, 223:90

Fructan:fructan 1-fructosyltransferase, a key enzyme for biosynthesis of graminan oligomers in hardened wheat

Original Article

DOI: 10.1007/s00425-005-0054-6

Cite this article as:
Kawakami, A. & Yoshida, M. Planta (2005) 223: 90. doi:10.1007/s00425-005-0054-6


Fructans play important roles not only as a carbon source for survival under persistent snow cover but also as agents that protect against various stresses in overwintering plants. Complex fructans having both ß-(2,1)- and ß-(2,6)-linked fructosyl units accumulate in wheat (Triticum aestivum L.) during cold hardening. We detected fructan: fructan 1-fructosyltransferase (1-FFT; EC activity for catalyzing the formation and extension of ß-(2,1)-linked fructans in hardened wheat tissues, cloned cDNAs (wft3 and wft4) of 1-FFT, and analyzed the enzymatic properties of a wft3 recombinant protein (Wft3m) produced by yeast. Wft3m transferred ß-(2,1)-linked fructosyl units to phlein, an extension of sucrose through ß-(2,6)-linked fructosyl units, as well as to inulin, an extension of sucrose through ß-(2,1)-linked fructosyl units, but could not efficiently synthesize long inulin oligomers. Incubation of a mixture of Wft3m and another recombinant protein of wheat, sucrose:fructan 6-fructosyltransferase (6-SFT), with sucrose and 1-kestotriose produced fructans similar to those that accumulated in hardened wheat tissues. The results demonstrate that 1-FFT produces branches of ß-(2,1)-linked fructosyl units to phlein and graminan oligomers synthesized by 6-SFT and contributes to accumulation of fructans containing ß-(2,1)- and ß-(2,6)-linked fructosyl units. In combination with sucrose:sucrose 1-fructosyltransferase (1-SST; EC and 6-SFT, 1-FFT is necessary for fructan synthesis in hardened wheat.


FructanGraminan biosynthesisWinter wheatCold hardeningFructan:fructan 1-fructosyltransferaseTriticum aestivum



Sucrose:sucrose 1fructosyltransferase


Fructan:fructan 1-fructosyltransferase


Sucrose:fructan 6-fructosyltransferase


Fructan:fructan 6G-fructosyltransferase


Fructan exohydrolase


High-performance anion exchange chromatography


Pulsed amperometric detector


Degree of polymerization


Wheat fructosyltransferase 1


Wheat fructosyltransferase 3


Wheat fructosyltransferase 4

Copyright information

© Springer-Verlag 2005

Authors and Affiliations

  1. 1.Laboratory of Fungal Disease, Department of Plant PathologyNational Agricultural Research CenterIbarakiJapan
  2. 2.Laboratory of Winter Stress, Department of Low Temperature ScienceNational Agricultural Research Center for Hokkaido RegionHokkaidoJapan