Abstract: Huanglongbing (HLB) is one of the most severe citrus diseases, which is usually transmitted by the Asian citrus psyllid (Diaphorina citri), and causes great economic loss. To understand the endosymbiotic microbiota of the citrus psyllid from Hainan and Fujian provinces in China, the partial conserved region of 16S rRNA was amplified by PCR, and subsequently the infection rate of each endosymbiont from two geographical populations of the citrus psyllid was detected by PCR using specific primer pairs in this stduy. Moreover, we detected the acquisition efficiency of the pathogen by adult citrus psyllid reared on Citrus reticulata cv. Tankan infected with Candidatus Liberibacter asiaticus (CLas), and the transmission efficiency to Citrus reticulata cv. Subcompressa via CLas-positive psyllids. The results demonstrated that the two geographical populations of the citrus psyllid had the same composition of endosymbiotic microbiota, including α-Proteobacteria, Wolbachia spp., γ-Proteobacteria, mycetocyte symbionts, β-Proteobacteria, Oxalobacter, and β-Proteobacteria, Herbaspirillum, and the infection rate of each endosymbiont from the two geographical populations was more than 95%. After the adult citrus psyllids were reared on CLas-infected C. reticulata cv. Tankan for 28 d, the acquisition efficiency was as high as 82%. The whole tree of C. reticulata cv. Subcompressa was infected after rearing the CLas-positive psyllids on it for 75 d. The results would provide some theoretical basis for the study of citrus psyllid and the effective control of HLB.

Key words: Citrus, Huanglongbing (HLB), Diaphorina citri, endosymbiont, pathogen transmission