PROGENY OF GENETIC CROSSES OF CFP TRANSGENIC SUGARBEET WITH TWO SALINAS GENOTYPES

Authors: Kuykendall, Larry; Panella, Leonard; Lewellen, Robert

Submitted to: Sugarbeet Research and Extension Reports
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/20/2005
Publication Date: 1/20/2005
Citation: Kuykendall, L.D., Panella, L.W., Lewellen, R.T. 2006. Progeny of genetic crosses of CFP transgenic sugarbeet with two salinas genotypes. Sugarbeet Research and Extension Reports. pp. E7-E13.

Interpretive Summary: In both U.S. and foreign sugar beet production, Cercospora-induced leaf spot disease is arguably the most severe problem reducing crop productivity and profitability. Moreover, foliar applications of fungicides are expensive and often are ineffective due to resistant strains, and there are negative environmental consequences. Since traditional plant breeding and genetics has not yet been successful in controlling sugar beet leaf spot disease, a molecular genetics approach has been pursued by scientists in the Molecular Plant Patholgy Lab in MD. A sugar beet was produced which carries a newly introduced gene responsible for resistance to the potent Cercospora-produced plant toxin called "cercosporin". This gene, called "CFP", was shown to be active and functional in sugar beet. Genetic crosses with agronomically superior types of sugar beet were performed using this new "T7" sugar beet, as scientists call it. Young plants from seeds resulting from crosses done at the Sugar Beet Research Unit in CO, are being grown in greenhouse in MD for evaluation of resistance to Cercospora leaf spot disease. This report will be of interest to sugarbeet geneticists and breeders who are developing disease resistant germplasm.

Technical Abstract: Cercospora-induced leaf spot disease, a serious problem for sugarbeet production in most of the United States’ growing regions, is not amenable to improvement by traditional breeding since resistance is moderate and exhibits low heritability. Therefore, a biotechnological approach has been pursued. In the MPPL at Beltsville, Maryland, we introduced the cercosporin toxin export gene CFP into Beta vulgaris L. This gene, isolated from Cercospora kikuchii, was developed and patented by R. G. Upchurch, ARS, Raleigh, North Carolina, as a novel means of constructing Cercospora resistance in plants. Beginning in 1998, we agrotransformed the East Lansing clone ‘Rel-1’, earlier developed by the late Joe Saunders. In 2003 and in 2004, we published two scientific journal articles on CFP introduction and the demonstration of CFP expression in transgenic sugarbeet clone T7. In 2004 and in 2005, in Ft. Collins, Colorado, CFP plants were crossed with plants of genotypes C842 and 9933 developed in Salinas, California. Evaluation of the progeny for Cercospora resistance will be a test of the concept that the CFP gene can improve Cercospora resistance. Currently thirty progeny from three crosses are being grown in a Beltsville greenhouse for disease testing.