Effect of bacillus subtilis based micrrobials on physiological and biochemical parameters of sugar beet (Beta vulgaris L.) plants infected with Alternaria alternata

Phytopathogenic Alternaria fungi are economically important causative agents of sugar beet ( Beta vulgaris L.) leaf diseases which significantly reduce root yield and quality. Promising agents for plant disease biocontrol are Bacillus subtilis based biologicals due to the ability to stimulate plant growth and immunity to many biotic stressors. Starting our experiments, we could not find publications on B. subtilis effects towards physiological parameters of sugar beet plants affected by Alternaria. This paper is the first to report that B. subtilis -based biologicals including novel Bashkirian isolate B. subtilis 10-4 prevent a decrease in leaf photosynthetic activity in sugar beet plants affected by A. alternata, activate hydrolytic enzyme inhibitors, suppress proline production, and increase sugar content in roots. Our objective was to estimate effects of Fitosporin-M, Vitaplan, and endophytic strain B. subtilis 10-4 on leaf photosynthetic pigments (chlorophyll a, b and carotenoids), leaf area index, activity of hydrolases (proteases and amylases) and their inhibitors, as well as proline and sugar levels in leaves, root level of sucrose, and productivity in healthy plants as compared to those artificially infected with A...