|Macias-velasco, Juan - University Of Texas|
|Patton, Mckenzie - University Of Texas|
|Bruson, Ryan - University Of Texas|
|Bextine, Blake - University Of Texas|
Submitted to: bioRxiv
Publication Type: Research Technical Update
Publication Acceptance Date: 10/15/2018
Publication Date: 10/18/2018
Citation: Macias-Velasco, J.F., Patton, M.F., Bruson, R.T., Hunter, W.B., Bextine, B.R. 2018. Evaluation of North American Asian citrus psyllid (Hemiptera: Liviidae) population genetics by cytochrome P450 melt curve analysis. bioRxiv. https://doi.org/10.1101/445734.
Interpretive Summary: Citrus production worldwide is severely limited due to citrus greening disease, also known as huanglongbing (HLB), caused by a plant-infecting bacterium transmitted by an insect called the Asian citrus psyllid (ACP). Currently growers suppress psyllid populations using chemical insecticides. Thus insecticide resistance issues are of great concern. Genes associated with resistance are in the cytochrome P450 gene family. A comparison of these genes across psyllid populations in North America determined the presence of two distinct resistance gene types. The genetic differences may account for differences in psyllid population susceptibility to insecticides.
Technical Abstract: Citrus production worldwide is currently facing significant losses due to citrus greening disease, also known as huanglongbing, HLB. The Asian Citrus Psyllid (ACP) (Diaphorina citri Kuwayama (Hemiptera: Liviidae) is a hemipteran insect which feeds on phloem of Citrus, and is the vector of the pathogen Candidatus Liberibacter asiaticus, Las, in North America. Previous work identified the Cytochrome P450 (CYP4) genes which are associated with insecticidal resistance to neonicotinoid insecticides. Psyllids infected with Las also show altered expression of CYP4 genes. In this study the genetic variation of CYP4 within ACP populations in North America were evaluated using melting curve analysis. Principal component analysis identified the presence of two haplotypes, which were significantly different from each other (P less than 0.05). The existence of these CYP4 differences sheds light on the potential evolution of insecticide resistance development in ACP in North America. These population changes may indicate either coevolution with Las, or differences in imidacloprid selective pressure in the United States and Mexico.