| B. tabaci is a worldwide and invasive pest and occupies an advantage on competing when compete with other herbivores. Our earlier research found out the tobacco that was fed by B. tabaci fist would inhibit the following feeding Myzus persicae population and had a negative effect of M. persicaes’ growth and reproduction,which also induced tobacco’ SA signaling pathway. We chose B. tabaci-tobacco-tobacco aphid as research system and transgenic NahG with altered NahG gene as well as it’s control Xanthi as material to conduct the following research. We aimed at the function of salicylic acid pathway mediating B. tabaci induced tobacco defense response against Aphidius growth and reproduction, and the change of salicylic acid in Xanthi and NahG induced by B. tabaci infestation so as to find out The function of salicylic acid pathway mediated by B. tabaci induced tobacco defense response against Aphidius. we determined defense related chemicals’ change in Xanthi and NahG induced by B infestation and try to find out the main effect chemicals in salicylic acid signaling pathway against M. persicae. Our research provide evidence to make it clear that the role of salicylic acid signaling pathway function mediated by Bemisia Tabaci induced tobacco defense response against Aphidius。Our main results are as follows:1. We studied Xanthi and NahG that was infested by B. tabaci first and their influence on M. persicaes’ growth and reproduction and find out that Xanthi’s white vein leaf infested by B. tabaci had an negative effect on M. persicaes’ growth and reproduction,72h after the start of feeding, the first instar B. tabaci only had a9% survival rate while the control nymph’s survival rate is59%and what’s more, the former had a longer development duration and reduced M persicaes’ fecundity compared with the control nymphs. Locality infested Xanthi’s leaf by B. tabaci has a minor effect on M. persicaes’growth and reproduction and has no difference between control while NahG that infested by B. tabaci has no obvious negative effect on M. persicaes’survival rate, fecundity and development duration. These result indicate that transgenic NahG that cannot accumulate SA blocked B induced tobacco’s defense against.2.We determined SA levels in Xanthi and NahG induced by B. tabaci infestation by high performance liquid chromatography (HPLC) method. SA levels in Xanthi increased quickly after B. tabaci infestation, while B. tabaci infestation don’t change the inner SA levels in Nah G. SA levels in Xanthi’s white vine leaf and leaves with B. tabaci increased obviously after B, tabaci infestation compared with controls. SA levels increased quickly after B. tabaci infestation for10d, which is7.5-9.9times higher than control leaves and SA levels increased higher in leaves with B. tabaci than that of system leaves.15d after B. tabaci infestated SA levels reduced obviously but still higher than that of controls. B. tabaci infestated don’t change inner SA levels in NahG.3. We determined the main defense related enzymes activities in Xanthi and NahG infested by B. tabaci. Proxidase (POD) activity in system and local leaves infested by B. tabaci were higher than that of non-infested plants. PPO activity in control Xanthi was induced compared with controls by45%to with B. tabaci-leaves and70.3%with white vine leaves and the scale in white leaves was higher than that of damaged leaves. PPO activity in NahG was also slightly induced by B. tabaci infestation while the scale was lower than that in Xanthi。B. tabaci infestation’influence on β-1,3-glucanase activities:we found out that β-1,3-glucanase activities in the white vine leaves of Xanthi was induced10d and15d after B, tabaci infestation by63.7%and53.3%compared with controls with-B-leaves was slightly induced10d after infestation although not obviously. β-1,3-glucanase activities in NahG was also slightly induced but not obvious compared with controls。... |
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