ISHS Acta Horticulturae 619: XXVI International Horticultural Congress: Potatoes, Healthy Food for Humanity: International Developments in Breeding, Production, Protection and Utilization
REDUCTION OF TOTAL STEROIDAL GLYCOALKALOIDS IN POTATO TUBERS USING ANTISENSE CONSTRUCTS OF A GENE ENCODING A SOLANIDINE GLUCOSYL TRANSFERASE |
| Authors: | K.F. McCue, P.V. Allen, D.R. Rockhold, M.M. Maccree, W.R. Belknap, L.V.T. Shephard, H. Davies, P. Joyce, D.L Corsini, C.P. Moehs |
| Keywords: | Solanine, Chaconine, Genetic Modification, Lenape, Desiree, Field Trials |
| Abstract:
Accumulation of steroidal glycoalkaloid (SGA) toxicants in potatoes affects food quality and safety. High levels of SGAs hamper breeding efforts to develop new varieties of potatoes with improved agronomic and post harvest properties. To speed breeding efforts for reducing SGAs in breeding lines and correcting flawed selections we are taking a molecular genetic approach to reduce SGAs. A cDNA encoding a solanidine glucosyltransferase (SGT) was isolated and used to construct antisense transgenes transcribed from either the Cauliflower Mosaic Virus 35S or a tuber-specific granule bound starch synthase promoter. Transgenic lines of potato (Solanum tuberosum) cultivar ‘Lenape’ expressing these transgenes exhibit phenotypes with significantly lower SGAs. Field trails over several years in Idaho and Wisconsin resulted in reproducible and statistically significant reductions of up to 40% of tuber SGAs. Reduction in SGAs is accompanied by expression of Sgt antisense RNA transcripts and a reduction in SGT protein levels. Analysis of transgenic cultivar ‘Desiree’ lines expressing an antisense Sgt revealed essentially complete down-regulation of solanine biosynthesis in several transgenic lines. Chaconine accumulation in these lines was not significantly affected. Additional transgenes encoding SGT and other SGA related sequences are currently being evaluated. | |
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