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Coordinated expression of functionally diverse fructosyltransferase genes is associated with fructan accumulation in response to low temperature in perennial ryegrass
Author(s) -
Hisano Hiroshi,
Kanazawa Akira,
Yoshida Midori,
Humphreys Mervyn O.,
Iizuka Masaru,
Kitamura Keisuke,
Yamada Toshihiko
Publication year - 2008
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/j.1469-8137.2008.02409.x
Subject(s) - fructan , invertase , biology , lolium perenne , gene , sucrose , perennial plant , biochemistry , genetics , botany
Summary• 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.