The GATA factor HANABA TARANU is required to position the proembryo boundary in the early Arabidopsis embryo.
Division of the Arabidopsis zygote defines two fundamentally different developmental domains, the proembryo and suspensor. The resulting boundary separates domain-specific gene expression, and a signal originating from the proembryo instructs the suspensor to generate the root stem cell niche. While root induction is known to require the phytohormone auxin and the Auxin Response Factor MONOPTEROS, it has remained largely elusive how the two domains involved in this process are initially specified. Here, we show that the GATA factor HANABA TARANU (HAN) is required to position the inductive proembryo boundary. Mutations in HAN cause a coordinated apical shift of gene expression patterns, revealing that HAN regulates transcription in the basal proembryo. Key auxin transporters are affected as early as the 8 cell stage, resulting in apical redistribution of auxin. Remarkably, han embryos eventually organize a root independent of MONOPTEROS and the suspensor around a new boundary marked by the auxin maximum.
Nawy
Tal
T
Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA.
Bayer
Martin
M
Mravec
Jozef
J
Friml
Jirí
J
Birnbaum
Kenneth D
KD
Lukowitz
Wolfgang
W
D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D017360:Arabidopsis / Q000196:embryology* / Q000235:genetics / Q000254:growth & development / Q000502:physiology; D029681:Arabidopsis Proteins / Q000235:genetics / Q000502:physiology*; D019521:Body Patterning / Q000235:genetics / Q000502:physiology; D050980:GATA Transcription Factors / Q000235:genetics / Q000502:physiology*; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D017403:In Situ Hybridization; D007210:Indoleacetic Acids / Q000378:metabolism; D018519:Meristem / Q000196:embryology; D008969:Molecular Sequence Data; D009154:Mutation; D010641:Phenotype; D018517:Plant Roots / Q000196:embryology; D030821:Plants, Genetically Modified
D029681:Arabidopsis Proteins; D050980:GATA Transcription Factors; C497900:HANABA TARANU protein, Arabidopsis; D007210:Indoleacetic Acids