Comparison of effects of acidic electrolyzed water and NaOCl on Tilletia indica teliospore germination

Definitive identification of free teliospores of Tilletia indica, causal ag ent of Karnal bunt of wheat, requires polymerase chain reaction (PCR)-based diagnostic tests. Since direct PCR amplification from teliospores has not been reliable, teliospores first must be germinated in order to obtain adeq uate DNA. We have routinely surface-sterilized teliospores for 2 min with 0 .4% (vol/vol) sodium hypochlorite (NaOCl) to stimulate germination and prod uce axenic cultures. However, we observed that some spores were killed even with a 2-min NaOCl treatment, the shortest feasible duration. Decreasing t he NaOCl concentration in our study from 0.4% to 0.3 and 0.2%, respectively , increased teliospore germination, but treatment times longer than 2 min s till progressively reduced the germination percentages. In testing alternat ive methods, we found "acidic electrolyzed water" (AEW),generated by electr olysis of a weak solution of sodium chloride, also surface-sterilized and i ncreased the rate of T. indica teliospore germination. In a representative experiment comparing the two methods, NaOCl (0.4%) for 2 min and AEW for 30 min increased germination from 19% (control) to 41 and 54%, respectively, by 7 days after treatment. Because teliospores can be treated with AEW for up to 2 h with little, if any, loss of viability, compared with 1 to 2 min for NaOCl, treatment with AEW has certain advantages over NaOCl for surface sterilizing and increasing germination of teliospores of suspect T. indica .