記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Wiley  

Extant land plants consist of two deeply divergent groups, tracheophytes and bryophytes, which shared a common ancestor some 500 million years ago. While information about vascular plants and the two of the three lineages of bryophytes, the mosses and liverworts, is steadily accumulating, the biology of hornworts remains poorly explored. Yet, as the sister group to liverworts and mosses, hornworts are critical in understanding the evolution of key land plant traits. Until recently, there was no hornwort model species amenable to systematic experimental investigation, which hampered detailed insight into the molecular biology and genetics of this unique group of land plants. The emerging hornwort model species, Anthoceros agrestis, is instrumental in our efforts to better understand not only hornwort biology but also fundamental questions of land plant evolution. To this end, here we provide an overview of hornwort biology and current research on the model plant A. agrestis to highlight its potential in answering key questions of land plant biology and evolution.

DOI： 10.1111/nph.16874

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Springer Science and Business Media LLC  

Hornworts comprise a bryophyte lineage that diverged from other extant land plants >400 million years ago and bears unique biological features, including a distinct sporophyte architecture, cyanobacterial symbiosis and a pyrenoid-based carbon-concentrating mechanism (CCM). Here, we provide three high-quality genomes of Anthoceros hornworts. Phylogenomic analyses place hornworts as a sister clade to liverworts plus mosses with high support. The Anthoceros genomes lack repeat-dense centromeres as well as whole-genome duplication, and contain a limited transcription factor repertoire. Several genes involved in angiosperm meristem and stomatal function are conserved in Anthoceros and upregulated during sporophyte development, suggesting possible homologies at the genetic level. We identified candidate genes involved in cyanobacterial symbiosis and found that LCIB, a Chlamydomonas CCM gene, is present in hornworts but absent in other plant lineages, implying a possible conserved role in CCM function. We anticipate that these hornwort genomes will serve as essential references for future hornwort research and comparative studies across land plants.

DOI： 10.1038/s41477-020-0618-2

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その他リンク： http://www.nature.com/articles/s41477-020-0618-2

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Springer Science and Business Media LLC  

Evolutionary mechanisms underlying innovation of cell types have remained largely unclear. In multicellular eukaryotes, the evolutionary molecular origin of sperm differentiation is unknown in most lineages. Here, we report that in algal ancestors of land plants, changes in the DNA-binding domain of the ancestor of the MYB transcription factor DUO1 enabled the recognition of a new cis-regulatory element. This event led to the differentiation of motile sperm. After neo-functionalization, DUO1 acquired sperm lineage-specific expression in the common ancestor of land plants. Subsequently the downstream network of DUO1 was rewired leading to sperm with distinct morphologies. Conjugating green algae, a sister group of land plants, accumulated mutations in the DNA-binding domain of DUO1 and lost sperm differentiation. Our findings suggest that the emergence of DUO1 was the defining event in the evolution of sperm differentiation and the varied modes of sexual reproduction in the land plant lineage.

DOI： 10.1038/s41467-018-07728-3

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その他リンク： http://www.nature.com/articles/s41467-018-07728-3

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：ACADEMIC PRESS INC ELSEVIER SCIENCE  

Land plant bodies develop from meristems, groups of pluripotent stem cells, which may persist throughout the life of a plant or, alternatively, have a transitory existence. Early diverging land plants exhibit indeterminate (persistent) growth in their haploid gametophytic generation, whereas later diverging lineages exhibit indeterminate growth in their diploid sporophytic generation, raising the question of whether genetic machinery directing meristematic functions was co-opted between generations. Class III HD-Zip (C3HDZ) genes are required for the establishment and maintenance of shoot apical meristems in flowering plants. We demonstrate that in the moss Physcomitrella patens, C3HDZ genes are expressed in transitory meristems in both the gametophytic and sporophytic generations, but not in the persistent shoot meristem of the gametyphyte. Loss-of-function of P. patens C3HDZ was engineered using ectopic expression of miR166, an endogenous regulator of C3HDZ gene activity. Loss of C3HDZ gene function impaired the function of gametophytic transitory meristematic activity but did not compromise the functioning of the persistent shoot apical meristem during the gametophyte generation. These results argue against a wholesale co-option of meristematic gene regulatory networks from the gametophyte to the sporophyte during land plant evolution, instead suggesting that persistent meristems with a single apical cell in P. patens and persistent complex meristems in flowering plants are regulated by different genetic programs. (C) 2016 Elsevier Inc. All rights reserved.

