Multiple AGAMOUS homologs from cucumber and petunia differ in their ability to induce reproductive organ fate.
The C function in Arabidopsis, which specifies stamen and carpel identity, is represented by a single gene called AGAMOUS (AG). From both petunia and cucumber, two MADS box genes have been isolated. Both share a high degree of amino acid sequence identity with the Arabidopsis AG protein. Their roles in specifying stamen and carpel identity have been studied by ectopic expression in petunia, resulting in plants with different floral phenotypes. Cucumber MADS box gene 1 (CUM1) induced severe homeotic transformations of sepals into carpelloid structures and petals into stamens, which is similar to ectopic AG expression in Arabidopsis plants. Overexpression of the other cucumber AG homolog, CUM10, resulted in plants with partial transformations of the petals into antheroid structures, indicating that CUM10 is also able to promote floral organ identity. From the two petunia AG homologs pMADS3 and Floral Binding Protein gene 6 (FBP6), only pMADS3 was able to induce homeotic transformations of sepals and petals. Ectopic expression of both pMADS3 and FBP6, as occurrs in the petunia homeotic mutant blind, phenocopies the pMADS3 single overexpresser plants, indicating that there is no additive effect of concerted expression. This study demonstrates that in petunia and cucumber, multiple AG homologs exist, although they differ in their ability to induce reproductive organ fate.
Kater
M M
MM
Department of Developmental Biology, DLO-Centre for Plant Breeding and Reproduction Research (CPRO-DLO), Droevendaalsesteeg 1, P.O. Box 16, 6700 AA Wageningen, The Netherlands.
Colombo
L
L
Franken
J
J
Busscher
M
M
Masiero
S
S
Van Lookeren Campagne
M M
MM
Angenent
G C
GC
D026342:AGAMOUS Protein, Arabidopsis; D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D018553:Cucumis sativus / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D026161:MADS Domain Proteins; D008969:Molecular Sequence Data; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D019657:Solanaceae / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D014157:Transcription Factors / Q000737:chemistry / Q000235:genetics / Q000502:physiology
D026342:AGAMOUS Protein, Arabidopsis; C111450:CUM protein, Cucumis sativus; D004268:DNA-Binding Proteins; D026161:MADS Domain Proteins; D010940:Plant Proteins; D014157:Transcription Factors