ARS | Publication request: GLYCOALKALOID LEVELS IN A GENETICALLY MODIFIED LENAPE.

Submitted to: American Journal of Potato Research
Publication Type: Abstract Only
Publication Acceptance Date: November 1, 1999
Publication Date: N/A

Interpretive Summary: Glycoalkaloids are naturally occurring toxic metabolites in potatoes. They usually are found at very low levels and do not present a problem. However some cultivars and breeding selections can accumulate high levels. One variety, Lenape, is not grown because of its higher than normal alkaloid levels. This research used the approach of modifying one of the potatoes own genes so that it would not accumulate as much of the toxic alkaloids. Although alkaloid accumulation was not stopped it was significantly reduced in a number of the genetically modified Lenape selections.

Technical Abstract: Microtuber discs were used in the transformation of the variety Lenape by Agrobacterium-mediated gene transfer. The new transgenic lines contained an antisense solanidine glucose-ADP glucosyltransferase SGT transgene, with the intention of inhibiting the biosynthesis of tuber glycoalkaloids. Thirteen transgenic lines of the variety Lenape were evaluated and characterized in replicated trials at two locations, Rhinelander and Aberdeen. In Aberdeen tubers from three transgenic lines had significantly lower glycoalkaloid levels than tubers of the variety Lenape. Glycoalkaloid concentrations of the transgenic lines ranged from 24.6 milligrams glycoalkaloids per 100 grams tuber fresh weight mg/100 g FW. In Rhinelander, similar reductions were measured, but they were not statistically significant. Western analysis revealed that lower levels of glycoalkaloids correlated with lower levels of the SGT protein. Northern analysis confirmed the presence of the antisense SGT RNA in the transgenic plants. Northern and Western analyses are consistent with the hypothesis that the antisense SGT gene inhibited the biosynthesis of the glycoalkaloids.