|OOSUMI, TERUK0 - Jr Simplot Company
Submitted to: American Journal of Potato Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/21/2009
Publication Date: 6/17/2009
Citation: Oosumi, T., Rockhold, D.R., Maccree, M.M., Deahl, K.L., Mc Cue, K.F., Belknap, W.R. 2009. Gene Rpi-bt1 from Solanum bulbocastanum confers resistance to late blight in transgenic potatoes. American Journal of Potato Research. 86(6):456-465.
Interpretive Summary: One of the most destructive diseases of potatoes is known as “Late Blight”. A fungus called Phytopthora infestans causes this disease. In an effort to find natural plant defenses against this devastating fungus we have searched for the source of known resistance in the wild potato relative Solanum bulbocastanum. By using molecular cloning techniques we have identified a gene that makes potatoes resistant to Phytopthora in green house experiments. This new gene will be added to the resources available to breeders for developing potatoes with natural resistance to this fungus and hopefully reduce the need for preventative chemical treatments in cultivated potatoes.
Technical Abstract: Phytophthora infestans, the causal agent of late blight is the most devastating pathogen of potato cultivation worldwide. Utilizing map based cloning, 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). The Rpi-bt1 gene under transcriptional control of the constitutive potato Ubi3 promoter was found to confer resistance to P. infestans in several transgenic potato lines in a whole plant greenhouse assay.