title: Duplication of a well-conserved homeodomain-leucine zipper transcription factor gene in barley generates a copy with more specific functions.
abstract: Three spikelets are formed at each rachis node of the cultivated barley (Hordeum vulgare ssp. vulgare) spike. In two-rowed barley, the central one is fertile and the two lateral ones are sterile, whereas in the six-rowed type, all three are fertile. This characteristic is determined by the allelic constitution at the six-rowed spike 1 (vrs1) locus on the long arm of chromosome 2H, with the recessive allele (vrs1) being responsible for the six-rowed phenotype. The Vrs1 (HvHox1) gene encodes a homeodomain-leucine zipper (HD-Zip) transcription factor. Here, we show that the Vrs1 gene evolved in the Poaceae via a duplication, with a second copy of the gene, HvHox2, present on the short arm of chromosome 2H. Micro-collinearity and polypeptide sequences were both well conserved between HvHox2 and its Poaceae orthologs, but Vrs1 is unique to the barley tribe. The Vrs1 gene product lacks a motif which is conserved among the HvHox2 orthologs. A phylogenetic analysis demonstrated that Vrs1 and HvHox2 must have diverged after the separation of Brachypodium distachyon from the Pooideae and suggests that Vrs1 arose following the duplication of HvHox2, and acquired its new function during the evolution of the barley tribe. HvHox2 was expressed in all organs examined but Vrs1 was predominantly expressed in immature inflorescence.
authors.affiliation: National Institute of Agrobiological Sciences, Tsukuba, Ibaraki, Japan.
authors.forename: Shun
authors.initials: S
authors.lastname: Sakuma
authors.forename: Mohammad
authors.initials: M
authors.lastname: Pourkheirandish
authors.forename: Takashi
authors.initials: T
authors.lastname: Matsumoto
authors.forename: Takato
authors.initials: T
authors.lastname: Koba
authors.forename: Takao
authors.initials: T
authors.lastname: Komatsuda
mesh_terms: D000595:Amino Acid Sequence; D002874:Chromosome Mapping; D017124:Conserved Sequence; D018628:Gene Dosage / Q000235:genetics*; D020440:Gene Duplication; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant / Q000235:genetics; D018398:Homeodomain Proteins / Q000235:genetics*; D001467:Hordeum / Q000235:genetics*; D016350:Leucine Zippers / Q000235:genetics*; D008969:Molecular Sequence Data; D010802:Phylogeny; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017386:Sequence Homology, Amino Acid; D014157:Transcription Factors / Q000235:genetics*
chemical_list: D018398:Homeodomain Proteins; D010940:Plant Proteins; D014157:Transcription Factors
references.citation: Plant Mol Biol. 2008 Jan;66(1-2):87-103
references.pmid: 17999151
references.citation: J Biochem Mol Biol. 2004 May 31;37(3):320-4
references.pmid: 15469713
references.citation: Nature. 2009 Jan 29;457(7229):551-6
references.pmid: 19189423
references.citation: Trends Plant Sci. 2007 Sep;12(9):419-26
references.pmid: 17698401
references.citation: Funct Integr Genomics. 2006 Apr;6(2):90-103
references.pmid: 16372189
references.citation: Biochim Biophys Acta. 1998 Oct 23;1442(1):1-19
references.pmid: 9767075
references.citation: EMBO J. 2002 Jun 17;21(12):3029-38
references.pmid: 12065416
references.citation: Plant Cell. 2006 Jan;18(1):15-28
references.pmid: 16326928
references.citation: Curr Opin Plant Biol. 2001 Apr;4(2):118-22
references.pmid: 11228433
references.citation: Curr Biol. 1995 Jul 1;5(7):737-9
references.pmid: 7583118
references.citation: Funct Integr Genomics. 2004 Mar;4(1):34-46
references.pmid: 14740255
references.citation: Proc Natl Acad Sci U S A. 2007 Jan 23;104(4):1424-9
references.pmid: 17220272
references.citation: Mol Genet Genomics. 2005 Dec;274(5):515-27
references.pmid: 16244872
references.citation: Hereditas. 2004;141(1):68-73
references.pmid: 15383074
references.citation: Funct Integr Genomics. 2008 May;8(2):149-64
references.pmid: 18210171
references.citation: Theor Appl Genet. 2007 Aug;115(4):489-99
references.pmid: 17619853
references.citation: Genetics. 2002 Mar;160(3):1153-62
references.pmid: 11901130
references.citation: Plant Mol Biol. 2004 Jul;55(5):663-77
references.pmid: 15604708
references.citation: Plant Cell. 2000 Mar;12(3):381-91
references.pmid: 10715324
references.citation: Proc Natl Acad Sci U S A. 1998 Mar 3;95(5):1971-4
references.pmid: 9482816
references.citation: Plant J. 2007 Feb;49(4):704-17
references.pmid: 17270010
references.citation: Genomics. 1996 Nov 1;37(3):327-36
references.pmid: 8938445
references.citation: Funct Integr Genomics. 2006 Apr;6(2):83-9
references.pmid: 16270217
references.citation: Theor Appl Genet. 2007 May;114(8):1357-65
references.pmid: 17375281
references.citation: J Mol Biol. 2001 Apr 20;308(1):39-47
references.pmid: 11302705
references.citation: Plant Cell Physiol. 2005 Dec;46(12):1954-63
references.pmid: 16215272
references.citation: Evolution. 1973 Jun;27(2):311-325
references.pmid: 28564784
references.citation: Genetics. 1999 Apr;151(4):1531-45
references.pmid: 10101175
references.citation: Proc Natl Acad Sci U S A. 2003 Oct 14;100(21):12265-70
references.pmid: 14530400
references.citation: Biochemistry. 2004 Dec 21;43(50):15845-51
references.pmid: 15595839
references.citation: Ann Bot. 2007 Nov;100(5):999-1008
references.pmid: 17761690
references.citation: Curr Opin Plant Biol. 2003 Apr;6(2):128-33
references.pmid: 12667868
references.citation: Proc Natl Acad Sci U S A. 2003 May 13;100(10):6263-8
references.pmid: 12730378
references.citation: Plant Physiol. 2005 Sep;139(1):509-18
references.pmid: 16055682
references.citation: Comp Funct Genomics. 2004;5(3):281-4
references.pmid: 18629160
references.citation: Int J Plant Genomics. 2008;2008:536104
references.pmid: 18309367
references.citation: EMBO J. 1993 Sep;12(9):3507-17
references.pmid: 8253077
references.citation: Transgenic Res. 2005 Aug;14(4):429-40
references.pmid: 16201409
references.citation: Curr Opin Plant Biol. 2005 Apr;8(2):155-62
references.pmid: 15752995
references.citation: PLoS Genet. 2007 Jul;3(7):e123
references.pmid: 17658954
references.citation: Proc Natl Acad Sci U S A. 2004 Jun 29;101(26):9903-8
references.pmid: 15161969
references.citation: Nature. 2009 Jan 29;457(7229):547-8
references.pmid: 19177121
references.citation: Biochem J. 1999 Jul 1;341 ( Pt 1):81-7
references.pmid: 10377247
references.citation: Funct Integr Genomics. 2009 Feb;9(1):67-79
references.pmid: 18958509
references.citation: Genomics. 1987 Oct;1(2):174-81
references.pmid: 3692487
references.citation: Plant Cell Physiol. 2008 Oct;49(10):1451-64
references.pmid: 18835840
references.citation: Nature. 2005 Aug 11;436(7052):793-800
references.pmid: 16100779