Phylogeography of Diaphorina citri (Hemiptera: Liviidae) and its primary endosymbiont, 'Candidatus Carsonella ruddii' : an evolutionary approach to host-endosymbiont interaction

BACKGROUND: In insects, little is known about the coevolution between their primary endosymbionts and hosts at the intraspecific level, and this study has examined codiversification between the notorious agricultural pest Diaphorina citri and its P"endosymbiont, 'Candidatus Carsonella ruddii' at the population level. RESULTS: Maximum likelihood, haplotype network, principal components and Bayesian clustering identified three lineages for D. citri and its P"endosymbiont: a Western clade containing individuals from Pakistan, Bhutan (Phuentsholing), Vietnam (Son La), USA, Myanmar and China (Ruili, Yunnan); a Central clade, with accessions originating from Southwest China, Bhutan (Tsirang) and Bangladesh; and an Eastern clade containing individuals from Southeast Asian countries, and East and South China. A more diverse genetic structure was apparent in the host mtDNA compared to their P"endosymbionts; however, the two sets of data were strongly congruent. CONCLUSION: This study provides evidence for the codiversification of D. citri and its P"endosymbiont during the invasion process from South Asia to East and Southeast Asia. We also suggested that the P"endosymbiont may facilitate investigations into the genealogy and migration history of the host. The biogeography of D. citri and its P"endosymbiont indicated that D. citri colonized and underwent a secondary dispersal from South Asia to East and Southeast Asia.