Masamitsu Wada

Masamitsu Wada
Tokyo Metropolitan University | TMU · Department of Biological Sciences

About

290
Publications
38,545
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13,304
Citations
Citations since 2017
13 Research Items
3648 Citations
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20172018201920202021202220230100200300400500600
20172018201920202021202220230100200300400500600
20172018201920202021202220230100200300400500600
Additional affiliations
April 2008 - March 2015
Kyushu University
Position
  • Professor

Publications

Publications (290)
Article
Chloroplast movement is regulated by dynamic reorganization of the actin cytoskeleton. To gain insight into the function of ACT2 in chloroplast movement, we examined the effect of the act2-3 mutation, in which a T-DNA is inserted at the second exon of the ACT2 gene, and investigated a transgenic Arabidopsis plant expressing the GFP-ACT2 fusion prot...
Article
Light-induced chloroplast movements control efficient light utilization in leaves, and thus, are essential for leaf photosynthesis and biomass production under fluctuating light conditions. Chloroplast movements have been intensively analyzed using wild-type and mutant plants of Arabidopsis thaliana. The molecular mechanism and the contribution to...
Article
Full-text available
Blue-light-induced chloroplasts movements play an important role in maximizing light utilization for photosynthesis in plants. Under a weak light condition, chloroplasts accumulate to the cell surface to capture light efficiently (chloroplast accumulation response). Conversely, chloroplasts escape from strong light and move to the side wall to redu...
Preprint
Plants have evolved unique responses to fluctuating light conditions in their environment. One such response, chloroplast photorelocation movement, optimizes photosynthesis under weak light and prevents photodamage under strong light. CHLOROPLAST UNUSUAL POSITIONING 1 (CHUP1) plays a pivotal role in the light-responsive chloroplast movements, which...
Chapter
Plants have evolved sophisticated mechanisms to survive in various environmental changes. Chloroplast movement is an essential response to optimize photosynthesis and to avoid photodamage under fluctuating light conditions. Chloroplasts accumulate at periclinal walls to maximize light absorption under weak light while they move to anticlinal walls...
Article
Full-text available
Leaf photosynthesis is regulated by multiple factors that help the plant to adapt to fluctuating light conditions. Leaves of sun-light-grown plants are thicker and contain more columnar palisade cells than those of shade-grown plants. Light-induced chloroplast movements are also essential for efficient leaf photosynthesis and facilitate efficient l...
Article
Under high light intensity, chloroplasts avoid absorbing excess light by moving to anticlinal cell walls (avoidance response), but under low light intensity, chloroplasts accumulate along periclinal cell walls (accumulation response). In most plant species, these responses are induced by blue light and are mediated by the blue-light photoreceptor,...
Article
Plants are sessile and require diverse strategies to adapt to fluctuations in the surrounding light conditions. Consequently, the photorelocation movement of chloroplasts is essential to prevent damages that are induced by intense light (avoidance response) and to ensure efficient photosynthetic activities under weak light conditions (accumulation...
Article
Plant cells connected to adjacent cells with rigid cell wall cannot change their position, so that appropriate nuclear positioning according to nuclear movement is indispensable for cellular development involving unequal cell division. Sessile plants are severely affected by fluctuating environmental conditions, so that movement of organelles inclu...
Article
Full-text available
Chloroplast movement is induced by blue light in a broad range of plant species. Weak light induces the chloroplast accumulation response and strong light induces the chloroplast avoidance response. Both responses are essential for efficient photosynthesis and are mediated by phototropin blue-light receptors. J-DOMAIN PROTEIN REQUIRED FOR CHLOROPLA...
Article
Chloroplast photorelocation movement, well-characterized light-induced response found in various plant species from alga to higher plants, is an important phenomenon for plants to increase photosynthesis efficiency and avoid photodamage. The signal for chloroplast accumulation movement connecting the blue light receptor, phototropin, and chloroplas...
Article
Light-induced chloroplast movement is found in most plant species, including algae and land plants. In land plants with multiple small chloroplasts, under weak light conditions, the chloroplasts move towards the light and accumulate on the periclinal cell walls to efficiently perceive light for photosynthesis (the accumulation response). Under stro...
