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Title: DNA ANALYSIS OF POTATO+SOLANUM BREVIDENS SOMATIC HYBRID LINES

Author
item POLGAR, ZSOLT - PANNON UNIV, HUNGARY
item WIELGUS, SUSAN - UNIVERSITY OF WISCONSIN
item HORVATH, SANDOR - PANNON UNIV, HUNGARY
item Helgeson, John

Submitted to: Journal of Theoretical and Applied Genetics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/11/1997
Publication Date: N/A
Citation: N/A

Interpretive Summary: Interspecific somatic hybrids are formed by the fusion of vegetative cells of two different species. It is very important to analyze the fate of the DNA of the two species in question as the successful transfer and expression of the genetic traits desired from the wild species may depend upon completeness of transfer. In this paper hybrids between the wild South American species, Solanum brevidens and the potato variety "white lady." were fused and the DNA of 3 of the hybrids was analyzed using randomly amplified polymorphic DNA (RAPD) primers. Although the plants being analyzed were derived from the same initial fusion event they were only obtained after a period of several weeks in tissue culture. The three shoots analyzed in this study were isolated from the same mass of tissue that resulted from culture of the initial fused cells. It was found that the shoots differed in DNA losses and that pieces of 4 of the 12 chromosomes of the hybrids were missing. These losses may be related to the substantial difference in the resistance of these plants to the bacterial soft rot pathogen, Erwinia carotovora. This disease is a major source of loss to farmers - up to perhaps $200 Million/year and knowledge of which pieces of DNA will carry resistance to the bacteria could prevent these losses if this information leads to identification of the genes responsible for resistance.

Technical Abstract: Three somatic hybrid lines between potato (cv. White Lady line no. Ke 79, 2n=2x=48+Solanum brevidens (PI 218228, 2n+2x+24) were evaluated using randomly amplified polymorphic DNA (RAPD) markers. The lines originated from the same callus but showed different reactions to Erwinia carotovora ssp. Carotovora, the cause of potato soft rot. By the use of 48 oligomer primers producing 99 scorable bands, DNA polymorphism were detected on 7 of 12 S. brevidens chromosomes. Loss of certain DNA segments on chromosome 5, 6, 9 and 11 were observed. Some of the variations could have taken place in early callus stage of development; others may have occurred after initiation of individual shoot regeneration. The possible involvement of missing RAPD products specific to one somatic hybrid that shows decreased resistance to bacterial soft rot is discussed.