title: Brassicaceae INDEHISCENT genes specify valve margin cell fate and repress replum formation.
abstract: Members of the Brassicaceae family, including Arabidopsis thaliana and oilseed rape (Brassica napus), produce dry fruits that open upon maturity along a specialised tissue called the valve margin. Proper development of the valve margin in Arabidopsis is dependent on the INDEHISCENT (IND) gene, the role of which in genetic and hormonal regulation has been thoroughly characterised. Here we perform phylogenetic comparison of IND genes in Arabidopsis and Brassica to identify conserved regulatory sequences that are responsible for specific expression at the valve margin. In addition we have taken a comparative development approach to demonstrate that the BraA.IND.a and BolC.IND.a genes from B. rapa and B. oleracea share identical function with Arabidopsis IND since ethyl methanesulphonate (EMS) mutant alleles and silenced transgenic lines have valve margin defects. Furthermore we show that the degree of these defects can be fine-tuned for crop improvement. Wild-type Arabidopsis produces an outer replum composed of about six cell files at the medial region of the fruits, whereas Brassica fruits lack this tissue. A strong loss-of-function braA.ind.a mutant gained outer replum tissue in addition to its defect in valve margin development. An enlargement of replum size was also observed in the Arabidopsis ind mutant suggesting a general role of Brassicaceae IND genes in preventing valve margin cells from adopting replum identity.
authors.affiliation: Department of Crop Genetics, John Innes Centre, Colney Lane, Norwich NR4 7UH, UK.
authors.forename: Thomas
authors.initials: T
authors.lastname: Girin
authors.affiliation: Department of Crop Genetics, John Innes Centre, Colney Lane, Norwich NR4 7UH, UK.
authors.forename: Pauline
authors.initials: P
authors.lastname: Stephenson
authors.affiliation: Department of Crop Genetics, John Innes Centre, Colney Lane, Norwich NR4 7UH, UK.
authors.forename: Cassandra M P
authors.initials: CMP
authors.lastname: Goldsack
authors.affiliation: Section of Cell and Developmental Biology, University of California at San Diego, La Jolla, CA 92093-0116, USA.
authors.forename: Sherry A
authors.initials: SA
authors.lastname: Kempin
authors.affiliation: Department of Crop Genetics, John Innes Centre, Colney Lane, Norwich NR4 7UH, UK.
authors.forename: Amandine
authors.initials: A
authors.lastname: Perez
authors.affiliation: Department of Plant Sciences, University of Oxford, South Parks Road, Oxford OX1 3RB, UK.
authors.forename: Nuno
authors.initials: N
authors.lastname: Pires
authors.affiliation: Department of Crop Genetics, John Innes Centre, Colney Lane, Norwich NR4 7UH, UK.
authors.forename: Penelope A
authors.initials: PA
authors.lastname: Sparrow
authors.affiliation: Department of Crop Genetics, John Innes Centre, Colney Lane, Norwich NR4 7UH, UK.
authors.forename: Thomas A
authors.initials: TA
authors.lastname: Wood
authors.affiliation: Section of Cell and Developmental Biology, University of California at San Diego, La Jolla, CA 92093-0116, USA.
authors.forename: Martin F
authors.initials: MF
authors.lastname: Yanofsky
authors.affiliation: Department of Crop Genetics, John Innes Centre, Colney Lane, Norwich NR4 7UH, UK.
authors.forename: Lars
authors.initials: L
authors.lastname: Østergaard
mesh_terms: D017360:Arabidopsis / Q000235:genetics* / Q000254:growth & development; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D051792:Basic Helix-Loop-Helix Proteins / Q000235:genetics* / Q000378:metabolism; D001937:Brassica / Q000235:genetics / Q000254:growth & development*; D017124:Conserved Sequence; D005638:Fruit / Q000254:growth & development*; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D009154:Mutation; D010802:Phylogeny; D030821:Plants, Genetically Modified / Q000235:genetics / Q000254:growth & development; D011401:Promoter Regions, Genetic; D018749:RNA, Plant / Q000235:genetics; D017422:Sequence Analysis, DNA
chemical_list: D029681:Arabidopsis Proteins; D051792:Basic Helix-Loop-Helix Proteins; D018749:RNA, Plant; C484035:INDEHISCENT protein, Arabidopsis
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