Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: March 13, 2009
Publication Date: January 1, 2010
Citation: Mc Cue, K.F., Oosumi, T., Rockhold, D.R., Deahl, K.L., Belknap, W.R. 2010. Cloning and Characterization of a Late Blight Resistance Gene (Rpi-bt1) and other Resistance Gene Analogs from Solanum bulbocastanum[abstract].American journal of Potato Research.87(1):133. Interpretive Summary: The Irish potato famine was the result of the disease called late blight. Wild relatives of the potato are known to possess resistance traits to Phytophthora infestans, the causal agent of the late blight disease. We have used closely associated markers to the disease to walk along the chromosome of the wild potato Solanum bulbocastanum and have identified a cluster of genes analogous to many well characterized pathogen resistance genes. Although the genes from the originally identified fragment did not confer resistance when transferred into potatoes, the information was used to isolate a gene that did confer resistance to Phytophthora in green house studies. This gene will be the subject of future investigations to develop cultivated potatoes with improved resistance to this devastating disease.
Technical Abstract: Phytophthora infestans, the causal agent of late blight is the most devastating pathogen of potatoes. Utilizing map based chromosome walking a genomic region containing a cluster of six nucleotide binding site-leucine-rich repeat resistance gene analogs was isolated from a bacterial artificial chromosome library of the wild potato species Solanum bulbocastanum. Four genes were pseudogenes, with coding sequences interrupted by either frame shift mutations or premature stop codons. However, neither of the two uninterrupted genes when introduced into susceptible potatoes conferred resistance to P. infestans. Specific primers for one of the pseudogenes were used to amplify an uninterrupted cDNA from P. infestans-infected S. bulbocastanum leaves. A corresponding gDNA was amplified from a late blight-resistant bulbocastanum–tuberosum introgression line (Rpi-bt1) and confirmed to be an S. bulbocastanum allele. The Rpi-bt1 gene under transcriptional control of the potato Ubi3 constitutive promoter was found to confer resistance to P. infestans in several transgenic potato lines in a whole plant greenhouse assay.