Dissertation

An assessment of the suitability of the Brachypodium distachyon ecotype Bd21 for use as a model ecotype susceptible to Magnaporthe grisea infection.

Jasen Finch

ABSTRACT

The model host/pathogen interaction between the model grass species Brachypodium distachyon and Magnaporthe grisea has previously been used to study  plant/pathogen interaction using non-targeted mass spectrometry approaches. Recently the B. distachyon genome has been sequenced using the ecotype Bd21 that shows a susceptible response to M. grisea. The aim of this project was to establish the suitability of Bd21 as a replacement model susceptible ecotype to ABR1 that is already in use in terms comparability of sampling, its response to M. grisea as well as the effect of ‘bagging’ stress on these ecotypes. The experimental approach utilised Flow Injection Electrospray-ionisation-Mass Spectrometry (FIE-MS)  metabolite fingerprinting to compare metabolomic differences and changes, as well as epifluorescence microscopy to investigate fungal invasion. It was established the standard sampling protocol was suitable for use with Bd21, although this ecotype showed the greatest response to ‘bagging’ stress; with reduced energy production via the TCA cycle characteristic. Bd21 exhibited a more susceptible response to M. grisea with pathogen proliferation occurring much earlier than in ABR1. Alterations to metabolism, during the response of Bd21, were identified that are common to  ABR1. Bd21 showed an exaggerated  response at 24 hours post inoculation, potentially making this ecotype highly suitable to investigating the early stages of this host pathogen interaction.

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