The Dynamics of Abscisic Acid and Cytokinins Content in the Leaves of Wheat–Aegilops Lines and Their Parental Forms Affected by Powdery Mildew

We studied the dynamics of abscisic acid and cytokinins content in wheat–aegilops lines and their parental forms affected by powdery mildew. Lines 95/99 i and 56/99 i demonstrated the types of resistance untypical of the soft wheat Rodina and Aegilops speltoides k-389 but typical of Ae. speltoides Tausch from other natural habitats. A relative stability of the hormonal balance in the course of the infection was demonstrated for lines 95/99 i and Ae. speltoides k-389 highly resistant to the pathogen penetration. Line 56/99 i was sensitive to the penetration; however, a subsequent prolonged hypersensitive response eliminated pathogen colonies surrounded by necrotic areas. A correlation between disbalanced hormonal metabolism of cytokinins and low resistance to the infection has been revealed for 56/99 i line and Rodina cultivar. Free form of abscisic acid was revealed in the intact plants of the parental forms. Bound form of this hormone was revealed in the infected plants of lines 95/99 i and 56/99 i as well as of Ae. speltoides k-389, which seems to be a marker of their different stress resistance according to the phenotypic manifestation of powdery mildew.