Microbial diversity of Asian longhorned beetle larval gut

Anoplophora glabripennis (Asian longhorned beetle), is a wood-boring pest that can develop in a wide range of healthy deciduous hosts in native and invaded areas. Gut microbiota often play important roles in the acquisition of nutrients for the growth and development of A. glabripennis larval. Here, we present the larval gut structure and studied the lignocellulose activities and microbial communities of larval gut fed on different host trees. We used PICRUSt2 to predict the functional profiles. The larval gut was divided into the foregut, the midgut and the hindgut, of which the midgut is the longest and forms a single loop under itself. A. glabripennis larval fed on a preferred host (Populus gansuensis) had the highest lignocellulose activities and microbial diversity compared with larvae reared either in a secondary host (Salix babylonica), a resistant host (Populus alba var. pyramidalis). Wolbachia as the most dominant bacteria was first found in larval gut feeding on S. babylonica and P. alba var. pyramidalis, while Enterococcus and Gibbsiella were the most dominant in P. gansuensis, followed by Wolbachia. As a lignocellulose-degrading fungi, Fusarium solani was dominant in the larval gut fed on different host trees. Functional prediction of bacterial and fungal communities in larval gut from different host trees revealed that they may encod enzymes involved in degrading lignocellulose, detoxification, and fixing nitrogen. Our research showed microbial community composition and lignocellulose activity using gut extracts from larvae both correlated well with host tree species. The gut microbial community has the endogenous potential to aid the larvae in lignocellulose degradation and extract nutrients from woody tissue, which likely contribute to its ability to thrive in a broad range of host trees.