DNA Barcoding And Database Construction Of Pseudococcidae

Mealybug( Hemiptera:Pseudococcidae) is a tinyinsect group that feeds on plant sap. Its adaptability and the reproductive capacity is very powerful, andeasilyleads todisaster to agriculture and forestry areas. Mealybug is high alert pestofour country. With highly covert, it brought great difficulties to our entry quarantine. The rapid and accurate identification is the foundation of effectively monitoring and controllingto mealybugs. But there are many problems in the morphological indentification method. So looking for more efficient and convenient method of identification is particularly urgent.DNA barcoding is an identification methodthat using sequence differences of molecular markers in species.In this study, we used the 5' and 3'-end of COI gene to verify the effectiveness of identification in Mealybugs. We acquired 502 sequences of 5'-end and 356 sequences of 3'-end from 538 mealybug samples. The sequence length of them was 649 bp and 820 bp. The average contents of AT were significantly higher than GC for the COI sequences in mealybugs.The intraspecific genetic distances range of 5' and 3'-end were 0%~8.03% and 0%~9.5%. The interspecific genetic distances range of 5' and 3'-end were 1.6%~22.89% and 1.99%~21.39%.Someoverlap was observed in the distribution of genetic distances among conspecific individuals andinterspecificindividuals. The variation of different geographic populations in Ferrisia virgata and Phenacoccus madeirensiswas very obvious, and had reached a level of species.Phylogenetic tree of NJ showed that all species could form an independent clade.Phylogenetic tree of Pseudococcus, Phenacoccus, Phenacoccus and Dysmicoccusin NJ method showed that COI gene candistinguishthe species of main genus in Pseudococcidae, and the result was basically consistent with morphological identification.The identification of closely related species was also effective.COI gene can be used for the genus-level and species-level identification, and it is a useful molecular maker for the identification and phylogenetic studies of mealybug insects.There is important significance for the discover of cryptic species. Database construction of Pseudococcidaeprovided the scientific basis and important reference to the quarantine treatment and the classification of mealybugs.