New Antiviral Agents Virus Star Role In The Mechanism

Bingduxing, one of a series of anti-TMV disease-resistant toxic agentias independently developed by our centre, have been proved to posses high bioactivity against TMV on Nicotiana glutinosa. In order to make it clear that the anti- TMV mechanism and anti-TMV function target, a series of traditional biochemical processes were carried out about Bingduxing in the present study.Experimental measurement about bioactivities against TMV by half-leaf inoculation revealed that Bingduxing had a curative inhibition rate of 66.23 %, at 500μg/mL in vivo, which was considered higher than that of a commercial product Ningnanmycin with a rate of 45.56 %. In addition, Bingduxing had a inhibition rate of 48.53 % in vitro, inactivation inhibition rate of 68.85%, protection inhibition rate of 48.98 % in vivo, and 50 % effective concenteations(EC₅₀) at 294.47μg/mL against TMV. Further more measurement on curative effect showed that Bingduxing from different formulation have different curative inhibition rate and 30% wettable powder had curative inhibition rate higher than Ningnanmycin at 500μg/mL.On the basis of experimental results, a field survey on the bioactivities of Bingduxing against TMV on Nicotiana glutinosa was conducted. Result showed that 30 % wettable powder smeared led to the lysis of TMV symptom, of which the curative inhibition rate was 61.19-76.08 % at 500μg/mL after 21 days (P<0.05). In addition, tobacco leaves after Bingduxing treatment were observed to become green as compared to that of the control in the field. It implied that the curative effect in vivo by half-leaf inoculation was comparable to the protective effect in field. Furthermore, it also indicated that Bingduxing acted on both leaves of Nicotiana glutinosa indoor and that of K-₃26 in field by the similar mechanism of action.We measured the enzyme activities of PAL, POD and SOD, Chlorophyll content and Pathogenesis related proteins (PR) in tobacco inoculated with Bingduxing. The result showed the agent could simulate tobacco to enhance enzyme activity so as to develop resistance. Regarding PR, Bingduxing can simulate tobacco to produce homogeneous proteins with TMV, three of which were shown to have molecular weight of 55 KDa by isoelectrofocusing at pH 4.9, these proteins appeared to be a part of the big subunit of ribulose-1, 5-bisphosphate carboxylase (RUBPCO).Scanned by Electron microscope (EM), TMV inactivation by Bingduxing for half an hour indicated that TMV were agglomerated in compared with those without inactivation.