Bemisia tabaci biotype Q dominates other biotypes across China

Abstract

Bemisia tabaci (Gennadius) biotype Q was first reported as an invasive species in 2005 in China. The present study is the first with this serious pest to determine the distribution and proportion with B. tabaci Q-SCAR (sequence characterized amplified region) marker, and to identify the distribution of the biotype Q through extensive survey and systematic sampling in most regions of China. We made 22 collections from 15 provinces in SepOct, 2007. The results showed that B. tabaci biotype Q was found in 19 collections from Shangdong, Gansu, Shaanxi, Guangxi, Zhejiang, Guizhou, Tianjin, Shanxi, Hunan, Henan, Hubei, Jiangsu, and Hainan provinces. The proportion (%) of B. tabaci biotype Q occurrence varied from 6.4% to 95.2% in these 19 collections, and it dominated (>50%) in 10 collections. The genetic divergence analysis based on mitochondrial cytochrome oxidase I (mtCOI) gene revealed that QSCAR marker was specific to biotype Q, and the non-Q biotypes mainly consisted of biotype B. The present results revealed that the biotype Q has become dominant across the country, and suggested that the displacement of non-Q biotypes by biotype Q has occurred in many regions. Furthermore, the introduction of the biotype Q might has mainly occurred through human activities rather than natural sources.