Isolation and characterization of antibacterial phylloplane bacteria Bacillus subtilis isolated from Terminalia arjuna leaves

Abstract

Bacterial diseases are becoming a major constraint during the rearing of tropical tasar silkworms. Because of the devastating nature of the disease, crop loss is severe; it is necessary to develop an eco-friendly biocontrol strategy that can be utilized in the tasar rearing plots. In the present study, the phylloplane bacteria were isolated from Terminalia arjuna and Terminalia tomentosa and were screened for antimicrobial potential against the tasar silkworm infecting pathogenic bacterial isolates. The promising bacteria was identified as Bacillus subtilis using biochemical as well molecular techniques (16s Ribosomal gene amplification). The treatment of Bacillus subtilis showed more survival as well as improved cocoon characteristics in both outdoor and indoor rearing conditions. Further, the treatment of Bacillus subtilis along with bacterial pathogens showed induction of protein, carbohydrate, and peroxidase activity and reduction in catalase activity which helps the tasar silkworm build resistance against bacterial pathogens. Hence, treatment of Bacillus subtilis during the rearing of tasar silkworm will reduce the bacterial infection which leads to enhanced tasar silk production.

Keywords: Phylloplane bacteria, Terminalia arjuna, Bacillus subtilis, molecular characterization.