De novo assembly and functional annotation of the emma field cricket (Teleogryllus emma) transcriptome

In recent years, insects have been used in animal-based foods for sustainable live-stock management and in the human diet as therapeutic foods. These insects are classified as edible and are widely consumed around the world for their broad medicinal and nutritional values. Antimicrobial peptides/proteins (AMPs) confer resistance to microbial pathogens and contribute to the immune function of insects. The emma field cricket (Teleogryllus emma) is widely consumed around the world for its broad-spectrum therapeutic effects. However, the absence of genetic information on T. emma is an obstacle to understanding the diversity and activity of its AMPs. Hence, deep sequencing of the T. emma transcriptome and expression profiling are essential. We report whole-body de novo transcriptome profiling of T. emma and analysis of its potential bacterial immunization-induced AMPs. We assembled 18.2 Gb of Illumina reads, generated 102,311 transcripts (minimum length: > 500 bp, N50: 2585 bp), and identified 67,838 unigenes. Of these unigenes, 39,937 (58.87%) matched known proteins in a Basic Local Alignment Search Tool search of the National Center for Biotechnology Information database. Functional analysis demonstrated that the 39,937 unigenes clustered under 5707 Gene Ontology terms. In addition, we identified 10 cDNAs encoding new AMPs via an in-silico approach using public databases. Our transcriptome data set and AMP profile greatly improve the understanding of T. emma genetics and provide a huge number of gene sequences, including those for genes of known and unknown function, for further study.