DOI： 10.1016/j.ydbio.2016.01.012

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担当区分：責任著者   記述言語：英語   掲載種別：論文集(書籍)内論文   出版者・発行元：ACADEMIC PRESS LTD-ELSEVIER SCIENCE LTD  

Land plants evolved from freshwater algaelike ancestors approximately 480 million years ago. Land plants developed many new morphological features during the evolution including the origin of a multicellular diploid sporophyte, a sporophytic apical meristem that produces complex body architecture, stomata and the production of lateral organs (leaves), vascular tissue, roots, seeds and flowers. Genetic changes drove the development of these morphological features and recent technological innovations in genomics and genetic modification technologies have allowed us to investigate these genetic changes. Here, I describe recent research on several transcription factors that contributed to the morphological evolution of land plants, including the homeodomain proteins KNOX, BELL and WOX, as well as transcription factors of the bHLH, NAC and FLO/LFY families. I also discuss the conservation of plant hormone signalling, which acts to coordinate the multicellular body plan.

DOI： 10.1016/bs.abr.2016.01.001

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記述言語：英語   掲載種別：論文集(書籍)内論文   出版者・発行元：ANNUAL REVIEWS  

The life cycles of eukaryotes alternate between haploid and diploid phases, which are initiated by meiosis and gamete fusion, respectively. In both ascomycete and basidiomycete fungi and chlorophyte algae, the haploid-to-diploid transition is regulated by a pair of paralogous homeodomain protein encoding genes. That a common genetic program controls the haploid-to-diploid transition in phylogenetically disparate eukaryotic lineages suggests this may be the ancestral function for homeodomain proteins. Multicellularity has evolved independently in many eukaryotic lineages in either one or both phases of the life cycle. Organisms, such as land plants, exhibiting a life cycle whereby multicellular bodies develop in both the haploid and diploid phases are often referred to as possessing an alternation of generations. We review recent progress on understanding the genetic basis for the land plant alternation of generations and highlight the roles that homeodomain-encoding genes may have played in the evolution of complex multicellularity in this lineage.

DOI： 10.1146/annurev-genet-120215-035227

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：PUBLIC LIBRARY SCIENCE  

Neofunctionalization following gene duplication is thought to be one of the key drivers in generating evolutionary novelty. A gene duplication in a common ancestor of land plants produced two classes of KNOTTED-like TALE homeobox genes, class I (KNOX1) and class II (KNOX2). KNOX1 genes are linked to tissue proliferation and maintenance of meri-stematic potentials of flowering plant and moss sporophytes, and modulation of KNOX1 activity is implicated in contributing to leaf shape diversity of flowering plants. While KNOX2 function has been shown to repress the gametophytic (haploid) developmental program during moss sporophyte (diploid) development, little is known about KNOX2 function in flowering plants, hindering syntheses regarding the relationship between two classes of KNOX genes in the context of land plant evolution. Arabidopsis plants harboring loss-of-function KNOX2 alleles exhibit impaired differentiation of all aerial organs and have highly complex leaves, phenocopying gain-of-function KNOX1 alleles. Conversely, gain-of-function KNOX2 alleles in conjunction with a presumptive heterodimeric BELL TALE homeobox partner suppressed SAM activity in Arabidopsis and reduced leaf complexity in the Arabidopsis relative Cardamine hirsuta, reminiscent of loss-of-function KNOX1 alleles. Little evidence was found indicative of epistasis or mutual repression between KNOX1 and KNOX2 genes. KNOX proteins heterodimerize with BELL TALE homeobox proteins to form functional complexes, and contrary to earlier reports based on in vitro and heterologous expression, we find high selectivity between KNOX and BELL partners in vivo. Thus, KNOX2 genes confer opposing activities rather than redundant roles with KNOX1 genes, and together they act to direct the development of all above-ground organs of the Arabidopsis sporophyte. We infer that following the KNOX1/KNOX2 gene duplication in an ancestor of land plants, neofunctionalization led to evolution of antagonistic biochemical activity thereby facilitating the evolution of more complex sporophyte transcriptional networks, providing plasticity for the morphological evolution of land plant body plans.

