Gene Regulation by the AGL15 Transcription Factor Reveals Hormone Interactions in Somatic Embryogenesis

Zheng, Qi; Zheng, Yumei; H, Ji; Burnie, Whitney; Perry, Sharyn E.

doi:10.1104/pp.16.00564

Cited by 65 publications

(60 citation statements)

References 70 publications

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“…A comparison of the transcriptional profiles of ARF s that were identified in the embryogenic cultures of various plants infers that the contribution of the individual ARF s to the mechanism of SE induction may differ between embryogenic cultures (Thibaud-Nissen et al 2003; Ooi et al 2012; Yang et al 2012; Xu et al 2013; Lin et al 2015; Indoliya et al 2016; Zheng et al 2016). …”

Section: Discussionmentioning

confidence: 99%

Expression profiling of AUXIN RESPONSE FACTOR genes during somatic embryogenesis induction in Arabidopsis

2017

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Key messageExtensive modulation of numerous ARF transcripts in the embryogenic culture of Arabidopsis indicates a substantial role of auxin signaling in the mechanism of somatic embryogenesis induction.AbstractSomatic embryogenesis (SE) is induced by auxin in plants and auxin signaling is considered to play a key role in the molecular mechanism that controls the embryogenic transition of plant somatic cells. Accordingly, the expression of AUXIN RESPONSE FACTOR (ARF) genes in embryogenic culture of Arabidopsis was analyzed. The study revealed that 14 of the 22 ARFs were transcribed during SE in Arabidopsis. RT-qPCR analysis indicated that the expression of six ARFs (ARF5, ARF6, ARF8, ARF10, ARF16, and ARF17) was significantly up-regulated, whereas five other genes (ARF1, ARF2, ARF3, ARF11, and ARF18) were substantially down-regulated in the SE-induced explants. The activity of ARFs during SE was also monitored with GFP reporter lines and the ARFs that were expressed in areas of the explants engaged in SE induction were detected. A functional test of ARFs transcribed during SE was performed and the embryogenic potential of the arf mutants and overexpressor lines was evaluated. ARFs with a significantly modulated expression during SE coupled with an impaired embryogenic response of the relevant mutant and/or overexpressor line, including ARF1, ARF2, ARF3, ARF5, ARF6, ARF8, and ARF11 were indicated as possibly being involved in SE induction. The study provides evidence that embryogenic induction strongly depends on ARFs, which are key regulators of the auxin signaling. Some clues on the possible functions of the candidate ARFs, especially ARF5, in the mechanism of embryogenic transition are discussed. The results provide guidelines for further research on the auxin-related functional genomics of SE and the developmental plasticity of somatic cells.Electronic supplementary materialThe online version of this article (doi:10.1007/s00299-017-2114-3) contains supplementary material, which is available to authorized users.

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Section: Discussionmentioning

confidence: 99%

Expression profiling of AUXIN RESPONSE FACTOR genes during somatic embryogenesis induction in Arabidopsis

2017

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“…It is possible that regulation of CcTIR1 by CcSERK1 occurs via alternative mechanisms at levels high enough to allow the expression of auxin‐responsive genes by the degradation of AUX/IAA transcriptional repressors (Hayashi ). The balance of CcTIR1 levels can be counteracted by CcAGL15 action; in Glycine max , GmAGL15 negatively regulated auxin signaling at many levels of the pathway, including the repression of TRI1 (Zheng et al ). In C. canephora somatic embryogenesis, CcAGL15 transcript level is increased by CcSERK1 but CcTIR1 expression is not affected, even though CcTIR1 expression requires CcSERK1 expression.…”

Section: Discussionmentioning

confidence: 99%

Ectopic expression of the Coffea canephora SERK1 homolog‐induced differential transcription of genes involved in auxin metabolism and in the developmental control of embryogenesis

