Screening of Bacillus spp. as potential biocontrol agents against sunflower pathogens

Abstract

Sunflower (Helianthus annuus L.) is one of the most important oilseed crops worldwide. Numerous pathogens can affect sunflower cultivation and production, causing serious yield losses. The control of sunflower pathogens is conditioned by the limited management strategies, and it is focused on genetic resistance and chemical treatments. However, the excessive usage of agrochemicals leads to the loss of soil fertility and gradual decrease of microbial diversity, which is subsequently reflected in reduced growth and yield. For as much, the use of Bacillus spp. is becoming more frequent in modern agriculture as an environmentally sustainable and safe alternative to synthetic pesticides and fertilizers. Spore-forming Bacillus spp. are well known to protect plants from seed or soil-borne pathogens by the synthesis of various metabolites with antifungal activity, such as hydrolytic enzymes and antibiotics. These bacteria are also reported to enhance plant growth through the phytohormone production and nutrient acquisition. This study aimed to select the most effective Bacillus spp. from a group of ten antagonistic strains by antifungal activity assay.