Broadening and improving the Turnip yellows virus resistance base in oilseed rape (BITYR)
Oilseed rape (scientific name: Brassica napus)
Oilseed rape is the 3rd most important oil plant in the world after palm and soybean (Sharma et al. 2012). The oil produced from the seed is most commonly used in the production of biodiesels and specialised industrial lubricants but rapeseed oil is now also becoming a popular edible oil. The byproduct of oil production, the seed meal, is also used as a protein rich animal feed.
Figure 1. The Triangle of U. (Stewart et al. 2003)
Oilseed rape or Brassica napus (AACC) is an amphidiploid species that resulted from the interspecific hybridization of Brassica rapa (AA) and Brassica oleracea (CC) (Fig. 1). Since B. napus shares both the A and C genomes of B. rapa and B. oleracea, respectively, genetic diversity within these relatives can be utilized in oilseed rape breeding.
Turnip yellows virus is a problem
Turnip yellows virus (TuYV) is transmitted by aphids, primarily the peach-potato aphid (Myzus persicae) in the UK and can decrease the yield of oilseed rape by as much as 30% in the UK costing the industry up to £69million per year (9% of the crop value) (REF).
TuYV can be symptomless or can cause non-specific symptoms that mimic plant stress responses to drought or nutrient deficiency. For this reason TuYV is hard to diagnose and many oilseed rape growers do not realise they have a problem until harvest.
Controlling Turnip yellows virus
Insecticide treatments are used to control TuYV by tragetting its aphid vectors. However, strict regulations on insecticide application and growing insecticide resistances within the aphids have prevented the successful control of TuYV. Consequently, research has been directed towards breeding TuYV resistance into oilseed rape cultivars as this removes the need for heavy insecticide application and overcomes the issue of insecticide resistance.
Existing sources of TuYV resistance in oilseed rape
Amalie is a winter oilseed rape variety, bred by Limagrain, which has increased resistance to TuYV compared to other common cultivars. Amalie successfully made the AHDB recommended list in 2015 (AHDB 2015) after showing yield advantages over TuYV susceptible varieties.
However, the gene(s) responsible for TuYV resistance in Amalie have not yet been identified and the mechanism of resistance is still unknown. It is therefore hard to determine the varieties effectiveness in controlling TuYV and its durability against resistance breaking.
Broadening and improving TuYV resistance in oilseed rape
As a result of the rapidly evolving nature of TuYV and the ambiguities with Amalie, it is essential to monitor and improve TuYV resistance within oilseed rape to ensure its sustainability. To do this novel sources of TuYV resistance will need to be identified and characterized. Sources of extreme TuYV resistance in B. oleracea and B. rapa have already been identified here at The Univeristy of Warwick but have yet to be characterized and integrated into oilseed rape. It is thought that integrating TuYV resistance genes from both A and C genome Brassica species, by interspecific crossing, will produce an oilseed rape variety with combined and superior TuYV resistance.
My research objectives
- To identify candidate gene(s) responsible for TuYV resistance in commercial oilseed rape varieties.
- To characterise and map novel sources of TuYV resistance in B. oleracea and B. rapa.
- To integrate the novel TuYV resistances found in B. oleracea and B. rapa into B. napus.
AHDB. (2015) AHDB recommended lists for cereals and oilseeds 2016/2017. Retrieved 08.02.2016.
Coleman, A. D. (2014) Control of Turnip yellows virus: Assessing impact on oilseed rape quality traits and dissecting circulative transmission by aphids. Home Grown Cereals Authority, John Innes Centre. Research review: 26: 26-28.
Sharma, M., Gupta, S. K., Mondal, A. K., Yadava, D. K., Vasudev, S., Singh, N., Mohapatra, T. and Prabhu, K. V. (2012) Technological innovations in major world oil crops. Springer New York. Volume 1. Pages 4-7.
Stewart, C. N., Halfhill, M. D. and Warwick, S. I. (2003) Transgene introgression from genetically modified crops to their wild relatives. Nature Reviews Genetics, 4, 806-817.