THE RELATION BETWEEN ISOZYMES OF BETA-1,3-GLUCANASE AND RESISTANCE OF NEAR-ISOGENIC MAIZE INBRED LINES TO EXSEROHILUM-TURCICUM

Beta-1,3-glucanase isozymes in leaves of maize susceptible or resistant to Exscrohilum turcicum were visualized using native polyacrylamide gel electrophoresis and staining with 2,3,5-triphenyltetrazolium chloride. In noninoculated leaves, 2 bands (B,C) with low intensity were observed in the susceptible cultivar Jubilee (Rfs 0.74, 0.77). In the susceptible line B37, one intense band (C) appeared (Rf = 0.77). Bands with Rfs of 0.74 and 0.77 were absent from the resistant isoline B37HtN, but two other bands (A,E) were detected (Rfs 0.70, 0.87). After inoculation of the three maize genotypes with E. turcicum, an intensification of all bands was detected in extracts prepared from the symptomless areas of inoculated leaves. In inoculated plants of line B37HtN bands B and C, which were absent from noninoculated leaves, were detected, as well as an additional isozyme (D, Rf 0.83). Infection of leaves with E. turcicum significantly increased total activity of beta-1,3-glucanase in leaf extracts from the resistant line B37HtN but not from the susceptible line B37. Differences between resistant and susceptible lines in patterns of isozymes of beta-1,3-glucanase before inoculation and in total activity of the enzyme after inoculation may be useful in rapid detection of resistance in maize to E. turcicum.