ETHYLENE AND MITOGEN-ACTIVATED PROTEIN KINASES IN REGULATION OF REDOX-STATUS IN COMMON WHEAT INFECTED WITH <i>STAGONOSPORA NODORUM</i>
The roles of ethylene, components of mitogen-activated protein kinase (MAPK) cascades and WRKY transcription factors in regulation of redox-status in infected by the causal agent of leaf blotch ( Stagonospora nodorum Berk.) leaves of common wheat ( Triticum aestivum L.) cultivars contrasting in the resistance to the pathogen were studied. Two peaks of the generation of hydrogen peroxide (H<sub>2</sub>O<sub>2</sub>) on the 15 minutes and 6 hours after infection in plants of a resistant variety were detected. These peaks were not found in susceptible variety. Ethylene suppressed the accumulation of H<sub>2</sub>O<sub>2</sub> regulating expression of genes TaRbohD and TaRbohF encoding isozymes of NADPH-oxidase, and inhibited induction of defense signal associated with oxidative burst. Oxidative burst default and suppression of the expression TaRbohF gene in susceptible variety and ethephone(chemical precursor of ethylene)-treated plants infected by S. nodorum were accompanied by accumulation of mRNA of MPK3/MPK6 genes, ethylene biosynthesis genes TaACS1, TaACO and genes of primary response on ethylene TaEIL1, TaPIE1 ( TaERF1 ) and significant increase of expression of TaWRKY53b gene. Oxidative burst infected by S. nodorum plants of resistant variety and plants treated with 1-methylcyclopropene (ethylene reception inhibitor) was associated with accumulation of transcripts of MPK6, MPK7 and TaWRKY13 genes. These factors led to suppression of biosynthesis and signaling pathway of ethylene.