Population Genetic Diversity And Genetic Structure Of Schlechtendalia Chinensis Based On AFLP Technology

Chinese gall aphids (Homoptera, Pemphigidae, Melaphidini) parasitize on species of the primary host-plant genus Rhus to form galls as Chinese galls, which are important medical and industrial materials.There are five genera and 11 species (the genus Kaburagia including four subspecies) in China, among which the species Schlechtendalia chinensis is most widely distributed, the most numerous and widely used, and Rhus chinensis Mill,is its unique primary host. So far, the study on this species S. chinensis mainly focused on its life cycle, reproduction, and observation to its primary and secondary hosts, however, little attention has been paid to the molecular level research.Amplified Fragment Length Polymorphism (AFLP) method is reproducible, reliable and high resolution for insect genetics study. In this study, the genetic diversity and genetic structure of S. chinensis from 13 populations (totally 214 individuals) were examined using AFLP method. The 13 populations are Shuifu in Yunnan Province; Tianzhu, Yonghong, Yangque, Danzhai,Taijiang in Guizhou province; Zhushan, Wufeng in Hubei province; Baohe, Chenggu in Shanxi province; Emei, Anxian in Sichuan province; Longsheng in Guangxi province. The main results are as following: Eight pairs of selective primers from 64 pairs of primer combinations were used to AFLP amplify the total DNA of S. chinensis samples. The primers yielded a total of 270 scorable loci,of which 99.63% loci were polymorphic. The percentage of polymorphic loci in different populations ranged from 22.69% to 53.33%,Nei's gene diversity index (H) from 0.0888 to 0.1580, and Shannon's index (I) from 0.1303 to 0.2348.The results showed the genetic diversity of Wufeng population is Highest, and genetic diversity of Baohe population is lowest. The Gst of S. chinensis population is 0.38,which showed that 62% genetic variation came from intra-populations, and 38% genetic variation from inter-populations. So the genetic variation of S. chinensis populations mainly comes from intra-populations. The overall Fst is 0.4566, which showed that the genetic differentiation among populations is high. Mental test detected no significant correlation between genetic distance and geographical distance (r=0.1011;P=0.8474>0.05).ME tree and PCA analysis showed that 13 populations grouped without correlation with their biological distribution. ME tree analysis showed that the 13 populations grouped into four major-clades. Clade I includes six populations (Baohe, Chenggu, Shuifu, Emei, Wufeng and Longsheng);Zhushan and Anxian populations comprise the cladeâ…¡;Tianzhu and Danzhai populations comprise the cladeâ…¢;cladeâ…£includes Yonghong, Yangque and Taijiang populations.In conclusion, the genetic diversity of S.chinensis populations is low, the genetic differentiation among populations is high. And the genetic diversity between populations isn't relative with geographic distance (P>0.05). Wufeng, Zhushan and Anxian populations with higher genetic diversity should be mainly conserved.