DOI： 10.1371/journal.pgen.1004980

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担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：COMPANY OF BIOLOGISTS LTD  

Many differentiated plant cells can dedifferentiate into stem cells, reflecting the remarkable developmental plasticity of plants. In the moss Physcomitrella patens, cells at the wound margin of detached leaves become reprogrammed into stem cells. Here, we report that two paralogous P. patens WUSCHEL-related homeobox 13-like ( PpWOX13L) genes, homologs of stem cell regulators in flowering plants, are transiently upregulated and required for the initiation of cell growth during stem cell formation. Concordantly, Delta ppwox13l deletion mutants fail to upregulate genes encoding homologs of cell wall loosening factors during this process. During the moss life cycle, most of the Delta ppwox13l mutant zygotes fail to expand and initiate an apical stem cell to form the embryo. Our data show that PpWOX13L genes are required for the initiation of cell growth specifically during stem cell formation, in analogy to WOX stem cell functions in seed plants, but using a different cellular mechanism.

DOI： 10.1242/dev.097444

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：OXFORD UNIV PRESS  

Class IV homeodomain leucine zipper (C4HDZ) genes are plant-specific transcription factors that, based on phenotypes in Arabidopsis thaliana, play an important role in epidermal development. In this study, we sampled all major extant lineages and their closest algal relatives for C4HDZ homologs and phylogenetic analyses result in a gene tree that mirrors land plant evolution with evidence for gene duplications in many lineages, but minimal evidence for gene losses. Our analysis suggests an ancestral C4HDZ gene originated in an algal ancestor of land plants and a single ancestral gene was present in the last common ancestor of land plants. Independent gene duplications are evident within several lineages including mosses, lycophytes, euphyllophytes, seed plants, and, most notably, angiosperms. In recently evolved angiosperm paralogs, we find evidence of pseudogenization via mutations in both coding and regulatory sequences. The increasing complexity of the C4HDZ gene family through the diversification of land plants correlates to increasing complexity in epidermal characters.

DOI： 10.1093/molbev/mst132

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担当区分：筆頭著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：AMER ASSOC ADVANCEMENT SCIENCE  

Unlike animals, land plants undergo an alternation of generations, producing multicellular bodies in both haploid (1n: gametophyte) and diploid (2n: sporophyte) generations. Plant body plans in each generation are regulated by distinct developmental programs initiated at either meiosis or fertilization, respectively. In mosses, the haploid gametophyte generation is dominant, whereas in vascular plants-including ferns, gymnosperms, and angiosperms-the diploid sporophyte generation is dominant. Deletion of the class 2 KNOTTED1-LIKE HOMEOBOX (KNOX2) transcription factors in the moss Physcomitrella patens results in the development of gametophyte bodies from diploid embryos without meiosis. Thus, KNOX2 acts to prevent the haploid-specific body plan from developing in the diploid plant body, indicating a critical role for the evolution of KNOX2 in establishing an alternation of generations in land plants.

DOI： 10.1126/science.1230082

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

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担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：WILEY-BLACKWELL  

Although the number and form of metazoan organs are determined in the embryo, plants continuously form organs via pluripotent stem cells contained within the meristem. Flowering plants have an indeterminate meristem in their diploid generation, whereas the common ancestor of land plants is inferred to have formed an indeterminate meristem in its haploid generation, as observed in the extant basal land plants, bryophytes, including mosses. It is hypothesized that the underlying gene networks for the diploid meristem were initially present in the haploid generation of the basal land plants and were eventually co-opted for expression in the diploid generation. In flowering plants, the class 1 KNOTTED1-LIKE HOMEOBOX (KNOX) transcription factors are essential for the function of the indeterminate apical meristem. Here, we show that the class 1 KNOX orthologs function in the diploid organ, with determinate growth in the moss Physcomitrella patens, but do not function in the haploid indeterminate meristem. We propose that the genetic networks governing the indeterminate meristem in land plants are variable, and the networks governing the diploid indeterminate meristem with the class 1 KNOX genes likely evolved de novo in the flowering plant lineage.

