ABC Transporter Subfamily E Is Critical for Gametogenesis and Eclosion in Lygus hesperus (Hemiptera: Miridae)

Although the ATP-binding cassette (ABC) transporter superfamily of proteins typically facilitates the movement of compounds across cellular membranes, the ABC E subfamily (ABCE) influences protein synthesis via non-transporter roles in ribosome biogenesis. Despite this essential role, our understanding of the impact that ABCE proteins have on insect physiology is limited. Here, we identified and characterized the ABCE gene from Lygus hesperus, a major agricultural pest of crops in North America. LhABCE transcripts were constitutively expressed throughout development and were present in all adult tissues tested. RNA interference (RNAi)-mediated knockdown of LhABCE transcripts in fifth instar nymphs resulted in high nymphal mortality and an incomplete molt. LhABCE knockdown in adults disrupted gametogenesis and reduced longevity. In females, oogenesis was impaired and oocytes did not progress beyond the pre-vitellogenic phase. In males, LhABCE knockdown reduced both spermatozoa abundance and male fertility. LhABCE knockdown, however, had little to no impact on hemolymph protein levels or the levels of circulating vitellogenin. Taken together, the results indicate that LhABCE is critical for the normal progression of processes like molting and gametogenesis that require coordinated bursts of protein synthesis and suggest that ABCE may play an important role in the mechanisms underlying those bursts.