The effects of cold-hardening and Microdochium nivale infection on oxidative stress and antioxidative protection of the two contrasting genotypes of winter triticale

Abstract

Pink snow mould resulting from Microdochium nivale (Samuels and I.C. Hallett) regularly infects winter triticale (× Triticosecale, Wittm.). Therefore, in the present paper we aimed to identify biochemical markers potentially involved in the increased resistance against M. nivale of this valuable crop. In our experiment, we used two doubled haploid (DH) lines with the highest and the lowest cold-induced snow mould resistance, previously identified in cold chamber tests. The impact of cold-hardening (4 weeks at 4 °C) as well as covering plants with an artificial system to mimic snow covers and inoculation with M. nivale mycelium in leaves of seedlings, different genotypes on the thiobarbituric acid-reactive substance (TBARS) level and superoxide dismutase (SOD), catalase (CAT) and peroxidase (POX) activities was assessed. Our studies indicate that, indeed, various genotypes differ in their response to the treatments in regard to the measured parameters. The leaf TBARS content was always lower in seedlings of snow mould-resistant DH1 line in comparison with susceptible DH92 ones, suggesting that tissue damage was more pronounced in plants of the second genotype. The activity of SOD and CAT had no correlation with the level of snow mould resistance. The cold-enhanced POX I activity was higher in DH1 seedlings under the snow-imitating covers with or without M. nivale inoculation in comparison with DH92 plants. Moreover, POX II activity was higher after cold-hardening in the resistant genotype. POX III activity was enhanced by abiotic stress in leaves of DH1 seedlings, while it was not detected in susceptible genotype in any experimental term.