Role of phenolic compounds in reaction of sugarcane cultivars to smut disease

Smut is the most important disease of sugarcane in Iran, and most of the plant growing areas in the world. The most effective method of disease management, is identification and cultivation of resistant varieties. The aim of this study was to investigate changes in the level of phenolic compounds in resistant and susceptible cultivars to disease and detection phenolic compounds resistance index, to accelerate the identification of resistant cultivars. Two cultivars NCO-310 and CP78-1628, susceptible and resistant to the disease were selected, and with apical meristem and lateral buds culture method, their seedlings with four leaves were produced. Seedlings were inoculated with a suspension of a mixture of two compatible mating type of pathogen. Stem of plants were sampled at 0-120 hour post-inoculation. Soluble and cell-wall binding phenolic acids were extracted from samples, and presence and concentration of phenolic acids p-coumaric , ferulic, p-hydroxybenzoic and syringic acids were detected and determined by high performance liquid chromatography (HPLC) method. Comparison the data obtained from HPLC device showed only titer of cell wall-bound phenolic acids ferulic and syringic showed enhancement, in the resistant cultivar, this reflects the role of these phenolic acids in the resistance reaction. Thus, these phenolic acids can be considered as an indicator of resistance, and in this way quickly identify resistant cultivars and management disease.