The Maize Transcription Factor KNOTTED1 Directly Regulates the Gibberellin Catabolism Gene<i>ga2ox1</i>

Bolduc, Nathalie; Hake, Sarah

doi:10.1105/tpc.109.068221

Cited by 265 publications

(256 citation statements)

References 49 publications

(88 reference statements)

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“…Furthermore, GA has been implicated in promoting cell differentiation, and members of the class I KNOX family have been shown to repress GA biosynthesis in the meristem center (Sakamoto et al, 2001;Bolduc and Hake, 2009). In agreement with earlier studies, the genome level analysis presented here shows poor representation of auxin and GA-responsive genes in the CZ.…”

Section: Discussionmentioning

confidence: 99%

A high-resolution gene expression map of theArabidopsisshoot meristem stem cell niche

et al. 2014

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The shoot apical meristem (SAM) acts as a reservoir for stem cells. The central zone (CZ) harbors stem cells. The stem cell progenitors differentiate in the adjacent peripheral zone and in the rib meristem located just beneath the CZ. The SAM is further divided into distinct clonal layers: the L1 epidermal, L2 sub-epidermal and L3 layers. Collectively, SAMs are complex structures that consist of cells of different clonal origins that are organized into functional domains. By employing fluorescence-activated cell sorting, we have generated gene expression profiles of ten cell populations that belong to different clonal layers as well as domains along the central and peripheral axis. Our work reveals that cells in distinct clonal layers exhibit greater diversity in gene expression and greater transcriptional complexity than clonally related cell types in the central and peripheral axis. Assessment of molecular functions and biological processes reveals that epidermal cells express genes involved in pathogen defense: the L2 layer cells express genes involved in DNA repair pathways and telomere maintenance, and the L3 layers express transcripts involved in ion balance and salt tolerance besides photosynthesis. Strikingly, the stem cell-enriched transcriptome comprises very few hormone-responsive transcripts. In addition to providing insights into the expression profiles of hundreds of transcripts, the data presented here will act as a resource for reverse genetic analysis and will be useful in deciphering molecular pathways involved in cell type specification and their functions.

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Section: Discussionmentioning

confidence: 99%

A high-resolution gene expression map of theArabidopsisshoot meristem stem cell niche

et al. 2014

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“…CKs activate cell division, whereas GAs promote cell elongation, which is a cell differentiation process -as is lignin deposition -and KNOX proteins regulate the balance between GAs and CKs in meristem and leaf founder cells. In the SAM, KNOX proteins raise CK levels by activating the transcription of ISOPENTENYL TRANSFEREASE7 (IPT7) and lower GA levels by directly inhibiting the biosynthetic gene GA 20-oxidase1 (GA20ox1) and activating the catabolic gene GA 2-oxidase1 (GA2ox1) (Bolduc and Hake, 2009;Jasinski et al, 2005;Sakamoto et al, 2001;Yanai et al, 2005). Genetic analyses demonstrate that this high CK:low GA ratio is important for KNOX function -to prevent cell differentiation and thus maintain pluripotent cell fate in the SAM.…”

Section: Hormones As Knox Downstream Effectors: a Balancing Actmentioning

confidence: 99%

KNOX genes: versatile regulators of plant development and diversity

2010

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SummaryKnotted1-like homeobox (KNOX) proteins are homeodomain transcription factors that maintain an important pluripotent cell population called the shoot apical meristem, which generates the entire above-ground body of vascular plants. KNOX proteins regulate target genes that control hormone homeostasis in the meristem and interact with another subclass of homeodomain proteins called the BELL family. Studies in novel genetic systems, both at the base of the land plant phylogeny and in flowering plants, have uncovered novel roles for KNOX proteins in sculpting plant form and its diversity. Here, we discuss how KNOX proteins influence plant growth and development in a versatile context-dependent manner.

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“…The expression of GA2oxidase at the base of the SAM in maize is maintained in part by KNOX and BELL transcription factors (Bolduc and Hake, 2009). The expression of the Knox and BELL genes was 2-to 4-fold higher in the phyB-1 buds at 8 DAP, which may enhance or maintain elevated expression of GA2oxidases.…”

Section: Maintenance Of Bud Vegetative Meristems In Phyb-1 Sorghummentioning

confidence: 99%

“…deactivates GA derived from young leaves and leaf primordia, thereby protecting the SAM from precocious transition into flowering (Sakamoto et al, 2001;Jasinski et al, 2005;Bolduc and Hake, 2009). The expression of GA2oxidase at the base of the SAM in maize is maintained in part by KNOX and BELL transcription factors (Bolduc and Hake, 2009).…”

Section: Maintenance Of Bud Vegetative Meristems In Phyb-1 Sorghummentioning

confidence: 99%

Transcriptome Profiling of Tiller Buds Provides New Insights into PhyB Regulation of Tillering and Indeterminate Growth in Sorghum

Kebrom

Mullet

2016

Plant Physiol.

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Phytochrome B (phyB) enables plants to modify shoot branching or tillering in response to varying light intensities and ratios of red and far-red light caused by shading and neighbor proximity. Tillering is inhibited in sorghum genotypes that lack phytochrome B (58M, phyB-1) until after floral initiation. The growth of tiller buds in the first leaf axil of wild-type (100M, PHYB) and phyB-1 sorghum genotypes is similar until 6 d after planting when buds of phyB-1 arrest growth, while wild-type buds continue growing and develop into tillers. Transcriptome analysis at this early stage of bud development identified numerous genes that were up to 50-fold differentially expressed in wild-type/phyB-1 buds. Up-regulation of terminal flower1, GA2oxidase, and TPPI could protect axillary meristems in phyB-1 from precocious floral induction and decrease bud sensitivity to sugar signals. After bud growth arrest in phyB-1, expression of dormancy-associated genes such as DRM1, GT1, AF1, and CKX1 increased and ENOD93, ACCoxidase, ARR3/6/9, CGA1, and SHY2 decreased. Continued bud outgrowth in wild-type was correlated with increased expression of genes encoding a SWEET transporter and cell wall invertases. The SWEET transporter may facilitate Suc unloading from the phloem to the apoplast where cell wall invertases generate monosaccharides for uptake and utilization to sustain bud outgrowth. Elevated expression of these genes was correlated with higher levels of cytokinin/sugar signaling in growing buds of wild-type plants.

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The Maize Transcription Factor KNOTTED1 Directly Regulates the Gibberellin Catabolism Genega2ox1

Cited by 265 publications

References 49 publications

A high-resolution gene expression map of theArabidopsisshoot meristem stem cell niche

A high-resolution gene expression map of theArabidopsisshoot meristem stem cell niche

KNOX genes: versatile regulators of plant development and diversity

Transcriptome Profiling of Tiller Buds Provides New Insights into PhyB Regulation of Tillering and Indeterminate Growth in Sorghum

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