Proteomic polyphenism in color morphotypes of diaphorina citri, insect vector of citrus greening disease

Authors: HOSSEINZADEH, SAEED - Cornell University; Higgins, Steven; Ramsey, John - John; Howe, Kevin; Griggs, Michael; Castrillo, Louela; Heck, Michelle

Submitted to: Journal of Proteome Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/8/2021
Publication Date: 4/23/2021
Citation: Hosseinzadeh, S., Higgins, S.A., Ramsey, J.S., Howe, K.J., Griggs, M., Castrillo, L.A., Heck, M.L. 2021. Proteomic polyphenism in color morphotypes of diaphorina citri, insect vector of citrus greening disease. Journal of Proteome Research. 20(5):2851-2866. https://doi.org/10.1021/acs.jproteome.1c00089.
DOI: https://doi.org/10.1021/acs.jproteome.1c00089

Interpretive Summary: Citrus greening is caused by a bacterial infection and plagues all species of citrus. The bacteria associated with citrus greening is transmitted from tree to tree by an insect vector, the Asian citrus psyllid. Not all individual psyllids are capable of transmitting the citrus greening bacterium. The genes and proteins that regulate this variation are not known, but previous research has shown that insects with different body colors, either gray, yellow or blue, show differences in transmission of the citrus greening bacterium according to the color. The yellow and gray insects acquire and transmit better than the blue insects. In this work, we showed that the immune systems of the different insect color types are distinct. The yellow and gray insects have a lower level of immunity proteins yet show a more robust immune response to the citrus greening bacterium as compared to the blue insects. New therapies that target the psyllid's immune response may provide a novel way to control acquisition and transmission of the citrus greening bacterium.

Technical Abstract: Diaphorina citri is a vector of “Candidatus Liberibacter asiaticus” (CLas), associated with citrus greening disease. D. citri exhibit at least two color morphotypes, blue and non-blue, the latter including gray and yellow morphs. Blue morphs have a greater capacity for long-distance flight and transmit CLas less efficiently as compared to non-blue morphs. Differences in physiology and immunity between color morphs of the insect vector may influence disease epidemiology and biological control strategies. We evaluated the effect of CLas infection on color morph and sex-specific proteomic profiles of D. citri. Immunity-associated proteins were more abundant in blue morphs as compared to non-blue morphs but were upregulated at a higher magnitude in response to CLas infection in non-blue insects. To test for differences in color morph immunity, we measured two phenotypes: (1) survival of D. citri when challenged with the entomopathogenic fungus Beauveria bassiana and (2) microbial load of the surface and internal microbial communities. Non-blue color morphs showed higher mortality at four doses of B. bassinana, but no differences in microbial load were observed. Thus, color morph polyphenism is associated with two distinct proteomic immunity phenotypes in D. citri that may impact transmission of CLas and resistance to B. bassiana under some conditions.