High-Throughput Extraction and Enzymatic Determination of Sugars and Fructans in Fructan-Accumulating Plants.

Fructans are carbohydrates present in more than 15% of flowering plants. They represent the major pool of carbohydrates in some species, especially when facing cold or drought. However, the functions of fructans with high or low degrees of polymerization (DP), their diurnal use, and the regulation of their synthesis and degradation in response to stresses still remain unclear. Here we present an enzymatic protocol adapted to 96-well microplates that simultaneously allows the determination of fructans and glucose, fructose, and sucrose. Moreover, the protocol allows to estimate the average DP of the fructans in the samples. The protocol is based on the enzymatic degradation of fructans into glucose and fructose and their subsequent conversion into gluconate 6-phosphate concomitant with the formation of NADH in the presence of ATP.