Search Results

You are looking at 1 - 3 of 3 items for

  • Author or Editor: Fiona Doohan x
Clear All Modify Search

Deoxynivalenol (DON) and zearalenone (ZON) are mycotoxins frequently detected in Fusarium -infected cereal grain. Both toxins are produced by Fusarium culmorum and F. graminearum during the development of Fusarium Head Blight (FHB) disease. We are developing tools to allow us to simultaneously detect DON and ZON production by Fusarium species. We generated a transgenic F. culmorum strain that expresses fluorescent proteins under the control of promoters of genes that are essential for the biosynthesis of DON (trichodiene synthase; Tri5 ) and ZON (a promoter that drives two polyketide synthetases, Zea1 and Zea2 ). We developed a duplex real time PCR assays for the concurrent analysis of Zea1 and Tri4 (another gene essential for DON production). We are currently generating a multiplex real time PCR version of this assay to detect Zea1 , Tri4 and a plant actin ( Act1 ) gene. This assay can be used to detect DON and ZON producers in grain; Act1 serves as a positive control plant gene in the reaction. We are also developing a multiplex real time RT-PCR assay to detect Zea1 , Tri4 and a F. culmorum/F. graminearum beta-tubulin ( Btub ) gene. Incorporation of the Btub enables normalization of Tri4 and Zea1 transcript expression, relative to fungal abundance.

Restricted access

Pseudomonads, including P. fluorescens strain MKB 158, can inhibit the development of Fusarium seedling blight disease on wheat and barley. Application of this and other pseudomonads as head sprays inhibits the development of Fusarium head blight disease (FHB) disease on wheat and barley under both field and glasshouse conditions. P. fluorescens strains MKB 158 and MKB 249 also reduced DON contamination of grain under field conditions. Evidence suggests that P. fluorescens does not directly inhibit the growth of Fusarium , but that it potentiates host resistance against this disease. Transcriptome profiling identified barley genes differentially expressed as early events in (a) bacterium-induced resistance to seedling blight and (b) heads following P. fluorescens and Fusarium culmorum co-inoculation. Bacterium-potentiated resistance to Fusarium affects the transcription of many genes that are involved in diverse processes, including cell rescue and defence, metabolism, cell cycle and DNA replication and signalling.

Restricted access

The Fusarium mycotoxin deoxynivalenol (DON) is a potent inhibitor of eukaryotic protein synthesis and acts as a virulence factor during infection of wheat heads. Some wheat genotypes can tolerate DON and resist its deleterious effects; others cannot. Transcriptome studies identified several genes up-regulated in spikelets of the DON-resistant wheat cultivar CM82036 in response to DON treatment. We will discuss how the finding presented herein and other recent findings contribute to the hypothesis that management of hormone homeostasis and alleviation of oxidative stress in DON-challenged wheat might facilitate cell survival and thereby retard fungal colonisation.

Restricted access