ORCID Profile
0000-0001-9474-5131
Current Organisations
Nara Institute of Science and Technology
,
University of Tokyo
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Publisher: Springer Science and Business Media LLC
Date: 26-03-2015
DOI: 10.1007/S10265-015-0714-Y
Abstract: Callus formation and de novo organogenesis often occur in the wounded tissues of plants. Although this regenerative capacity of plant cells has been utilized for many years, molecular basis for the wound-induced acquisition of regeneration competency is yet to be elucidated. Here we find that wounding treatment is essential for shoot regeneration from roots in the conventional tissue culture of Arabidopsis thaliana. Furthermore, we show that an AP2/ERF transcription factor WOUND INDUCED DEDIFFERENTIATION1 (WIND1) plays a pivotal role for the acquisition of regeneration competency in the culture system. Ectopic expression of WIND1 can bypass both wounding and auxin pre-treatment and increase de novo shoot regeneration from root explants cultured on shoot-regeneration promoting media. In Brassica napus, activation of Arabidopsis WIND1 also greatly enhances de novo shoot regeneration, further corroborating the role of WIND1 in conferring cellular regenerative capacity. Our data also show that sequential activation of WIND1 and an embryonic regulator LEAFY COTYLEDON2 enhances generation of embryonic callus, suggesting that combining WIND1 with other transcription factors promote efficient and organ-specific regeneration. Our findings in the model plant and crop plant point to a possible way to efficiently induce callus formation and regeneration by utilizing transcription factors as a molecular switch.
Publisher: Oxford University Press (OUP)
Date: 13-09-2017
DOI: 10.1104/PP.17.01035
Publisher: Oxford University Press (OUP)
Date: 14-02-2022
DOI: 10.1093/PCP/PCAC017
Abstract: Many plants are able to regenerate upon cutting, and this process can be enhanced in vitro by incubating explants on hormone-supplemented media. While such protocols have been used for decades, little is known about the molecular details of how incubation conditions influence their efficiency. In this study, we find that warm temperature promotes both callus formation and shoot regeneration in Arabidopsis thaliana. We show that such an increase in shoot regenerative capacity at higher temperatures correlates with the enhanced expression of several regeneration-associated genes, such as CUP-SHAPED COTYLEDON 1 (CUC1) encoding a transcription factor involved in shoot meristem formation and YUCCAs (YUCs) encoding auxin biosynthesis enzymes. ChIP-sequencing analyses further reveal that histone variant H2A.Z is enriched on these loci at 17°C, while its occupancy is reduced by an increase in ambient temperature to 27°C. Moreover, we provide genetic evidence to demonstrate that H2A.Z acts as a repressor of de novo shoot organogenesis since H2A.Z-depleted mutants display enhanced shoot regeneration. This study thus uncovers a new chromatin-based mechanism that influences hormone-induced regeneration and additionally highlights incubation temperature as a key parameter for optimizing in vitro tissue culture.
Publisher: Wiley
Date: 12-2008
Publisher: Springer Science and Business Media LLC
Date: 29-06-2015
Abstract: Plant somatic cells are generally acknowledged to retain totipotency, the potential to develop into any cell type within an organism. This astonishing plasticity may contribute to a high regenerative capacity on severe damage, but how plants control this potential during normal post-embryonic development remains largely unknown(1,2). Here we show that POLYCOMB REPRESSIVE COMPLEX 2 (PRC2), a chromatin regulator that maintains gene repression through histone modification, prevents dedifferentiation of mature somatic cells in Arabidopsis thaliana roots. Loss-of-function mutants in PRC2 subunits initially develop unicellular root hairs indistinguishable from those in wild type but fail to retain the differentiated state, ultimately resulting in the generation of an unorganized cell mass and somatic embryos from a single root hair. Strikingly, mutant root hairs complete the normal endoreduplication programme, increasing their nuclear ploidy, but subsequently reinitiate mitotic ision coupled with successive DNA replication. Our data show that the WOUND INDUCED DEDIFFERENTIATION3 (WIND3) and LEAFY COTYLEDON2 (LEC2) genes are among the PRC2 targets involved in this reprogramming, as their ectopic overexpression partly phenocopies the dedifferentiation phenotype of PRC2 mutants. These findings unveil the pivotal role of PRC2-mediated gene repression in preventing unscheduled reprogramming of fully differentiated plant cells.