Article
Full-text available
Chloroplasts move toward weak light to increase photosynthetic efficiency, and migrate away from strong light to protect chloroplasts from photodamage and eventual cell death. These chloroplast behaviors were first observed more than 100 years ago, but the underlying mechanism has only recently been identified. Ideal plant materials, such as fern g...
Data
Chloroplast avoidance responses sequentially induced by one-half irradiation of a chloroplast with strong blue light microbeam (10 × 10 µm2) of 30 Wm−2 in A. capillus-veneris dark-adapted prothallial cell. Photographs were taken every 15 sec and played back 150 times faster than the normal speed. Tsuboi Wada (2011) JPR 124, 201–21071)
Data
Chloroplast accumulation response induced by sequential irradiation with a blue microbeam (10 µm in diameter, 113 µmol m−2 s−1, peak at 453 nm, 1 min) in a dark-adapted prothallial cell of Adiantum capillus-veneris. The second microbeam was given 18 min after the first beam irradiation, namely, before the chloroplast reached the first beam-irradiat...
Data
Chloroplast accumulation response induced by red microbeam (8 µm in diameter, 10 Wm−2 for 1 min), which is mediated by neochrome. During the movement (18 min after the first microbeam), far-red light (20 Wm−2, for 1 min) was given to convert the active form of neochrome Pfr to in-active Pr form, resulting the chloroplast stop moving. When the same...
Data
Chloroplast movement induced by continuous and simultaneous irradiation at two adjacent areas with red microbeams (4 µm in diameter, 10 Wm−2, 20 µm apart) in a dark-adapted prothallial cell of A. capillus-veneris. Chloroplasts near anticlinal wall move towards the middle part of the two beams, but not to any one of the two beams. Photographs were t...
Data
Avoidance response of chloroplasts on the periclinal wall of the uppermost palisade cell of Arabidopsis thaliana. The circular area enclosed with blue lines was irradiated continuously with blue light laser (458 nm, 377 µmol m−2 s−1). Actin filaments are visualized with GFP-mTalin that binds actin filaments. Photographs were taken every 32 sec and...
Data
Avoidance response of chloroplasts at the anticlinal wall of the uppermost palisade cell of A. thaliana. Inside the rectangular area was irradiated. Cp-actin filaments is seen between the chloroplast and the plasma membrane during the avoidance movement. Other details are the same as Movie 6.
Article
Full-text available
Significance The photoreceptor phototropin mediates various blue light-induced responses, including phototropism, chloroplast movement, stomatal opening, and leaf flattening. Two BTB/POZ proteins, NONPHOTOTROPIC HYPOCOTYL 3 (NPH3) and ROOT PHOTOTROPISM 2 (RPT2), were identified as early signaling components in phototropin-mediated phototropism and...
Article
Full-text available
Light-induced chloroplast movement and attachment to the plasma membrane are dependent on actin filaments. In Arabidopsis thaliana, the short actin filaments on the chloroplast envelope, cp-actin filaments, are essential for chloroplast movement and positioning. Furthermore, cp-actin-filament-mediated chloroplast movement is necessary for the stron...
Data
Chloroplast photorelocation movement induced by strong blue light in mutant plants. (a, b) Changes in leaf transmittance rates from 2 to 6 min after changes in light fluence rate (3 and 20 μmol m–2 s–1) are indicated as percentage transmittance change over 1 min. Data for (a) in chup1, pmi1, and thrum1 backgrounds and (b) in the phototropin mutant...
Article
Full-text available
During the course of green plant evolution, numerous light responses have arisen that optimize their growth under fluctuating light conditions. The blue light receptor phototropin mediates several photomovement responses at the tissue, cellular and organelle levels. Chloroplast photorelocation movement is one such photomovement response, and is fou...
Article
The blue light (BL) receptor phototropin (phot) is specifically found in green plants; it regulates various BL-induced responses such as phototropism, chloroplast movement, stomatal opening, and leaf flattening. In Arabidopsis thaliana, two phototropins—phot1 and phot2—respond to blue light in overlapping but distinct ways. These BL-receptor-mediat...
