Ectopic expression of a novel MYB gene modifies the architecture of the Arabidopsis inflorescence.
The Arabidopsis thaliana mutants fus3, lec1 and abi3 have pleiotropic defects during late embryogenesis. Mutant embryos fail to enter the maturation programme and initiate a vegetative germination pathway instead. Screening for genes which are differentially expressed in the fus3 mutant of Arabidopsis resulted in the isolation of several members of the MYB family. MYB domain proteins in plants represent an extended gene family of transcription factors, suggesting their participation in a variety of plant specific cellular functions. Here, the authors describe one of these genes, designated AtMYB13, representing a novel member of the MYB gene family. The structure of the gene as well as its genomic organisation and localisation are reported. The expression of the gene is regulated by dehydration, exogenous abscisic acid, light and wounding. A chimeric AtMYB13 promoter/GUS gene is tissue-specifically expressed in transgenic Arabidopsis plants. The GUS staining was predominantly detected in the shoot apex zone and at the basis of developing flowers. In addition, the AtMYB13 gene promoter is active at branching points of the inflorescence. Furthermore, ectopic expression of the AtMYB13 gene has a characteristic impact on the architecture of the inflorescence leading to peculiar hook structures at pedicel branching points. In addition, some transgenic plants exhibit a reversed order of first flowers and axillary buds. These data suggest a function of the AtMYB13 gene product in linking shoot morphogenic activity with environmental as well as intrinsic signals.
Kirik
V
V
Institut für Pflanzengenetik und Kulturpflanzenforschung, Gatersleben, Germany.
Kölle
K
K
Wohlfarth
T
T
Miséra
S
S
Bäumlein
H
H
D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000196:embryology* / Q000235:genetics* / Q000254:growth & development; D029681:Arabidopsis Proteins; D001483:Base Sequence; D002874:Chromosome Mapping; D017931:DNA Primers / Q000235:genetics; D018744:DNA, Plant / Q000235:genetics / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics*; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D005966:Glucuronidase / Q000235:genetics; D008969:Molecular Sequence Data; D005810:Multigene Family; D009154:Mutation; D010940:Plant Proteins / Q000235:genetics*; D030821:Plants, Genetically Modified; D016133:Polymerase Chain Reaction; D011401:Promoter Regions, Genetic; D020598:Proto-Oncogene Proteins c-myb; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D015854:Up-Regulation
C511988:ATR1 protein, Arabidopsis; D029681:Arabidopsis Proteins; C511989:CPC protein, Arabidopsis; D017931:DNA Primers; D018744:DNA, Plant; D004268:DNA-Binding Proteins; D010940:Plant Proteins; D020598:Proto-Oncogene Proteins c-myb; D011993:Recombinant Fusion Proteins; D005966:Glucuronidase