Signal molecules involved in the regulation of the wheat defense response to Septoria nodorum infection

Abstract

The response of Triticum aestivum L. to infection by Septoria nodorum Berk, a pathogen causing speckled leaf blotch, was studied. The effect of salicylic acid (SA) and jasmonic acid (JA) signal molecules, as well as chitooligosaccharides (COSs) with different acetylation degrees (ADs), on the accumulation of hydrogen peroxide (Н2О2) in wheat leaves and the pathogenesis-related (PR) proteins of oxalate oxidase (AJ556991.1), peroxidase (TC 151917), and proteinase inhibitor (EU293132.1) was investigated. Treatment with the signal molecules inhibited S. nodorum growth and stimulated Н2О2 accumulation, as well as PR gene expression. SA and COS with 65% AD are found to be more efficient in Н2О2 induction and elevation of the transcriptional level of the oxalate oxidase and peroxidase genes. At the same time, JA and COS with 30% AD stimulated transcription of the proteinase inhibitor gene. The results suggest the existence of differential means of defense response induction by signal molecules with more prospects for the regulation of plant immunity.