Development of novel blast resistant wheat varieties for Bangladesh by genome editing

Wheat blast is a devastating disease that appeared for the first time in Bangladesh in February 2016. In a very short period of time the disease has already destroyed 15,000 Hectares of wheat. Farmers have resorted to burning wheat fields to try to prevent wheat blast from spreading. This is a potentially catastrophic situation in one of the world's poorest countries. Unless wheat blast is controlled, the disease threatens wheat production, not only in Bangladesh, but right across Asia. An urgent response to wheat blast disease is required.

As soon as news of the outbreak emerged, the co-applicants of this proposal formed a collaboration with Prof. Md. Tofazzal Islam of Bangabanhu Sheikh Mujibur Rahman Agricultural University (BSMRAU) in Bangladesh and obtained diseased material to identify the origin of the wheat blast disease. This demonstrated that wheat blast in Bangladesh is caused by a fungus that has spread from South America, probably by importation of infected wheat grain.

This Global Challenges Research Fund project describes a novel strategy that we believe offers the most rapid means by which wheat blast could be controlled. We aim to use the very latest genome editing methods to modify wheat plants so that they are able to resist fungal infection. We have identified potential disease susceptibility factors which, if modified (or removed), may make wheat plants better able to defend themselves against wheat blast. This is a novel approach, which would result in non-GM wheat varieties, which can be provided to farmers very quickly.

We aim to work with scientists and agricultural professionals in Bangladesh to make sure we can apply the advanced genome editing methods in this project within Bangladesh and train scientists there to use the procedures routinely. We will also work with local agricultural extension services to work out the best way to make wheat varieties generated in the project available to farmers as rapidly as possible, and at the scale necessary to halt this devastating disease.

The overall aim of this project is to develop wheat varieties that are durably resistant to wheat blast disease. Wheat blast is a devastating disease that emerged in Bangladesh in 2016 and already threatens wheat cultivation. Wheat blast is a new and urgent problem that has already infected over 15,000 Hectares of wheat, about 16% of wheat production in the country. The consequences of this disease spreading to neighboring countries would be catastrophic to food security in the region (for news reports see Nature 28 Apr. 2016 532:421-2; Science 22 Apr 2016 352:388-39)

This project will build on collaborations we have built with Bangladeshi scientists at Bangabanhu Sheikh Mujibur Rahman Agricultural University (BSMRAU) and associated agricultural extension services and seek to develop local expertise and capacity to combat wheat blast. We aim to use knowledge of disease resistance to rice blast (a closely related disease) to develop resistant wheat varieties.

In the last five years, it has become apparent that there are genes in rice that are important for susceptibility to rice blast disease. When these genes are mutated, they lead to disease resistance. We have identified putative orthologs of 10 susceptibility genes (S-genes). We will modify these genes using CRISPR-Cas editing. The resulting mutants will be evaluated for resistance to wheat blast and phenotypically characterised. Once we have established this proof-of-concept, we will train scientists from our Bangladesh collaborator, Prof Tofazzal Islam's research group in CRISPR-Cas editing , so we can carry out further editing in Bangladesh-adapted wheat varieties in future. We will work to develop durably resistant non-GM wheat varieties, which can be released to farmers to combat wheat blast and prevent its spread across Asia.

The principal impact of this research will be the development of wheat plants that exhibit resistance to blast disease by a completely new and novel means. We aim to test the idea that genes which encode disease susceptibility factors can be modified by genome editing to generate plants showing enhanced disease resistance. If this proof-of-concept experimental strategy is successful, we will have developed wheat blast resistant lines much more rapidly than by any other potential means.

We will test these cultivars very thoroughly and then train our Bangladesh partners in the genome editing procedures necessary for adopting this approach to wheat blast control. We will work with them to disseminate this know-how, so that genome editing becomes a routine procedure in future breeding programmes.

The impact activities of this BBSRC GCRF foundation award project will be made real through a programme of intense training to ensure that CRISPR-Cas editing can be utilised for wheat cultivar improvement in Bangladesh, and that S-gene mutations shown to lead to enhanced wheat blast resistance can be engineered or crossed into Bangladesh-adapted, widely grown, cultivars. At the same time, we will establish procedures for a disease surveillance programme to ensure that wheat blast isolates can be readily identified and genotypically characterised in Bangladesh, and that this information is used in local wheat breeding programmes.

Information sharing will be achieved through workshops associated with each training event, in which we will engage with a broader group of stakeholders, including agricultural extension services, farmers and Bangladesh government officials. We will establish extensive dialogue with local growers and agricultural service professionals through our partner, Prof Md. Tofazzal Islam (MTI), who will co-ordinate all activities in Bangladesh, supported by Bangabanhu Sheikh Mujibur Rahman Agricultural University (BSMRAU) and the Bangladesh Institute for Nuclear Agriculture (see letters of support).

Finally, all co-investigators are strongly committed to open data and transparent scientific communication. We will regularly disseminate knowledge of this project through www.wheatblast.net and promote the work extensively through social media.