John P. Helgeson

Plant Pathology and Research Leader, USDA-ARS Plant Disease Resistance Research Unit
Ph.D.: University of Wisconsin-Madison in Botany

Research Program

Wild Solanum species related to potato harbor many potentially useful disease resistance genes. The full use of these genes has been hampered, however, by sexual incompatibilities between the wild species and potato. We are using somatic hybridization, the fusion of leaf protoplasts of two species, to capture these resistance genes. Presently we have new genes for resistances to most of the major potato diseases. Our current efforts center on the genetic analyses of these materials with restriction fragment length polymorphism (RFLP) and randomly amplified polymorphic DNA (RAPD) probes. Our goal is to map the resistance genes initially to specific chromosomes and then to more precise locations in the potato genome in order to follow traits by marker-assisted breeding and, eventually, to clone disease resistance genes that might then be reinserted into useful cultivars to provide new resistances. Efforts center on resistances to Erwinia soft rot, bacterial wilt, Verticillium wilt, early blight, and late blight.

Selected Publications

Naess, S.K. J. M. Bradeen, S. M. Wielgus, G. T. Haberlach, J. M. McGrath and J. P. Helgeson. 2001. Analysis of introgression of Solanu bulbocastanum DNA into potato breeding lines. Mol. Gen. Genomics. 265:694-704.

Naess, S.K., J.M. Bradeen, S.M. Wielgus, G.T. Haberlach, J.M. McGrath and J.P. Helgeson. 2000. Resistance to late blight in Solanum bulbocastanum is mapped to Chromosome 8. Theor. Appl. Genet. 101: 697-704.

Helgeson, J. P. and G. T. Haberlach. 1999. Somatic hybrids of Solanum tuberosum and related species. in Plant Biotechnology and in vitro Biology in the 21st Century. A. Altman, M. Ziv, S. Izhar, eds. Kluwer Academic Publishers. Dordrecht. pp 151-154.

Laferriere, L.T., J. P. Helgeson and C. Allen. 1999. Developing bacterial wilt resistant breeding lines from Solanum tuberosum - S. commersonii somatic hybrids. Theor. Appl. Genet. 98:1272-1278.

Helgeson, J.P., J.D. Pohlman, S. Austin, G.T. Haberlach, S.M. Wielgus, D. Ronis, L. Zambolim, P. Tooley, J.M. McGrath, R.V. James, and W.R. Stevenson. 1998. Somatic hybrids between Solanum bulbocastanum and potato: a new source of resistance to late blight. Theor. Appl. Genet. 96:738-742.

McGrath, J.M. and Helgeson, J.P. 1998. Differential behavior of Solanum brevidens ribosomal DNA loci in a somatic hybrid and its progeny with potato. Genome 41: 435-439.

McGrath, J.M., Wielgus, S.M. and Helgeson, J.P. 1996. Segregation and recombination of Solanum brevidens synteny groups in progeny of somatic hybrids with S. tuberosum: Intragenomic equals or exceeds intergenomic recombination. Genetics 142: 1335-1348.

Williams, C.E., S M. Wielgus, C. Guenther, G.T. Haberlach, H. Kim-lee, and J. P. Helgeson. 1993. RFLP analysis of chromosomal segregation in progeny from an interspecific hexaploid somatic hybrid between Solanum brevidens and S. tuberosum. Genetics 135:1167-1173.

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