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Methods in Molecular Biology (Clifton,... 2019UV-B phototropism in etiolated Arabidopsis seedlings has only been shown recently and needs further exploration. Here we elaborate on how to generate a customized setup...
UV-B phototropism in etiolated Arabidopsis seedlings has only been shown recently and needs further exploration. Here we elaborate on how to generate a customized setup with a unilateral UV-B light source, the required plant materials, different growth substrates, and a framework for data analysis.
Topics: Arabidopsis; Arabidopsis Proteins; Gene Expression Regulation, Plant; Phototropism; Seedlings; Ultraviolet Rays
PubMed: 30694471
DOI: 10.1007/978-1-4939-9015-3_10 -
Cells Jan 2021Phototropins are plasma membrane-associated photoreceptors of blue light and UV-A/B radiation. The genome encodes two phototropins, and , that mediate phototropism,...
Phototropins are plasma membrane-associated photoreceptors of blue light and UV-A/B radiation. The genome encodes two phototropins, and , that mediate phototropism, chloroplast positioning, and stomatal opening. They are well characterized in terms of photomorphogenetic processes, but so far, little was known about their involvement in photosynthesis, oxidative stress responses, and cell death. By analyzing , single, and double mutants, we demonstrated that both phototropins influence the photochemical and non-photochemical reactions, photosynthetic pigments composition, stomata conductance, and water-use efficiency. After oxidative stress caused by UV-C treatment, and single and double mutants showed a significantly reduced accumulation of HO and more efficient photosynthetic electron transport compared to the wild type. However, all mutants exhibited higher levels of cell death four days after UV-C treatment, as well as deregulated gene expression. Taken together, our results reveal that on the one hand, both phot1 and phot2 contribute to the inhibition of UV-C-induced foliar cell death, but on the other hand, they also contribute to the maintenance of foliar HO levels and optimal intensity of photochemical reactions and non-photochemical quenching after an exposure to UV-C stress. Our data indicate a novel role for phototropins in the condition-dependent optimization of photosynthesis, growth, and water-use efficiency as well as oxidative stress and cell death response after UV-C exposure.
Topics: Antioxidants; Arabidopsis; Arabidopsis Proteins; Biomass; Cell Death; Fluorescence; Gene Expression Profiling; Gene Expression Regulation, Plant; Homeostasis; Hydrogen Peroxide; Mutation; Oxidative Stress; Photosynthesis; Pigments, Biological; Plant Leaves; Plant Stomata; Protein Serine-Threonine Kinases; RNA, Messenger; Transcriptome; Ultraviolet Rays; Water
PubMed: 33498294
DOI: 10.3390/cells10020200 -
Environmental Microbiology Jan 2016Light plays an important role for most organisms on this planet, serving either as a source of energy or information for the adaptation of biological processes to... (Review)
Review
Light plays an important role for most organisms on this planet, serving either as a source of energy or information for the adaptation of biological processes to specific times of day. The fungal kingdom is estimated to contain well over a million species, possibly 10-fold more, and it is estimated that a majority of the fungi respond to light, eliciting changes in several physiological characteristics including pathogenesis, development and secondary metabolism. Two model organisms for photobiological studies have taken centre-stage over the last few decades--Neurospora crassa and Aspergillus nidulans. In this review, we will first discuss our understanding of the light response in N. crassa, about which the most is known, and will then juxtapose N. crassa with A. nidulans, which, as will be described below, provides an excellent template for understanding photosensory cross-talk. Finally, we will end with a commentary on the variability of the light response among other relevant fungi, and how our molecular understanding in the aforementioned model organisms still provides a strong base for dissecting light responses in such species.
Topics: Aspergillus nidulans; DNA, Fungal; Gene Expression Regulation, Fungal; Light; Neurospora crassa; Phototropism
PubMed: 26373782
DOI: 10.1111/1462-2920.13055 -
Biochemical and Biophysical Research... Dec 2020Auxin plays an important role in plant growth and development; for example, it regulates the elongation and division of plant cells, the formation of plantlet's...
