Mitsuyasu Hasebe

• National Institute for Basic Biology

The evolution of green plants from aquatic to terrestrial environments is thought to have been facilitated by the acquisition of gametangia, specialized multicellular organs housing gametes. Antheridia and archegonia, responsible for producing and protecting sperm and egg cells, undergo formative cell divisions to produce a cell to differentiate in...

A spatiotemporal understanding of gene function requires the precise control of gene expression in each cell. Here, we use an infrared laser–evoked gene operator (IR-LEGO) system to induce gene expression at the single-cell level in the moss Physcomitrium patens by heating a living cell with an IR laser and thereby activating the heat shock respons...

Body shape and size diversity and their evolutionary rates correlate with species richness at the macroevolutionary scale. However, the molecular genetic mechanisms underlying the morphological diversification across related species are poorly understood. In beetles, which account for one-fourth of the known species, adaptation to different trophic...

Anisotropic cell expansion is crucial for the morphogenesis of land plants, as cell migration is restricted by the rigid cell wall. The anisotropy of cell expansion is regulated by mechanisms acting on the deposition or modification of cell wall polysaccharides. Besides the polysaccharide components in the cell wall, a layer of hydrophobic cuticle...

The most extreme environments are the most vulnerable to transformation under a rapidly changing climate. These ecosystems harbor some of the most specialized species, which will likely suffer the highest extinction rates. We document the steepest temperature increase (2010–2021) on record at altitudes of above 4,000 meters, triggering a decline of...

An Arabidopsis mutant displaying impaired stomatal responses to CO2 , cdi4, was isolated by a leaf thermal imaging screening. The mutated gene PECT1 encodes CTP:phosphorylethanolamine (PE) cytidylyltransferase. The cdi4 exhibited a decrease in PE levels and a defect in light-induced stomatal opening as well as low CO2 -induced stomatal opening. We...

Excess boron (B) is toxic to plants and thereby causes DNA damage and cell death in root meristems. However, the underlying mechanisms which link boron and DNA damage remain unclear. It has been reported that the rpt5a-6 mutant of the 26S proteasome is sensitive to excess boron, resulting in more frequent cell death in root meristem and reduced roo...

Cell division is essential for development and involves spindle assembly, chromosome separation, and cytokinesis. In plants, the genetic tools for controlling the events in cell division at the desired time are limited and ineffective owing to high redundancy and lethality. Therefore, we screened cell division-affecting compounds in Arabidopsis tha...

Plant cells are surrounded by a cell wall and do not migrate, which makes the regulation of cell division orientation crucial for development. Regulatory mechanisms controlling cell division orientation may have contributed to the evolution of body organization in land plants. The GRAS family of transcription factors was transferred horizontally fr...

Mycorrhizae are one of the most fundamental symbioses between plants and fungi, with ectomycorrhizae being the most widespread in boreal forest ecosystems. Ectomycorrhizal fungi are hypothesized to have evolved convergently from saprotrophic ancestors in several fungal clades, especially members of the subdivision Agaricomycotina. Studies on fungal...

Animals possess specialized systems, e.g., neuromuscular systems, to sense the environment and then move their bodies quickly in response. Mimosa pudica, the sensitive plant, moves its leaves within seconds in response to external stimuli; e.g., touch or wounding. However, neither the plant-wide signaling network that triggers these rapid movements...

Cell division is essential for growth and development and involves events such as spindle assembly, chromosome separation, and cell plate formation. In plants, the tools used to control these events at the desired time are still poor because the genetic approach is ineffective owing to a high redundancy and lethality, as well as harmful side effect...

Introduction Half a century since the creation of the International Association of Bryologists, we carried out a review to identify outstanding challenges and future perspectives in bryology. Specifically, we have identified 50 fundamental questions that are critical in advancing the discipline. Methods We have adapted a deep-rooted methodology of...

Harnessing plant genetic resources including wild plants enables exploitation of agronomically unfavorable lands to secure food in the future. The genus Vigna , family Fabaceae, consists of many species of such kind, as they are often adapted to harsh environments including marine beach, arid sandy soil, acidic soil, limestone karst and marshes. He...

