Insulin-like Peptide Gene CDNA Cloning, The Development And Expression Of Whitefly, Bemisia Tabaci Middle East-Asia Minor1

The whitefly Bemisia tabaci is one of the invasive species in China, which caused great damage to crops. The whiteflies were called super pests, and received extensive attention all over the world. This study focused on the invasive species Bemisia tabaci the insulin-like peptide gene cloning and developmental expression and the impact on the dynamic change when feeding on the tabaco infected by TYLCCNV. The main results are as follows:1. Cloning and sequence analysis of the insulin-like peptide gene in the whitefly, Bemisia tabaci MEAM1The full length of insulin-like peptide gene cDNA in Bemisia tabaci MEAM1was cloned. The cDNA was590bp and the open reading frame was about450bp, which had149amino acids with a molecular weight17.3kDa. The isoelectric point was9.248. By online signal peptide analysis, the23amino acids at N-terminal was the signal peptide. By the homologous comparision, the results showed that this gene had the conserved B chain and A chain with cysteines. The A chain had the typical characteristics of insulin super family, which contained CC-3X-C-8X-C structure.2. The expression profiling of the insulin-like peptide at different developmental time and different tissues in Bemisia tabaci MEAMlThe relative expression level of insulin-like peptide gene at different developmental time and different tissues was detected by using semi-quantitative PCR and real-time quantitative PCR. The insulin-like peptide gene was expressed at relative low level at the pseudo-pupal stage and newly eclosed adults. The insulin-like peptide gene began to express on the1st day after eclosion and increased gradually and reached the peak level on the5th day after eclosion. Then the transcript level began to reduce. This gene was expressed at all the head, thorax and abdomen, but the relative expression level was higher on the2nd day after eclosion with no significant difference, and in the head and thorax on the5th day after eclosion with no significant difference. Besides, the head got overexpression on the7th day after eclosion with significant difference compared to the thorax and abdomen. 3. The impact on the transcription level of insulin-like peptide gene in Bemisia tabaci MEAM1when feeding on the tobacco infected by tomato yellow leaf curl China virusBy using real-time quantitative PCR, we found that the whitefly got higher insulin-like peptide gene expressed when feeding on the TYLCCNV infected plants compared with the healthy tobacco,with signifcant differnece. The relative expression level reached the peak on the1st day after ecosion, and then increased gradually from the3rd day after eclosion. When feeding on the TYLCCNV+TYLCCNB co-infected plants, the whiteflies also expressed more insulin-like peptide gene than healthy plants. The difference was signicant since the3rd day after eclosion. When feeding on the TYLCCNV+TYLCCNB co-infected tobacco, the insulin-like peptide gene was expressed at higher level since the3rd day after eclosion compared with the TYLCCNV infected tobacco. the difference was significant. On the7th day after eclosion, the relative expression level was similar with non-significant difference.