Reinterpretation of 'sperm pump' or 'sperm syringe' function with notes on other male internal reproductive organs in the Asian citrus psyllid, Diaphorina citri (Hemiptera:Liviidae)

Authors: CICERO, J - University Of Florida; Hunter, Wayne; CANO, L - University Of Florida; SAHA, S - Boyce Thompson Institute; MUELLER, L - Boyce Thompson Institute; BROWN, S - Kansas State University

Submitted to: Arthropod Structure and Development
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/22/2020
Publication Date: 2/12/2020
Citation: Cicero, J.M., Hunter, W.B., Cano, L.M., Saha, S., Mueller, L.A., Brown, S.J. 2020. Reinterpretation of 'sperm pump' or 'sperm syringe' function with notes on other male internal reproductive organs in the Asian citrus psyllid, Diaphorina citri (Hemiptera:Liviidae). Arthropod Structure and Development. 54(2020)100915. https://doi.org/10.1016/j.asd.2020.100915.
DOI: https://doi.org/10.1016/j.asd.2020.100915

Interpretive Summary: To limit the spread of bacterial pathogens of citrus, that are spread during psyllid feeding on the leaves of citrus trees, researchers have focused on the psyllid’s biology, specifically reproduction. Disruption of reproduction could provide a strategy to suppress psyllid populations and thus reduce the transmission of the bacterium Liberibacter asiaticus (Las) to newly planted citrus seedlings. Examination of the male psyllid reproductive system identified internal structures needed for successful mating. It was determined that the last psyllid instar does not have a mature drum/spout complex, which delivers the sperm during mating. By suppressing the genes responsible for forming these critical structures, the adult males would either be sterile, or unable to successfully mate. Mate disruption strategies have been shown effective in other pest systems, and thus could be utilized in the citrus/psyllid/huanglongbing (HLB) pathosystem to reduce psyllid populations and reduce the spread of HLB to newly planted citrus seedlings. Gene datasets on psyllid reproduction were produced from The Citrus Greening Solutions Project (USDA-NIFA Award 2014-70016-23028) and provide the essential information to develop such treatment solutions. The data sets are freely available at https://citrusgreening.org/, to advance all research on solutions to HLB in citrus.

Technical Abstract: In-depth anatomical studies of the Asian citrus psyllid, (ACP) Diaphorina citri Kuwayama (Hemiptera: Liviidae) focused on the internal anatomy of psyllid biology specifically reproduction. By understanding and targeting the elements of reproduction, strategies for suppressing psyllid populations could also reduce the spread of the bacteria. Examination of the male psyllid reproductive system elucidated basic internal genitalia, as well as newly identified features. It was determined that the last psyllid instar does not have a mature drum/spout complex, which delivers the sperm during mating. Thus, these organs provide likely interdiction sites to disrupt during development of pharate adults. Identification and suppression of these genes responsible for forming these critical structures, would result in either sterile adult males and/or males that were unable to successfully mate. Mate disruption strategies have been shown effective in other pest systems, and thus may be utilized in the citrus/psyllid/HLB pathosystem to reduce psyllid populations and reduce the spread of HLB to newly planted citrus seedlings. Genetic resources produced under The Citrus Greening Solutions Project (USDA-NIFA Award 2014-70016-23028) provide the essential information to develop treatment solutions. The data sets are freely available at https://citrusgreening.org/, to advance all research for solutions to HLB in citrus.