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Journal of Experimental Botany Sep 2023This article comments on: Pang L, Kobayashi A, Atsumi Y, Miyazawa Y, Fujii N, Dietrich D, Bennett MJ, Takahashi H. 2023. MIZU-KUSSEI1 (MIZ1) and GNOM/MIZ2 control not...
This article comments on: Pang L, Kobayashi A, Atsumi Y, Miyazawa Y, Fujii N, Dietrich D, Bennett MJ, Takahashi H. 2023. MIZU-KUSSEI1 (MIZ1) and GNOM/MIZ2 control not only positive hydrotropism but also phototropism in Arabidopsis roots. Journal of Experimental Botany 74, 5026–5038.
Topics: Phototropism; Arabidopsis; Tropism
PubMed: 37702013
DOI: 10.1093/jxb/erad293 -
Stress Biology Jul 2023Phototropism is a classic adaptive growth response that helps plants to enhance light capture for photosynthesis. It was shown that hydrogen peroxide (HO) participates...
Phototropism is a classic adaptive growth response that helps plants to enhance light capture for photosynthesis. It was shown that hydrogen peroxide (HO) participates in the regulation of blue light-induced hypocotyl phototropism; however, the underlying mechanism is unclear. In this study, we demonstrate that the unilateral high-intensity blue light (HBL) could induce asymmetric distribution of HO in cotton hypocotyls. Disruption of the HBL-induced asymmetric distribution of HO by applying either HO itself evenly on the hypocotyls or HO scavengers on the lit side of hypocotyls could efficiently inhibit hypocotyl phototropic growth. Consistently, application of HO on the shaded and lit sides of the hypocotyls led to reduced and enhanced hypocotyl phototropism, respectively. Further, we show that HO inhibits hypocotyl elongation of cotton seedlings, thus supporting the repressive role of HO in HBL-induced hypocotyl phototropism. Moreover, our results show that HO interferes with HBL-induced asymmetric distribution of auxin in the cotton hypocotyls. Taken together, our study uncovers that HO changes the asymmetric accumulation of auxin and inhibits hypocotyl cell elongation, thus mediating HBL-induced hypocotyl phototropism.
PubMed: 37676397
DOI: 10.1007/s44154-023-00111-3 -
Quantitative Plant Biology 2023An increasing number of collaborative projects between artists and scientists raises the question regarding their value, particularly when considering the redirection of...
An increasing number of collaborative projects between artists and scientists raises the question regarding their value, particularly when considering the redirection of resources. Here we provide a personal account of our collaborative efforts, as an artist and a scientist. We propose that one of the most significant outcomes is something that cannot be planned for in advance: serendipitous events. Such events lead to fresh perspectives and imaginative ideas, the fairy dust underlying many great works of art and science. The unexpected nature of these desired outcomes requires from us a leap of faith on the one hand, and a deep trust in our 'partner in crime' on the other.
PubMed: 37587987
DOI: 10.1017/qpb.2023.7 -
Inclination of polarized illumination increases symmetry of structures grown inorganic phototropism.Materials Horizons Oct 2023Inclination of unpatterned, linearly polarized illumination in the plane of the electric field oscillation effected increased directional feature alignment and decreased...
Inclination of unpatterned, linearly polarized illumination in the plane of the electric field oscillation effected increased directional feature alignment and decreased off-axis order in Se-Te deposits generated by inorganic phototropic growth relative to that produced using normal incidence. Optically based growth simulations reproduced the experimental results indicating a photonic basis for the morphology change. Modeling of the light scattering at the growth interface revealed that illumination inclination enhances scattering that localizes the optical field along the polarization plane and suppresses cooperativity in defect-driven scattering. Thus, the symmetry of the deposited structures increased as the asymmetry of the illumination increased, as measured by the inclination of the illumination incidence away from the surface normal.
PubMed: 37581003
DOI: 10.1039/d3mh00839h -
Plants (Basel, Switzerland) Aug 2023Nowadays, not only the roots, but also leaves and flowers of ginseng are increasingly popular ingredients in supplements for healthcare products and traditional...
Nowadays, not only the roots, but also leaves and flowers of ginseng are increasingly popular ingredients in supplements for healthcare products and traditional medicine. The cultivation of the shade-loving crop, ginseng, is very demanding in terms of the light environment. Along with the intensity and duration, light direction is another important factor in regulating plant morphophysiology. In the current study, three lighting directions-top (T), side (S), or top + side (TS)-with an intensity of 30 ± 5 μmol·m·s photosynthetic photon flux density (PPFD) were employed. Generally, compared with the single T lighting, the composite lighting direction, TS, was more effective in shaping the ginseng with improved characteristics, including shortened, thick shoots; enlarged, thick leaves; more leaf trichomes; earlier flower bud formation; and enhanced photosynthesis. The single S light resulted in the worst growth parameters and strongly inhibited the flower bud formation, leading to the latest flower bud observation. Additionally, the S lighting acted as a positive factor in increasing the leaf thickness and number of trichomes on the leaf adaxial surface. However, the participation of the T lighting weakened these traits. Overall, the TS lighting was the optimal direction for improving the growth and development traits in ginseng. This preliminary research may provide new ideas and orientations in ginseng cultivation lodging resistance and improving the supply of ginseng roots, leaves, and flowers to the market.
