Fructan of the inulin neoseries is synthesized in transgenic chicory plants (Cichorium intybus L.) harbouring onion (Allium cepa L.) fructan:fructan 6G-fructosyltransferase.
Fructan (polyfructosylsucrose) is an important storage carbohydrate in many plant families. fructan:fructan 6G-fructosyltransferase (6G-FFT) is a key enzyme in the formation of the inulin neoseries, a type of fructan accumulated by members of the Liliales. We have cloned the 6G-FFT from onion by screening a cDNA library using barley sucrose:fructan 6-fructosyltransferase (6-SFT) as a probe. The deduced amino acid sequence showed a high homology with plant invertases and 6-SFT. Incubation of protein extracts from transgenic tobacco plants with the trisaccharide 1-kestose and sucrose resulted in the formation of neokestose and fructans of the inulin neoseries with a degree of polymerization up to six. Introduction of the onion 6G-FFT into chicory resulted in the synthesis of fructan of the inulin neoseries, in addition to the synthesis of linear inulin.
Vijn
I
I
Department of Molecular Cell Biology, University of Utrecht, The Netherlands.
van Dijken
A
A
Sprenger
N
N
van Dun
K
K
Weisbeek
P
P
Wiemken
A
A
Smeekens
S
S
D000490:Allium / Q000201:enzymology*; D000595:Amino Acid Sequence; D018651:Cichorium intybus; D005630:Fructans / Q000096:biosynthesis*; D015723:Gene Library; D006602:Hexosyltransferases / Q000096:biosynthesis / Q000737:chemistry / Q000378:metabolism*; D001467:Hordeum / Q000201:enzymology; D007444:Inulin / Q000096:biosynthesis*; D008969:Molecular Sequence Data; D030821:Plants, Genetically Modified / Q000378:metabolism*; D010947:Plants, Toxic; D011523:Protoplasts / Q000201:enzymology; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D014026:Nicotiana / Q000201:enzymology; D014617:Vacuoles / Q000201:enzymology
D005630:Fructans; D011993:Recombinant Fusion Proteins; D007444:Inulin; D006602:Hexosyltransferases; C105700:fructan - fructan 6G-fructosyltransferase; C097181:sucrose - fructan 6-fructosyltransferase