Reclassification of the pathogen for empty-gut disease of Chinese oak silkworm, Antheraea pernyi

Author: Lin-Ling Wang ¹, Feng Qin ¹, Ce Song ² and Ze-Yang Zhou ^1*

Received 30 January 2010, accepted 9 April 2010.

Abstract

Empty-gut disease is a common disease of Chinese oak silkworm, Antheraea pernyi (Tussah). The study on the pathogen of the disease is of great help in prevention and cure of the disease. Previous studies showed that the pathogen was a new species in the genus Streptococcus, which was therefore named as Streptococcus pernyi sp.nov. In this study, with the purified pathogen, we performed some physiological and biochemical experiments, and also cloned and sequenced 16S rRNA gene of the pathogen. Subsequently, we analyzed its similarity and genetic distance with other related bacteria by using DNAstar software, and a NJ tree was then constructed for phylogenic analysis by MEGA 3.0. Unexpectedly, the results showed that the pathogen causing empty-gut disease of Tussah belongs to the genus Enterococcus with 99% bootstrap support. Therefore, Streptococcus pernyi sp.nov should be renamed as Enterococcus pernyi. Reclassification of the pathogen should keep pace with the development of modern taxonomy. In doing so, it will better our understanding of the pathogen and contribute to further study of the pathogen.

Key words: Empty-gut disease of Tussah, pathogen, 16S rRNA gene, Streptococcus pernyi sp.nov, Enterococcus pernyi.