KNAT6: an Arabidopsis homeobox gene involved in meristem activity and organ separation.
The homeobox gene family plays a crucial role during the development of multicellular organisms. The KNOTTED-like genes from Arabidopsis thaliana (KNAT6 and KNAT2) are close relatives of the meristematic genes SHOOT MERISTEMLESS (STM) and BREVIPEDICELLUS, but their function is not currently known. To investigate their role, we identified null alleles of KNAT6 and KNAT2. We demonstrate that KNAT6 contributes redundantly with STM to the maintenance of the shoot apical meristem (SAM) and organ separation. Consistent with this role, the expression domain of KNAT6 in the SAM marks the boundaries between the SAM and cotyledons. The lack of meristematic activity in the knat6 stm-2 double mutant and the fusion of cotyledons were linked to the modulation of CUP-SHAPED COTYLEDON (CUC) activity. During embryogenesis, KNAT6 is expressed later than STM and CUC. In agreement with this fact, CUC1 and CUC2 were redundantly required for KNAT6 expression. These data provide the basis for a model in which KNAT6 contributes to SAM maintenance and boundary establishment in the embryo via the STM/CUC pathway. KNAT2, although the closest related member of the family to KNAT6, did not have such a function.
Belles-Boix
Enric
E
Laboratoire de Biologie Cellulaire, Institut Jean-Pierre Bourgin, Institut National de la Recherche Agronomique, 78026 Versailles Cedex, France.
Hamant
Olivier
O
Witiak
Sarah Melissa
SM
Morin
Halima
H
Traas
Jan
J
Pautot
Véronique
V
D000483:Alleles; D017360:Arabidopsis / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D049452:Green Fluorescent Proteins / Q000032:analysis; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D018519:Meristem / Q000166:cytology / Q000378:metabolism / Q000502:physiology*; D009154:Mutation; D010641:Phenotype; D011993:Recombinant Fusion Proteins / Q000032:analysis; D015398:Signal Transduction; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism / Q000502:physiology*
D029681:Arabidopsis Proteins; C426007:CUC1 protein, Arabidopsis; C107294:CUC2 protein, Arabidopsis; C478975:CUC3 protein, Arabidopsis; D018398:Homeodomain Proteins; C092213:KNAT2 protein, Arabidopsis; C491111:KNAT6 protein, Arabidopsis; D011993:Recombinant Fusion Proteins; C097496:STM protein, Arabidopsis; D014157:Transcription Factors; D049452:Green Fluorescent Proteins