The primary aim of this project was to identify and characterise Fusarium species associated with the basal rot of Allium species and internal fruit rot of sweet peppers in the UK. The secondary objective was to develop quick molecular markers to identify Fusarium oxysporum f. sp. cepae (FOC) causing onion basal rot. Isolates representing diverse Fusarium species taken from onions, garlic, shallot and leeks obtained from different production and processing sites in the UK were collected. F. proliferatum was found for the first time to be a causal agent of onion basal rot in the UK, but F. oxysporum was by far the most common species and F. oxysporum isolates belonged to at least two different genotypes based on a sequence comparison of several “housekeeping” genes, and overall, appeared to be polyphyletic. None of the housekeeping genes studied correlate with pathogenicity. Secreted in xylem (SIX) genes offer more promise for the specific identification of F. oxysporum formae speciales (Lievens et al., 2009a) and a homologue of the SIX7 gene was found only in a few FOC isolates suggesting that SIX7 is not absolutely necessary for pathogenicity. Whole genome sequencing of a FOC isolate was carried out in order to understand pathogenicity and identify novel effector genes. This work revealed the presence of further homologues of published SIX genes, namely SIX3, SIX5 and SIX9. The presence of SIX3 and SIX5 has only been reported from F. oxysporum f. sp. lycopersici previously. Additionally, screening of eleven new candidate effector genes suggested that FOC isolates have different gene sets which correspond to the continuous variation of aggressiveness found within the FOC population. Fusarium lactis, F. proliferatum and F. solani were identified in association with internal fruit rot of sweet pepper obtained from three different production sites in the UK.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:582269 |
| Date | January 2012 |
| Creators | Vágány, Viktória |
| Publisher | University of Warwick |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://wrap.warwick.ac.uk/56393/ |
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