Earlier than expected introductions of the Bemisia tabaci B mitotype in Brazil reveal an unprecedented, rapid invasion history

During 1991, in Brazil, the presence of the exotic Bemisia tabaci B mitotype was reported in Sao Paulo state. However, the duration from the time of initial introduction to population upsurges is not known. To investigate whether the 1991 B mitotype outbreaks in Brazil originated in Sao Paulo or from migrating populations from neighboring introduction sites, country-wide field samples of B. tabaci archived from 1989-2005 collections were subjected to analysis of mitochondrial cytochrome oxidase I (mtCOI) and nuclear RNA-binding protein 15 (RP-15) sequences. The results of mtCOI sequence analysis identified all B. tabaci as the NAFME 8 haplotype of the B mitotype. Phylogenetic analyses of RP-15 sequences revealed that the B mitotype was likely a hybrid between a B type parent related to a haplotype Ethiopian endemism (NAFME 1-3), and an unidentified parent from the North Africa-Middle East (NAF-ME) region. Results provide the first evidence that this widely invasive B mitotype has evolved from a previously undocumented hybridization event. Samples from Rio de Janeiro (1989) and Ceara state (1990), respectively, are the earliest known B mitotype records in Brazil. A simulated migration for the 1989 introduction predicted a dispersal rate of 200-500 km/year, indicating that the population was unlikely to have reached Ceara by 1990. Results implicated two independent introductions of the B mitotype in Brazil in 1989 and 1990, that together were predicted to have contributed to the complete invasion of Brazil in only 30 generations.

Automated summary

This study investigated the origin and spread of the Bemisia tabaci B mitotype outbreaks in Brazil in 1991. The results revealed a previously undocumented hybridization event, with the B mitotype likely being a hybrid between a B type parent related to Ethiopian endemism and an unidentified parent from the North Africa-Middle East region. The study also found evidence of two independent introductions of the B mitotype in Brazil in 1989 and 1990, which together led to the complete invasion of Brazil in just 30 generations.