Integrated strategy to prevent mycotoxin risks (Inspyr)

Fusarium head blight (FHB) of cereals is caused by a number of fungi, chiefly Fusarium species. It is of particular concern because the Fusarium species produce trichothecene mycotoxins (DON, NIV, T2 and HT-2) within grain that are harmful to human and animal consumers. FHB disease poses an increasing threat to the UK wheat and barley crops. New species have appeared and spread in the UK for which climate change may, in part, be responsible. Future predicted climate changes are likely to exacerbate risks of epidemics in the UK. The EU recently set limits for DON and limits for T2/HT-2 are imminent. It is vital that the UK is positioned to be able to comply with this legislation. It is widely recognised that resistant varieties offer the best option to control FHB. All wheat and barley breeders consider it as a major but difficult target for resistance breeding. Incorporation of high levels of resistance to FHB into wheat and barley will be critical to prevent DON, T2, HT-2 and NIV mycotoxin contamination of grain from becoming a major problem for all elements of the UK food and feed chains. Timely application with appropriate fungicides can restrict disease development and mycotoxin accumulation. Under moderate to high disease pressure, however, fungicide application often fails to reduce DON contamination to below EU legislative limits in susceptible varieties such as those currently grown in the UK. Our previous work showed that much of the susceptibility of UK varieties is due to linkage between a gene that affects the height of wheat, Rht2 (also referred to as Rht-D1b) which is in almost all UK varieties, with a gene nearby on the chromosome that increases susceptibility to FHB. This association must be broken to enable breeders to produce FHB resistant varieties with acceptable agronomic characters. The project will produce molecular markers to the region about Rht2 allowing plant breeders to maintain this agronomically important gene in their breeding programmes while selecting against the linked FHB susceptibility factor. This project aims to identify resistance to Fusarium head blight (FHB) in wheat and barley that will function against all the causal fungi associated with this disease. This project will focus on the identification of Type 1 resistance (resistance to initial infection) in wheat and barley. We have developed new tools to characterise so-called 'Type 1' resistance (resistance to initial infection), which is important for preventing infection of wheat and barley against Fusarium species that produce DON mycotoxin and those that produce the more toxic T2 and HT-2 toxins as well as against non toxin producing FHB pathogens such as Microdochium species. Plant breeding companies can immediately use the plant materials, genetic knowledge and molecular markers linked to FHB resistance within their breeding programmes to produce new resistant varieties with good characters for growing as crops in the UK. This project will determine how fungicide application influences disease and toxin accumulation in varieties with different levels of FHB resistance. The project will demonstrate how individual FHB resistances affect the RL disease score, revealing how many, and what forms of resistance are required to ensure that toxin levels in UK grain do not exceed EU limits. The project will identify the components required to establish a sustainable, integrated approach to ensure that toxin levels in cereal grain remain below EU limits. An integrated approach, based on varieties with significantly enhanced resistance and appropriate fungicide application offers the best means to achieve sustainable control of FHB and minimise the risk of mycotoxins entering the food and feed chains.

This project will identify resistance to Fusarium head blight (FHB) in wheat and barley that will function against all the causal fungi associated with this disease. Two forms of Fusarium head blight (FHB) resistance are recognised: Type 1 (resistance to initial infection) and Type 2 (resistance to spread within the head). We have shown that Type 2 resistance is of relevance mainly to DON-producing isolates of only some FHB-causing species and mainly for wheat. In contrast, Type 1 resistance should be effective against all FHB species including producers of T-2 and HT-2 and to all cereals (not just wheat). For this reason, the project will focus on identifying Type 1 resistance. FHB resistance will be identified in wheat lines and characterised by genetic mapping of selected populations. Breeding partners will produce double haploid populations for genetic mapping. We will also undertake fine mapping of the Type 1 FHB resistance on chromosome 4AS of T. macha by reference to syntenous regions on rice and Brachypodium. Current UK wheat varieties are highly vulnerable to FHB and much of this is associated with the Rht2 (also referred to as Rht-D1b) semi-dwarfing gene. This project will exploit synteny between wheat, rice and Brachypodium to break the linkage between FHB susceptibility and Rht2 (Rht-D1 locus). The identification and characterising of FHB resistance in barley will be undertaken using complementary approaches. Association genetics will be used to identify genomic regions associated with FHB resistance within a large set of barley varieties. Genetic mapping will be carried out for selected barley populations to confirm results from association genetics. This project will use defined genetic wheat line stocks differing in single FHB resistances to reveal how individual FHB resistances interact with fungicide application to influence disease and toxin accumulation.

British wheat and barley varieties are highly or moderately susceptible to Fusarium Head Blight (FHB). No commercially significant variety is sufficiently resistant to remove the need for fungicide application to control the species responsible for FHB under conditions conducive for infection. This research is being undertaken as a LINK project. As such it will involve a wide range of parties within the food and feed chain sector who will benefit both directly and indirectly from this research. Beneficiaries will include: Plant breeders, farmers, millers, maltsters, food and feed processors, wildlife and human and animal consumers of cereals and cereal-based products and the rural environment. A major benefit of the project will be to assist plant breeders to more effectively develop varieties with resistance towards all the fungal species that cause FHB. The project it will identify new resistance sources and molecular markers for breeders to use in marker-assisted breeding programmes. This project will benefit both the agricultural industry and the environment through increased production efficiency and reduced carbon foot-print. It will benefit growers by identifying and developing varieties that have an inherently low risk of mycotoxin contamination and thereby reducing yield loss and the likelihood of grain being rejected for processing or animal feed. Growers will benefit through new highly resistant varieties with desirable agronomic characteristics. These will combine increased yield with reduced inputs to significantly improve efficiency. It will benefit food and feed processors, millers and maltsters because widespread cultivation of FHB resistant varieties will also reduce the need for highly expensive mycotoxin testing. The resistance identified within this project would be ideal for incorporation into varieties for use in organic cereal production and so extending the relevance of the project to a wide spectrum of growers, processors and end-users. The principal environmental impact of this project will be to enhance the efficiency of cereal production and reduce the carbon and environmental 'footprint' of cereal crop production. By developing an integrated strategy to minimise FHB and associated mycotoxin contamination of grain this project will have a positive secondary environmental impact by reducing inappropriate fungicide usage, again leading to enhanced efficiency. At harvest, a significant proportion of Fusarium-infected grain passes though the combine harvester and remains in the field. These heavily toxin contaminated grains pose a threat to birds and other wildlife if consumed by them. By assisting breeders to produce FHB resistant varieties for cultivation in the UK this project will reduce the risk of Fusarium mycotoxins entering wildlife food-chains. Another obvious significant benefit of this project relates to food safety for human and animal consumers of cereals and cereal products. This project will lead to the production of cereal varieties with high levels of resistance to FHB and reduce/eliminate the risk of mycotoxins accumulating in grain. This will ensure compliance within the industry with imminent European legislation for T2 and HT2 toxins in cereals. The research within this project will be undertaken within a formal collaboration agreement between the academic and industrial partners. HGCA is a major contributor to this project and they have a significant technology transfer role to the agricultural sector. A condition of HGCA funding is an undertaking to participate in communication activities. The active participation of plant breeding companies and a major agrochemical company will ensure that the outcomes of this research are immediately applied.