Publications by authors named "Mayumi Wakazaki"

Article Synopsis
  • - The study investigates how SARS-CoV-2 buds and transports its virions from the ERGIC to the cell surface, revealing that the vesicles involved have a protein coat known as coatomer complex I (COPI).
  • - Researchers observed that during infection, the distribution of COPI and the ERGIC changed, suggesting they play a role in the virus's replication process.
  • - Depleting a key COPI component, COPB2, confined the SARS-CoV-2 virions within the ERGIC and significantly reduced viral release, indicating that targeting COPI could be a potential strategy for developing antiviral treatments.
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  • Chloroplasts in different species, like Chlamydomonas reinhardtii and C. applanata, exhibit complex shapes such as cup-like forms and starfish-like structures, challenging the traditional view that they are merely spheroid.
  • Advanced imaging techniques revealed that C. reinhardtii chloroplasts have features like large and small holes that aid in metabolite transport, along with an increase in volume under certain conditions.
  • The study suggests a need to rethink our understanding of chloroplast morphology and evolution, moving away from the idea that chloroplasts are uniform in shape and closely resembling cyanobacteria.
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In Catharanthus roseus, monoterpenoid indole alkaloids (MIAs) are produced through the cooperation of four cell types, with final products accumulating in specialized cells known as idioblasts and laticifers. To explore the relationship between cellular differentiation and cell type-specific MIA metabolism, we analyzed the expression of MIA biosynthesis in germinating seeds. Embryos from immature and mature seeds were observed via stereomicroscopy, fluorescence microscopy, and electron microscopy.

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Serine metabolism is involved in various biological processes. Here we investigate primary functions of the phosphorylated pathway of serine biosynthesis in a non-vascular plant Marchantia polymorpha by analyzing knockout mutants of MpPGDH encoding 3-phosphoglycerate dehydrogenase in this pathway. Growth phenotypes indicate that serine from the phosphorylated pathway in the dark is crucial for thallus growth.

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  • Properly patterned cell walls in plants are crucial for their functions, with protoxylem and metaxylem vessel cells showing distinct wall structures.
  • The scaffold protein MIDD1 is key in regulating microtubule patterns, affecting how cell walls are deposited, and its phase separation helps to adjust spacing in these vessel cells.
  • MIDD1's interaction with ROP GTPases is essential, as disruptions can lead to narrower gaps in protoxylem walls, highlighting phase separation's role in fine-tuning cell wall patterns in Arabidopsis thaliana.
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  • - This research uncovers a unique mechanism that allows the plant Vigna riukiuensis to tolerate salt, highlighting its ability to accumulate sodium in its leaves, unlike its relative V. nakashimae which restricts sodium allocation.
  • - While initially suspected to have vacuoles for sodium storage, no differences in vacuole formation were found when compared to a salt-sensitive species, V. angularis; instead, an abundance of starch granules in the chloroplasts was observed in V. riukiuensis.
  • - The study suggests that these starch granules may play a role in trapping sodium near them, providing new insights into how certain plants manage salt stress and adding to previous findings related to other species like
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Mobilisation of seed storage reserves is important for seedling establishment in . In this process, sucrose is synthesised from triacylglycerol via core metabolic processes. Mutants with defects in triacylglycerol-to-sucrose conversion display short etiolated seedlings.

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Programmed cell death (PCD) in lateral root caps (LRCs) is crucial for maintaining root cap functionality. Endoplasmic reticulum (ER) bodies play important roles in plant immunity and PCD. However, the distribution of ER bodies and their communication with vacuoles in the LRC remain elusive.

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  • Land plant spermatozoids have unique features like spline structures, multilayered structures, and multiple flagella, but the processes behind their development (spermatogenesis) are not fully understood.
  • Researchers identified specific genes, known as BLD10s, that play a crucial role in sperm development by analyzing genetic data and testing their functions in liverworts and mosses.
  • Mutations in BLD10 genes lead to issues in cell structure during sperm formation, indicating that these genes are important for proper chromatin organization and cellular changes necessary for sperm production.
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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).

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  • Plants use nitrogen sources like nitrate and ammonium from soil, but high levels of ammonium can be toxic to their growth.
  • The study reveals that the way plants assimilate ammonium through GLUTAMINE SYNTHETASE 2 (GLN2) in the plastid is the main cause of this toxicity, rather than just the accumulation of ammonium itself.
  • It was found that toxic ammonium levels increase acidity in plant shoots, leading to stress, and using an alkaline solution can help reduce this acidity and alleviate the toxicity.
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  • Parasitic plants like Striga hermonthica and Phtheirospermum japonicum infect other plants using specialized structures called haustoria, which contain different types of cells that play roles in parasitism.
  • This study presents a 3-D reconstruction of haustoria from these two species, highlighting their complex internal structures and how they interact with host plants like rice and Arabidopsis.
  • Key findings include differences in the cellular organization of haustoria, especially at the connection points to the host's xylem, which are crucial for further understanding how these parasitic plants function.
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Euglena gracilis exhibits photomovements in response to various light stimuli, such as phototactic and photophobic responses. Our recent study revealed that carotenoids in the eyespot apparatus are required for triggering phototaxis in this alga. However, the role of chloroplasts in eyespot formation is not understood.

