A Genome-Wide Identification and Analysis of the Basic Helix-Loop-Helix Transcription Factors in Brown Planthopper, Nilaparvata lugens.

The basic helix-loop-helix (bHLH) transcription factors in insects play essential roles in multiple developmental processes including neurogenesis, sterol metabolism, circadian rhythms, organogenesis and formation of olfactory sensory neurons. The identification and function analysis of bHLH family members of the most destructive insect pest of rice, , may provide novel tools for pest management. Here, a genome-wide survey for sequences identified 60 sequences (s) encoded in the draft genome of . Phylogenetic analysis of the bHLH domains successfully classified these genes into 40 families in group A (25), B (14), C (10), D (1), E (8) and F (2). The number of with introns is higher than many other insect species, and the average intron length is shorter than those of . High number of ortholog families of was found suggesting functional conversation for these proteins. Compared to other insect species studied, has the highest number of bHLH members. Furthermore, gene duplication events of , , , , , and were found in s. In addition, a putative full set of genes is defined and compared with another insect species. Thus, our classification of these members provides a platform for further investigations of bHLH protein functions in the regulation of , and of insects in general.