting Actinomycetes (PGPA), specifically Saccharopolyspora thermophila, in combating Fusarium wilt caused by Fusarium solani in cucumber plants. Fusarium wilt is a significant soil-borne disease that adversely affects crop yield and quality, posing a substantial threat to global agriculture. Traditional chemical treatments are often ineffective and can have detrimental environmental effects, making the exploration of biological control methods essential. In this study, the efficacy of Saccharopolyspora thermophila was evaluated in promoting plant growth and inducing systemic resistance in cucumber plants against Fusarium solani. The research involved isolating and characterizing Saccharopolyspora thermophila from rhizospheric soil, assessing its antagonistic activity against Fusarium solani through in vitro assays, and conducting greenhouse trials to determine its impact on plant growth parameters and disease suppression. To further understand the mechanisms of disease suppression and growth promotion, various biochemical assays were conducted, including the measurement of phenylalanine ammonia- lyase (PAL) activity, peroxidase activity, and phenolic content in cucumber plants treated with Saccharopolyspora thermophila. The assays demonstrated that plants inoculated with Saccharopolyspora thermophila showed a significant increase in PAL and peroxidase activities compared to controls, indicating an enhanced defense response. Moreover, phenolic content was also higher in treated plants, suggesting that Saccharopolyspora thermophila triggers the production of phenolic compounds, which play a vital role in plant defense mechanisms. These biochemical changes were correlated with a reduction in disease severity and an increase in plant growth parameters, highlighting the dual role of Saccharopolyspora thermophila in both promoting plant health and defending against pathogens. The results of this study suggest that Saccharopolyspora thermophila is a promising biocontrol agent that not only promotes plant growth but also provides sustainable disease management against Fusarium wilt. The application of PGPA like Saccharopolyspora thermophila could reduce the reliance on chemical pesticides, leading to more sustainable agricultural practices. This study contributes to the growing body of knowledge on biological control methods and highlights the potential of actinomycetes in integrated disease management strategies.