Pérez-Pascual

Jiménez-Guillen

Villanueva-Alonzo

et al. 2018

Physiologia Plantarum

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Somatic embryogenesis receptor-like kinase 1 (SERK1) is a membrane receptor that might serve as common co-regulator of plant cell differentiation processes by forming heterodimers with specific receptor-like kinases. The Coffea canephora SERK1 homolog (CcSERK1) was cloned in this work, and its early function in the transcription of embryogenesis master genes and of genes encoding proteins involved in auxin metabolism was investigated by externally manipulating its expression in embryogenic leaf explants, before the appearance of embryogenic structures. Overexpression of CcSERK1 early during embryogenesis caused an increase in the number of somatic embryos when the 55-day process was completed. Suppression of CcSERK1 expression by RNA interference almost abolished somatic embryogenesis. Real time-PCR experiments revealed that the transcription of the CcAGL15, CcWUS, CcBBM, CcPKL, CcYUC1, CcPIN1 and CcPIN4 homologs was modified in direct proportion to the expression of CcSERK1 and that only CcLEC1 was inversely affected by the expression levels of CcSERK1. The expression of the CcYUC4 homolog was induced to more than 80-fold under CcSERK1 overexpression conditions, but it was also induced when CcSERK1 expression was silenced. The level of CcTIR1 was not affected by CcSERK1 overexpression but was almost abolished during CcSERK1 silencing. These results suggest that CcSERK1 co-regulates the induction of somatic embryogenesis in Coffea canephora by early activation of YUC-dependent auxin biosynthesis, auxin transport mediated by PIN1 and PIN4, and probably auxin perception by the TIR1 receptor, leading to the induction of early-stage homeotic genes (CcAGL15, CcWUS, CcPKL and CcBBM) and repression of late-stage homeotic genes (CcLec1).

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“…Little is known about the regulators of the SE-associated auxin-related miRNAs and among the candidates is FUSCA3 (FUS3), which is structurally and functionally related to LEC2, and was suggested to control the MIR156, MIR160, MIR166, and MIR396 genes in an embryogenic culture of Arabidopsis [116]. In addition, another key regulator of the embryogenic transition, the AGAMOUS LIKE15 (AGL15) TF, which interacts with LEC2 and FUS3 in the auxin-mediated pathway of SE induction (reviewed in [117]) has been postulated to control auxin signaling in both Arabidopsis and soybean via the direct stimulation of a miR167a-encoding gene [118].…”

Section: Auxin-related Mirnas Fine-tune the Genetic Network That Contmentioning

confidence: 99%

Epigenetic Regulation of Auxin-Induced Somatic Embryogenesis in Plants

Wójcikowska

Wójcik

Gaj

2020

IJMS

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Somatic embryogenesis (SE) that is induced in plant explants in response to auxin treatment is closely associated with an extensive genetic reprogramming of the cell transcriptome. The significant modulation of the gene transcription profiles during SE induction results from the epigenetic factors that fine-tune the gene expression towards embryogenic development. Among these factors, microRNA molecules (miRNAs) contribute to the post-transcriptional regulation of gene expression. In the past few years, several miRNAs that regulate the SE-involved transcription factors (TFs) have been identified, and most of them were involved in the auxin-related processes, including auxin metabolism and signaling. In addition to miRNAs, chemical modifications of DNA and chromatin, in particular the methylation of DNA and histones and histone acetylation, have been shown to shape the SE transcriptomes. In response to auxin, these epigenetic modifications regulate the chromatin structure, and hence essentially contribute to the control of gene expression during SE induction. In this paper, we describe the current state of knowledge with regard to the SE epigenome. The complex interactions within and between the epigenetic factors, the key SE TFs that have been revealed, and the relationships between the SE epigenome and auxin-related processes such as auxin perception, metabolism, and signaling are highlighted.

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Gene Regulation by the AGL15 Transcription Factor Reveals Hormone Interactions in Somatic Embryogenesis

Cited by 65 publications

References 70 publications

Expression profiling of AUXIN RESPONSE FACTOR genes during somatic embryogenesis induction in Arabidopsis

Expression profiling of AUXIN RESPONSE FACTOR genes during somatic embryogenesis induction in Arabidopsis

Ectopic expression of the Coffea canephora SERK1 homolog‐induced differential transcription of genes involved in auxin metabolism and in the developmental control of embryogenesis

Epigenetic Regulation of Auxin-Induced Somatic Embryogenesis in Plants

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