DNA topoisomerase 1 (TOP1) plays general roles in DNA replication and transcription by regulating DNA topology in land plants and metazoans. TOP1 is also involved in specific developmental events; however, whether TOP1 plays a conserved developmental role among multicellular organisms is unknown. Here, we investigated the developmental roles of TOP...

Plant and animal stem cells can self-renew and give rise to differentiated cells to form tissues or organs. Unlike differentiated cells in animals, those in land plants can be readily reprogrammed into stem cells, reflecting the plasticity of plant cell identity. The moss Physcomitrium patens (synonym: Physcomitrella patens) is highly regenerable,...

Light is a critical signal perceived by plants to adapt their growth rate and direction. Although many signaling components have been studied, how plants respond to constantly fluctuating light remains underexplored. Here, we showed that in the moss Physcomitrium ( Physcomitrella ) patens , the PSTAIRE-type cyclin-dependent kinase PpCDKA is dispens...

Non-linear microscopy, such as multi-photon excitation microscopy, offers spatial localities of excitations, thereby achieving 3D cross-sectional imaging with low phototoxicity even in thick biological specimens. We had developed a multi-point scanning two-photon excitation microscopy system using a spinning-disk confocal scanning unit. However, it...

Animal and plant somatic cells have the capacity to switch states or reprogram into stem cells to adapt during stress and injury. This ability to deal with stochastic changes or reprogramming of somatic cells also needs macroautophagy/autophagy. Here, we expand on this notion and provide a primary example of how overexpression of ATG8/LC3 in the mo...

Some sea slugs sequester chloroplasts from algal food in their intestinal cells and photosynthesize for months. This phenomenon, kleptoplasty, poses a question of how the chloroplast retains its activity without the algal nucleus. There have been debates on the horizontal transfer of algal genes to the animal nucleus. To settle the arguments, this...

Organisms withstand normal ranges of environmental fluctuations by producing a set of phenotypes genetically programmed as a reaction norm; however, extreme conditions can expose a misregulation of phenotypes called a hidden reaction norm. Although an environment consists of multiple factors, how combinations of these factors influence a reaction n...

Plant movements are generally slow, but some plant species have evolved the ability to move very rapidly at speeds comparable to those of animals. Whereas movement in animals relies on the contraction machinery of muscles, many plant movements use turgor pressure as the primary driving force together with secondarily generated elastic forces. The m...

Parasitic plants form a specialized organ, a haustorium, to invade host tissues and acquire water and nutrients. To understand the molecular mechanism of haustorium development, we performed a forward genetics screening to isolate mutants exhibiting haustorial defects in the model parasitic plant Phtheirospermum japonicum. We isolated two mutants t...

The leaves of the carnivorous plant Venus flytrap, Dionaea muscipula (Dionaea) close rapidly to capture insect prey. The closure response usually requires two successive mechanical stimuli to sensory hairs on the leaf blade within approximately 30 s (refs. 1–4). An unknown biological system in Dionaea is thought to memorize the first stimulus and t...

[This corrects the article DOI: 10.3389/fmicb.2020.01628.].

DNA damage can result from intrinsic cellular processes and from exposure to stressful environments. Such DNA damage generally threatens genome integrity and cell viability¹. However, here we report that the transient induction of DNA strand breaks (single-strand breaks, double-strand breaks or both) in the moss Physcomitrella patens can trigger th...

Epigenetic DNA base methylation plays important roles in gene expression regulation. We here describe a gene expression regulation network consisting of many DNA methyltransferases each frequently changing its target sequence-specificity. Our object Helicobacter pylori, a bacterium responsible for most incidence of stomach cancer, carries a large a...

Some sea slugs sequester chloroplasts from algal food in their intestinal cells and photosynthesize for months. This phenomenon, kleptoplasty, poses a question of how the chloroplast retains its activity without the algal nucleus, and there have been debates on the horizontal transfer of algal genes to the animal nucleus. To settle the arguments, w...

