Molecular Identification Of Species Of Whiteflies And Biotypes Of Bemisia Tabaci In Shanghai

Whiteflies (Hemiptera,Aleyrodidae) are tiny pests of worldwide.Exact identification is the founding of quarantine,control and other research.But the taxonomy of whiteflies is based upon the exuviae of the fourth insatr lavae and some species show morphological plasticity,those incesased the difficulty of correct identification.Molecular marker methods have been used in species identification and other domain of animals with the development of technology.However,there are few species of whiteflies have been studied by molecular methods.In this paper mitochondrial cytochrome oxidase I (COI) and mitochondrial cytochrome b (Cytb) gene were used to identify whiteflies of Shanghai area with method of morphology, the biotypes of Bemisia tabaci in Shanghai were also analyzed in this paper.In this study,27species in13genera of whiteflies belongin to sbufamily Aleyrodidae were described in Shanghai,including four new records species.Five species Aleurocanthus spiniferus (Quaintance),5emisia tabaci(Gennadius),Dialeurodes citri (Ashmead), Dialeurodes ouchii (Takahashi) and Siphoninus phillyreae (Haliday) are serious pests in Shanghai.The mitochondrial cytochrome oxidase I (COI) gene partial sequences (658bp) of17whiteflies were amplified with universal primers,nucletides,composition,transition and transversion,genetic distance of this segment had being analyzed,the results indicated that genetic distance between species (0.169-0.249) was far greater than with species(0.000-0.003),the mean distance between species was0.274. Phologentic tree were constructed using3different methods (NJ,MP,UPGMA) base on COI sequences download from Genbank and sequenced in this study,whitefly individuals of same species were successfully clustered by three phologenetic tree,the bootstrap values of original divergence among intraspecies haplotypes amount to100%, the results indicated that COI gene was suitable for molecular identification at infraspecific category.Fragment of348bp mitochondrial cytochrome b (Cytb) gene of16whiteflies were suquenced using designed primers CytbFl and CytbRl,the date showed that intra-species Kimura2-parameter distance was less than0.010, the interspecies divergences among16whitefly species pairs ranged from0.170to0.500,the average interspecies genetic distance is0.331,the congeneric interspecies sequences divergences scope of0.170-0.266.Phylogenetic tree reconstructed with methods of NJ,MP and UPGMA,the topology of three tree are almost identical,the bootstrap values of original divergence among instraspecies haplotypes amount to100%,and cogeneric species formed a branch.these results support that Cytb gene can be used to identify whitefly species,and Cytb show a rapid rates of evolution than COI.The gene sequence of mitochondrial cytochrome oxidase I (mtDNA COI) were used to identify biotypes of Bemisia tabaci (Gennadius) in Shanghai area. The results show that Bemisia tabaci population of Jiading, Jinshan and Xuhui area were Q biotype only, the population of Minhang was composed of B biotype only, other area population of Bemisia tabaci was composed of two biotypes, included B and Q biotype. In this study totally45population were identified,31population were Q biotype,68.9%proportion and B biotype31.1%respectively. In addition, the most population collected at greenhouse was Q biotype(91.7%), it indicated that Q biotype has spread widely in Shanghai area, and has possibility of replace the B biotype as a main crop pest in Shanghai area.