Accelerated breeding of black rot resistant brassicas for the benefit of east African smallholders

Lead Research Organisation: Harper Adams University
Department Name: Crops and Environment Sciences

Abstract

Plant disease resistance genes can protect crops against pathogens that have the corresponding avirulence (avr) genes. In many cases, the protection conferred by single, generally dominant, disease resistance (R) genes is short lived as the pathogen strains can evolve through mutation and selection, favouring strains with altered or missing avr genes that are therefore able to cause disease. Broad spectrum disease resistance that is quantitative, involving several genes, is generally expected to be more durable. However, this kind of resistance is more difficult to exploit in breeding programmes. The basis of this plant defence strategy is currently unknown. We have chosen quantitative resistance to Xanthomonas campestris pv campestris (Xcc) in Brassica rapa as a model for investigation. Xcc causes black rot of crucifers. This seed-borne disease is one of the most important diseases of Brassicas worldwide. In previous Brassica research at WHRI we have identified good sources of resistance and mapped the location of the major genetic components. In this project we will exploit the exciting new developments in Brassica rapa genomics and emerging information on the close relatedness of the Brassica and Arabidopsis genomes to characterise the resistance and identify the genes involved. The combination of the above resources in the proposed project will allow us to deliver novel and exciting information on the fundamental basis of quantitative disease resistance in a crop species. Key practical outcomes of this work will be resistant plant material with tightly linked molecular markers and information on the extent of natural variation for resistance in Brassica genomes that could be exploited in plant breeding to provide durable resistance to a very significant pathogen.

Publications

10 25 50

Related Projects

Project Reference Relationship Related To Start End Award Value
BB/F004338/1 31/12/2008 30/11/2010 £596,652
BB/F004338/2 Transfer BB/F004338/1 01/12/2010 31/03/2013 £347,526
 
Description 1. New information on the distribution and molecular characterisation of Xcc in East Africa was produced. Incorporation of the Xcc data into the CABI Plantwise database will assist plant breeders in choosing suitable germplasm and targets for resistance breeding, and provide information to extension specialists advising farmers on suitable Brassica cultivars for planting.
2. Further characterisation of Xcc resistance in brassica confirmed that it is absent or rare across a wide representative sample of the C genome and showed that the resistance in B. rapa is broad-spectrum and robust against a range of Xcc isolates, reinforcing it's potential for resistance breeding.
3. The capacity building grant provided training and resources to significantly improve the capability of KARI pathologists to identify and characterise Xcc and the opportunity to develop further research links in this area.
Exploitation Route Incorporation of the Xcc data into the CABI Plantwise database will assist plant breeders in choosing suitable germplasm and targets for resistance breeding, and provide information to extension specialists advising farmers on suitable Brassica cultivars for planting.
3. The capacity building grant provided training and resources to significantly improve the capability of KARI pathologists to identify and characterise Xcc and the opportunity to develop further research links in this area.
Sectors Agriculture, Food and Drink

 
Title Culture collection of Xcc isolates from E. Africa 
Description A set of 249 new Xcc isolates collected from East Africa for this project have been added to the Xcc culture collection at Warwick. A subset which are representative of the pathotype and genetic diversity have been sent to the project partners in Kenya. 
Type Of Material Biological samples 
Year Produced 2012 
Provided To Others? Yes  
Impact This collection (and the associated database described elsewhere) greatly extends information on the distribution of races of this important bacterial pathogen in E. Africa. It has been shared with project partners in Kenya for use by pathologists, breeders, growers and other researchers. 
 
Title DNA sequences of Xcc genes involved in pathogenicity 
Description 97 DNA sequences for Xcc gyraseB genes have been deposited in the NCBI under GenBank accession numbers HQ200306-HQ200403. 94 DNA sequences for Xcc AvrXccC genes have been deposited in NCBI under GenBank accession numbers HQ169543- HQ169637. 89 DNA sequences for Xcc xopXccN genes have been deposited in NCBI under GenBank accession numbers JF312229- JF312318. These sequences will aid in studies of molecular pathology and genetic diversity of Xanthomonas spp. in Africa and elsewhere. 
Type Of Material Biological samples 
Year Produced 2012 
Provided To Others? Yes  
Impact These sequences will aid in studies of molecular pathology and genetic diversity of Xanthomonas spp. in Africa and elsewhere. 
 
