Aquaporin identification in potato psyllids

Bactericera cockerelli, a phloem feeder insect, also known as the potato/tomato psyllid, is a serious pest of solanaceous crops. On this class of insects, the control of water transport is essential to maintain their internal fluid homeostasis and osmoregulation. Aquaporin proteins are believed to be involved in this function. Aquaporins are channel membrane proteins that function to simplify the selective bidirectional transport of water and uncharged low molecular-weight solutes across biological membranes.

The aim of this study was to identify aquaporin genes on potato psyllid transcriptome and to observe their expression in different life stages and tissues. To accomplish our goals, recently our laboratory generated a psyllid RNASeq library using the Illumina Genome Analyzer II (GAII) Platform. Transcriptome analysis on this library revealed the presence of four putative genes which encode aquaporin like-proteins.

We identified and confirmed the full-length cDNA sequence of the four aquaporin candidates. We performed multiple sequence alignments of the coding sequence generated and the phylogenetic analysis suggests that B. cockerelli has 2 putative aquaglyceroporins, 1 aquaporin and 1 atypical aquaporin. To study the expression pattern of these aquaporin-like genes; first we determined the expression of these aquaporin genes at different life stages: egg, 2^nd instar nymph, 4^th instar nymph, young adult, and adult male and female. We measured the transcript levels in dissected psyllid tissues (bacteriocyte, guts, head, ovaries and testis) using RT-PCR expression analysis. Finally, we determined the specific expression pattern for these aquaporin-like genes using in situ hybridization assays.