Utilising the Virus Resistance Gene TuRB01 to Evaluate the Utility of
Warwick University’s Diversity Fixed foundation Sets for Gene Mining
Adam R. Baker1 , Carol E. Jenner1, Isobel Parkin2, Guy Barker1 and John A. Walsh1
1School of Life Sciences, University of Warwick, Wellesbourne, Warwick, CV35 9EF, UK, 2Agriculture & AgriFood Canada, Saskatoon Research Centre,
Saskatchewan , S7N 0X5 Canada
Introduction
TuMV Resistance in Brassica 01 (TuRB01) is a single dominant gene which was originally identified and mapped in
Brassica napus (Walsh et al., 1999). Subsequently we identified what appeared to be the same gene in Brassica rapa
(TuRB01b; Walsh & Jenner, 2002). TuRB01 confers extreme resistance to pathotype 1 isolates of Turnip mosaic virus
(TuMV). TuMV is an important pathogen of brassica crops worldwide and has caused significant losses in cabbage in
recent years in the UK.
TuMV infected cabbage displaying classic ‘cigar burn’ symptoms. Inset
Electron micrograph of TuMV particles.
Results
Although TuRB01 confers resistance to pathotype 1 isolates
of TuMV, it is overcome by a number of other pathotypes.
The gene has been mapped to an interval on chromosome
A6 of B. napus. The interval contains three conventional R
genes.
DNA has been extracted from a number of plant lines
possessing TuRB01 and a number of plant lines lacking
TuRB01. Candidate 2 was found to code for a truncated
protein and therefore is considered unlikely to be TuRB01.
Candidates 1 and 3 were amplified by PCR, the genes were
cloned and then sequenced from a number of plant lines.
As a library of sequences is compiled comparisons are
being made between susceptible and resistant lines.
Plants lacking TuRB01 (left) are susceptible to TuMV and display
stunted growth and mosaic symptoms as well as greatly reduced yields
of seeds. Plants possessing TuRB01 (right) show extreme resistance.
Brassica lines possessing and lacking TuRB01 and sequencing of
candidate genes
Line
TuRB01 present
B0RG3
Sequenced
B0RG1
Sequenced
Yes
No
Yes
Yes
No
Yes
B. rapa
+
+
+
+
Yes
Yes
10
B. rapa
+
No
Yes
11
B. rapa
-
No
Yes
12
B. rapa
No
Yes
13
B. oleracea
-
No
Yes
1
B. napus
2
B. napus
3
B. napus
4
B. napus
5
B. napus
6
B. napus
7
B. napus
8
B. napus
9
Yes
No
No
Yes
Yes
Yes
No
Yes
No
Yes
Future Work
The interval containing TuRB01 will be sequenced in further lines enabling associations between genetic variation and
functionality to be established. This will enable a PCR assay to be developed that will allow rapid screening of the
Diversity Fixed Foundation Sets for the presence of TuRB01.
Acknowledgements
We thank DEFRA for funding this work as part of the VeGIN project
References
Walsh J.A., Jenner C.E. (2002) '"Turnip mosaic virus" and the quest for durable resistance', Molecular Plant Pathology, 3 289 - 300
Walsh, J.A., Sharpe, A.G., Jenner, C.E. & Lydiate, D.J., (1999) 'Characterisation of resistance to turnip mosaic virus in oilseed rape (Brassica napus) and genetic mapping
of TuRB01.', Theoretical and Applied Genetics, 99 1149 - 1154