November 25, 2011
The genetic modification of plants is an invaluable tool used by scientists globally to gain a better understanding of the functions of certain genes in plants. Even if it is not used directly to create improved crop varieties, genetic modification is invaluable for probing gene function and identifying genomic markers that give breeders tools and knowledge to improve crop plants and so help deliver enough food in the future. The John Innes Centre, which is strategically funded by BBSRC, has been at the forefront of developing efficient transformation technologies in a variety plant species, and now new funding is to help develop this technology for an important Brassica species.
Brassica crops are important for both UK arable agriculture and horticulture, and the closest crop relatives to Arabidopsis thaliana, the model plant studied by many research groups. Genetic modification, or transformation, is used routinely in Arabidopsis, where the ability to modify genes or to switch them on and off has led to a wealth of potentially exciting traits being identified.
In order to translate and validate the claims made in the model species into economically important crop species, such as Brassica, access to robust transformation resources is required. Dr Penny Sparrow and colleagues recently presented a summary of current Brassica transformation resources available to the UK and wider research community, at the 'GM From Basic Research to Application' conference, which was organised by the Association for Applied Biologists and held at Rothamsted Research.
Techniques for genetically modifying, or transforming, plants have to be specially tailored for each individual species. In 2003, as part of a project funded by the Department for Environment, Food and Rural Affairs (Defra) the Biotechnology Resources for Arable Crop Transformation (BRACT) facility was established. This developed transformation protocols and resources for wheat, barley and Brassica with expertise from the John Innes Centre and Rothamsted Research.
As part of this work researchers developed highly efficient, easy to follow routine transformation protocols for transforming Brassicas and these protocols are now freely available to researchers on the BRACT website. Also included are step-by-step photo guides to help researchers successfully use them. BRACT resources also include access to seeds of easily-transformable Brassica genotypes, pBRACT constructs tailored for each of the crops, as well as training packages for researchers to come and gain hands on experience of the techniques. The group also offer a full transformation service as well as offering progeny testing, and can provide advice on grant applications, from costings through to project design and timescale guidance.
BRACT collaborates with research institutes, companies and universities both in the UK and internationally to support translationary research. Plant Bioscience Limited (PBL) has funded through its Technology Development Programme several projects led by Dr Penny Sparrow that have generated crop data in Brassica which has successfully been used to promote the commercial uptake of these technologies.
So what's next in the pipeline? The recent publication of the Brassica rapa genome sequence, together with the B. rapa TILLING reverse genetics resource at JIC, is leading to a demand for B. rapa transformation. B. rapa and B. oleracea are the two diploid progenitors of the crop plant oilseed rape (Brassica napus), which consists of both of their genomes combined and duplicated. The study of gene function in B. rapa helps to simplify things before applying them to the polyploid oilseed rape.
B. rapa has historically been one of the hardest Brassica species to transform, but work carried out by Dr Sparrow and Professor Lars Østergaard, as part of the BBSRC funded 'Adding Value to Brassica' programme, led to the development of a transformation system for an oilseed B. rapa genotype. Efficiencies currently remain too low to be able to offer this as a transformation resource to the research community, but a successful strategic Tools and Resources grant bid, has now resulted in over £100,000 funding from BBSRC to further develop this system and ultimately add it to the BRACT portfolio of resources available to the research community.
The similarity in fruit morphology between the model plant, Arabidopsis and Brassica species provides an ideal system to unravel, for example, fundamental aspects of organ formation and to develop tools for crop improvement. Recent work at the JIC by Prof. Østergaard, for example, has demonstrated how knowledge of pod shatter control in Arabidopsis can be used to understand the process in Brassicas. This knowledge has significant implications for UK agriculture where unsynchronised pod shatter in oilseed rape accounts for over 10% seed loss every year.
Oilseed rape is seen as a relatively under-developed crop, compared to wheat, which has had thousands of years of intensive selective breeding, so there remains scope for scientists and breeders to improve on this. Prof. Østergaard is now looking at how his discoveries can be translated into oilseed rape and the development of efficient transformation protocols will aid in this type of translational research. Efficient transformation in B. rapa will allow other researchers all over the world to better understand the genetics behind important traits in oilseed rape.
Photo: Population of transgenic B. oleracea plants flowering in a glasshouse.
Credit: John Innes Centre
Brassica transformation resources
Sparrow P. A. C., Smedley M., Harwood W. (2011)
Aspects of Biology GM From Basic Research to Application (110) 32-36.
For more about the Brassica rapa genome sequence visit: news.jic.ac.uk/2011/08/brassicarapagenome
For more about the TILLING reverse genetics resource at JIC visit: news.jic.ac.uk/2011/01/revgenuk-reverse-genetics-goes-forwards
For more about the BBSRC funded programme 'Adding value to Brassica' visit: www.brassica.info/ukbrc/advab