Segregation of unknown signaling components in potato complicates marker-assisted selection for Ve-mediated Verticillium resistance
A. KUMAR (1), D. Halterman (2), D. Rouse (3), S. Jansky (1) (1) Department of Horticulture, University of Wisconsin-Madison, U.S.A.; (2) U.S. Department of Agriculture-Agricultural Research Service, Vegetable Crops Research Unit, Madison, Wisconsin, U.S.A.; (3) Department of Plant Pathology, University of Wisconsin-Madison, U.S.A.

Verticillium wilt (VW), caused primarily by soil-borne fungi Verticillium dahliae Kleb and V. albo-atrum Reinke and Berthold is characterized by unilateral wilting of leaves, chlorosis, and premature senescence. VW is mainly controlled by fumigating fields with metam sodium, which has negative economic and environmental impacts. Therefore, host resistance is considered to be the best means of controlling disease. One likely candidate for a potato VW resistance (R) gene is a relative of the tomato Ve gene, which has been used in tomato breeding for decades. A set of molecular markers was developed within a Ve-like gene from resistant potato. Although resistance conferred by Ve is a dominant trait, the gene does not appear to act alone. This was found in a study in our lab where a tetraploid clone homozygous for Ve was crossed to the susceptible cultivar White pearl. All progeny presumably carry Ve, so they were expected to be resistant to VW. However, some were found to be susceptible. Since in tomato, the Ve gene requires the accessory somatic embryogenesis receptor-like protein kinases SERK1 and SERK3/BAK1, NDR1, EDS1, NRC1, ACIF, MEK2 for proper function, it is reasonable to expect that they have a similar role in Ve resistance signaling in potato. Cloning of SERK1 and SERK3/ BAK1 genes from 6 different potato genotypes varying in resistance or susceptibility to VW didn’t reveal any differences. Further gene expression of Ve, SERK1, and SERK3/BAK1, NDR1, EDS1, NRC1, ACIF, MEK2 will be measured and will be related to the resistance phenotype. Based on difference in gene expression, promoters of candidate genes will be sequenced to study the regulation of resistance related genes. Also, the sequence information will be used to develop functional molecular markers, which will be validated and used for introgression of Verticillium wilt resistance in potato breeding for all market classes. 

Abstract Number: P17-551
Session Type: Poster