Tracking the biogeography of the Asian Citrus Psyllid Diaphorina citri spread in China using mitogenomes and endosymbionts

Abstract

Abstract Diaphorina citri is the vector of “Candidatus Liberibacter asiaticus” (CLas), a bacterium associated with the citrus disease as Huanglongbing (HLB). Previous mitochondrial genome (i.e. mitogenome) analyses revealed the prevalence of two major mitochondrial groups (MGs) of D. citri in China, geographically distributed by elevation gradients. We estimated the population diversity of D. citrifrom sampling 54 major citrus-producing areas within 11 provinces/regions of China, through comparing assembled de novo mitogenomes. Additionally, endosymbiont genomes were recovered for “Ca. Carsonella ruddii” (CaCr) and “Ca. Profftella armature” (CaPa) from full-DNA next generation sequencing of 31 samples from the same pool. Most of quantified D. citri diversity came from single nucleotide polymorphisms (SNPs) in five genes: nad3, cox2, rrnL, cob, and atp6. Nine SNPs clustered the analysed D. citri mitogenomes into two major mitochondrial groups (MG) comprising seven subgroups. Independent phylogenetic trees were generated for the endosymbionts CaCr and CaPa, and a CaPa plasmid, supporting patterns obtained for D. citri mitogenomes while adding complexity layers. Additional information from 64 CaCr, 58 CaPa, and 6 CaPa plasmids provided 38 SNPs and two gaps that converged with the independent results of mitogenomes analyses. Furthermore, subgroups within the original MG clusters were revealed by 87 SNPs and one gap. Thus, combined analyses of D. citri mitogenomes and associated endosymbionts proved useful in uncovering layers of population diversity, pointing to patterns in the natural history of an invasive species. Further understanding of D. citri and endosymbionts can aid D. citri HLB management protocols and forecast territorial expansion events.