-
The New Phytologist Sep 2021Characterising the processes that control auxin dynamics is essential to understanding how auxin regulates plant development. Over recent years, several studies have... (Review)
Review
Characterising the processes that control auxin dynamics is essential to understanding how auxin regulates plant development. Over recent years, several studies have investigated auxin diffusion through plasmodesmata, characterising this cell-to-cell diffusion and demonstrating that it affects auxin distributions. Furthermore, studies have shown that plasmodesmatal auxin diffusion affects developmental processes, including phototropism, lateral root emergence and leaf hyponasty. This short Tansley Insight review describes how these studies have contributed to our understanding of auxin dynamics and discusses potential future directions in this area.
Topics: Gene Expression Regulation, Plant; Indoleacetic Acids; Phototropism; Plant Development; Plant Roots; Plasmodesmata
PubMed: 34053083
DOI: 10.1111/nph.17517 -
Physiologia Plantarum Jul 2020Positive phototropism is the process through which plants orient their organs toward a directional light source. While the blue light receptors phototropins (phot) play... (Review)
Review
Positive phototropism is the process through which plants orient their organs toward a directional light source. While the blue light receptors phototropins (phot) play a major role in phototropism toward blue (B) and ultraviolet (UV) radiation, recent research showed that the UVB light receptor UVR8 also triggers phototropism toward UVB. In addition, new details of the molecular mechanisms underlying the activity of these receptors and interaction with other environmental signals have emerged in the past years. In this review, we summarize the current knowledge about hypocotyledoneous and inflorescence stem growth reorientation toward B and UVB, with a focus on the molecular mechanisms.
Topics: Arabidopsis; Arabidopsis Proteins; Chromosomal Proteins, Non-Histone; Light; Phototropins; Phototropism; Ultraviolet Rays
PubMed: 32208516
DOI: 10.1111/ppl.13098 -
Plant & Cell Physiology Sep 2021The disruption of the sumoylation pathway affects processes controlled by the two phototropins (phots) of Arabidopsis thaliana, phot1 and phot2. Phots, plant UVA/blue...
The disruption of the sumoylation pathway affects processes controlled by the two phototropins (phots) of Arabidopsis thaliana, phot1 and phot2. Phots, plant UVA/blue light photoreceptors, regulate growth responses and fast movements aimed at optimizing photosynthesis, such as phototropism, chloroplast relocations and stomatal opening. Sumoylation is a posttranslational modification, consisting of the addition of a SUMO (SMALL UBIQUITIN-RELATED MODIFIER) protein to a lysine residue in the target protein. In addition to affecting the stability of proteins, it regulates their activity, interactions and subcellular localization. We examined physiological responses controlled by phots, phototropism and chloroplast movements, in sumoylation pathway mutants. Chloroplast accumulation in response to both continuous and pulse light was enhanced in the E3 ligase siz1 mutant, in a manner dependent on phot2. A significant decrease in phot2 protein abundance was observed in this mutant after blue light treatment both in seedlings and mature leaves. Using plant transient expression and yeast two-hybrid assays, we found that phots interacted with SUMO proteins mainly through their N-terminal parts, which contain the photosensory LOV domains. The covalent modification in phots by SUMO was verified using an Arabidopsis sumoylation system reconstituted in bacteria followed by the mass spectrometry analysis. Lys 297 was identified as the main target of SUMO3 in the phot2 molecule. Finally, sumoylation of phot2 was detected in Arabidopsis mature leaves upon light or heat stress treatment.
Topics: Arabidopsis; Arabidopsis Proteins; Chloroplasts; Escherichia coli; Ligases; Lysine; Mutation; Phototropism; Plant Leaves; Plants, Genetically Modified; Protein Serine-Threonine Kinases; Seedlings; Small Ubiquitin-Related Modifier Proteins; Sumoylation
PubMed: 33594440
DOI: 10.1093/pcp/pcab027 -
The Plant Journal : For Cell and... Apr 2023Directional movements impact the ability of plants to respond and adjust their growth accordingly to the prevailing light environment. The plasma-membrane associated...