DOI： 10.1111/j.1525-142X.2008.00271.x

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：AMER ASSOC ADVANCEMENT SCIENCE  

We report the draft genome sequence of the model moss Physcomitrella patens and compare its features with those of flowering plants, from which it is separated by more than 400 million years, and unicellular aquatic algae. This comparison reveals genomic changes concomitant with the evolutionary movement to land, including a general increase in gene family complexity; loss of genes associated with aquatic environments ( e. g., flagellar arms); acquisition of genes for tolerating terrestrial stresses ( e. g., variation in temperature and water availability); and the development of the auxin and abscisic acid signaling pathways for coordinating multicellular growth and dehydration response. The Physcomitrella genome provides a resource for phylogenetic inferences about gene function and for experimental analysis of plant processes through this plant's unique facility for reverse genetics.

DOI： 10.1126/science.1150646

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：CELL PRESS  

As more plant genome sequences become available, researchers are increasingly using comparative genomics to address some of the major questions in plant biology. Such questions include the evolution of photosynthesis and multicellularity, the developmental genetic changes responsible for alterations in body plan, and the origin of important plant innovations such as roots, leaves, and vascular tissue.

DOI： 10.1016/j.cell.2007.04.004

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：BLACKWELL PUBLISHING INC  

Members of the class 1 knotted-like homeobox (KNOX) gene family are important regulators of shoot apical meristem development in angiosperms. To determine whether they function similarly in seedless plants, three KNOX genes (two class 1 genes and one class 2 gene) from the fern Ceratopteris richardii were characterized. Expression of both class 1 genes was detected in the shoot apical cell, leaf primordia, marginal part of the leaves, and vascular bundles by in situ hybridization, a pattern that closely resembles that of class 1 KNOX genes in angiosperms with compound leaves. The fern class 2 gene was expressed in all sporophyte tissues examined, which is characteristic of class 2 gene expression in angiosperms. All three CRKNOX genes were not detected in gametophyte tissues by RNA gel blot analysis. Arabidopsis plants overexpressing the fern class 1 genes resembled plants that overexpress seed plant class 1 KNOX genes in leaf morphology. Ectopic expression of the class 2 gene in Arabidopsis did not result in any unusual phenotypes. Taken together with phylogenetic analysis, our results suggest that (a) the class 1 and 2 KNOX genes diverged prior to the divergence of fern and seed plant lineages, (b) the class 1 KNOX genes function similarly in seed plant and fern sporophyte meristem development despite their differences in structure, (c) KNOX gene expression is not required for the development of the fern gametophyte, and (d) the sporophyte and gametophyte meristems of ferns are not regulated by the same developmental mechanisms at the molecular level.

DOI： 10.1111/j.1525-142X.2005.05008.x

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担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：COMPANY OF BIOLOGISTS LTD  

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.

