A consortium of researchers working across five continents, including BBSRC-funded scientists in the UK, has published the genome of the wild strawberry (Fragaria vesca). The research, published today (26/12/2010) in the journal Nature Genetics will help strawberry breeders to develop disease resistance and improve fruit quality to benefit consumers.
Dr Dan Sargent, based at East Malling Research (EMR) in Kent, collaborated on the international project as part of the BBSRC (Biotechnology and Biological Sciences Research Council) Crop Science Initiative which was set up to fund research to underpin future plant breeding. Dr Sargent hopes that the genome will help to identify genes that convey disease resistance, particularly to strawberry wilt (Verticillium dahliae) the most wide-spread soil-borne pathogen of cultivated strawberries. Although resistant varieties of strawberry do currently exist, they do not meet the quality criteria required to sell to consumers. Having access to the wild strawberry genome may allow breeders to produce varieties which need reduced pesticide treatment but retain the best characteristics of taste, appearance and nutrition.
The researchers found that the wild strawberry genome possesses around 35,000 genes, about one and a half times the number humans have, most of which, they predict will have been retained by the varieties we eat. Strawberries are a valuable crop with sales of home-grown strawberries in the UK alone of £231M in 2009. The wild strawberry is also closely related to other important food crops including apples, peaches, pears and raspberries, and to roses, and its genome sequence will help breeders of all of these plants to produce new varieties with improved traits.
Dr Sargent said: “The wild strawberry is an important genome to sequence because it is closely related to a number of important things that we eat. Because farmers have been cross-breeding and hybridising food crops for centuries to improve traits like taste and nutritional value they tend to have large complicated genomes but the wild strawberry’s is relatively small so we can get access to all of these useful genes comparatively easily.”
The international group sequenced the wild strawberry genome by breaking it up into millions of short segments which were sequenced individually and then re-assembled. The UK-based team at EMR worked on piecing together the genome using a map based on other strawberry genomes that they had worked on.
Dr Sargent continued: “Historically genomes have been sequenced using a combination of longer and shorter sequences. The shorter sequences are quicker and cheaper to sequence but, like with a jigsaw, reassembling the complete picture is harder with lots of little pieces than with fewer big ones. For the first time for a plant this genome was sequenced entirely using short sequences. We were able to assimilate all of these small pieces at EMR because previous strawberry genomes we’d worked on were like the picture on the box that told us what the wild strawberry’s chromosomes should look like.”