Studies On Molecular Identification And Genetic Variation Among Populations Of Wolfberry Gall Mites From China

The wolfberry gall eriophiod mite as the common Lyciums pest includes the several injurious plant-feeding mites in wolfberry-planting area.They can damage the flowers,axillary buds and leaves,forming blister like galls appearing on both the upper and lower surfaces of leaves and giving rise to reduce the ability of a plant to photosynthesise and lower yields.In this study,the three-spotted eriophidae mite,Aceria tjyingi,A.paramacrodonis and A.pallida were identified in basic of morphological and molecular identification,then the patterns of genetic diversity and populations structure of them were examined based on the COI and 28S,respectively.Lastly,we also evaluated the usefulness of these sequence data for control measures on this three species.(1)We identified the mites collected from 12 geographic areas in three wolfberry-planting areas.Although A.tj'yingi,A.paramacrodonis and A.pallida were identified in basic of morphological identification,the classify taxon of them were fully controversial because of similar morphologic characters.Therefore,the COI and 28S sequence as the DNA barcodes were used to identify and determine whether this three species were the synonyms of Aceria kuko.Results of K2P genetic distance showed interspecific genetic distances were much less than 2%,and haplotype network revealed ancient haplotypes were also found among them based on the COI and 28S sequences,respectively.All the consequences affirmed they were the same species.(2)The 449bp portion of the COI gene was amplified and sequenced revealing 43 polymorphic nucleotide sites representing 37 COI haplotypes.For the COI gene region,nucleotide diversity(Pi)and haplotype(Hd)diversity varied from 0.00106(GD)to 0.00482(XJ)and 0.34167(GD)to 0.81287(Jingtai area in GS),respectively.The highest levels of haplotype and nucleotide diversity were observed in GS and QH.haplotype(HI)were found in all geographic populations at high frequency;For the 28S sequence,a 468bp portion of sequences was amplified and sequenced revealing 22 polymorphic nucleotide sites representing 22 haplotypes.Pi and Hd varied from 0(XJ,NX)to 0.003 l(GSB)and(XJ,NX)to 0.5947(GSC).Haplotypes H1,H2,H3 were found in all geographic populations at higher frequency.The highest levels of haplotype and nucleotide diversity were also same as the COI gene.Therefore,we inferred that GS and QH may be the origin of the species.(3)In the COI region,the pairwise Fst between HB,XJ and most other populations showed obvious differentiation and remarkable level.Mantel tests of isolation by distance for population pairs found the significant correlations between geographic distance and Fst/(1-Fst).Analysis of AMOVA suggested the low level of population structure,having strong gene flow.The mismatch distribution of the COI,neutral test(besides HB)and star-like network patterns all showed that the history of past population expansion in gojiberry-planting area were still evident.The migrants per generation of populations were found by Migrate-n in the three producing-areas based on the COI;In the 28S,the result of AMOVA,Neutral test(besides HB,NX,NMG,XJ)and star-like network patterns all were the same as the COI.The low and significant differentiation was observed between QHC,GSB,GSC,HB and other populations.However,IBD of 28S was not correlated with geographical distance.The estimates of migration from the northwestern to the northern and southern was high migrants per generation,respectively.It may result from human Commercial trade.