'Horticulture' CRISPR Cas-mediated and inter-species transfer of broad-spectrum, potentially durable disease resistance in crop plants (CRIMIST-DR).

The virus called turnip mosaic virus (TuMV) is an important pathogen infecting many crop plant types, reducing yields and making them unmarketable. In order to reproduce, the virus has to use certain proteins in plants. Without these proteins it cannot reproduce. One such plant protein is called the eukaryotic initiation factor iso4E [eIF(iso)4E]. We have shown that in Chinese cabbage (Brassica rapa sub-species pekinensis) which has three copies of eIF(iso)4E, if one of the copies is missing, the virus cannot reproduce, but the plant is unaffected. Chinese cabbage varieties with this resistance (that was identified and characterised at the University of Warwick) are currently being developed by an international seed company (Syngenta). Chinese cabbage is the most important vegetable brassica crop worldwide. We have been unable to identify any resistance to TuMV in the related and important plant species Brassica oleracea, which includes broccoli, cabbage, cauliflower, kale, Brussels sprouts etc. In collaboration between the Elizabeth Creak Horticultural Technology Centre and the Plant Virology Group at the University of Warwick, NIAB and the commercial plant breeding company Syngenta, we aim to knock out the copy of eIF(iso)4E that TuMV needs in order to reproduce in B. oleracea utilising gene editing technology, thereby establishing a technique to rapidly develop virus-resistant varieties of the different B. oleracea types. In collaboration with the commercial seed company Syngenta, we also aim to move the copy of eIF(iso)4E that the virus cannot use from Chinese cabbage into B. oleracea by conventional crossing, in order to develop virus-resistant plants by this alternative route.