DOI： 10.1242/dev.00644

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：UNIV CHICAGO PRESS  

The morphological variation among reproductive organs of extant seed plants makes assessment of organ homology difficult. Comparisons of expression patterns of homeotic genes that control organ development will yield new information about the homology of organs to assess inferences deduced from previous morphological studies. In angiosperms, the FLORICAULA/LEAFY (FLO/LFY) genes convert a vegetative shoot meristem to a floral meristem by inducing floral homeotic genes, most of which belong to the MADS-box gene family. To provide insights into the evolution of reproductive organs in seed plants, a FLO/LFY homologue (GpLFY) was cloned from Gnetum parvifolium. GpLFY mRNA was expressed in both the vegetative shoot apex and the female strobilus. The GpLFY mRNA signal was detected in early developmental stages of the collar and the ovule primordium, including the nucellus and three envelopes. A comparison of FLO/LFY gene expression in Gnetum and the conifer Pinus radiata indicates that the Gnetum collar and ovule are homologous with the conifer bract and ovule-ovuliferous scale complex, respectively. Overexpression of GpLFY in transgenic Arabidopsis promoted a conversion of a shoot meristem to a floral primordium. The Arabidopsis LFY null mutant, lfy-26, with a malformed flower, was complemented by overexpression of GpLFY. These results indicate that the inductive pathway from the FLO/LFY gene to the MADS-box genes already existed in the common ancestor of angiosperms and gymnosperms.

DOI： 10.1086/323417

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担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Society for Molecular Biology and Evolution  

Homeobox genes encode transcription factors involved in many aspects of developmental processes. The homeodomain-leucine zipper (HD-Zip) genes, which are characterized by the presence of both a homeodomain and a leucine zipper motif, form a clade within the homeobox superfamily and were previously reported only from vascular plants. Here we report the isolation of 10 HD-Zip genes (named Pphb1-Pphb10) from the moss Physcomitrella patens. Based on a phylogenetic analysis of the 10 Pphb genes and previously reported vascular plant HD-Zip genes, all of the Pphb genes except Pphb3 belong to three of the four HD-Zip subfamilies (HD-Zip I, II, and III), indicating that these subfamilies originated before the divergence of the vascular plant and moss lineages. Pphb3 is sister to the HD-Zip II subfamily and has some distinctive characteristics, including the difference of the a1 and d1 sites of its leucine zipper motif, which are well conserved in each HD-Zip subfamily. Comparison of the genetic divergence of representative HD-Zip I and II genes showed that the evolutionary rate of HD-Zip I genes was faster than that of HD-Zip II genes.

DOI： 10.1093/oxfordjournals.molbev.a003828

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Universal Academy Press Inc.  

The moss, Physcomitrella patens has been used as a useful material in many fields, because of its simple body plan, ease of gene targeting, and other reasons. Although many mutants have been reported, no method to isolate the corresponding genes was reported. We developed a gene tagging and gene-trap system in P. patens by using the shuttle mutagenesis technique, which has been used in the budding yeast. In 5264 tagged lines, 203 mutants with altered developmental or morphological phenotypes were obtained. In 129 of 4757 gene-trap lines, β-glucuronidase (GUS) activity was detected in some tissue. Although multiple copies of a tag were detected in many tagged lines by Southern analyses, most copies are likely integrated at the same locus according to PCR analyses.

DOI： 10.1093/dnares/7.1.9

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記述言語：日本語   出版者・発行元：日本蘚苔類学会  

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記述言語：日本語   出版者・発行元：日本蘚苔類学会  

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記述言語：日本語   出版者・発行元：日本蘚苔類学会  

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記述言語：日本語   出版者・発行元：日本蘚苔類学会  

DOI： 10.24474/bryologicalresearch.10.9_301_1

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記述言語：日本語   出版者・発行元：日本蘚苔類学会  

DOI： 10.24474/bryologicalresearch.10.9_303_2

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記述言語：日本語   出版者・発行元：日本蘚苔類学会  

DOI： 10.24474/bryologicalresearch.10.6_175_1

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記述言語：英語   掲載種別：研究発表ペーパー・要旨（国際会議）   出版者・発行元：OXFORD UNIV PRESS  

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記述言語：英語   掲載種別：研究発表ペーパー・要旨（国際会議）   出版者・発行元：OXFORD UNIV PRESS  

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記述言語：英語   掲載種別：研究発表ペーパー・要旨（国際会議）   出版者・発行元：OXFORD UNIV PRESS  

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記述言語：英語   出版者・発行元：Japanese Society of Plant Physiologists  

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その他リンク： https://projects.repo.nii.ac.jp/?action=repository_uri&item_id=184659

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記述言語：日本語  

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記述言語：日本語  

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