Auxin plays an important role in plant growth and development; for example, it regulates the elongation and division of plant cells, the formation of plantlet's geotropism and phototropism, and the growth of main lateral roots and hypocotyl. IAA gene is associated with auxin and can response to biotic and abiotic stress in plants. However, the regulatory effect of auxin on anthocyanin accumulation has been rarely reported. In this study, we show that auxin inhibites the accumulation of anthocyanin and decreases the expression of genes related to anthocyanin synthesis in calli, leaves, and seedlings of apple. The expression levels of MdIAA family genes were determined, and we found that MdIAA26 significantly responded to auxin, which also induced MdIAA26 degradation. Functional analysis of MdIAA26 showed that overexpressing MdIAA26 in apple calli and Arabidopsis could promote the accumulation of anthocyanin and up-regulate the genes related to anthocyanin synthesis. Furthermore, the MdIAA26-overexpressing Arabidopsis could counteract auxin-induced inhibition on anthocyanin accumulation, which indicates that auxin inhibits the accumulation of anthocyanin in apple by degrading MdIAA26 protein.
Topics: Anthocyanins; Arabidopsis; Databases, Genetic; Gene Expression Regulation, Plant; Indoleacetic Acids; Malus; Plant Leaves; Plant Proteins; Plants, Genetically Modified; Seedlings; Signal Transduction; Up-Regulation
PubMed: 32981681
DOI: 10.1016/j.bbrc.2020.09.065 -
AoB PLANTS Feb 2022Phototropism is an essential response in some plant organs and features several signalling molecules involved in either photo-sensing or post-sensing responses. Annexins...
Phototropism is an essential response in some plant organs and features several signalling molecules involved in either photo-sensing or post-sensing responses. Annexins are involved in regulating plant growth and its responses to various stimuli. Here, we provide novel data showing that two members of the Annexin family in , AtANN1 and AtANN2, may be involved in the phototropism of etiolated hypocotyls. In wild type, unilateral blue light (BL) induced a strong phototropic response, while red light (RL) only induced a weak response. The responses of single- or double-null mutants of the two annexins, including , and , were significantly weaker than those observed in wild type, indicating the involvement of AtANN1 and AtANN2 in BL-induced phototropism. Unilateral BL induced asymmetric distribution of DR5-GFP and PIN3-GFP fluorescence in hypocotyls; notably, fluorescent intensity on the shaded side was markedly stronger than that on the illuminated side. In etiolated , or / hypocotyls, unilateral BL-induced asymmetric distributions of DR5-GFP and PIN3-GFP were weakened or impaired. Herein, we suggest that during hypocotyls phototropic response, AtANN1 and AtANN2 may be involved in BL-stimulated signalling by regulating PIN3-charged auxin transport.
PubMed: 35079328
DOI: 10.1093/aobpla/plab075 -
Methods in Molecular Biology (Clifton,... 2022Plants utilize light as sole energy source. To maximize light capture, they are able to detect the light direction and orient themselves toward the light source. This...
Plants utilize light as sole energy source. To maximize light capture, they are able to detect the light direction and orient themselves toward the light source. This phototropic response is mediated by the plant blue-light photoreceptors phototropin1 and phototropin2 (phot1 and phot2). Although fully differentiated plants also exhibit this response, it can be best observed in etiolated seedlings. Differences in light between the illuminated and shaded site of a seedling stem lead to changes in the auxin distribution, resulting in cell elongation on the shaded site. Since phototropism connects light perception, signaling, and auxin transport, it is of great interest to analyze this response with a fast and simple method. Moreover, pre-exposure to red light enhances the phototropic response via phytochrome A (phyA) and phyB action. Here we describe a method to analyze the phototropic response of Arabidopsis seedlings to blue light and the enhanced response with a red-light pretreatment. With numerous mutants available, its fast germination, and its small size, Arabidopsis is well suited for this analysis. Different genotypes can be simultaneously probed in less than a week.
Topics: Arabidopsis; Arabidopsis Proteins; Indoleacetic Acids; Light; Photoreceptors, Plant; Phototropism; Seedlings
PubMed: 35467199
DOI: 10.1007/978-1-0716-2297-1_4 -
Methods in Molecular Biology (Clifton,... 2019Physiological responses, such as phototropism and carotenogenesis, are usually exhibited through a specific cascade composed of several gene functions. The number of...
Physiological responses, such as phototropism and carotenogenesis, are usually exhibited through a specific cascade composed of several gene functions. The number of such gene functions can be determined by means of complementation analysis. For this purpose, a procedure is needed to produce heterokaryons easily and with a high success rate. Here, we present a method of grafting sporangiophores from different mutants to obtain heterokaryotic regenerates at the graft union, based on the large size of the sporangiophore and its remarkable regeneration capability.