Most plants grow and develop by taking up nutrients from the soil while continuously under threat from foraging animals. Carnivorous plants have turned the tables by capturing and consuming nutrient-rich animal prey, enabling them to thrive in nutrient-poor soil. To better understand the evolution of botanical carnivory, we compared the draft genom...

A stable multimodal system is developed by combining two common-path digital holographic microscopes (DHMs): coherent and incoherent, for simultaneous recording and retrieval of three-dimensional (3-D) phase and 3-D fluorescence imaging (FI), respectively, of a biological specimen. The 3-D FI is realized by a single-shot common-path off-axis fluore...

The ANGUSTIFOLIA (AN) gene regulates the width of leaves by controlling the diffuse growth of leaf cells in the medio‐lateral direction in Arabidopsis thaliana. In the genome of the moss Physcomitrella patens, we found two normal ANs (PpAN1‐1 and 1‐2). Both PpAN1 genes complemented the A. thaliana an‐1 mutant phenotypes. An analysis of spatiotempor...

Cytokinesis is fundamental for cell proliferation [1, 2]. In plants, a bipolar short-microtubule array forms the phragmoplast, which mediates vesicle transport to the midzone and guides the formation of cell walls that separate the mother cell into two daughter cells [2]. The phragmoplast centrifugally expands toward the cell cortex to guide cell-p...

Epigenetic modifications, including histone modifications, stabilize cell-specific gene expression programmes to maintain cell identities in both metazoans and land plants1–3. Notwithstanding the existence of these stable cell states, in land plants, stem cells are formed from differentiated cells during post-embryonic development and regeneration4...

The evolutionary origin of periodical mass‐flowering plants (shortly periodical plants), exhibiting periodical mass flowering and death immediately after flowering, has not been demonstrated. Within the genus Strobilanthes (Acanthaceae), which includes more than 50 periodical species, Strobilanthes flexicaulis on Okinawa Island, Japan, flowers greg...

Next-generation sequencing technologies have made it possible to carry out transcriptome analysis at the single-cell level. Single-cell RNA-sequencing (scRNA-seq) data provide insights into cellular dynamics , including intercellular heterogeneity as well as inter-and intra-cellular fluctuations in gene expression that cannot be studied using popul...

Elysia chlorotica, a sacoglossan sea slug found off the East Coast of the United States, is well-known for its ability to sequester chloroplasts from its algal prey and survive by photosynthesis for up to 12 months in the absence of food supply. Here we present a draft genome assembly of E. chlorotica that was generated using a hybrid assembly stra...

Background Next-generation sequencing technologies have made it possible to carry out transcriptome analysis at the single-cell level. Single-cell RNA-sequencing (scRNA-seq) data provide insights into cellular dynamics, including intercellular heterogeneity as well as inter- and intra-cellular fluctuations in gene expression that cannot be studied...

Eggs and sperm are reproductive cells produced, respectively, in archegonia and antheridia in all land plants except seed plants, in which gametangia are highly reduced. The moss Physcomitrella patens is a suitable model plant to study the molecular mechanisms underlying the development of archegonia and antheridia and to gain an insight into their...

MIKC classic (MIKCC)-type MADS-box genes encode transcription factors that function in various developmental processes, including angiosperm floral organ identity. Phylogenetic analyses of the MIKCC-type MADS-box family, including genes from non-flowering plants, suggest that the increased numbers of these genes in flowering plants is related to th...

Carnivorous plant genome research has focused on members of the Lamiales and Oxalidales; the most complete sequences are for Utricularia gibba and Cephalotus follicularis. The size-limited U. gibba genome highlights the importance of small-scale tandem duplications, which likely play roles in this species’ carnivorous adaptation. Sequencing of the...

Stem cells self-renew and produce precursor cells that differentiate to become specialized cell types. Land plants generate several types of stem cells that give rise to most organs of the plant body and whose characters determine the body organization. The moss Physcomitrella patens forms eight types of stem cells throughout its life cycle. Under...

Significance Cell division axis orientation is critical for differentiation and morphogenesis. In animal cells, centrosome-driven mitotic spindle orientation is key to orient cell divisions. However, in naturally acentrosomal plants, the mechanism underlying spindle orientation is poorly understood. Using two model systems, asymmetrically dividing...

