Vitellogenesis in potato psyllid, Bactericera cockerelli

The potato psyllid, Bactericera cockerelli (Hemiptera: Triozidae) is the vector of the Gram negative bacterium “Candidatus Liberibacter solanacearum”, the causal agent of Zebra Chip disease of potato. The insect life cycle is well studied but the molecular mechanisms involved in vitellogenesis and egg production are unknown. One of the most important proteins for vitellogenesis and egg production is Vitellogenin (Vg), a phosphoglycolipoprotein. In most insects, Vgs are large proteins (200-700 kDa), synthetized, proteolytically cleaved, and post-translationally modified in the fat body tissue. In order to understand the processes involved in vitellogenesis, first we identified and cloned two B. cockerelli vitellogenin-like genes (BcVG1-like and BcVG6-like). Second, we determined that psyllid oviposition was cyclic: a cycle lasted 3 to 4 days and each cycle was separated by 1 day with no or reduced oviposition. Third, we analyzed gene expression during the oviposition cycle. Our results showed changes in BcVg1-like expression at different points in the cycle, whereas no significant differences were observed for BcVg6-like.