In vivo inhibition of trans-plasma membrane electron transport by antiviral drugs in grapevine

Electrophysiological techniques were applied to investigate the action of antiviral drugs during transplasma events in in vivo grapevine cells infected by GLRaV-1 and GLRaV-3. Carbon fiber microelectrodes and redox-sensitive dyes were used to measure trans-plasma membrane electron transport (t-PMET) activity in healthy and infected samples treated with ribavirin, tiazofurin and oseltamivir. Each drug caused a reduction in oxidation current (expressed as D[Fe2?]) in healthy samples, indicating t-PMET inhibition. In almost all infected samples, the effect of drugs on t-PMET activity was significantly lower, suggesting that higher content of NADH in infected plants can interfere with t-PMET inhibition caused by drugs. Moreover, virus-infected samples exhibited elevated t-PMET activity compared to healthy samples. Analogous effects were observed by dye tests. Considering the effects of drugs on trans-plasma membrane potential, tests showed the activity of a proton pump during drug treatments with no significant difference with regard to health status.