| Bemisia tabaci (Gennadius) B biotype spread rapidly when it invades in China. It has been a key pest of various vegetables, cotton and tobacco and so on. We found that B. tabaci was predomination in competing with M. persicae. We chose B. tabaci--tobacco-M. persicae as research system, studied the effect of tobacco's defense response induced by B. tabaci on development and reproduction of M. persicae and B. tabaci itself. We also investigated defense signial pathway on tobacco induced byB. tabaci to explor the action of it in defensing M. persicae. We explored the difference of physiological adaptability of the two insects to defense response of tobacco induced by B. tabaci. This research had important academic meaning for showing competitive replacement mechanism of B.tabaci to M. persicae, and implementing sustainable control effectively. Major results as follows:1 There was disadvantaged influence of tobacco damaged by B. tabaci on development and fecundity of M. persicae, but no influence on B. tabaci itself. On systemic white-vein leaves, livability of M. persicae nymphae was 35.4% and 29.9% when feeding 72 and 96h, the control was 94.3% and 91.5%. Livability of adult of M. persicae was 42.9% when feeding 12h on systemic white-vein leaves. Fecundity of adult of M. persicae was significantly fall. Accumulative number of eggs per female was 25.6 when feeding 12h on systemic white-vein leaves, control is 32.5. Meanwhile, there was nearly no disadvantaged influence on livability of M. persicae nymphae on local leaves of induced tobacco plants. There was no disadvantaged influence on livability,fecundity and development of B. tabaci itself on systemic and local leaves of induced tobacco plants.2 Nymphae of B. tabaci can induce strong SA signical pathway, but not induce significant JA signical pathway after feeding on tobacco plants.(1) The activity of PAL andβ-1,3-glucanase which are two key enzyme in SA signical pathway were significantly rise. On systemic white-vein leaves, The maximal activity of PAL andβ-1,3-glucanase was as 2.23 and 1.65 times as control on 15d and 10d,respectively. On local leaves,the maximum activity of PAL was as 2.25 times as control on 10d.However the activity ofβ-1,3-glucanase was no significant difference. The activity of LOX which is the key enzyme of JA signial pathway was no significant difference on local leaves,and significantly repressed on systemic white-vwin leaves.(2)The gene expression amout of PAL,PR1 and PR5 in SA signial pathway was significantly rise on systemic and local leaves of induced plants. The gene expression amout of AOS gene in JA signial pathway is a little rise in the two leaves, but the gene expression amout of LOX and COI in JA signial pathway was no significant difference.(3)Content of SA in induced tobacco plants by B. tabaci was significantly rise. On systemic white-vein leaves, content of SA was significantly rise on 10 and 15d, and gradually fall later. Content of SA was as 29.71 times as control plants on 10 days. Meanwhile, on local leaves, content of SA was as 20.94 times as control on 10 days,but no significant difference on later times. Content of SA was nearly no difference in induced plants.3 Application of exogenous SA can induce defence reponses of tobacco plants to M. persicae. It indicated that SA signal pathway had important effect to M. persicae on tobacco plants induced by B. tabaci.(1) Application of exogenous SA on tobacco had disadvantaged influence on livability and development of M. persicae. Degree of the influence on M. persicae of the three concentration was 1mM>2mM>0.5mM. Application of exogenous SA on tobacco plants nearly had no effect on survivol and developmental period of B. tabaci. Application of exogenous JAon tobacco can expedite the development of M. persicae. Degree of the effect on M. persicae of the three concentration was 1mM>2mM>0.5mM. Application of exogenous JA on tobacco had a slight effects on B. tabaci.0.5mM of JA slightly slower the development of B. tabaci nymphae,2mM of JA can expedite the development of it, 1mM of JA had no significant effect on it. Application of exogenous JA on tobacco had no effect on livability of B. tabaci and M. persicae.The systemic leaves had the same trend, but degree of effect was lower than the local leaves.(2) Application of exogenous1mM SA and 2mMeJA on tobacco to research the influence on B. tabaci and M. persicae of time effect. It indicated that the influence was the most significant on 5 days, the influence was slight on 2 days, and was no influence on 8 days.4 There was different influence on activities of detoxification metabolize enzymes,protective enzymes and digest enzymes between B. tabaci and M. persicae. (1) The activity of Carboxylesterase of B. tabaci was significantly increase from 12h to 72h. The maximal activity was as 1.71 times as control on 12h. The activity of Glutathione S-transferase of B. tabaci was significantly increase on 48 and 72 times. The maximal activity was as 2.34 times as control on 48h. The activity of Carboxylesterase of M. persicae was significantly decrease with the time of feeding. The minimal activity was as 0.78 times as control on 24h. The activity of Glutathione S-transferase of M. persicae was significantly decrease on 12,48 and 72h. The minimal activity was as 0.74 times as control on 12h.There was no influence on acetylcholine esterase of the two insects.The nympha of the two insects has the same result.Km and Vmax of the two enzyme of the two insects changed inordinately.It showed that the activities of the two enzymes qualitative changed.(2) The activities of PPO and SOD in B. tabaci significantly increased after feeding on the preinfested tobacco plants for 6,12,24,48 and 72 h, and the POD activity in B. tabaci also significantly increased after feeding on the preinfested tobacco plants for 6,48 and 72 h, respectively.The maximum activities of SOD, PPO and POD in B. tabaci on the preinfested tobacco plants were 1.62,2.71 and 2.57 times higher than those in the control, respectively. In contrast, the activities of PPO and SOD in M. persicae increased a little in most time-span after feeding on the preinfested tobacco plants, while the SOD activity was obviously suppressed after feeding on the preinfested tobacco plants for 12 h. POD activity in M. persicae was significantly inhibited except after feeding on the preinfested tobacco plants for 24 h(3) The activities of protease and amylase in B. tabaci significantly increased in all time-span after feeding on the preinfested tobacco plants, the maximum activities were 1.54 and 1.33 times that in the control, respectively. Activities of protease and amylase in M. persicae did not change after feeding on the preinfested tobacco plants for 6 h(P>0.05); however, the activities were inhibited with the extending of feeding time, the lowest activities in M. persicae feeding on the preinfested tobacco plants was 0.39 and 0.72 times that in the control, respectively.
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