煙草粉蝨 (半翅目：粉蝨科) 體內番茄捲葉病毒之偵測及其內共生菌之分子變異

Abstract

Bemisia tabaci (Gennadius) is a globally distributed insect pest in the field. It has a wide range of host plants and is thought to be a species complex with many biotypes. In Taiwan, biotypes B, An, and Nauru have been recorded. The economic impacts of this insect pest consist of its damage to host plant health by sucking plant juices, its pollution of plants by secreting honeydew, and its transmission of plant viruses. The most serious damage caused by B. tabaci is its transmission of Tomato leaf curl Taiwan virus (ToLCTWV) to tomato plants in Taiwan. In this research, we collected B. tabaci from many tomato fields in Taiwan, and detected the ToLCTWV from B. tabaci by polymerase chain reaction (PCR). At the same time, specific primer sets were used to identify the biotypes of B. tabaci. In this research, 98.97% of the examined B. tabaci specimens were biotype B, and all of viruliferous B. tabaci specimens with the ToLCTWV were biotype B. Moreover, we studied the phylogeny and phylogeography using molecular markers. The results showed that the ToLCTWV can be separated into western and eastern Taiwan “variants”. Genetic distance analysis revealed that the variants of western Taiwan are closely related. On the contrary, genetic distances among variants of eastern Taiwan were more variable. Furthermore, we studied the retention possibility of the ToLCTWV among B. tabaci biotypes, and found that both the B and Nauru biotypes can maintain the ToLCTWV. In contrast, retention of the ToLCTWV by biotype An was weak after 10 days of infection. In the study of symbionts of B. tabaci, we found that sequence similarity of the protective gene against virus particles was 73% between biotypes Nauru and B. Furthermore, phylogenetic analysis of 16S rDNA showed that the primary symbionts were consistently grouped with B. tabaci biotypes and the geographic distribution.