Homology difference analysis of invasive mealybug speciesPhenacoccus solenopsisTinsley in Southern China with COI gene sequence variability
AbstractThe mealybug speciesPhenacoccus solenopsis(P. solenopsis) has caused much agricultural damage since its recent invasion in China. However, the source of this invasion remains unclear. This study uses molecular methods to clarify the relationships among different population ofP. solenopsisfrom China, USA, Pakistan, India, and Vietnam to determine the geographic origin of the introduction of this species into China.P. solenopsissamples were collected from 25 different locations in three provinces of Southern China. Samples from the USA, Pakistan, and Vietnam were also obtained. Parts of the mitochondrial genes for cytochrome oxidase I (COI) were sequenced for each sample. Homologous DNA sequences of the samples from the USA and India were downloaded from Gen Bank. Two haplotypes were found in China. The first was from most samples from the Guangdong, Guangxi, and Hainan populations in the China and Pakistan groups, and the second from a few samples from the Guangdong, Guangxi, Hainan populations in the China, Pakistan, India, and Vietnam groups. As shown in the maximum likelihood of trees constructed using the COI sequences, these samples belonged to two clades. Phylogenetic analysis suggested that mostP. solenopsismealybugs in Southern China are probably closely related to populations in Pakistan. The variation, relationship, expansion, and probable geographic origin ofP. solenopsismealybugs in Southern China are also discussed.