Screening Of Fine Aphid Schlechtendalia Chinensis Strains Forming Horned Gall

Horned gall, a kind of Chinese galls, was formed by the aphid Schlechtendalia chinensis (Hemiptera:Aphididae:Eriosomatinae: Fordini), which parasitizes on Rhus plants. Chinese gallnuts are rich in tannin acid, and the products have widely been used in different field, such as medicines, chemistry-industry and foods etc. However, the galls in the producting is basically from natural formation, which can’t meet the market demand now. Also, all different kind of galls were mixed together to extract the tannin acid and further sythsesize the different derivatives etc. Our country has made the standard for the Chinses gall grade according to tannin acid’s contents. In this study, we will combined the genetic diversity of gall aphids S. chinensis and chemstry compounds to screen the fine strain of horned gall resouces in order to guide artificial cultivation and improve the output of the Chinese galls.The genetic diversity, genetic construction and phylogeography of S. chinensis populations from 20 geographies 435 individuals were examined using mtDNA COI and Cytb genes sequences as genetic markers. Combined the data of annin acid contents from the published articles, the fine gall aphids strains forming horned gall were screened. The main results are as followin:1) We totally obtained 1,167bp DNA sequence in length with combined Cytb (474bp) and COI (693bp) genes, which included 32 variable sites (about 2.74%). The sequences of S.chinensis owed high A+T%, and the value of the third site was much higher than the other two sites.2) All the obtained sequences of S.chinensis populations appeared 43 different haplotypes. The Hap5 is the main one and might be the original haplotype.3) Among the genetic diversity index Danzhai and Wufeng populations were more higher. Danzhai and Wufeng populations of S.chinensis can be used as the introduction of fine strains for other areas to reproduce.4) The Molecular variance analysis (AMOVA) of S.chinensis populations showed that the genetic variation within populations were greatly higher than that between populations, which indicated that the gene flow between populations is limited. There existed the relative relationship between the population genetic distance and geographic distance, which might be resulted from the isolation of mountains, rivers etc. The artificial plants in different areas by exchanged the aphid larve strains might devolop the fine strains and increase the qualities of galls.5) The NJ/MP phylogenetic trees and TCS network relationship suggested that the most populations of S.chinensis clustered together as a group according to distribution area. Hubei and Guizhou could be the original center of this species S.chinensis.6) By the data analysis combined DNA sequences and tannin acid contents, it was found that the horned gall resouce--aphid S.chinensis strains in Danzhai and Wufeng was fine strains, which could be introduced to other areas for widespread cultivation.