title: Clusters of genes encoding fructan biosynthesizing enzymes in wheat and barley.
abstract: Fructans are soluble carbohydrates with health benefits and possible roles in plant adaptation. Fructan biosynthetic genes were isolated using comparative genomics and physical mapping followed by BAC sequencing in barley. Genes encoding sucrose:sucrose 1-fructosyltransferase (1-SST), fructan:fructan 1-fructosyltransferase (1-FFT) and sucrose:fructan 6-fructosyltransferase (6-SFT) were clustered together with multiple copies of vacuolar invertase genes and a transposable element on two barley BAC. Intron-exon structures of the genes were similar. Phylogenetic analysis of the fructosyltransferases and invertases in the Poaceae showed that the fructan biosynthetic genes may have evolved from vacuolar invertases. Quantitative real-time PCR was performed using leaf RNA extracted from three wheat cultivars grown under different conditions. The 1-SST, 1-FFT and 6-SFT genes had correlated expression patterns in our wheat experiment and in existing barley transcriptome database. Single nucleotide polymorphism (SNP) markers were developed and successfully mapped to a major QTL region affecting wheat grain fructan accumulation in two independent wheat populations. The alleles controlling high- and low- fructan in parental lines were also found to be associated in fructan production in a diverse set of 128 wheat lines. To the authors' knowledge, this is the first report on the mapping and sequencing of a fructan biosynthetic gene cluster and in particular, the isolation of a novel 1-FFT gene from barley.
authors.affiliation: Australian Centre for Plant Functional Genomics and School of Agriculture, Food and Wine, Waite Research Institute, The University of Adelaide, PMB 1, Glen Osmond 5064, South Australia, baolam.huynh@ucr.edu
authors.forename: Bao-Lam
authors.initials: BL
authors.lastname: Huynh
authors.forename: Diane E
authors.initials: DE
authors.lastname: Mather
authors.forename: Andreas W
authors.initials: AW
authors.lastname: Schreiber
authors.forename: John
authors.initials: J
authors.lastname: Toubia
authors.forename: Ute
authors.initials: U
authors.lastname: Baumann
authors.forename: Zahra
authors.initials: Z
authors.lastname: Shoaei
authors.forename: Nils
authors.initials: N
authors.lastname: Stein
authors.forename: Ruvini
authors.initials: R
authors.lastname: Ariyadasa
authors.forename: James C R
authors.initials: JC
authors.lastname: Stangoulis
authors.forename: James
authors.initials: J
authors.lastname: Edwards
authors.forename: Neil
authors.initials: N
authors.lastname: Shirley
authors.forename: Peter
authors.initials: P
authors.lastname: Langridge
authors.forename: Delphine
authors.initials: D
authors.lastname: Fleury
mesh_terms: D000595:Amino Acid Sequence; D002874:Chromosome Mapping / Q000379:methods; D018744:DNA, Plant / Q000737:chemistry / Q000235:genetics; D005630:Fructans / Q000032:analysis / Q000096:biosynthesis* / Q000235:genetics; D018506:Gene Expression Regulation, Plant / Q000235:genetics; D006602:Hexosyltransferases / Q000235:genetics / Q000378:metabolism; D001467:Hordeum / Q000201:enzymology* / Q000235:genetics; D008969:Molecular Sequence Data; D005810:Multigene Family / Q000235:genetics*; D010802:Phylogeny; D018515:Plant Leaves / Q000201:enzymology / Q000235:genetics; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D020641:Polymorphism, Single Nucleotide; D040641:Quantitative Trait Loci / Q000235:genetics; D018749:RNA, Plant / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D014908:Triticum / Q000201:enzymology* / Q000235:genetics; D014617:Vacuoles / Q000201:enzymology; D043324:beta-Fructofuranosidase / Q000235:genetics; D001426:Bacterial Proteins
chemical_list: D018744:DNA, Plant; D005630:Fructans; D006602:Hexosyltransferases; D010940:Plant Proteins; D018749:RNA, Plant; D043324:beta-Fructofuranosidase; C114852:1,2-beta-fructan 1(F)-fructosyltransferase; C021451:inulosucrase; D001426:Bacterial Proteins