This letter proposes a method of configuring a testing target to evaluate the performance of adaptive optics microscopes. In this method, a testing slide with fluorescent beads is used to simultaneously determine the point spread function and the field of view. The point spread function is reproduced to simulate actual biological samples by etching...

Under certain circumstances differentiated cells can be reprogrammed to form stem cells in land plants, but only a portion of the cells reprograms successfully. A long-distance inhibitory signal from reprogrammed cells to surrounding cells has been reported in some ferns. Here we show the existence of anisotropic inhibitory signal to regulate stem...

Carnivorous plants exploit animals as a nutritional source and have inspired long-standing questions about the origin and evolution of carnivory-related traits. To investigate the molecular bases of carnivory, we sequenced the genome of the heterophyllous pitcher plant Cephalotus follicularis, in which we succeeded in regulating the developmental s...

Both land plants and metazoa have the capacity to reprogram differentiated cells to stem cells. Here we show that the moss Physcomitrella patens Cold-Shock Domain Protein 1 (PpCSP1) regulates reprogramming of differentiated leaf cells to chloronema apical stem cells and shares conserved domains with the induced pluripotent stem cell factor Lin28 in...

PpCSP1-Citrine protein enriched during cytokinesis in an excised leaf of nPpCSP1-Citrine-3'UTR #1 line. Selected frames during cytokinesis are shown in Supplementary Fig. 3.

PpCSP1-Citrine protein accumulation in growing protonemata of nPpCSP1-Citrine-3'UTR #1 line.

PpCSP1 promoter activity and PpCSP1-Citrine protein accumulation in an excised leaf of PpCSP1pro:LUC nPpCSP1-Citrine-3'UTR #2 line. Selected frames (0, 24, and 48 hours) are shown in Fig. 2d.

Supplementary Figures, Supplementary Tables and Supplementary References

PpCSP1-Citrine protein accumulation in an excised leaf of nPpCSP1-Citrine-nosT #136 line. Selected frames (0, 24, and 48 hours) are shown in Fig. 4c.

PpCSP1-Citrine protein accumulation in an excised leaf of nPpCSP1-Citrine-3'UTR #1 line. Selected frames (0, 24, and 48 hours) are shown in Fig. 2a.

Protonema growth of the wild type, nPpCSP1-Citrine-nosT #136 line, and ppcsp1 ppcsp2 ppcsp3 ppcsp4 #29 line.

It has recently been noted that micrographs in Fig 4 contain inconsistent background signals. The corrected figure is shown here with different images from the same experiment in panels A and B, which were derived from the same dataset underlying Fig 4 in the original paper. The source data for the new figure 4 can be found online.

Polyamines are small basic compounds present in all living organisms and act in a variety of biological processes. However, the mechanism of polyamine sensing, signaling and response in relation to other metabolic pathways remains to be fully addressed in plant cells. As one approach, we isolated Arabidopsis mutants that show increased resistance t...

Packaging of eukaryotic DNA largely depends on histone modifications that affect the accessibility of DNA to transcriptional regulators, thus controlling gene expression. The Polycomb group (PcG) chromatin remodeling complex deposits a methyl group on lysine 27 of histone 3 leading to repressed gene expression. Plants encode homologs of the Enhance...

Major life cycle transitions happen after changes in stem cells trigger new developmental programs. In moss, expression of the homeobox transcription factor BELL1 is sufficient to induce sporophyte stem cells from the gametophyte phase, without having to go through fertilization.

Novel developmental programs often evolve via cooption of existing genetic networks. To understand this process, we explored cooption of the TAS3 tasiRNA pathway in the moss Physcomitrella patens. We find an ancestral function for this repeatedly redeployed pathway in the spatial regulation of a conserved set of Auxin Response Factors. In moss, thi...

Novel developmental programs often evolve via cooption of existing genetic networks. To understand this process, we explored cooption of the TAS3 tasiRNA pathway in the moss Physcomitrella patens . We find an ancestral function for this repeatedly redeployed pathway in the spatial regulation of a conserved set of Auxin Response Factors. In moss, th...