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  • The phloem is responsible for transporting nutrients and signaling molecules in plants, mainly made up of sieve elements (SEs) and companion cells (CCs).
  • A new culture system called VISUAL-CC was developed to study the differentiation of CCs in the model plant Arabidopsis, revealing a negative correlation between SE and CC differentiation.
  • The ratio of SEs to CCs is influenced by the activity of GSK3 kinase; mutants with altered GSK3 activity show significant changes in the number of SEs and CCs, suggesting GSK3 acts as a switch for cell fate in the phloem.
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  • * The study compared the effects of two rice GS isoforms (OsGS1;1 and OsGS1;2) on root metabolism using various analytical methods, revealing that OsGS1;1 significantly impacts sugar and organic nitrogen levels and enhances photosynthesis-related gene expression.
  • * While OsGS1;1 influences a wide range of metabolic processes, including chloroplast development and metabolic balance in roots, OsGS1;2 focuses mainly on amino acid levels without significantly impacting carbon metabolism. *
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Many plants can reproduce vegetatively, producing clonal progeny from vegetative cells; however, little is known about the molecular mechanisms underlying this process. Liverwort (Marchantia polymorpha), a basal land plant, propagates asexually via gemmae, which are clonal plantlets formed in gemma cups on the dorsal side of the vegetative thallus [1]. The initial stage of gemma development involves elongation and asymmetric divisions of a specific type of epidermal cell, called a gemma initial, which forms on the floor of the gemma cup [2, 3].

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Patterned cell wall deposition is crucial for cell shapes and functions. In Arabidopsis xylem vessels, ROP11 GTPase locally inhibits cell wall deposition through microtubule disassembly, inducing pits in cell walls. Here, we show that an additional ROP signaling pathway promotes cell wall growth at pit boundaries.

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  • Plant vacuoles are crucial for growth and development, and two main theories exist about how they form: one suggests they originate from endosome fusion while the other proposes they come from the endoplasmic reticulum.
  • This study utilized 3D electron tomography, revealing that small vacuoles (SVs) act as the initial stages of vacuole development in Arabidopsis root cells and that these SVs primarily stem from the fusion of multivesicular bodies (MVBs).
  • Analysis showed that the formation of central vacuoles relies on the transition from MVBs to SVs and requires functional MVBs and membrane fusion processes, as evidenced by studies of mutants lacking these capabilities.
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The plastid evolved from a symbiotic cyanobacterial ancestor and is an essential organelle for plant life, but its developmental roles in roots have been largely overlooked. Here, we show that plastid translation is connected to the stem cell patterning in lateral root primordia. The gene encodes a plastid-localized protein that is a conserved bacterial ribosomal protein S6 of β/γ proteobacterial origin.

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Spatial control of cell-wall deposition is essential for determining plant cell shape [1]. Rho-type GTPases, together with the cortical cytoskeleton, play central roles in regulating cell-wall patterning [2]. In metaxylem vessel cells, which are the major components of xylem tissues, active ROP11 Rho GTPases form oval plasma membrane domains that locally disrupt cortical microtubules, thereby directing the formation of oval pits in secondary cell walls [3-5].

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We developed a wide-range and high-resolution transmission electron microscope acquisition system and obtained giga-pixel images of tobacco BY-2 cells during the log and stationary phases of cell growth. We demonstrated that the distribution and ultrastructure of compartments involved in membrane traffic (i.e.

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Maintenance of plastid and mitochondrial genome stability is crucial for photosynthesis and respiration, respectively. Recently, we have reported that RECA1 maintains mitochondrial genome stability by suppressing gross rearrangements induced by aberrant recombination between short dispersed repeats in the moss Physcomitrella patens. In this study, we studied a newly identified P.

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Rapid growth of plant cells by cell division and expansion requires an endomembrane trafficking system. The endomembrane compartments, such as the Golgi stacks, endosome and vesicles, are important in the synthesis and trafficking of cell wall materials during cell elongation. However, changes in the morphology, distribution and number of these compartments during the different stages of cell proliferation and differentiation have not yet been clarified.

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The development of cells specialized for water conduction or support is a striking innovation of plants that has enabled them to colonize land. The NAC transcription factors regulate the differentiation of these cells in vascular plants. However, the path by which plants with these cells have evolved from their nonvascular ancestors is unclear.

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