Genetic distinctions among the Mediterranean and Chinese populations ofBemisia tabaciQ biotype and their endosymbiontWolbachiapopulations

Abstract

The sweetpotato whitefly, Bemisia tabaci, is a cryptic species complex composed of more than 24 different biotypes around the world. The Q biotype of B. tabaci, which is thought to have originated in the Mediterranean Basin, is now a widespread and serious agricultural pest. In this study, the genetic differences among Q biotype populations from Mediterranean countries and China were investigated. Based on their mt COI gene sequences, the Q biotype populations could be divided into two groups, which were labelled as MedBasin 1 and MedBasin 2. MedBasin 1 is indigenous to the western Mediterranean area while MedBasin 2 is indigenous to the eastern Mediterranean area. Genetic variation was greater in the MedBasin 1 populations than in the MedBasin 2 populations. Unlike the introductions into the USA, which involved both Medbasin1 and MedBasin2 populations, all B. tabaci Q biotype populations in China belonged to MedBasin 1. Wolbachia detection in eight representative Q biotype populations from China, Egypt and Syria indicated that all of the populations were infested with Wolbachia, and the infection rate of the Chinese populations (42.5%) were not significantly different from that of Egypt and Syria (51.4%). Phylogenetic analysis indicated that the evolution of the Wolbachia populations was not closely linked with the evolution of their B. tabaci hosts.

Evidence for a new genetic variant in the Bemisia tabaci species complex and the prevalence of the biotype Q in southern Italy

“…From their native regions, both biotypes have spread all over the world because of the trade of the host plants; they have colonized the invasion areas and have displaced less-injurious indigenous populations (Brown 2007) because of their superior adaptability to environments highly disturbed by agricultural practices (Delatte et al 2009), asymmetric mating interactions Crowder et al 2010) and indirect vector-virus mutualism via host plants (Jiu et al 2007). Recent studies have shown a considerable genetic variability amongst mitochondrial lineages of biotype Q. Phylogenetic analysis of COI haplotypes revealed the occurrence of two widespread subgroups, Q1 (western Mediterranean populations) and Q2 (eastern Mediterranean populations), both of which have spread to not native geographic areas (Tsagkarakou et al 2007;Chu et al 2008;Ahmed et al 2009), and two more groups, namely, Q3, consisting of populations from Burkina Faso only, besides ASL (Africa silverleafing) consisting of Sub-Saharan populations only (Gueguen et al 2010).…”

Fluorescence in situ hybridization analysis of endosymbiont genera reveals novel infection patterns in a tomato-infesting Bemisia tabaci population from Brazil

“…Biological differences between Wolbachia strains from Brazil and Israel could be an explanation for these variations. Genetic variability among Wolbachia populations from B. tabaci MED Q from China and Mediterranean regions has been identified (Ahmed et al 2009). In fact, there are already reports of at least two distinct Wolbachia strains coexisting, for example, in closely related mulberry leafhopper species (Mitsuhashi et al 2002).…”

Morphological and genetic variation of the pine shoot tunnel beetle Placusa pinearum (Staphylinidae) in China

“…Previously, Thomas (2009) reported a tribal-level phylogeny of the subfamily Aleocharinae by using partial sequences of the 12S and 16S mitochondrial genes, and Ahn et al (2009) reported a phylogeny of 21 species in the tribe Liparocephalini by using partial sequences of mtDNA COI and COII as well as 12S and 18S rDNA. Notably, several studies have suggested that mtDNA COI is an ideal marker for examining interspecific or intraspecific phylogenetic relationships among insects (Sole et al, 2008;Ahmed et al, 2009). However, to date, only 1 mtDNA COI gene sequence of Placusa sp can be found in GenBank (accession No.…”