A male Ginkgo tree at Kami Yagisawa, Minobu-cho, Yamanashi Prefecture, Japan, is shown to possess a small, localized, branch that produces ovules that mature into viable seeds. This tree is recognized as an Ohatsuki Icho because of the occasional production of pollen sacs on otherwise normal vegetative leaves, but most of the abundant male cones th...

Ligand receptor-based signaling is a means of cell-to-cell communication for coordinating developmental and physiological processes in multicellular organisms. In plants, cell-producing meristems utilize this signaling to regulate their activities and ensure for proper development. Shoot and root systems share common requirements for carrying out t...

The temporal resolution of a two-photon excitation laser scanning microscopy (TPLSM) system is limited by the excitation laser beam's scanning speed. To improve the temporal resolution, the TPLSM system is equipped with a spinning-disk confocal scanning unit. However, the insufficient energy of a conventional Ti:sapphire laser source restricts the...

Differentiated cells are in a non-dividing, quiescent state, but some differentiated cells can reenter the cell cycle in response to appropriate stimuli. Quiescent cells are generally arrested at the G0/G1 phase, reenter the cell cycle, and progress to the S phase to replicate their genomic DNA. On the other hand, some types of cells are arrested a...

Complex morphology is an evolutionary outcome of phenotypic diversification. In some carnivorous plants, the ancestral planar leaf has been modified to form a pitcher shape. However, how leaf development was altered during evolution remains unknown. Here we show that the pitcher leaves of Sarracenia purpurea develop through cell division patterns o...

The root meristem (RM) is a fundamental structure that is responsible for postembryonic root growth. The RM contains the quiescent center (QC), stem cells and frequently dividing meristematic cells, in which the timing and the frequency of cell division are tightly regulated. In Arabidopsis thaliana, several gain-of-function analyses have demonstra...

Analyses of cellular and subcellular dynamics in living cells and tissues with their three-dimensional (x, y, z) structural information are superior to those with single-plane information. Two-photon spinning disk confocal microscopy is a good method for taking spatially and temporally high-resolution images for reconstruction of three-dimensional...

Membrane trafficking to the protein storage vacuole (PSV) is a specialized process in seed plants. However, this trafficking mechanism to PSV is poorly understood. Here, we show that three types of Beige and Chediak-Higashi (BEACH)-domain proteins contribute to both vacuolar protein transport and effector-triggered immunity (ETI). We screened a gre...

To characterize leaf cell wall proteins relating the architectural changes of leaves, we analyzed Nicotiana tabacum leaf cell wall proteins that were extracted by the treatment with lithium chloride. Some of these proteins showed amino acid sequence homology to some germin-like proteins (GLP). Based of those sequences, we isolated the cDNA encoding...

Ferns are the only major lineage of vascular plants not represented by a sequenced nuclear genome. This lack of genome sequence information significantly impedes our ability to understand and reconstruct genome evolution not only in ferns, but across all land plants. Azolla and Ceratopteris are ideal and complementary candidates to be the first fer...

Anhydrobiosis represents an extreme example of tolerance adaptation to water loss, where an organism can survive in an ametabolic state until water returns. Here we report the first comparative analysis examining the genomic background of extreme desiccation tolerance, which is exclusively found in larvae of the only anhydrobiotic insect, Polypedil...

Cell-to-cell communication is a fundamental mechanism for coordinating developmental and physiological events in multicellular organisms. Heterotrimeric G proteins are key molecules that transmit extracellular signals; similarly, CLAVATA signaling is a crucial regulator in plant development. Here, we show that Arabidopsis thaliana Gβ mutants exhibi...

Burkholderia sp. strain RPE67 is a bacterial symbiont isolated from a field-collected bean bug, Riptortus pedestris. To under-stand the genetic basis of the insect-microbe symbiosis, we performed whole-genome sequencing of the Burkholderia strain, re-vealing an 8.69-Mb genome consisting of three chromosomes and three plasmids.