Abstract

Pathogenicity assessment studies in economically important species like silkworms are very important for the development of sericulture-based industries. The present study is a sincere attempt in this regard. The objective of this study is to isolate and identify a pathogenic bacterial strain from the gut of diseased Eri silkworms (Samia ricini) and assess its pathogenicity. Hence, gut bacterial colonies from S. ricini were isolated, and out of them, one strain (P1) was used for this study, which was identified as Bacillus cereus (PP505527) by 16S rRNA sequencing. Different concentrations of the strain were prepared to study the lethality of the bacterium. The Lethal concentration (LC50) value of B. cereus was recorded to be 8.90 × 107, 2.55 × 106, 1.83 × 105, and 4.67 × 102 CFU/ml at 24, 48, 72, and 96 hours, respectively. The current study might provide valuable insights into understanding the disease prognosis of Eri silkworms and potential disease management strategies for these economically important silkworms.

Key words: Samia ricin, 16S rRNA sequencing, Bacillus cereus, Lethal concentration (LC50)