PubMed: 37571002
DOI: 10.3390/plants12152849 -
Plant, Cell & Environment Nov 2023Plants are constantly exposed to a multitude of external signals, including light. The information contained within the full spectrum of light is perceived by a battery... (Review)
Review
Plants are constantly exposed to a multitude of external signals, including light. The information contained within the full spectrum of light is perceived by a battery of photoreceptors, each with specific and shared signalling outputs. Recently, it has become clear that UV-B radiation is a vital component of the electromagnetic spectrum, guiding growth and being crucial for plant fitness. However, given the large overlap between UV-B specific signalling pathways and other photoreceptors, understanding how plants can distinguish UV-B specific signals from other light components deserves more scrutiny. With recent evidence, we propose that UV-B signalling and other light signalling pathways occur within distinct tissues and cell-types and that the contribution of each pathway depends on the type of response and the developmental stage of the plant. Elucidating the precise site(s) of action of each molecular player within these signalling pathways is key to fully understand how plants are able to orchestrate coordinated responses to light within the whole plant body. Focusing our efforts on the molecular study of light signal interactions to understand plant growth in natural environments in a cell-type specific manner will be a next step in the field of photobiology.
Topics: Signal Transduction; Plants; Light Signal Transduction; Ultraviolet Rays
PubMed: 37554043
DOI: 10.1111/pce.14680 -
Tree Physiology Nov 2023Lianas employ a variety of searching mechanisms to find support; however, it is not clear to what extent environmental signals are used to help direct the search....
Lianas employ a variety of searching mechanisms to find support; however, it is not clear to what extent environmental signals are used to help direct the search. Several adventitious root climbers have been shown to bend away from light and grow toward darker areas or objects, in one case including actual tree trunks. In the literature, this negative phototropism (NP) has also been informally and inconsistently reported from a temperate root climber Hedera helix L. (common ivy). In this study, rigorous laboratory tests have confirmed the occurrence of NP in both seedlings and prostrate shoots of H. helix. Furthermore, a field experiment with potted ivy seedlings placed around tree trunks demonstrated their ability to remotely locate trees. This finding was corroborated by a survey of growth directions in wild-growing prostrate ivy shoots in two woodland habitats. An additional outdoor experiment showed that the ability to locate support is expressed in shade but supressed by full sun conditions. These results show that H. helix uses NP to locate support and indicate that this ability is a component of the species' shade escape strategy.
Topics: Trees; Phototropism; Hedera; Ecosystem; Forests; Seedlings
PubMed: 37334935
DOI: 10.1093/treephys/tpad077 -
Journal of Experimental Botany Sep 2023In response to unilateral blue light illumination, roots of some plant species such as Arabidopsis thaliana exhibit negative phototropism (bending away from light),...
In response to unilateral blue light illumination, roots of some plant species such as Arabidopsis thaliana exhibit negative phototropism (bending away from light), which is important for light avoidance in nature. MIZU-KUSSEI1 (MIZ1) and GNOM/MIZ2 are essential for positive hydrotropism (i.e. in the presence of a moisture gradient, root bending towards greater water availability). Intriguingly, mutations in these genes also cause a substantial reduction in phototropism. Here, we examined whether the same tissue-specific sites of expression required for MIZ1- and GNOM/MIZ2-regulated hydrotropism in Arabidopsis roots are also required for phototropism. The attenuated phototropic response of miz1 roots was completely restored when a functional MIZ1-green fluorescent protein (GFP) fusion was expressed in the cortex of the root elongation zone but not in other tissues such as root cap, meristem, epidermis, or endodermis. The hydrotropic defect and reduced phototropism of miz2 roots were restored by GNOM/MIZ2 expression in either the epidermis, cortex, or stele, but not in the root cap or endodermis. Thus, the sites in root tissues that are involved in the regulation of MIZ1- and GNOM/MIZ2-dependent hydrotropism also regulate phototropism. These results suggest that MIZ1- and GNOM/MIZ2-mediated pathways are, at least in part, shared by hydrotropic and phototropic responses in Arabidopsis roots.
Topics: Arabidopsis; Phototropism; Arabidopsis Proteins; Plant Roots; Tropism; Guanine Nucleotide Exchange Factors
PubMed: 37220914
DOI: 10.1093/jxb/erad193 -
The New Phytologist Aug 2023Plants perceive the direction of gravity during skotomorphogenic growth, and of gravity and light during photomorphogenic growth. Gravity perception occurs through the...
Plants perceive the direction of gravity during skotomorphogenic growth, and of gravity and light during photomorphogenic growth. Gravity perception occurs through the sedimentation of starch granules in shoot endodermal and root columella cells. In this study, we demonstrate that the Arabidopsis thaliana GATA factors GNC (GATA, NITRATE-INDUCIBLE, CARBON METABOLISM-INVOLVED) and GNL/CGA1 (GNC-LIKE/CYTOKININ-RESPONSIVE GATA1) repress starch granule growth and amyloplast differentiation in endodermal cells. In our comprehensive study, we analysed gravitropic responses in the shoot, root and hypocotyl. We performed an RNA-seq analysis, used advanced microscopy techniques to examine starch granule size, number and morphology and quantified transitory starch degradation patterns. Using transmission electron microscopy, we examined amyloplast development. Our results indicate that the altered gravitropic responses in hypocotyls, shoots and roots of gnc gnl mutants and GNL overexpressors are due to the differential accumulation of starch granules observed in the GATA genotypes. At the whole-plant level, GNC and GNL play a more complex role in starch synthesis, degradation and starch granule initiation. Our findings suggest that the light-regulated GNC and GNL help balance phototropic and gravitropic growth responses after the transition from skotomorphogenesis to photomorphogenesis by repressing the growth of starch granules.
Topics: Arabidopsis; GATA Transcription Factors; Arabidopsis Proteins; Cytokinins; Starch; Gravitropism; Mutation; Plant Roots; Transcription Factors
PubMed: 37219878
DOI: 10.1111/nph.18992