Comparative transcriptomic analysis of labial salivary glands of Helicoverpa armigera and H. assulta.
The generalist Helicoverpa armigera and its specialist sibling Helicoverpa assulta share many similarities, but have two opposite directions of host range evolution. Relative to H. assulta, H. armigera has to cope with an enormous diversity of host nutrients and defenses. This may be achieved by adapting to divergent host environments via evolving additional host use related genes involved in digestion and detoxification, or by modifying distinct host environments to one or a few standard host nutrient/defense environments to which H. armigera are specialized via secretion of effectors, toxins and host-cell interaction proteins. To test this hypothesis, a total of 99 and 89 pairs of labial salivary glands were individually dissected out from 48 hr-old 6th instar larvae of H. armigera and H. assulta, respectively. The obtained RNA samples extracted from the H. armigera and H. assulta labial salivary glands were sequenced on an Illumina Hiseq 2000 platform for comparative transcriptome analysis.