IDRIS- Improving Disease Resistance In Strawberry

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Berry crops have been one of the great success stories of British horticulture in recent years. During this century, the retail value of berry sales has increased from £146 million in 2000 to £783m in 2011, now representing 18.4 per cent of total UK fruit sales. Strawberries are 60% of the sector and continue to experience strong growth with sales increasing by 10% between March 2011 and March 2012. These achievements have been driven by scientific and technological advances, including improved cultivars, better control of pests and diseases and innovations allowing more intensive production. Modern cultivars have achieved a significant extension of the season, higher yields per plant, higher percentage of Class 1 fruit and improved eating quality, which has increased demand.Despite this impressive performance in recent years, the UK strawberry industry now faces some serious challenges, with more variable and unpredictable weather conditions causing problems for growers, and the withdrawal of many fungicides and soil fumigants leading to increased crop losses from soil-borne diseases such as wilt, crown rot and red core, caused by Verticillium dahliae, Phytophthora cactorum and Phytophthora fragariae respectively. Our previous work resulted in a genome sequence for the diploid wild strawberry (through international collaboration) and molecular markers for wilt resistance that are now being deployed at EMR for marker assisted breeding. This is the first programme in the world to develop molecular markers for wilt resistance. Ongoing work aims to provide markers for mildew resistance (a major airborne pathogen), and this proposed work will provide markers which will facilitate more effective selection for resistance to crown rot and red core. This culmination of this work will lead to protection against the major soil and airborne pathogens in the UK. Moreover, we wish to ask more basic questions about the evolution of plant-pathogen interactions and generate a draft genome sequence for the cultivated strawberry (whose genome is four times bigger than the diploid woodland strawberry, as it contains eight copies of each chromosome, rather than two). A genome sequence for the cultivated strawberry is essential for the identification of molecular pathways and processes controlling disease resistance and other agronomic traits, as well as basic studies into how genes have changed throughout evolution. For example, comparisons between the diploid wild strawberry and octoploid cultivated strawberry will improve our understanding of how relationships between plants and their pathogens change between simple and more complex plant genomes. We wish to identify plant resistance genes that recognise conserved, slowly evolving proteins in pathogens, that will allow wide host resistance to many pathogen races and lead to durable resistance. Industry are enthusiastic to support a targeted pre-breeding programme underpinned by research that leads to a more effective molecular breeding approach, taking advantage of the latest developments in genomics to accelerate the breeding process. Ultimately, improved cultivars would become publicly available, via licensed propagators, to growers throughout the UK and the EU. Currently, although strawberries are perennial, the standard industry practice is to maintain the plants in the ground for only 8 to 15 months, as cropping for multiple seasons usually results in a build-up of soil diseases that have deleterious effects on both yield and fruit quality. Plants with strong and reliable resistance would allow cropping for multiple years, which would lead to sustainable intensification, reduce production costs and lower fungicide inputs. For consumers this work will lead to strawberries that have had significantly fewer chemicals applied to them and a considerably lowered carbon cost of production because the energy inputs associated with frequent replanting have been reduced.