ARS | Publication request: IDENTIFICATION OF RB-ORTHOLOGOUS GENES FROM LATE BLIGHT RESISTANCE DIPLOID POTATO.

Submitted to: Phytopathology
Publication Type: Proceedings
Publication Acceptance Date: July 30, 2005
Publication Date: July 30, 2005
Citation: Liu, Z., Halterman, D.A. 2005. Identification of rb-orthologous genes from late blight resistance diploid potato. Phytopathology. 95:6 (Supplement) p. S62.

Technical Abstract: Late blight, caused by the oomycete pathogen, Phytophthora infestans, is a devastating disease of potatoes and tomatoes. A wild potato species indigenous to Mexico, Solanum demissum has provided the primary germplasm for breeding late blight resistance in cultivated potato. However, new virulent races of P. infestans have coevolved which rapidly overcome the resistance. Improving genetic resistance to late blight is a major issue in potato breeding. Durable resistance is present in some other wild potato species. A gene RB, cloned from the Mexican diploid potato species Solanum bulbocastanum, confers broad spectrum resistance to potato late blight. RB encodes a protein belonging to CC-NBS-LRR (coiled coil-nucleotide binding site-leu-rich repeat) class of resistance proteins. It is likely involved in perception of Phytophthora and signaling to elicit resistance. A Mexican diploid potato species S. verrucosum is documented to also contain broad spectrum late blight resistance. There are a total of eight susceptible and resistant S. verrucosum accessions available from the U.S. Potato Genebank (Sturgeon Bay, WI). To identify RB-like genes and understand the molecular basis of RB-mediated late blight resistance, we have amplified RB orthologs from S. verrucosum using a homology-based PCR approach.