Topics: Phototropism; Phycomyces
PubMed: 30694477
DOI: 10.1007/978-1-4939-9015-3_16 -
The New Phytologist Sep 2021Shade and warmth promote the growth of the stem, but the degree of mechanistic convergence and functional association between these responses is not clear. We analysed...
Shade and warmth promote the growth of the stem, but the degree of mechanistic convergence and functional association between these responses is not clear. We analysed the quantitative impact of mutations and natural genetic variation on the hypocotyl growth responses of Arabidopsis thaliana to shade and warmth, the relationship between the abundance of PHYTOCHROME INTERACTING FACTOR 4 (PIF4) and growth stimulation by shade or warmth, the effects of both cues on the transcriptome and the consequences of warm temperature on carbon balance. Growth responses to shade and warmth showed strong genetic linkage and similar dependence on PIF4 levels. Temperature increased growth and phototropism even within a range where damage by extreme high temperatures is unlikely to occur in nature. Both cues enhanced the expression of growth-related genes and reduced the expression of photosynthetic genes. However, only warmth enhanced the expression of genes involved in responses to heat. Warm temperatures substantially increased the amount of light required to compensate for the daily carbon dioxide balance. We propose that the main ecological function of hypocotyl growth responses to warmth is to increase the access of shaded photosynthetic organs to light, which implies functional convergence with shade avoidance.
Topics: Arabidopsis; Arabidopsis Proteins; Gene Expression Regulation, Plant; Hypocotyl; Phototropism
PubMed: 33909310
DOI: 10.1111/nph.17430 -
Plant Biotechnology (Tokyo, Japan) Dec 2020Environmental stimuli such as gravity and light modify the plant development to optimize overall architecture. Many physiological and molecular biological studies of...
Environmental stimuli such as gravity and light modify the plant development to optimize overall architecture. Many physiological and molecular biological studies of gravitropism and phototropism have been carried out. However, sufficient analysis has not been performed from a mechanical point of view. If the biological and mechanical characteristics of gravitropism and phototropism can be accurately grasped, then controlling the environmental conditions would be helpful to control the growth of plants into a specific shape. In this study, to clarify the mechanical characteristics of gravitropism, we examined the transverse bending moment occurring in cantilevered pea () sprouts in response to gravistimulation. The force of the pea sprouts lifting themselves during gravitropism was measured using an electronic balance. The gravitropic bending force of the pea sprouts was in the order of 10 Nmm in the conditions set for this study, although there were wide variations due to individual differences.
PubMed: 33850437
DOI: 10.5511/plantbiotechnology.20.1201b -
Plant Signaling & Behavior Dec 2022The blue light photoreceptors, phototropin 1 (phot1) and phot2, and their signal transducer, NONPHOTOTROPIC HYPOCOTYL3 (NPH3), are activators of the phototropic...
The blue light photoreceptors, phototropin 1 (phot1) and phot2, and their signal transducer, NONPHOTOTROPIC HYPOCOTYL3 (NPH3), are activators of the phototropic responses of hypocotyls. In a recent study, we reported that the control of NPH3 phosphorylation at serine 7 (S7: or S5), S213, S223, S237, S467, S474 (or S476), and S722 (or S723) contributes to the photosensory adaptation of phot1 signaling during the phototropic response. Phosphomimetic NPH3 mutant and unphosphorylatable NPH3 mutant on those serine residues function efficiently under blue light conditions at fluence rates of 10 µmol m s and 10 µmol m s or more, respectively. We here demonstrate that phosphomimetic NPH3, but not unphosphorylatable NPH3, promotes phot2-dependent phototropism under blue light condition at 100 µmol m s. This result suggests that phot1 negatively controls phot2 signaling through the dephosphorylation of NPH3 at those residues and that the hyperactivation of phot1- and phot2-NPH3 complexes does not occur at the same time under high intensity blue light. We hypothesize that the dephosphorylation of NPH3 on those serine residues suppresses both phot1 and phot2 signaling, which results in different impacts on phot1- and phot2-dependent hypocotyl phototropism due to the differences in the photosensitivity and activation levels of phot1 and phot2.
Topics: Arabidopsis; Arabidopsis Proteins; Hypocotyl; Light; Phosphoproteins; Phosphorylation; Phototropins; Phototropism; Serine
PubMed: 35068333
DOI: 10.1080/15592324.2022.2027138