Publisher: Oxford University Press (OUP)
Date: 09-2013
Publisher: Informa UK Limited
Date: 12-2013
DOI: 10.4161/PSB.27432
Publisher: Elsevier BV
Date: 12-2015
DOI: 10.1016/J.PBI.2015.09.004
Abstract: How cells differentiate and acquire erse arrays of determined states in multicellular organisms is a fundamental and yet unanswered question in biology. Molecular genetic studies over the last few decades have identified many transcriptional regulators that activate or repress gene expression to promote cell differentiation in plant development. What has recently emerged as an additional important regulatory layer is the control at the epigenetic level by which locus-specific DNA methylation and histone modification alter the chromatin state and limit the expression of key developmental regulators to specific windows of time and space. Accumulating evidence suggests that histone acetylation is commonly linked with active transcription and this mechanism is adopted to control sequential progression of cell differentiation. Histone H3 trimethylation at lysine 27 and DNA methylation are both associated with gene repression, and these mechanisms are often utilised to promote and/or maintain the differentiated status of plant cells.
Publisher: Oxford University Press (OUP)
Date: 23-12-2016
DOI: 10.1105/TPC.16.00623
Publisher: Elsevier BV
Date: 10-2020
Publisher: American Association for the Advancement of Science (AAAS)
Date: 07-07-2023
Abstract: Plants can regenerate their bodies via de novo establishment of shoot apical meristems (SAMs) from pluripotent callus. Only a small fraction of callus cells is eventually specified into SAMs but the molecular mechanisms underlying fate specification remain obscure. The expression of WUSCHEL (WUS) is an early hallmark of SAM fate acquisition. Here, we show that a WUS paralog, WUSCHEL-RELATED HOMEOBOX 13 (WOX13), negatively regulates SAM formation from callus in Arabidopsis thaliana . WOX13 promotes non-meristematic cell fate via transcriptional repression of WUS and other SAM regulators and activation of cell wall modifiers. Our Quartz-Seq2–based single cell transcriptome revealed that WOX13 plays key roles in determining cellular identity of callus cell population. We propose that reciprocal inhibition between WUS and WOX13 mediates critical cell fate determination in pluripotent cell population, which has a major impact on regeneration efficiency.
Publisher: Annual Reviews
Date: 29-04-2019
DOI: 10.1146/ANNUREV-ARPLANT-050718-100434
Abstract: Plants reprogram somatic cells following injury and regenerate new tissues and organs. Upon perception of inductive cues, somatic cells often dedifferentiate, proliferate, and acquire new fates to repair damaged tissues or develop new organs from wound sites. Wound stress activates transcriptional cascades to promote cell fate reprogramming and initiate new developmental programs. Wounding also modulates endogenous hormonal responses by triggering their biosynthesis and/or directional transport. Auxin and cytokinin play pivotal roles in determining cell fates in regenerating tissues and organs. Exogenous application of these plant hormones enhances regenerative responses in vitro by facilitating the activation of specific developmental programs. Many reprogramming regulators are epigenetically silenced during normal development but are activated by wound stress and/or hormonal cues.
Publisher: Oxford University Press (OUP)
Date: 20-10-2022
DOI: 10.1093/PCP/PCAC146
Abstract: Plants have the regenerative ability to reconnect cut organs, which is physiologically important to survive severe tissue damage. The ability to reconnect organs is utilized as grafting to combine two different in iduals. Callus formation at the graft junction facilitates organ attachment and vascular reconnection. While it is well documented that local wounding signals provoke callus formation, how callus formation is differentially regulated at each cut end remains elusive. Here, we report that callus formation activity is asymmetrical between the top and bottom cut ends and is regulated by differential auxin accumulation. Gene expression analyses revealed that cellular auxin response is preferentially upregulated in the top part of the graft. Disruption of polar auxin transport inhibited callus formation from the top, while external application of auxin was sufficient to induce callus formation from the bottom, suggesting that asymmetric auxin accumulation is responsible for active callus formation from the top end. We further found that the expression of a key regulator of callus formation, WUSCHEL-RELATED HOMEOBOX 13 (WOX13), is induced by auxin. The ectopic callus formation from the bottom end, which is triggered by locally supplemented auxin, requires WOX13 function, demonstrating that WOX13 plays a pivotal role in auxin-dependent callus formation. The asymmetric WOX13 expression is observed both in grafted petioles and incised inflorescence stems, underscoring the generality of our findings. We propose that efficient organ reconnection is achieved by a combination of local wounding stimuli and disrupted long-distance signaling.
