Genetic diversity and population structure analysis of Diaphorina citri Kuwayama in Guangxi based on mitochondrial gene sequences

【Objective】To study the genetic diversity and population structure of Diaphorina citri Kuwayama in Guangxi，this study provided research foundation for the strategy of controlling D. citri.【Method】Mitochondrial genome sequences of D. citri from 9 regions，Guangdong，Guizhou，Yunnan，Hainan and Guangxi of China，Thai Binh of Vietnam and Siem Reap of Cambodia，were analyzed to identify and design primers for polymorphic sites. Amplification and sequencing on D. citri gene mitochondrial sequences from Hepu，Huanjiang，Fuchuan，Xilin，Yongfu and Youjiang in Guangxi were conducted. DnaSP 6.12 was used to analyze the polymorphism and haplotype diversity of the sequences；and phylogenetic trees were constructed using maximum likelihood method and Bayes method；haplotype network was generated using PopART software to depict the population genetic structure and relationships.【Result】The mitochondrial genome sequences of 9 D. citri samples from China，Thai Binh of Vietnam and Siem Reap of Cambodia were compared and analyzed，resulting in the identification of 22 polymorphic sites. Primers were designed for the regions surrounding these polymorphic sites，and 5 pairs of effective primers were selected，which included 8 polymorphic sites. Mitochondrial genes of 18 D. citri collected from 6 citrus producing areas in Guangxi were amplified and sequenced by PCR using 5 pairs of primers，resulting in a mitochondrial gene sequence with a total length of 2272 bp. Analysis showed that D. citri in Guangxi contained 6 haplotypes，the haplotype diversity was 0.882，with a nucleotide diversity of 0.00181. Maximum likelihood evolutionary tree，Bayesian evolutionary tree and haplotype network analysis showed that the genetic distance between Xilin D. citri population in Guangxi and D. citri populations at high altitude in southwestern China such as Yunnan，Guizhou and Sichuan was relatively close，while populations in other regions were more closely related to those in southern China and southeastern Asia.【Conclusion】D. citri populations in Guangxi exhibit high haplotype diversity and low nucleotide diversity，implying obvious differentiation and diversity of population structure. The genetic differentiation of D. citri population in Guangxi is affected by geographical distance，and there is correlation between the two.