Genome-wide identification of Coptotermes formosanus immune genes and their potential roles in termite control.

[Display omitted] • Screening of immune genes of Coptotermes formosanus by genome analysis increases the number of known immune genes. • Metarhizium anisopliae and nematodes induce a significant change in the expression of about 10 immune genes. • Most of immune genes affected by M. anisopliae and nematodes shows a significant decrease in the expression level. • The lethal effect of M. anisopliae on termites significantly increases after inhibition of Cf PGRP-SC1, Cf SCRB3 and CfHemocytin. In recent years, the use of microbes to control termites has attracted increasing attention. It was found that pathogenic bacteria, nematodes, and fungi effectively control termites under laboratory conditions. However, their effects have not been replicated in the field, and one reason for this is the complex immune defense mechanisms of termites, which are mainly regulated by immune genes. Therefore, altering the expression of immune genes may have a positive influence on the biocontrol efficacy of termites. Coptotermes formosanus Shiraki is one of the most economically important termite pests worldwide. Currently, the large-scale identification of immune genes in C. formosanus is primarily based on cDNA library or transcriptome data rather than at the genomic level. In this study, we identified the immune genes of C. formosanus according to genome-wide analysis. In addition, our transcriptome analysis showed that immune genes were significantly downregulated when C. formosanus was exposed to the fungus Metarhizium anisopliae or nematodes. Finally, we found that injecting dsRNA to inhibit three immune genes (CfPGRP-SC1 , CfSCRB3 , and CfHemocytin), which recognize infectious microbes, significantly increased the lethal effect of M. anisopliae on termites. These immune genes show great potential for C. formosanus management based on RNAi. These results also increase the number of known immune genes in C. formosanus which will provide a more comprehensive insight into the molecular basis of immunity in termites. [ABSTRACT FROM AUTHOR]