Fructan metabolism in wheat under abiotic stress conditions

Abstract

Accumulation of fructan in different organs of wheat plants is important physiological factor to cope with different environmental stresses. Fructans are fructose based oligo- and polysaccharides derived from sucrose. Depend on the linkage among frucosyle residues, different types of fructan molecules could be found in the plant species. In wheat stem, levan-type (containing β-(2,1) linkage) and graminan-type fructan (containing β-(2,1) and β-(2,6) linkages) are accumulated. Three different enzymes of 1-SST, 6-SFT, and 1-FFT are believed to be involved in wheat fructan biosynthesis. Since the fructan synthesis in wheat is complex, therefore various type and amount of fructan are found among wheat cultivars. Hydrolysis of fructans are catalyzed by 1-FEH and 6-FEH preferentially degrading β-(2,1) and β-(2,6) linked fructan, respectively. Wheat cultivar with greater fructan accumulation and mobilization in the stem are resistance to terminal heat and drought stresses. Fructans increases tolerance to salt stress by cell membrane stabilization, osmotic adjustment and preservation of current photosynthesis. During cold hardening, wheat seedling accumulates water soluble carbohydrates as well as fructan in their leaves and crown

Keywords

• cold stress
• drought stress
• fructan metabolism
• salt stress
• wheat