Article
Full-text available
Chloroplast photorelocation movement is an essential physiological response for sessile plant survival and the optimization of photosynthetic ability. Simple but effective experiments on the physiological, cell biological and molecular genetic aspects have been widely used to investigate the signaling components of chloroplast photorelocation movem...
Article
Full-text available
Plants and animals express multiple actin isoforms in a manner that is dependent on tissues, organs and the stage of development. Previous genetic analyses suggested that individual actin isoforms have specific roles in cells, but there is little biochemical evidence to support this hypothesis. In this study, we purified four recombinant Arabidopsi...
Article
Chloroplast movement in 9 climbing plant species was investigated. It is thought that chloroplasts, generally escape from strong light to avoid photodamage but accumulate towards weak light to perform photosynthesis effectively. Unexpectedly, however, the leaves of climbing plants grown under strong sunlight showed very low or no chloroplast photor...
Article
Full-text available
Organelle movement and positioning play important roles in fundamental cellular activities and adaptive responses to environmental stress in plants. To optimize photosynthetic light utilization, chloroplasts move towards weak blue light (the accumulation response) and escape from strong blue light (the avoidance response). Nuclei also move in respo...
Article
Full-text available
RNA interference is commonly used for posttranscriptional silencing of target gene transcripts. In fern gametophytes, however, sequence-specific gene silencing is possible by introducing double-stranded DNA fragments into gametophyte cells by particle bombardment. Silencing could be transmitted all over the gametophyte through live cells. Further,...
Article
Full-text available
The expression of the gene for a proteinase (Rep1) is upregulated by gibberellins. The CAACTC regulatory element (CARE) of the Rep1 promoter is involved in the gibberellin response. We isolated a cDNA for a CARE-binding protein containing a Myb domain in its carboxyl-terminal region and designated the gene Carboxyl-terminal Myb1 (CTMyb1). This gene...
Article
Phototropins are blue-light sensitive photoreceptor proteins in plants. Phototropins consist of two LOV (light, oxygen and voltage sensor) domains (LOV1 and LOV2) that undergo photochemical reactions. Although the photochemical reaction of the LOV2 domain has been investigated extensively, the reaction of the LOV1 domain remains unresolved. In this...
Article
Chloroplast photo-relocation movement is crucial for plant survival; however, the mechanism of this phenomenon is still poorly understood. Especially, the signal that goes from photoreceptor to chloroplast is unknown, although the photoreceptors (phototropin 1 and 2) have been identified and an actin structure (chloroplast actin filaments) has been...
Article
Full-text available
Blue-light-induced chloroplast photorelocation movement is observed in most land plants. Chloroplasts move toward weak-light-irradiated areas to efficiently absorb light (the accumulation response) and escape from strong-light-irradiated areas to avoid photodamage (the avoidance response). The plant-specific kinase phototropin is the blue-light rec...
Article
Full-text available
Over-excitation of photosynthetic apparatus causing photoinhibition is counteracted by non-photochemical quenching (NPQ) of chlorophyll fluorescence, dissipating excess absorbed energy into heat. The PsbS protein plays a key role in this process, thus making the PsbS-less npq4 mutant unable to carry out qE, the major and most rapid component of NPQ...
Article
Full-text available
Significance High-light–induced avoidance movements of chloroplasts and nuclei from the leaf cell surface to the side walls are essential for minimizing damage from strong visible light and UV light, respectively. Phototropins, blue-light photoreceptors, regulate short actin filaments on the plasma membrane side of chloroplasts, allowing chloroplas...
Article
Full-text available
Organelle movement and positioning are essential for proper cellular function. A nucleus moves dynamically during cell division and differentiation and in response to environmental changes in animal, fungal, and plant cells. Nuclear movement is well-studied and the mechanisms have been mostly elucidated in animal and fungal cells, but not in plant...
Article
Plants are photosynthetic organisms that have evolved unique systems to adapt fluctuating environmental light conditions. In addition to well-known movement responses such as phototropism, stomatal opening, and nastic leaf movements, chloroplast photorelocation movement is one of essential cellular responses to optimize photosynthetic ability and a...
