Submitted to: Acta Horticulturae
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/20/2002
Publication Date: 12/14/2003
Citation: Simko, I., Haynes, K.G., Jones, R.W., Costanzo, S., Christ, B.J. 2003. Identification of molecular markers linked to the Verticillium wilt resistance gene homologue in potato (Solanum tuberosum L.). Acta Horticulturae. 619:127-133. Interpretive Summary: Verticillium wilt is a vascular disease of potatoes caused by the fungal species Verticillium. Most potato cultivars are susceptible to Verticillium wilt, with yield losses of up to 50% reported. Two genes with resistance to Verticillium wilt have been reported in tomatoes. Tomatoes and potatoes are closely related genetically, so this research was conducted to see if the same genes with resistance to Verticillium wilt in tomatoes were present in potatoes. One resistance gene was found in potatoes that was very similar to both of the resistance genes found in tomatoes. This information will be used to develop new potato cultivars with resistance to Verticillium wilt using marker assisted selection in the future. The potato industry and the consumer will benefit from this research.
Technical Abstract: Verticillium wilt is a vascular disease predominantly caused by the soil-borne fungi Verticillium dahliae and Verticillium albo-atrum. Most of the commercial potato cultivars grown in the USA are susceptible to Verticillium, resulting in significant crop losses. Development of new cultivars with resistance gene(s) against the pathogen can be assisted with molecular marker technology that allows identification and tracking of resistance genes. In tomato, resistance to Verticillium dahliae is conferred by two closely linked genes (Ve1, Ve2) that were mapped to chromosome 9. We have employed primers that amplify the leucine-rich repeat (LRR) domain from tomato Ve1 and Ve2 genes. Verticillium resistance gene homologues have been detected in resistant cv. Reddale when using these primers and genomic DNA as a template. Deduced amino acid sequence shared high identity with Ve1 (87%-90%) and Ve2 (88%-91%) tomato resistance genes. The StVe1 - a potato homologue to the Ve1 gene - mapped to the genomic position corresponding to the tomato Ve1 gene. Microsatellite markers linked to the StVe1 have been used to screen 48 (mostly) tetraploid genotypes of various pedigrees. One of the tested markers showed high linkage with Verticillium resistance (p < 0.001). The correlation is mainly based on the complete absence of resistant genotypes that lack the STM1051 marker (~190bp size band). The STM1051 marker has a potential use in the detection of genotypes that are susceptible to Verticillium. Our results suggest that there may be a direct evolutionary relationship between Verticillium resistance genes in potato and tomato. This research will benefit the potato industry and the consumer through the development of new disease resistant potato cultivars, and will enhance scientists' understanding of the relationship among disease resistant genes in different crop species.