Abstract: To determine the defense responses of tobacco plants to Myzus persicae induced by Bemisia tabaci B biotype and their temporal effect and explore their role in interspecific competition between B. tabaci and M. persicae, we investigated the effect of tobacco defense responses induced by B. tabaci on the development of M. persicae with the method of clip-cage. Moreover, the changes of major nutritional indices in tobacco plants preinfested by B. tabaci were also studied using biochemical analysis. The results showed that B. tabaci B biotype could induce the defense responses of tobacco plants to M. persicae distinctly.  These responses inhibited the survival and development of M. persicae significantly and had distinct temporal effects.  The mortalities of M. persicae fed on systemic white-vein leaves preinfested by B. tabaci nymphs for 5 d were 36.13% higher than those on the control leaves. After infestation by B. tabaci nymphs for 10 d, the mortalities of M. persicae were 72.78% higher than those on the control leaves, and the average relative growth rates were reduced significantly compared with the control. After infestation by B. tabaci nymphs for 15 d, the mortalities were still 58.89% higher than those on the control plants. On the 10th day of the infestation by B. tabaci nymphs, B. tabaci nymphs fed on treated plants were wiped off, and then the 1st nymphs of M. persicae were placed on the white-vein leaves. After that, they were clip-caged immediately.  Significant differences in the mortalities and relative growth rates of M. persicae were found between the systemic white-vein leaves of control plants and the leaves of treated plants within 15 days after removing B. tabaci nymphs（P<0.05）. But the differences were no longer found on the 20th day after removing B. tabaci nymphs. The results suggest that the defense responses of the systemic white-vein leaves of tobacco plants induced by B. tabaci should continue being expressed for about 15 d. The damaged leaves preinfested by B. tabaci have no significant negative influence on the mortalities and relative growth rates of M. persicae compared with the control leaves.  Both soluble sugar and soluble protein contents are reduced in the systemic white-vein leaves preinfested by B. tabcai B biotype, which have distinct negative correlation with the mortalities of M. persicae.

Key words: Bemisia tabcai B biotype, Myzus persicae, tobacco, induced resistance, temporal effect, development, nutritional indices