Genetic groups and endosymbiotic microbiota of the Bemisia tabaci species complex in Japanese agricultural sites

The whitefly Bemisia tabaci is a cryptic species complex of at least 24 genetically distinct species. Thus far, one obligate and seven facultative symbiotic bacteria have been reported from the B. tabaci species complex. Both genetic groups and infected symbionts are extremely important to estimate the pest status of B. tabaci. In this study, we collected 340 whiteflies from 39 agricultural sites, covering an entire region of the B. tabaci habitat in Japan, and examined the genotypes and symbiont community composition at subspecies level. Use of the cleaved amplified polymorphic sequence technique and mitochondrial cytochrome oxidase subunit I gene sequencing detected five genetic groups: indigenous species JpL and Asia II 6, invasive species Middle East-Asia Minor 1 (MEAM1) and Mediterranean Subclade Q1 (MED Q1), and a genetic group previously undetected in Asia, Mediterranean Subclade Q2 (MED Q2). The genetic groups exhibited characteristic infection statuses with regard to their facultative symbionts, as observed in other countries. The endosymbiotic microbiota of the Japanese MED Q1 was different from that in neighbouring countries, but similar to that in the French or Uruguayan MED Q1. These results may indicate that Japanese MED Q1 species have not invaded from neighbouring countries, but from distant countries by international transportation. All Japanese MED Q2 species were infected with Rickettsia, some of which are regarded as conferring a female-biased sex ratio and fitness benefit on B. tabaci. The results suggest that MED Q2 may be prevalent in Japan and neighbouring countries.