Induced systemic resistance against three foliar diseases of Agrostis stolonifera by (2R,3R)-butanediol or an isoparaffin mixture

摘要

Induced systemic resistance (ISR) is a type of plant defence mechanism typically activated by non-pathogenic root-associated micro-organisms and systemic priming of gene expression in response to subsequent pathogen challenge. ISR was found to be activated by PC1, a mixture of food-grade synthetic isoparaffins and (2R,3R)-butanediol, a volatile organic compound produced by bacteria. In controlled environment tests, application of PC1 or (2R,3R)-butanediol to the soil reduced the diseased leaf area of Agrostis stolonifera by 20–40% for the fungal pathogens, Microdochium nivale, Rhizoctonia solani or Sclerotinia homoeocarpa compared to the water control. In A. stolonifera, expression of the jasmonate synthesis-related genes, AsAOS1, encoding an allene oxide synthase, and AsOPR4, encoding a 12-oxo-phytodienoic acid reductase, and expression of a pathogenesis-related protein gene, AsGns5, encoding an acidic β-1,3-glucanase, were primed for increased expression by PC1 or (2R,3R)-butanediol when M. nivale was inoculated 7 days later. However, the compounds differed in their ability to induce expression prior to pathogen challenge. PC1 induced AsAOS1 expression upon treatment, whereas (2R,3R)-butanediol induced expression of AsOPR4 and AsGns5 upon treatment. These results indicate that both (2R,3R)-butanediol and PC1 can produce ISR in A. stolonifera but may do so through different mechanisms.