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 trans-plasma 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 Δ[Fe(2+)]) 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.