Population Genetic Structure Analysis Of Flower Thrips,Frankliniella Intonsa(Trybom)

Flower thrips,Frankliniella intonsa(Trybom),which belongs to Thysanoptera,Terebrantia,Thripidae,Frankliniella,is an economically important pest within the insect order Thysanoptera and also is the important endemic species in China.It needs to further understand the genetic structure and genetic diversity of the flower thrips in China for better prevention and cure.However,there have been rare reports on the population genetic structure analysis of F.intonsa.Wolbachia pipientis is a diverse group of a-proteobacteria found to infect numerous terrestrial arthropods and it may have phenotypic effects on the reproductive processes of their hosts.The Wolbachia phenotypes above on their host might enhance their rapid spread throughout host populations and contribute to rapid speciation in arthropods.This reproductive advantage can also alter host population genetics in that Wolbachia-infected females produce more offspring with their own mitochondrial DNA(mtDNA)haplotypes than uninfected females.However,there have also been rare reports on the Wolbachia infection status of the flower thrips Frankliniella intonsa(Trybom).This study used histone H3 and mitochondrial COI molecular markers to study the 26 flower thrips population genetic composition,genetic differentiation and genetic diversity.We detected the diversity and infection status of the Wolbachia in F.intonsa across 26 geographic localities in China using wsp and MLST markers.We explored the effect of Wolbachia on mitochondrial DNA genetic diversity of host through comparing the mitochondrial DNA COI data between infected-Wolbachia individuals and uninfected individuals.An analysis of molecular variation(AMOVA)was implemented in Arlequin v3.01 to formally assess and determine whether the presence of Wolbachia caused the population differentiation.The main conclusions of this research are as follows:(1)We studied the genetic composition and genetic diversity of 26 flower thrips population across China employed histone H3 molecular markers and combined with COI data.Results showed that there were a total of 140 flower thrips H3 haplotype and the H3 haplotype diversity of 26 geographic populations were generally higher(Hd,0.867-1.000).FST,which based H3 gene,showed that there was little genetic differentiation or no differentiation in the flower thrips populations of China.Most of the negative FST values show that there is no differentiation and there is a strong genetic drift between populations.AMOVA analysis results showed that most of flower thrips variation mainly from the variation between individuals within a population.The differentiation between groups is small in H3 gene,but the mtDNA gene has a significant differentiation between groups.(2)Using the surface protein of Wolbachia(wsp)sequence data and the multiple locus sequences typing(MLST)data.The results revealed that 22 out of 26 screened populations were infected by Wolbachia.The average infection frequency was 27.08%.We detected five Wolbachia strains(wFint1,wFint2,wFint3,wFint4 and wFint5),which were unambiguously assigned to supergroup B.The wFintl and wFint4 strains have a broad distribution and similar prevalence.They were found in 18 and 14 geographic populations.The northwestern population and northeastern population were only infected with the wFint5 strain.(3)By comparing the relationship between infection status of Wolbachia and mitochondrial DNA COI haplotype,the results show that the multiple infections have occurred independently.Horizontal transmission has played an important role in the distribution of Wolbachia in F.intonsa.The comparison of Wolbachia data collected in this study to mtDNA data obtained in a previous study suggested that the presence of Wolbachia was related to a reduction in mtDNA diversity.The results AMOVA and neutral test further support this conclusion.It may be that the specific F.intonsa Wolbachia strain associated with a recent selective spread of a particular mtDNA haplotype.