Effect of antiviral chemicals on in vitro regeneration response and production of PLRV-free plants of potato

Abstract

Potato leaf roll virus (PLRV) is causing serious loss in yield and quality of potatoes. In the present study, the effect of seven antiviral chemicals viz. Acyclovir, 5-Azacytidine, Cytarabine, 5-Bromouracil, Ribavirin, 2-Thiouracil and Zidovudine on regeneration response and production of PLRV-free plants under in vitro conditions is reported. MS medium supplemented with 0.1 mg L⁻¹ GA₃, 0.1 mg L⁻¹ NAA and 500 mg L⁻¹ malt extract was used for regeneration of plantlets from nodal explants. DAS-ELISA and RT-PCR was used for virus indexing of the mother plant and in vitro-regenerated plantlets. Explants of PLRV positive potato plants were cultured on this medium containing different concentrations (5 – 30 mg L⁻¹) of antiviral chemicals. Shoot regeneration response varied between tested antiviral chemicals and was decreased with increase in concentration of antiviral chemicals from 5 to 30 mg L⁻¹. Antiviral chemicals at 30 mg L⁻¹ concentration showed strong inhibitory effect on regeneration response of shoots. In vitro regenerated plantlets tested negative in both ELISA and RT-PCR were only considered as virus free. When regeneration response and number of virus-free plants produced was compared, 2- thiouracil and ribavirin (25 mg L⁻¹) were found to be effective. 2- thiouracil (25 mg L⁻¹) gave 38.68% PLRV free plants with 30.55% cultures showing shoot regeneration and ribavirin (25 mg L⁻¹) gave 39.62% PLRV-free plants with 36.80% cultures showing shoot regeneration. Regeneration response of explants was better on 5-Bromouracil at 30 mg L⁻¹ concentrations but it was found least effective in production of PLRV-free potato plants.