Biosynthesis of α-solanine and α-chaconine in potato leaves (Solanum tuberosum L.) – A 13CO2 study
Sebastian Baur, Oliver Frank, H. Hausladen, Ralph Hückelhoven, Thomas Hofmann, Wolfgang Eisenreich +1 more
Food Chemistry
Abstract
α-Solanine and α-chaconine are the major glycoalkaloids (SGAs) in potatoes, but up to now the biosynthesis of these saponins is not fully understood. In planta<sup>13</sup>CO<sub>2</sub> labeling experiments monitored by nuclear magnetic resonance spectroscopy (NMR) and high-resolution mass spectrometry (HRMS) unraveled the SGA biosynthetic pathways from CO<sub>2</sub> photosynthates via early precursors to the SGAs. After a pulse of ~ 700 ppm <sup>13</sup>CO<sub>2</sub> for four hours, followed by a chase period for seven days, specific <sup>13</sup>C-distributions were detected in SGAs from the leaves of the labeled plant. NMR analysis determined the positional <sup>13</sup>C-enrichments in α-solanine and α-chaconine characterized by <sup>13</sup>C<sub>2</sub>-pairs in their aglycones. These patterns were in perfect agreement with a mevalonate-dependent biosynthesis of the isopentenyl diphosphate and dimethylallyl diphosphate precursors. The <sup>13</sup>C-distributions also suggested cyclization of the 2,3-oxidosqualene precursor into the solanidine aglycone backbone involving a non-stereoselective hydroxylation step of the sterol a mixture of 25S-/25R-epimers of the SGAs.
Extracted Claims
4 claims extracted from this paper into the knowledge graph
SGA biosynthesis involves cyclization of 2,3-oxidosqualene
“The 13C-distributions also suggested cyclization of the 2,3-oxidosqualene precursor into the solanidine aglycone backbone involving a non-stereoselective hydroxylation step of the sterol a mixture of ...”
α-chaconine biosynthesized from CO2 photosynthates
“α-Solanine and α-chaconine are the major glycoalkaloids (SGAs) in potatoes, but up to now the biosynthesis of these saponins is not fully understood. In planta13CO2 labeling experiments monitored by n...”
SGA biosynthesis involves mevalonate-dependent biosynthesis
“These patterns were in perfect agreement with a mevalonate-dependent biosynthesis of the isopentenyl diphosphate and dimethylallyl diphosphate precursors.”