Drug Screening Of New Anti-tobacco Mosaic Virus And Mechanism Of A Preliminary Study

Bioassay experiment by half-leaf method revealed that the compounds 2005196 (3-benzylamino-3-[1-(R)-4-fluorophenyl ethyl amidocyanogen]-2-cyanoacrylate) and 2006172 (3-methylthio-3-(diethoxy ethyl)phosphonyl-2-cyanoacrylate) had comparable curative activities of 55.6% and 53.3% with the standard Ningnanmycin(51.7%) against TMV at 500μg/mL in vivo. The median effective concenteations(EC5o) values were 218.7μg/mL and 275.4μg/mL, respectively. In addition, 2005196 and 2006172 had inactivation activities of 52.5% and 80.8%, protection activities of 60.4% and 44.7% respectively in vivo.On the basis of experimental results, a potted plant survey in lab on the bioactivities of the compounds against TMV on Nicotiana glutinosa was conducted. Result showed that the compound 2005196 led to the lysis of TMV symptom, with a the curative inhibition rate of 60.6% at 250μg/mL after 45 days (P<0.05). In addition, tobacco leaves followed by treatment with the compound 2005196 were found to become green as compared to that of the control in lab. It implied that the curative effect in vivo by half-leaf method was comparable to the protective effect in lab. Furthermore, it also indicated that the compound 2005196 acted on both leaves of Nicotiana glutinosa indoor and that of K-₃26 in lab by the similar mechanism of action. The enzyme activities of PAL, POD and SOD, Chlorophyll content and Pathogenesis Related Proteins (PR) in tobacco inoculated with the compound 2005196 and 2006172 were measured. The result showed the compound could stimulate tobacco to enhance enzyme activity so as to develop resistance. Regarding PR, the compound 2005196 can stimulate tobacco to produce homogeneous proteins with TMV.