Does foliar application of salicylic acid protects nitrate reductase and enhances resistance in virus infected maize?

Abstract

The present study was conducted to assess whether exogenous applied salicylic acid (SA) as a foliar spray could ameliorate the adverse effects of virus infection in two maize cultivars (maize cv. sabaini and maize cv. Nab El-gamal). The plants were grown under normal field conditions for two weeks in sand clay soil, and then sprayed with either 2 or 4 mM SA. Two weeks later, plants were subjected to infection with two different concentrations of virus (TMV1 and TMV2), and were harvested 10 days later. Fresh and dry matter, shoot and root lengths, proline, soluble protein, soluble sugars as well as nitrate reductase activity were measured. Both fresh and dry matter were decreased under virus infection however, SA enhanced the fresh and dry matter production in both cultivars regardless the type of virus or SA concentration used. In roots, both fresh and dry matters were not affected. The shoot length was enhanced by salicylic acid than root length regardless the concentration used or virus treatment. The water content was much higher in shoots than roots especially in maize cultivar sabaini. Proline was accumulated in SA virus infected plants than reference control especially in cv sabaini. Soluble proteins and soluble sugars were accumulated in SA virus infected plants and in cv sabaini more than Nab El-gamal as compared with reference control. NRA was reduced in virus infected cultivars and cv sabaini was dramatically affected than Nab El-gamal. Treatment of plants with SA had a positive effect on preserving the activity of NR but was still less than the reference control regardless the cultivar used.

Keywords: Nitrate reductase, proline, protein, salicylic acid, sugars, viruses.

African Journal of Biotechnology Vol 13(23) 2330-2335