Midgut surface proteome of the Asian citrus psyllid, Diaphorina citri

The Asian citrus psyllid (ACP), Diaphorina citri, is the most important pest in citrus worldwide. This insect vectors the bacterium Candidatus Liberibacter asiaticus (CLas), the presumed causative agent of huanglongbing (HLB), a devastating disease in citrus. CLas is more efficiently transmitted by ACP nymphs as they are more susceptible to infection than adults. As plant pathogens exploit proteins on the gut surface of their vectors, here we plan to test the hypothesis that the most abundant gut surface proteins interact with CLas. To this end, we conducted proteomic analysis and compared the relative abundance of gut surface proteins between adults and nymphs. Brush border membrane vesicles (BBMV) were prepared from dissected guts of both nymphs and adults, and samples run in triplicate on a timsTOF mass spectrometer. A total of 1516 and 1219 proteins were identified in BBMV from ACP adults and nymphs, respectively. Bioinformatics analysis software and manual curation predicted that 125 adult and 100 nymph proteins localize to the surface of the microvilli. Seven of the predicted gut surface proteins were only detected in nymphs, the primary vectors of CLas. Plasma membrane proteins were further categorized into integral membrane and GPI-anchored proteins. The relative abundance of proteins was determined based on the total spectrum count after data normalization using the normalized spectrum abundance factor (NSAF) method. Knowledge of the ACP gut surface proteome will provide insight for potential interdiction of CLas interaction with the psyllid gut toward management of HLB.