Broadening and improving the Turnip yellows virus resistance base in oilseed rape (BITYR)

Lead Research Organisation: University of Warwick
Department Name: School of Life Sciences

Abstract

Turnip yellows virus (TuYV, formerly known as Beet western yellows virus) is a very important pathogen affecting oilseed rape (OSR, Brassica napus) crops in the UK and Europe. Of the viruses infecting OSR, it is the most common and the most damaging. Estimates of yield reductions from TuYV infection of OSR in the UK alone are upto 30%, resulting in losses of £67-180 million/annum.

OSR is the 3rd most widely grown field crop in the UK and crucial to UK food production as a break crop between wheat crops it has also been one of the most profitable arable crops for farmers in recent years.

TuYV is transmitted by the very common peach-potato aphid Myzus persicae. Once aphids acquire the virus they transmit it for life.

The earlier plants are infected by TuYV, the greater the yield loss. The only way to prevent early TuYV infection has been the neonicotinoid seed treatments applied to most OSR seeds in the past. The active ingredients of these seed treatments have now been banned by the EU because of alleged effects on bees. There is an urgent need to develop new ways of controlling TuYV to protect yields and reduce losses. The best approach is to develop OSR varieties with natural resistance to the virus.

The pant breeding company Limagrain have developed and are selling an OSR variety called Amalie with partial resistance to TuYV. Amalie is susceptible to TuYV, but the amount of virus accumulating in plants is reduced and yield losses ameliorated relative to other OSR varieties. University of Warwick (UoW) identified another OSR source of partial resistance to TuYV with reduced virus accumulation and reduced yield loss. They have also identified a number of more extreme sources of resistance in the close relatives of OSR, Brassica oleracea (cabbage, cauliflower etc.) and Brassica rapa (turnips etc.). UoW have also been investigating the diversity of TuYV and have a collection of virus isolates representing different genetic groups.

These discoveries provide the opportunity for synergy between Limagrain and the University of Warwick by collaborating to:

- combine OSR resistances to improve virus control and yields
- broaden the TuYV resistance base in order to reduce the risk of break down of the resistance sources
- begin to exploit the more extreme sources of resistance from OSR relatives

Publications

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Studentship Projects

Project Reference Relationship Related To Start End Student Name
BB/M017206/1 05/10/2015 04/10/2019
1644951 Studentship BB/M017206/1 05/10/2015 31/01/2020 Shannon Greer
 
Description There are a number of commercially available varieties of oilseed rape (OSR, Brassica napus) that possess the same Turnip yellows virus (TuYV) resistance. The mechanism(s) and gene(s) responsible for TuYV resistance in these varieties are unknown. In an attempt to elucidate the first candidate genes responsible for TuYV resistance and the first against a virus belonging to the Luteoviridae family, a population segregating for the commercial TuYV resistance has been created and screened with a selection of DNA markers. The screen identified resistance-linked markers and has identified an interval of the OSR genome, associated with the resistance that contains approximately 300 genes.

OSR arose from the recent interspecific hybridisation of Brassica rapa and Brassica oleracea. Owing to the recentness of the hybridisation event, the genetic diversity within OSR is more restricted compared to the progenitor species. Therefore, the more genetically diverse progenitor species can be screened for TuYV resistance capable of being integrated into OSR. To broaden the TuYV resistance base in OSR, resistance in B. rapa and B. oleracea lines have been characterised and mapped as part of this project and a BBSRC Impact Acceleration Award. To do this, populations segregating for the B. rapa or B. oleracea TuYV resistances were created and screened with a selection of DNA markers. The latter was carried out through collaborations with Limagrain Europe and University of Western Australia. Results suggested, that both resistances are novel (different to the commercial resistance), dominantly inherited and possibly controlled by multiple genes.

Combination and integration of the TuYV resistances from the characterised B. rapa and B. oleracea lines into OSR has been attempted using resynthesis; a technique that involves the interspecific crossing of the two lines. Resynthesised oilseed rape plants have successfully been produce by this method and have been shown to have possess TuYV-resistance that is comparable in strength to the commercial resistance.

During this project, the first Brazilian isolate of TuYV has been sequenced following an international placement hosted at the University of Warwick. The Brazilian TuYV isolate sequence is very different to the sequences of European isolates and will deposited in GenBank after publication of a note.
Exploitation Route In this project and follow on BBSRC Impact Acceleration Award funding, novel Turnip yellows virus (TuYV) resistance has been identified and mapped in Brassica rapa and Brassica oleracea lines. These TuYV-resistant B. rapa and B. oleracea lines were crossed to produce 'resynthesised' oilseed rape (OSR, Brassica napus) plants possessing combined TuYV resistance. These resynthesised OSR plants are off particular interest to Limagrain UK Ltd. (industrial sponsor of this project), who want to include them in their elite OSR breeding program. Furthermore, TuYV resistance-linked markers, identified from mapping of the B. rapa and B. oleracea lines, can be used to accelerate the introgression of the novel resistances into commercial varieties of OSR, using marker-assisted selection.

Additional TuYV resistant B. oleracea lines not currently being utilised under a project, have been identified at the University of Warwick and have had interest from industry. These lines can also be utilised by subsequent research projects to further broaden and improve TuYV resistance in OSR and also vegetable brassicas.
Sectors Agriculture, Food and Drink

 
Description Conference Travel Grant
Amount £1,000 (GBP)
Organisation The British Society of Plant Pathology 
Sector Charity/Non Profit
Country United Kingdom
Start 08/2018 
End 01/2019
 
Description University of Warwick UKRI Innovation Fellowships: BBSRC Flexible Talent Mobility Accounts
Amount £90,000 (GBP)
Funding ID BB/R506588/1 
Organisation Biotechnology and Biological Sciences Research Council (BBSRC) 
Sector Public
Country United Kingdom
Start 11/2017 
End 03/2019
 
Description Food security public outreach event (University of Warwick) 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Public/other audiences
Results and Impact Public outreach event which involved manning a stall showcasing the impact of plant viruses on food security and the importance of genetic resistance to plants viruses.
Year(s) Of Engagement Activity 2017