Article
Full-text available
Phytochrome (phy) in etiolated seedlings of wild-type (WT) Arabidopsis (Ler) and its transgenic lines (TL) L15 and L20 transformed with Adiantum capillus-veneris PHY1 cDNA (Okamoto et al., 1997) was investigated using low-temperature (85K) fluorescence spectroscopy and photochemistry. It was found that while WT seed germination requires stimulation...
Article
Plants evolved photoprotective mechanisms in order to counteract the damaging effects of excess light in oxygenic environments. Among them, chloroplast avoidance and non-photochemical quenching concur in reducing the concentration of chlorophyll excited states in the photosynthetic apparatus to avoid photooxidation. We evaluated their relative impo...
Article
Full-text available
Phototropins (phot1 and phot2 in Arabidopsis thaliana) relay blue light intensity information to the chloroplasts, which move toward weak light (the accumulation response) and away from strong light (the avoidance response). Chloroplast-actin (cp-actin) filaments are vital for mediating these chloroplast photorelocation movements. In this report, w...
Article
Full-text available
Fern gametophytes are a good model system to study cell biology and photobiology. Because they are very sensitive to light, have a very simple structure, either linear or two-dimensional, and are not covered with any other tissue, manipulation and observation of cells are quite easy compared with three-dimensional vascular plant tissues including f...
Chapter
Chloroplast photorelocation movement is one of the photomovement responses which facilitate efficient light utilization for photosynthesis. Recent molecular genetic studies using various land plant species identified many molecular components which mediate photoperception, signal transduction and motility system for chloroplast photorelocation move...
Article
Full-text available
Under low light conditions, chloroplasts gather at a cell surface to maximize light absorption for efficient photosynthesis, which is called the accumulation response. Phototropin1 (phot1) and phototropin2 (phot2) were identified as blue light photoreceptors in the accumulation response that occurs in Arabidopsis thaliana and Adiantum capillus-vene...
Article
Full-text available
Many organisms, including bacteria, fungi, animal, plants and algae, utilize blue light to adapt to a fluctuating light environment. Plants and algae such as photosynthetic stramenopiles in particular require light energy for photosynthesis and have thus evolved a range of sophisticated light-sensing systems to efficiently utilize light information...
Article
Full-text available
Premise of study: Phototropins (phot) are blue light receptor proteins that mediate phototropism and control photomovement responses, such as chloroplast photorelocation movement and stomatal opening. Arabidopsis thaliana has two phototropins, phot1 and phot2. Although both phot1 and phot2 redundantly mediate photomovement responses, phot2 uniquel...
Article
Full-text available
Chloroplasts change their position to adapt cellular activities to fluctuating environmental light conditions. Phototropins (phot1 and phot2 in Arabidopsis) are plant-specific blue light photoreceptors that perceive changes in light intensity and direction and mediate actin-based chloroplast photorelocation movements. Both phot1 and phot2 regulate...
Article
Full-text available
Light is one of the most important environmental factors regulating the growth and development of leaves. As the primary photosynthetic organs, leaves have a laminar structure in many dicotyledonous plants. The regulation of leaf flatness is a key mechanism for the efficient absorption of light under the low light conditions. In the present study,...
Article
Full-text available
Chloroplasts require association with the plasma membrane for movement in response to light and for appropriately positioning within the cell to efficiently capture photosynthetic light. In Arabidopsis, CHLOROPLAST UNUSUAL POSITIONING 1 (CHUP1), KINESIN-LIKE PROTEIN FOR ACTIN-BASED CHLOROPLAST MOVEMENT 1 (KAC1) and KAC2 are required for both the pr...
Article
Full-text available
Phototropins (phot1 and phot2), plant specific blue-light receptor kinases, mediate a range of physiological responses in Arabidopsis, including phototropism, chloroplast photorelocation movement, stomatal opening, and leaf flattening. Phototropins consist of two photoreceptive domains at their N-terminus, LOV1 and LOV2, and a serine/threonine kina...
