Oats for the future: deciphering potential of host resistance and RNAi to minimise mycotoxin contamination under present and future climate scenarios

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Mycotoxins are natural contaminants of a wide range of staple foods produced by fungi under conducive environmental conditions. The consumption of mycotoxin contaminated foods can result in several acute and chronic diseases in humans and animals. Oats, which have become more popular because if their health benefits can be infected by a Fusarium species, F.langsethiae, which can contaminate oats with the mycotoxins T-2/HT2 toxins. The EU has maximum recommended levels for these two toxins in place. F.langsethiae infects oats during ripening but produces no visible symptoms and is thus difficult to assess except by measuring the mould biomass in the ripening oat grain or by analytically quantifying the amounts of T2/HT-2 present. Limited work has been done on screening oat cultivars for resistance to F.langsethiae infection. Climate change (CC) scenarios has been suggested to probably exacerbate fungal infection and mycotoxin production partially via increases in pest reproduction and damage to ripening crops. Thus there is interest in understanding the relationships between interacting factors of CC including elevated temperature (+2-4oC), x2 or x3 existing CO2 concentrations (400 ppm vs 800 and 1200 ppm CO2) and episodes of drought stress. Very little information is available on how these interacting CC factors impact on infection by this Fusarium species and contamination of oats with the associated mycotoxin. This project is a collaborative project between Cranfield University in the UK and University College Dublin in Ireland to jointly address the issues of a better understanding of the relationship between this important fungal pathogen on different oat cultivars, the impact that CC factors will have on infection and mycotoxin contamination and the development of some novel methods for blocking the production of the mycotoxins.The objectives can be summarised as being (a) In vitro examination of the effect of interacting environmental factors on growth and expression of biosynthetic gene clusters of F.langsethiae during colonisation of oat-based media and oat grains and on T-2/HT-2 toxin production by strains from the UK and Ireland. The effect of interacting CC factors the life cycle of the pathogen will be quantified. RNA-Seq technology will be used to study the gene regulation, focusing on the trichothecenes type A gene cluster for the first time; (b) a range of UK and Heritage Irish oat lines will be screened for distinct gene expression profiles relevant to differential mycotoxin contamination and potential resistance using sequencing approaches; (c) 'In planta' studies using two heritage and UK oat CVs will examine CC factors on plant/fungus gene expression patterns and differential mycotoxin contamination using non-acclimatised and acclimatised strains of F.langsethiae. The effects on shifts/fluctuations in T-2/HT-2 toxin production will be quantified; (d) the relative competitiveness of F.langsethiae and other Fusarium species such as F.graminearum and F.sporotrichioides and oat mycobiota will be examined under normal agronomic and CC conditions in in vitro and in planta studies on dominance at a molecular, colony and ecosystem level; and (e) minimisation strategies using interference RNA technology and novel delivery systems to interfere with the key TRI genes involved in T-2/HT-2 production. In planta trials will be carried out to test control efficacy of toxin production under normal agronomic and CC conditions for the first time.