Coordinated expression of functionally diverse fructosyltransferase genes is associated with fructan accumulation in response to low temperature in perennial ryegrass.
* Fructan is the major nonstructural carbohydrate reserve in temperate grasses. To understand regulatory mechanisms in fructan synthesis and adaptation to cold environments, the isolation, functional characterization and genetic mapping of fructosyltransferase (FT) genes in perennial ryegrass (Lolium perenne) are described. * Six cDNAs (prft1-prft6) encoding FTs were isolated from cold-treated ryegrass plants, and three were positioned on a perennial ryegrass linkage map. Recombinant proteins were produced in Pichia pastoris and enzymatic activity was characterized. Changes in carbohydrate levels and mRNA levels of FT genes during cold treatment were also analysed. * One gene encodes sucrose-sucrose 1-fructosyltransferase (1-SST), and two gene encode fructan-fructan 6G-fructosyltransferase (6G-FFT). Protein sequences for the other genes (prfts 1, 2 and 6) were similar to sucrose-fructan 6-fructosyltransferase (6-SFT). The 1-SST and prft1 genes were colocalized with an invertase gene on the ryegrass linkage map. The mRNA levels of prft1 and prft2 increased gradually during cold treatment, while those of the 1-SST and 6G-FFT genes first increased, but then decreased before increasing again during a longer period of cold treatment. * Thus at least two different patterns of gene expression have developed during the evolution of functionally diverse FT genes, which are associated in a coordinated way with fructan synthesis in a cold environment.
Hisano
Hiroshi
H
Research Faculty of Agriculture, Hokkaido University, Sapporo 060-8589, Japan.
Kanazawa
Akira
A
Research Faculty of Agriculture, Hokkaido University, Sapporo 060-8589, Japan.
Yoshida
Midori
M
National Agricultural Research Center for Hokkaido Region, Hitsujigaoka, Sapporo 062-8555, Japan.
Humphreys
Mervyn O
MO
Institute of Grassland and Environmental Research, Plas Gogerddan, Aberystwyth, Ceredigion SY23 3EB, UK.
Iizuka
Masaru
M
Graduate School of Science, Osaka City University, 3-3-138 Sugimoto, Osaka 558-8585, Japan.
Kitamura
Keisuke
K
Research Faculty of Agriculture, Hokkaido University, Sapporo 060-8589, Japan.
Yamada
Toshihiko
T
Field Science Center for Northern Biosphere, Hokkaido University, Sapporo 060-0811, Japan.
D000595:Amino Acid Sequence; D050260:Carbohydrate Metabolism; D002851:Chromatography, High Pressure Liquid; D002874:Chromosome Mapping; D002999:Clone Cells; D003080:Cold Temperature; D018076:DNA, Complementary / Q000235:genetics / Q000302:isolation & purification; D018744:DNA, Plant / Q000378:metabolism; D005630:Fructans / Q000378:metabolism*; D018628:Gene Dosage; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D006602:Hexosyltransferases / Q000737:chemistry / Q000235:genetics*; D008129:Lolium / Q000201:enzymology* / Q000235:genetics*; D008954:Models, Biological; D008969:Molecular Sequence Data; D010802:Phylogeny; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D017422:Sequence Analysis, DNA; D001426:Bacterial Proteins
D018076:DNA, Complementary; D018744:DNA, Plant; D005630:Fructans; D006602:Hexosyltransferases; D012333:RNA, Messenger; C021451:inulosucrase; D001426:Bacterial Proteins