Article
Full-text available
Gene silencing technology, such as RNA interference (RNAi), is commonly used to reduce gene expression in plant cells, and exogenous double-stranded RNA (dsRNA) can induce gene silencing in higher plants. Previously, we showed that the delivery of double-stranded DNA (dsDNA) fragments, such as PCR products of an endogenous gene sequence, into fern...
Article
Full-text available
Chloroplasts change their intracellular distribution in response to light intensity. CHUP1 (CHLOROPLAST UNUSUAL POSITIONING1) is indispensable for this response in Arabidopsis thaliana. However, involvement of CHUP1 in light-induced chloroplast movement is unknown in other plants. In this study, CHUP1 orthologues were isolated from a moss, Physcomi...
Article
Full-text available
Phytochromes in seed plants are known to move into nuclei in a red light-dependent manner with or without interacting factors. Here, we show phytochrome relocation to the nuclear region in phytochrome-dependent Adiantum capillus-veneris spore germination by partial spore-irradiation experiments. The nuclear or non-nuclear region of imbibed spores w...
Article
Full-text available
In a recent publication using an actin-visualized line of Arabidopsis (Ichikawa et al. 2011, ref. 11), we reported a detailed analysis with higher time resolution on the dynamics of chloroplast actin filaments (cp-actin filaments) during chloroplast avoidance movement and demonstrated a good correlation between the biased configuration of cp-actin...
Article
Full-text available
The phototropin (phot)-dependent intracellular relocation of chloroplasts is a ubiquitous phenomenon in plants. We have previously revealed the involvement of a short cp-actin (chloroplast actin) filament-based mechanism in this movement. Here, the reorganization of cp-actin filaments during the avoidance movement of chloroplasts was analyzed in hi...
Article
Full-text available
Chloroplast movement is essential for plants to survive under various environmental light conditions. Phototropins-plant-specific blue-light-activated receptor kinases-mediate the response by perceiving light intensity and direction. Recently, novel chloroplast actin (cp-actin) filaments have been identified as playing a pivotal role in the directi...
Article
Full-text available
Chloroplasts change their positions in a cell in response to light intensities. The photoreceptors involved in chloroplast photo-relocation movements and the behavior of chloroplasts during their migration were identified in our previous studies, but the mechanism of movement has yet to be clarified. In this study, the behavior of actin filaments u...
Article
Full-text available
Chloroplast photorelocation movement is essential for the sessile plant survival and plays a role for efficient photosynthesis and avoiding photodamage of chloroplasts. There are several ways to observe or detect chloroplast movement directly or indirectly. Here, techniques for the induction of chloroplast movement and how to detect the responses,...
Article
Full-text available
Chloroplasts migrate in response to different light intensities. Under weak light, chloroplasts gather at an illuminated area to maximize light absorption and photosynthesis rates (the accumulation response). In contrast, chloroplasts escape from strong light to avoid photodamage (the avoidance response). Photoreceptors involved in these phenomena...
Article
Full-text available
Chloroplasts change their intracellular positions in response to their light environment. Under darkness, chloroplasts assume special positions that are different from those under light conditions. Here, we analyzed chloroplast dark positioning using Adiantum capillus-veneris gametophyte cells. When chloroplasts were transferred into darkness, duri...
Article
Full-text available
To optimize photosynthetic activity, chloroplasts change their intracellular location in response to ambient light conditions; chloroplasts move toward low intensity light to maximize light capture, and away from high intensity light to avoid photodamage. Although several proteins have been reported to be involved in the chloroplast photorelocation...
Data
(a) The velocity of chloroplast avoidance movement induced by three sequential irradiations to different halves of the same chloroplast in an A. thaliana palisade cell. (b) The lag times before the start of chloroplast movement or a change in direction to escape subsequent irradiations with sequential strong microbeams. Data were obtained from phot...
Data
(a) Photographs showing chloroplast movement in an Arabidopsis thaliana palisade cell induced by three sequential irradiations of a blue microbeam 100 μm2 square. A dark-adapted palisade cell with a few chloroplasts still attached along the periclinal wall is shown. The chloroplast at the center of the cell (arrow) was continually observed and phot...