Publisher: Springer Science and Business Media LLC
Date: 04-11-2019
DOI: 10.1038/S42003-019-0646-5
Abstract: Plant somatic cells reprogram and regenerate new tissues or organs when they are severely damaged. These physiological processes are associated with dynamic transcriptional responses but how chromatin-based regulation contributes to wound-induced gene expression changes and subsequent cellular reprogramming remains unknown. In this study we investigate the temporal dynamics of the histone modifications H3K9/14ac, H3K27ac, H3K4me3, H3K27me3, and H3K36me3, and analyze their correlation with gene expression at early time points after wounding. We show that a majority of the few thousand genes rapidly induced by wounding are marked with H3K9/14ac and H3K27ac before and/or shortly after wounding, and these include key wound-inducible reprogramming genes such as WIND1 , ERF113/RAP2.6 L and LBD16 . Our data further demonstrate that inhibition of GNAT-MYST-mediated histone acetylation strongly blocks wound-induced transcriptional activation as well as callus formation at wound sites. This study thus uncovered a key epigenetic mechanism that underlies wound-induced cellular reprogramming in plants.
Publisher: Oxford University Press (OUP)
Date: 07-2020
DOI: 10.1104/PP.20.00626
Publisher: Oxford University Press (OUP)
Date: 03-11-2021
Abstract: Highly efficient tissue repair is pivotal for surviving damage-associated stress. Plants generate callus upon injury to heal wound sites, yet regulatory mechanisms of tissue repair remain elusive. Here, we identified WUSCHEL-RELATED HOMEOBOX 13 (WOX13) as a key regulator of callus formation and organ adhesion in Arabidopsis (Arabidopsis thaliana). WOX13 belongs to an ancient subclade of the WOX family, and a previous study shows that WOX13 orthologs in the moss Physcomitrium patens (PpWOX13L) are involved in cellular reprogramming at wound sites. We found that the Arabidopsis wox13 mutant is totally defective in establishing organ reconnection upon grafting, suggesting that WOX13 is crucial for tissue repair in seed plants. WOX13 expression rapidly induced upon wounding, which was partly dependent on the activity of an AP2/ERF transcription factor, WOUND-INDUCED DEDIFFERENTIATION 1 (WIND1). WOX13 in turn directly upregulated WIND2 and WIND3 to further promote cellular reprogramming and organ regeneration. We also found that WOX13 orchestrates the transcriptional induction of cell wall-modifying enzyme genes, such as GLYCOSYL HYDROLASE 9Bs, PECTATE LYASE LIKEs and EXPANSINs. Furthermore, the chemical composition of cell wall monosaccharides was markedly different in the wox13 mutant. These data together suggest that WOX13 modifies cell wall properties, which may facilitate efficient callus formation and organ reconnection. Furthermore, we found that PpWOX13L complements the Arabidopsis wox13 mutant, suggesting that the molecular function of WOX13 is partly conserved between mosses and seed plants. This study provides key insights into the conservation and functional ersification of the WOX gene family during land plant evolution.
Publisher: The Company of Biologists
Date: 05-2016
DOI: 10.1242/DEV.134668
Abstract: Compared with animals, plants generally possess a high degree of developmental plasticity and display various types of tissue or organ regeneration. This regenerative capacity can be enhanced by exogenously supplied plant hormones in vitro, wherein the balance between auxin and cytokinin determines the developmental fate of regenerating organs. Accumulating evidence suggests that some forms of plant regeneration involve reprogramming of differentiated somatic cells, whereas others are induced through the activation of relatively undifferentiated cells in somatic tissues. We summarize the current understanding of how plants control various types of regeneration and discuss how developmental and environmental constraints influence these regulatory mechanisms.
Publisher: Wiley
Date: 10-08-2021
DOI: 10.1111/NPH.17594
Abstract: Wounding triggers de novo organogenesis, vascular reconnection and defense response but how wound stress evoke such a erse array of physiological responses remains unknown. We previously identified AP2/ERF transcription factors, WOUND INDUCED DEDIFFERENTIATION1 (WIND1) and its homologs, WIND2, WIND3 and WIND4, as key regulators of wound‐induced cellular reprogramming in Arabidopsis. To understand how WIND transcription factors promote downstream events, we performed time‐course transcriptome analyses after WIND1 induction. We observed a significant overlap between WIND1‐induced genes and genes implicated in cellular reprogramming, vascular formation and pathogen response. We demonstrated that WIND transcription factors induce several reprogramming genes to promote callus formation at wound sites. We, in addition, showed that WIND transcription factors promote tracheary element formation, vascular reconnection and resistance to Pseudomonas syringae pv. tomato DC3000. These results indicate that WIND transcription factors function as key regulators of wound‐induced responses by promoting dynamic transcriptional alterations. This study provides deeper mechanistic insights into how plants control multiple physiological responses after wounding.
Publisher: Oxford University Press (OUP)
Date: 15-02-2018
DOI: 10.1093/PCP/PCY013
No related grants have been discovered for Momoko Ikeuchi.