Genome-wide transcriptional response of the causal soybean sudden death syndrome pathogen Fusarium virguliforme to a succinate dehydrogenase inhibitor fluopyram.

Abstract

BACKGROUND\nSuccinate dehydrogenase inhibitors (SDHIs) have been widely used to manage plant diseases caused by phytopathogenic fungi. Although attention to and use of SDHI fungicides has recently increased, molecular responses of fungal pathogens to SDHIs have often not been investigated. A SDHI fungicide, fluopyram, has been used as a soybean seed treatment and has displayed effective control of Fusarium virguliforme, one of the causal agents of soybean sudden death syndrome. To examine genome-wide gene expression of F. virguliforme to fluopyram, RNA-seq analysis was conducted on two field strains of F. virguliforme with differing SDHI fungicide sensitivity in the absence and presence of fluopyram.\n\n\nRESULTS\nThe analysis indicated that several xenobiotic detoxification related genes, such as those of deoxygenase, transferases, and transporters, were highly induced by fluopyram. Among the genes, four ATP-binding cassette (ABC) transporters were characterized by the yeast expression system. The results revealed that expressions of three ABC-G transporters were involved in reduced sensitivity to multiple fungicides including fluopyram. Additionally, heterologous expression of a major facilitator superfamily (MFS) transporter that was highly expressed in the fluopyram insensitive F. virguliforme strain in the yeast system conferred decreased sensitivity to fluopyram.\n\n\nCONCLUSION\nThis study demonstrated that xenobiotic detoxification related genes were highly up-regulated in response to fluopyram and expression of ABC or MFS transporter genes was associated with reduced sensitivity to the SDHI fungicide. This is the first transcriptomic analysis of the fungal species response to fluopyram and the finding will help elucidate the molecular mechanisms of SDHI resistance. This article is protected by copyright. All rights reserved.