Morphological and biochemical aspects of the salivary glands of the western chinch bug, Blissus occiduus

The western chinch bug, Blissus occiduus Barber, is a serious pest of buffalograss.  Increasing attention has been given to insect saliva and its role in plant-insect interactions.  Although previous research has investigated the feeding behaviors of chinch bugs in the Blissus complex, no study to date has explored salivary gland morphology and the associated salivary secretions of this insect.  In this study, light (LM) and scanning electron microscopy (SEM) was used to visualize whole and sectioned B. occiduus salivary glands.  Microscopy revealed a pair of tri-lobed principal glands and a pair of tubular accessory glands of differing cellular types.  The salivary gland proteome was characterized using liquid chromatography tandem mass spectrometry (LC-MS/MS).  Proteome analysis resulted in B. occiduus sequences matching 228 non-homologous protein sequences of the pea aphid, Acyrthosiphon pisum, with many specific to the proteins present in the salivary proteome of A. pisum.  A number of sequences were assigned the molecular function of hydrolase and oxido-reductase activity, with one specific protein sequence revealing a peroxidase-like molecular function.  This is the first study to characterize the salivary proteome of B. occiduus and the first of any species in the family Blissidae.