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

This is a BBSRC iCASE studentship. The student will spend at least 3 months working with the industrial partner Limagrain UK Ltd. The University of Warwick’s Agricultural and Veterinary group within the School of Life Sciences were placed 2nd out of 29 UK university departments in the Agriculture, Veterinary and Food Science unit of assessment of the recent ‘Research Excellence Framework’ (REF) and =1st for impact.

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

Key experimental skills involved: Plant growing, handling, crossing and selfing; plant virus inoculation; serological and molecular virus detection; use of molecular markers for plant genotyping; plant DNA sequence handling and analysis.

Keywords: Plant pathology; plant viruses; plant virology; disease resistance; resistance genes; gene mapping; brassicas; oilseed rape; Turnip yellows virus.