Title B. rapa SNP database 
Description A panel of 1556 Brassica SNPs generated from transcriptome sequence of the B. rapa mapping parents during this project will be made publicly available through the Defra VeGIN website. 
Type Of Material Database/Collection of data 
Year Produced 2013 
Provided To Others? Yes  
Impact Increased density of polymorphic SNP markers on the Brassica rapa genetic map for use by researchers and breeders. 
URL http://www2.warwick.ac.uk/fac/sci/lifesci/research/vegin/
 
Title Database of Xcc isolates from East Africa 
Description A database of the geographical source, host plant and characterisation data for 249 Xcc isolates collected from East Africa during this project is available and this has been passed to CABI partners for incorporation into the CABI Plantwise initiative knowledge bank. 
Type Of Material Database/Collection of data 
Year Produced 2012 
Provided To Others? Yes  
Impact Incorporation of the Xcc data into the CABI Plantwise database will assist plant breeders in choosing suitable germplasm and targets for resistance breeding, and provide information on regional distribution of races of the pathogen to extension specialists advising farmers on suitable Brassica cultivars for planting. 
URL http://www.plantwise.org/
 
Title Xcc genomic sequences 
Description Illumina genomic sequence from 4 Xcc race 4 isolates from Africa, including Kenya, Tanzania, Zambia & Namibia, 2 additional race 4 isolates from the UK and Portugal and a race 5 isolate from Tanzania has been produced. To ensure that this data will be used and accessible to African researchers, it will be incorporated into a pangenomic database of X. campestris that is currently being developed with collaborators at University of Exeter (led by David Studholme). This database has been assembled from reference genomes of standard races of the major Xcc pathovars. Genome sequence of the Xcc isolates will be released via GenBank along with publication in a refereed journal. 
Type Of Material Database/Collection of data 
Year Produced 2013 
Provided To Others? Yes  
Impact Genome sequence of the Xcc isolates will be released via GenBank along with publication in a refereed journal. 
 
Description EH Malvern Show 2012 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Public/other audiences
Results and Impact Co-PI (Holub) was a presenter at the Three Countries Agricultural Show, Malvern (16 June 2012). Engaged with members of the public on diseases in plants.

a follow-up presentation at a stake-holder workshop on horticultural food security at the Warwick Crop Centre
Year(s) Of Engagement Activity 2012
 
Description EH workshop on Hort Food Security 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Professional Practitioners
Results and Impact Discussion of environmental & supply-chain factors that threaten food security

not known
Year(s) Of Engagement Activity 2012
 
Description JV Fascination of Plants day Oxford 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? Yes
Geographic Reach International
Primary Audience Public/other audiences
Results and Impact Huge number of visitors and huge interest.

The event has grown and become an annual event with worldwide participants.
Year(s) Of Engagement Activity 2012
URL http://www.plantday.org/
 
Description JV contribution to Channel 4 TV Food Unwrapped programme 
Form Of Engagement Activity A press release, press conference or response to a media enquiry/interview
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Public/other audiences
Results and Impact Segment on role of Xanthomonas bacteria in food processing shown on 'Food Unwrapped' episode 6 on Oct 22 2012

Raised public awareness of use of microbial products in food industry.
Year(s) Of Engagement Activity 2012
URL http://www.youtube.com/watch?v=dqvc-3Iub1E&feature=context-shows&list=SL
 
Description P Hand University Open Days 
Form Of Engagement Activity Participation in an open day or visit at my research institution
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Schools
Results and Impact lively Q&A about careers in Agriculture and research

Increase in student applications to Harper Adams University
Year(s) Of Engagement Activity 2013,2014
 
Description PH article in 'Leading In Research' 
Form Of Engagement Activity A magazine, newsletter or online publication
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Public/other audiences
Results and Impact Brochure widely distributed at public open days and to policymakers and industry stakeholders. Also published online.

difficult to quantify.
Year(s) Of Engagement Activity 2013
URL http://www.harper-adams.ac.uk/publications/research/
 
Description PH contribution to BBSRC Bioscience behind secure harvests 
Form Of Engagement Activity A magazine, newsletter or online publication
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Public/other audiences
Results and Impact BBSRC publication 'Bioscience behind Secure Harvests' produced and widely distributed.

not known.
Year(s) Of Engagement Activity 2010