title: Changes in genome-wide gene expression during allopolyploidization and genome stabilization in hexaploid wheat.
abstract: Allopolyploidization is an important evolutionary event in plants, but its genome-wide effects are not fully understood. Common wheat, Triticum aestivum (AABBDD), evolved through amphidiploidization between T. turgidum (AABB) and Aegilops tauschii (DD). Here, global gene expression patterns in the seedlings of a synthetic triploid wheat line (ABD), its chromosome-doubled hexaploid (AABBDD) and stable synthetic hexaploid (AABBDD), and the parental lines T. turgidum (AABB) and Ae. tauschii (DD) were compared using an oligo-DNA microarray to identify metabolic pathways affected by the genome conflict that occurs during allopolyploidization and genome stabilization. Characteristic gene expression patterns of non-additively expressed genes were detected in the newly synthesized triploid and hexaploid, and in the stable synthetic hexaploid. Hierarchical clustering of all differentially expressed and non-additively expressed genes revealed that the gene expression patterns of the triploid (ABD) were similar to those of the maternal parent (AABB), and that expression patterns in successive generations arising from self-pollination became closer to that of the pollen parent (DD). The non-additive gene expression profiles markedly differed between the triploid (ABD) and chromosome-doubled hexaploid (AABBDD), as supported by Gene Ontology (GOSlim) analysis. Four hundred and nineteen non-additively expressed genes were commonly detected in all three generations. GOSlim analysis indicated that these non-additively expressed genes were predominantly involved in "biological pathways". Notably, four of 11 genes related to sugar metabolism displayed elevated expression throughout allopolyploidization. These may be useful candidates for promoting heterosis and adaptation in plants.
authors.affiliation: Kihara Institute for Biological Research and Department of Life and Environmental System Science, Yokohama City University.
authors.forename: Yeonju
authors.initials: Y
authors.lastname: Jung
authors.forename: Kanako
authors.initials: K
authors.lastname: Kawaura
authors.forename: Kohei
authors.initials: K
authors.lastname: Mishina
authors.forename: Shun
authors.initials: S
authors.lastname: Sakuma
authors.forename: Masahiro
authors.initials: M
authors.lastname: Kishii
authors.forename: Yasunari
authors.initials: Y
authors.lastname: Ogihara
mesh_terms: D000704:Analysis of Variance; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant / Q000235:genetics*; D042822:Genomic Instability / Q000235:genetics*; D046228:Microarray Analysis; D011123:Polyploidy; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014908:Triticum / Q000235:genetics*