A cytokinin-sensitive mutant of the moss,Physcomitrella patens, defective in chloroplast division

Abel, W. O.; Knebel, W.; Koop, Hans‐Ulrich; Marienfeld, Joachim R.; Quader, H.; Reski, Ralf; Schnepf, E.; Spörlein, B.

doi:10.1007/bf01354234

Cited by 65 publications

(33 citation statements)

References 32 publications

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“…Therefore, Pphb7 induction by BA is likely caused by increase of rhizoid initials accompanying adventitious bud formation. While exogenous cytokinin induces chloroplast division in protonemata (Abel et al, 1989), the numbers of plastids in wild-type and Pphb7-disrupted rhizoids treated with 10-µM BA for 48 hours were similar to that in non-treated rhizoids (data not shown). This implies that the regulation of plastid division in rhizoids differs from that in protonemata.…”

Section: Auxin and Pphb7 Function In Rhizoid Cell Differentiationmentioning

confidence: 71%

Involvement of auxin and a homeodomain-leucine zipper I gene in rhizoid development of the mossPhyscomitrella patens

et al. 2003

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Differentiation of epidermal cells is important for plants because they are in direct contact with the environment. Rhizoids are multicellular filaments that develop from the epidermis in a wide range of plants, including pteridophytes, bryophytes, and green algae; they have similar functions to root hairs in vascular plants in that they support the plant body and are involved in water and nutrient absorption. In this study, we examined mechanisms underlying rhizoid development in the moss, Physcomitrella patens, which is the only land plant in which high-frequency gene targeting is possible. We found that rhizoid development can be split into two processes: determination and differentiation. Two types of rhizoids with distinct developmental patterns (basal and mid-stem rhizoids) were recognized. The development of basal rhizoids from epidermal cells was induced by exogenous auxin, while that of mid-stem rhizoids required an unknown factor in addition to exogenous auxin. Once an epidermal cell had acquired a rhizoid initial cell fate, expression of the homeodomain-leucine zipper I gene Pphb7 was induced. Analysis of Pphb7 disruptant lines showed that Pphb7 affects the induction of pigmentation and the increase in the number and size of chloroplasts, but not the position or number of rhizoids. This is the first report on the involvement of a homeodomain-leucine zipper I gene in epidermal cell differentiation.

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Section: Auxin and Pphb7 Function In Rhizoid Cell Differentiationmentioning

confidence: 71%

Involvement of auxin and a homeodomain-leucine zipper I gene in rhizoid development of the mossPhyscomitrella patens

et al. 2003

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“…Previously isolated P. patens mutants, BAR, PC22, and P24, exhibited a reduced number of gametophores in comparison with the wild type, although the genes responsible have not been identified. This defect was augmented by the exogenous addition of cytokinin or the induction of a cytokinin biosynthesis gene (Ashton et al, 1979;Abel et al, 1989;Reutter et al, 1998). In addition, the number of gametophores decreased in the BAR 77 mutant line, and the exogenous addition of auxin exacerbated the defect, indicating that auxin is also involved in the formation of…”

Section: Interaction Of Apbs With Auxin and Cytokininmentioning

confidence: 99%

AP2-type transcription factors determine stem cell identity in the moss Physcomitrella patens

et al. 2012

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SUMMARYStem cells are formed at particular times and positions during the development of multicellular organisms. Whereas flowering plants form stem cells only in the sporophyte generation, non-seed plants form stem cells in both the sporophyte and gametophyte generations. Although the molecular mechanisms underlying stem cell formation in the sporophyte generation have been extensively studied, only a few transcription factors involved in the regulation of gametophyte stem cell formation have been reported. The moss Physcomitrella patens forms a hypha-like body (protonema) and a shoot-like body (gametophore) from a protonema apical cell and a gametophore apical cell, respectively. These apical cells have stem cell characteristics and are formed as side branches of differentiated protonema cells. Here, we show that four AP2-type transcription factors orthologous to Arabidopsis thaliana AINTEGUMENTA, PLETHORA and BABY BOOM (APB) are indispensable for the formation of gametophore apical cells from protonema cells. Quadruple disruption of all APB genes blocked gametophore formation, even in the presence of cytokinin, which enhances gametophore apical cell formation in the wild type. All APB genes were expressed in emerging gametophore apical cells, but not in protonema apical cells. Heat-shock induction of an APB4 transgene driven by a heat-shock promoter increased the number of gametophores. Expression of all APB genes was induced by auxin but not by cytokinin. Thus, the APB genes function synergistically with cytokinin signaling to determine the identity of the two types of stem cells.

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“…In order to monitor mitochondria and ER simultaneously in a plant, we used fluorescently labeled organelles of the model moss Physcomitrella patens, which provides a uniquely high rate of homologous recombination in plants (Strepp et al, 1998) and is amenable to confocal microscopy studies (Abel et al, 1989;Furt et al, 2012;Vidali and Bezanilla, 2012;Müller et al, 2015). We generated a stable transgenic moss line constitutively expressing mitochondria-targeted mEOS (mtEOS; Mathur et al, 2010) and transiently transfected protoplasts of this line with an ER marker that comprises a signal peptide, mCerulean, and a C-terminal KDEL ER retention signal (spCerKDEL).…”

Section: Resultsmentioning

confidence: 99%

Molecular Mechanisms and Physiological Significance of Organelle Interactions and Cooperation

2017

Frontiers Research Topics

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A cytokinin-sensitive mutant of the moss,Physcomitrella patens, defective in chloroplast division

Cited by 65 publications

References 32 publications

Involvement of auxin and a homeodomain-leucine zipper I gene in rhizoid development of the mossPhyscomitrella patens

Involvement of auxin and a homeodomain-leucine zipper I gene in rhizoid development of the mossPhyscomitrella patens

AP2-type transcription factors determine stem cell identity in the moss Physcomitrella patens

Molecular Mechanisms and Physiological Significance of Organelle Interactions and Cooperation

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