The PLETHORA Genes Mediate Patterning of the Arabidopsis Root Stem Cell Niche

Aida, Mitsuhiro; Beis, Dimitris; Heidstra, Renze; Willemsen, Viola; Blilou, Ikram; Galinha, Carla; Nussaume, Laurent; Noh, Yoo Sun; Amasino, Richard M.; Scheres, Ben

doi:10.1016/j.cell.2004.09.018

Cited by 1,033 publications

(1,204 citation statements)

References 42 publications

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“…The activation of root meristem-expressed genes by BBM is intriguing. BBM, like the related AP2/ERF PLETHORA1 (PLT1) and PLT2 genes is expressed in the root meristem (Aida et al 2004), but unlike PLT1/PLT2 overexpression, BBM overexpression does not appear to induce ectopic root or root meristem formation in Arabidopsis. This suggests that many of the root meristem-expressed BBM target genes may play a more general role in maintaining cells in an undifferentiated state.…”

Section: Discussionmentioning

confidence: 99%

BABY BOOM target genes provide diverse entry points into cell proliferation and cell growth pathways

Passarinho¹,

Ketelaar²,

Xing³

et al. 2008

Plant Mol Biol

106

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Ectopic expression of the Brassica napus BABY BOOM (BBM) AP2/ERF transcription factor is sufficient to induce spontaneous cell proliferation leading primarily to somatic embryogenesis, but also to organogenesis and callus formation. We used DNA microarray analysis in combination with a post-translationally regulated BBM:GR protein and cycloheximide to identify target genes that are directly activated by BBM expression in Arabidopsis seedlings. We show that BBM activated the expression of a largely uncharacterized set of genes encoding proteins with potential roles in transcription, cellular signaling, cell wall biosynthesis and targeted protein turnover. A number of the target genes have been shown to be expressed in meristems or to be involved in cell wall modifications associated with dividing/growing cells. One of the BBM target genes encodes an ADF/cofilin protein, ACTIN DEPOLYMERIZING FACTOR9 (ADF9). The consequences of BBM:GR activation on the actin cytoskeleton were followed using the GFP:FIMBRIN ACTIN BINDING DOMAIN2 (GFP:FABD) actin marker. Dexamethasone-mediated BBM:GR activation induced dramatic changes in actin organization resulting in the formation of dense actin networks with high turnover rates, a phenotype that is consistent with cells that are rapidly undergoing cytoplasmic reorganization. Together the data suggest that the BBM transcription factor activates a complex network of developmental pathways associated with cell proliferation and growth.

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Section: Discussionmentioning

confidence: 99%

BABY BOOM target genes provide diverse entry points into cell proliferation and cell growth pathways

Passarinho¹,

Ketelaar²,

Xing³

et al. 2008

Plant Mol Biol

106

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show abstract

“…Adventitious root (stem cell) formation, in addition to being stimulated by auxin, is also induced by ectopic expression of the BBM-related Arabidopsis AP2/ERF transcription factors, PLETHORA1 (PLT1) and PLT2 (Aida et al 2004). PLT1/PLT2 expression does not appear to alter auxin levels, but rather is upregulated in response to auxin accumulation (Aida et al 2004).…”

Section: Discussionmentioning

confidence: 99%

Heterologous expression of the BABY BOOM AP2/ERF transcription factor enhances the regeneration capacity of tobacco (Nicotiana tabacum L.)

Srinivasan

Liu

Heidmann

et al. 2006

Planta

145

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Gain-of-function studies have shown that ectopic expression of the BABY BOOM (BBM) AP2/ ERF domain transcription factor is suYcient to induce spontaneous somatic embryogenesis in Arabidopsis (Arabidopsis thaliana (L.) Heynh) and Brassica napus (B. napus L.) seedlings. Here we examined the eVect of ectopic BBM expression on the development and regenerative capacity of tobacco (Nicotiana tabacum L.) through heterologous expression of Arabidopsis and B. napus BBM genes. 35S::BBM tobacco lines exhibited a number of the phenotypes previously observed in 35S::BBM Arabidopsis and B. napus transgenics, including callus formation, leaf rumpling, and sterility, but they did not undergo spontaneous somatic embryogenesis. 35S::BBM plants with severe ectopic expression phenotypes could not be assessed for enhanced regeneration at the seedling stage due to complete male and female sterility of the primary transformants, therefore fertile BBM ectopic expression lines with strong misexpression phenotypes were generated by expressing a steroid-inducible, posttranslationally controlled BBM fusion protein (BBM:GR) under the control of a 35S promoter. These lines exhibited spontaneous shoot and root formation, while somatic embryogenesis could be induced from in-vitro germinated seedling hypocotyls cultured on media supplemented with cytokinin. Together these results suggest that ectopic BBM expression in transgenic tobacco also activates cell proliferation pathways, but diVerences exist between Arabidopsis/B. napus and N. tabacum with respect to their competence to respond to the BBM signalling molecule.

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“…Arabidopsis BBM and the other arabidopsis AIL / PLT genes are expressed in the embryo and the root and/or shoot meristems, where they act redundantly to maintain embryo growth and to define and maintain the stem cell niches (Aida et al., 2004; Galinha et al., 2007; Mudunkothge & Krizek, 2012). Overexpression of AIL5 also triggers somatic embryo and adventitious organ formation (Tsuwamoto, Yokoi, & Takahata, 2010).…”

Section: A Network Of Arabidopsis Transcription Factors Controls Somamentioning

confidence: 99%

“…PLT2 has a role in root meristem maintenance, and plt2 mutant seedlings have shorter roots than wild‐type seedlings (Aida et al., 2004; Galinha et al., 2007). PLT2 functions redundantly with BBM during zygotic embryogenesis: plt2 or bbm mutant embryos do not show abnormal phenotypes, but the plt2 / bbm double mutant arrests at the two‐celled stage (Galinha et al., 2007; Horstman et al., 2015).…”

Section: A Network Of Arabidopsis Transcription Factors Controls Somamentioning

confidence: 99%

A transcriptional view on somatic embryogenesis

2017

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Somatic embryogenesis is a form of induced plant cell totipotency where embryos develop from somatic or vegetative cells in the absence of fertilization. Somatic embryogenesis can be induced in vitro by exposing explants to stress or growth regulator treatments. Molecular genetics studies have also shown that ectopic expression of specific embryo‐ and meristem‐expressed transcription factors or loss of certain chromatin‐modifying proteins induces spontaneous somatic embryogenesis. We begin this review with a general description of the major developmental events that define plant somatic embryogenesis and then focus on the transcriptional regulation of this process in the model plant Arabidopsis thaliana (arabidopsis). We describe the different somatic embryogenesis systems developed for arabidopsis and discuss the roles of transcription factors and chromatin modifications in this process. We describe how these somatic embryogenesis factors are interconnected and how their pathways converge at the level of hormones. Furthermore, the similarities between the developmental pathways in hormone‐ and transcription‐factor‐induced tissue culture systems are reviewed in the light of our recent findings on the somatic embryo‐inducing transcription factor BABY BOOM.

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The PLETHORA Genes Mediate Patterning of the Arabidopsis Root Stem Cell Niche

Cited by 1,033 publications

References 42 publications

BABY BOOM target genes provide diverse entry points into cell proliferation and cell growth pathways

BABY BOOM target genes provide diverse entry points into cell proliferation and cell growth pathways

Heterologous expression of the BABY BOOM AP2/ERF transcription factor enhances the regeneration capacity of tobacco (Nicotiana tabacum L.)

A transcriptional view on somatic embryogenesis

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