Use this URL to cite or link to this record in EThOS: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.537847
Title: Pathogenicity determinants of Fusarium graminearum on wheat ears
Author: Beacham, Andrew Mark
Awarding Body: University of Exeter
Current Institution: University of Exeter
Date of Award: 2011
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Abstract:
Some specialist microbes can deploy a range of mechanisms to cause disease on one or more host plant species. To identify entirely new classes of pathogenicity and virulence factors, a bioinformatics-reverse genetics approach has been applied to a plant pathogen where near complete genomic sequence information was available. A genomic region was identified on chromosome 1 of the important cereal pathogen Fusarium graminearum that contains a significant grouping of homologues of known virulence genes. Targeted deletion of these genes revealed a role for the neutral trehalase (NTH1) and protein kinase A regulatory subunit (PKAR) genes in the rate of disease symptom spread by F. graminearum, in addition to the previously reported SNF1 Ser/Thr protein kinase and STE7 MAP kinase kinase genes. Subsequent investigation of further genes at this locality revealed the presence of a gene, here named Fusarium graminearum Contributor to Virulence 1 (FCV1), which represent a novel class of gene required for a full rate of symptom spread. Targeted deletion of FCV1 led to a reduced rate of disease development by F. graminearum on wheat ears and Arabidopsis floral tissue, but did not affect trichothecene mycotoxin production. The fcv1 deletion mutant also exhibits altered hyphal growth, reduced asexual sporulation and altered sensitivity to oxidative and osmotic stress. In the complemented strain, wild-type traits were completely or partially restored. This micro-region of < 40 kb containing these five important genes represents a novel type of gene cluster containing genes required for a full rate of disease development. This micro-region is located in a genomic region of low recombination, is highly conserved in three other Fusarium species, but is less conserved in other plant pathogenic species. The micro-region is not defined by a distinct GC content or coordinated gene expression patterns, nor is it flanked by highly repetitive sequences. This micro-region is distinct from the previously identified fungal and bacterial virulence gene clusters and the clustered biosynthesis-associated genes required to synthesis metabolites which contribute to pathogenicity. This method for novel disease development-contributing gene identification is applicable to any sequenced pathogen species.
Supervisor: Talbot, Nick J. Sponsor: BBSRC ; Syngenta
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.537847  DOI: Not available
Keywords: Fusarium Ear Blight ; Fusarium graminearum ; Plant Pathology ; Fungi ; Gene cluster
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