Gibberellins hypersensitivity hinder the interaction of Bipolaris sorokiniana (Scc.) under cross talks with IAA and transzeatin

Gibberellins are considered to play an important role in modulating plant–pathogen interactions. In order to find this, we studied the effect of GA4 on the interactions of Bipolaris sorokiniana (Scc.) (BIPOL) with Triticum aestivum. After inoculating the roots of hydroponically grown T. avestivum with BIPOL, the GA4 level shot up by 26%. The increased level of GA4 elicited a hypersensitive response (HR) in the T. aestivum seedlings. The elicitation in HR was confirmed through measurement of HR-inducing signaling compounds (i.e. c-di-GMP, cAMP, phosphatidic acid, pure and esterified oxo-phytodeinoic acid, and jasmonic acid). The concentration of HR-inducing signaling compounds in the treated T. aestivum seedlings was 31% higher compared to the control seedlings. Moreover, the induced HR response lowered the indole-3-acetic acid (IAA) level by 15% and the transzeatin (TZn) level by 22%. However, the application of 10 mM uniconazole through aerial spray inhibited GA4 biosynthesis in T. aestivum seedlings. Also, BIPOL colonized the roots of T. aestivum seedlings after uniconazole treatment and promoted seedling growth through increased relative growth rate (14%) and net assimilation rate (27%).