De novo transcriptome of the desert beetle Microdera punctipennis (Coleoptera: Tenebrionidae) using Illumina RNA-seq technology.

Insects in Tenebrionidae have unique stress adaptations that allow them to survive temperature extremes. We report here a gene expression profiling of Microdera punctipennis, a beetle in desert region, to gain a global view of its environmental adaptations. A total of 48,158,004 reads were obtained by transcriptome sequencing, and the de novo assembly yielded 56,348 unigenes with an average length of 666 bp. Based on similarity searches with a cut-off E-value of 10(-5) against two protein sequence databases, 41,109 of the unigenes (about 72.96%) were matched to known proteins. An in-depth analysis of the data revealed a large number of genes were associated with environmental stress, including genes that encode heat shock proteins, antifreeze proteins, and enzymes such as chitinase, trehalose, and trehalose-6-phosphate synthase. This study generated a substantial number of M. punctipennis transcript sequences that can be used to discover novel genes associated with stress adaptation. These sequences are a valuable resource for future studies of the desert beetle and other insects in Tenebrionidae. Transcriptome analysis based on Illumina paired-end sequencing is a powerful approach for gene discovery and molecular marker development for non-model species.