Screen Of Anti-TMV Substance From Plants And It's Inhibiting Mechanism On TMV

The anti-TMV activities were determined with crude extracts from 26 species plants of 14 families. The results indicated that ethanol extracts from 17 plants had more than 50% inhibiting rate on TMV among all extracts. There were 9 plants whose inhibiting rates were more than 80%. Ethanol crude extracts whose inhibiting rates were more than 50% had been extracted by other organic solvent and their inhibiting rates on TMV were determined. It showed that a majority of anti-TMV substance was in n-butylalcohol extracts, water extracts were in the next place, fewness was in chloroform extracts. 2 out of 17 extracts had more than 60% inhibiting rates after discarding the tannins. They were extracts from Bidens pilosa (84.5%) or Epimedium grandiflorum (69.1%) while others were less than 30%. It showed that tannins were likely the primary inhibitor in many plants' extract. It indicated that among the 26 plants only 3 ethanol extracts from Wedelia chinensis , Allium sativum , Cassia tora had strong inhibition on TMV in discs of tobacco leaves while other extracts didn't inhibit multiplication of TMV in the discs tobacco leaves.The flavonoids from Bidens pilosa were extracted by extracting with organic solvent and isolated by Sephadex-LH20 column chromatography. It showed that there were more than 2 flavonoids in the extracts as it was identified with chemical preliminary screen or silica gel folium chromatography. The anti-TMV activities of flavonoids extracted from Bidens pliosa were determined. It showed that infectivity of Tobacco mosaic virus (TMV) in Nicotiana glutinosa was strongly inhibited by flavonoids from Bidens pliosa .The inhibition rate was 91.3% when leaves were inoculated with TMV after incubated with flavonoids at 100 μg/mL, but it didn't inhibit multiplication of TMV in the infected leaf discs. It showed that the flavonoids may bind TMV coat protein based on routine PAGE. The infectivity of TMV recovered by dialyzing from incubations with flavonoids or extracting flavonoids from virus particles showed that the flavonoids didn't have directviricidal effect; flavonoids reduced infectivity of TMV and retarded symptoms expression if sprayed in Nicotiana tobacum 12h before inoculation.The naphtha was extracted from Allium sativum by distilling with vapour and its components were detected by MS, the result indicated the garlic naphtha was composed of more than 8 ingredients. The crystal from the flower of Wedelia chinensis was detected by chemical method, infrared, MS, the results indicated that the crystal was likely a lactone and its molecule weight was 256 . It was named WCLA. The anti-TMV activities of garlic naphtha and WCLA were determined. It showed that the inhibiting rate of garlic naphtha was 74.8% when leaves were inoculated with TMV after incubated with naphtha at 2000μg/mL and the inhibiting rate was only 33.7% if the concentration of naphtha was 500 ug/mL. But the WCLA didn't inhibit infectivity of TMV when TMV incubated with WCLA. The inhibiting rate of garlic naphtha and WCLA on multiplication of TMV were 82.6% and 69.1% when the infected leaves by TMV were dipped in solution of 400 μg/mL garlic naphtha or WCLA; The inhibiting rate of garlic naphtha on multiplication of TMV in the infected leaf discs was 76.5% when the concentration of naphtha was 400 ug/mLand the inhibiting rate of WCLA was 71.4% when its concentration was 500 μg/mL . It could be seen that some particles of TMV were split under electron microscope when TMV incubated with garlic naphtha, but the number and shape of TMV didn't change when TMV incubated with WCLA. It was proposed that the garlic naphtha interferes with an interaction between TMV coat proteins leading to split. It also showed that garlic naphtha and WCLA could interfere with aggregation of TMV-CP in vitro. If garlic naphtha and WCLA were sprayed in Nicotiana tobacum at 1000 ug/mL 30min and 2d after inoculation, the inhibiting rates of them on multiplication of TMV were 49.5% and 42.4%, the increasing rates of gross of chlorophyll in the tobacco we...