Assessment of gut microbiota associated with oak tasar silkworm, Antheraea proylei J. (Lepidoptera: Saturniidae)

Abstract

Antheraea proylei J, is an economically important silkworm of North Eastern region of India reared for the production of the tasar silk. The silkworm is often exposed to various microbial diseases caused by bacteria and viruses. The disease causes significant damage to larvae and elicit pupal mortality, thus posing a serious threat to the linked economic activities. The gut microbiome of silkworms play an important role, in nutrient acquisition and immunity. In this study, we have reported molecular characterization and histopathological assessment of gut associated bacteria of healthy and diseased tasar silkworms. As compared to healthy silkworms, diseased infected silk glands shows loss of turbidity, secretory layer not distinguishable to tunica propria and lumen distorted. Both secretory and absorptive cells were found to be hypertrophied. Body fat becomes vacuolated and soft when compared to the healthy silkworms. Bacterial profile of healthy and diseased silkworm respectively was identified by 16S rRNA gene sequencing and analysis. Bacillus toyonensis and Bacillus thuringiensis were commonly found in healthy larvae whereas Bacillus aryabhattai and Bacillus megaterium were found in diseased larvae. The family Bacillus of phylum Firmicutes was dominant in both healthy and diseased silkworms. To the best of our knowledge, this is the first attempt to study A. proylei midgut microbiota from a biodiversity hotspot in North Eastern India. The present study might be helpful in disease prognosis and further comprehensive analysis on midgut microflora may lead towards the development of effective strategies for management of these economic silkworms.