Factors affecting fructosyltransferases and fructan exohydrolase activities in Agave tequilana Weber var. azul

There is great interest in the fructosyltransferases (FTFs) involved in fructan metabolism and agents affecting their activity. Agaves accumulate fructans, fructose polymers linked by glycosidic beta(2-1) and beta(2-6) bonds in linear or branched configurations. In plants, fructans provide protection under stress conditions. The sucrose:sucrose 1-fructosyltransferase (1-SST), fructan:fructan 1-fructosyltransferase (1-FFT), fructan:fructan 6G-fructosyltransferase (6G-FFT), and fructan exohydrolase (FEH) activities were analyzed in micropropagated Agave tequilana plants in the absence and presence of HgCl2, AgNO3, MgCl2, sodium deoxycholate (DNa), and sodium dodecyl sulfate (SDS). Kestose, nystose and neokestose were synthesized by the respective FTFs. HgCl2 and AgNO3 inhibited all FTFs, mainly up to 90 % in 1-SST and 1-FFT. DNa increased 1-SST (32 %) and 1-FFT (45 %) activities, and SDS increased 6G-FFT activity by 96 %. Finally, AgNO3 inhibited FEH activity by 78 %. Our results might be relevant on the regulation of FTFs in agave and other crops, for instance by the increment the fructans synthesis in stressed plants.