Fire Blight Resistant Apples
In an international collaboration between a NIFA National Research Initiative plant genome project and HortResearch in New Zealand, robust DNA markers for fire blight resistance are being developed. Fire blight caused by the bacterial disease Erwinia amyloyora, has devastating effects on apple production. More than $100 million a year is lost due to fire blight and cost of control. Utilization of these markers will facilitate efficient breeding of superior apple varieties with improved fire blight resistance, resulting in reduced dependence on synthetic pesticides, greater stability in production levels over time, and improved competitiveness of the U.S. fruit industry in the global market.
More than 650 expressed sequence tags (EST) associated with apple's response to fire blight disease were identified using functional genomics. The ESTs were ranked for their potential impact on resistance based on bioinformatics and inferences drawn from model systems and scientific literature. Simple Sequence Repeat (SSR) and Single Nucleotide Polymorphism (SNP) markers derived from highly ranked ESTs were mapped. A major QTL for fire blight resistance has been located. SSR and SNP markers were mapped to this QTL, as well as to the positions corresponding to the location of at least two other QTLs. To date, of 28 candidate fire blight resistant gene EST-based markers that have been mapped, six have co-located to or near known fire blight resistance QTLs.
The research was published online in the August 2008 journal of Tree Genetics and Genomes.
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