Directional movements impact the ability of plants to respond and adjust their growth accordingly to the prevailing light environment. The plasma-membrane associated protein, ROOT PHOTOTROPISM 2 (RPT2) is a key signalling component involved in chloroplast accumulation movement, leaf positioning, and phototropism, all of which are regulated redundantly by the ultraviolet/blue light-activated AGC kinases phototropin 1 and 2 (phot1 and phot2). We recently demonstrated that members of the NON-PHOTOTROPIC HYPOCOTYL 3 (NPH3)/RPT2-like (NRL) family in Arabidopsis thaliana, including RPT2, are directly phosphorylated by phot1. However, whether RPT2 is a substrate for phot2, and the biological significance of phot phosphorylation of RPT2 remains to be determined. Here, we show that RPT2 is phosphorylated by both phot1 and phot2 at a conserved serine residue (S591) within the C-terminal region of the protein. Blue light triggered the association of 14-3-3 proteins with RPT2 consistent with S591 acting as a 14-3-3 binding site. Mutation of S591 had no effect on the plasma membrane localization of RPT2 but reduced its functionality for leaf positioning and phototropism. Moreover, our findings indicate that S591 phosphorylation within the C-terminus of RPT2 is required for chloroplast accumulation movement to low level blue light. Taken together, these findings further highlight the importance of the C-terminal region of NRL proteins and how its phosphorylation contributes to phot receptor signalling in plants.
Topics: Arabidopsis; Phototropism; Phosphorylation; Phototropins; Arabidopsis Proteins; Protein Serine-Threonine Kinases; Plants, Genetically Modified; Light; Plant Leaves; Chloroplasts; Phosphoproteins
PubMed: 36794876
DOI: 10.1111/tpj.16144 -
Journal of Experimental Botany Nov 2019In the literature, Helianthus annuus L. (sunflower) movements are generally described as heliotropic. It is generally believed that the leaves and flowers of the growing... (Review)
Review
In the literature, Helianthus annuus L. (sunflower) movements are generally described as heliotropic. It is generally believed that the leaves and flowers of the growing H. annuus plant track the sun as the sun moves across the sky from east to west. This paper, however, challenges current interpretation regarding H. annuus movements, as the literature generally excludes the rotation of the earth around its own axis, gravity, and the possible role of gravitation. The general exclusion of the earth's rotation in the literature may also have resulted in flawed research design in studies conducted on H. annuus movements, which in turn may have directed researchers towards the misinterpretation of results. This paper aims to include the possible role of the Earth's rotation, gravity, and gravitation when describing H. annuus movements and to provide possible alternative explanations for the results achieved by researchers. This paper further includes concepts and examples relevant to plant movements, such as the rhythms often associated with plant movements, the physiology of plant movements, referring to turgor pressure as the main force behind plant movements, and plant rhythmic clocks and their characteristics, in order to explain the alternative views and to relate them to H. annuus movements.
Topics: Helianthus; Movement; Phototropism; Sunlight
PubMed: 31504705
DOI: 10.1093/jxb/erz381 -
Plants (Basel, Switzerland) Jul 2020Light absorption by plants changes the composition of light inside vegetation. Blue (B) and red (R) light are used for photosynthesis whereas far-red (FR) and green... (Review)
Review
Light absorption by plants changes the composition of light inside vegetation. Blue (B) and red (R) light are used for photosynthesis whereas far-red (FR) and green light are reflected. A combination of UV-B, blue and R:FR-responsive photoreceptors collectively measures the light and temperature environment and adjusts plant development accordingly. This developmental plasticity to photoreceptor signals is largely regulated through the phytohormone auxin. The phytochrome, cryptochrome and UV Resistance Locus 8 (UVR8) photoreceptors are inactivated in shade and/or elevated temperature, which releases their repression of Phytochrome Interacting Factor (PIF) transcription factors. Active PIFs stimulate auxin synthesis and reinforce auxin signalling responses through direct interaction with Auxin Response Factors (ARFs). It was recently discovered that shade-induced hypocotyl elongation and petiole hyponasty depend on long-distance auxin transport towards target cells from the cotyledon and leaf tip, respectively. Other responses, such as phototropic bending, are regulated by auxin transport and signalling across only a few cell layers. In addition, photoreceptors can directly interact with components in the auxin signalling pathway, such as Auxin/Indole Acetic Acids (AUX/IAAs) and ARFs. Here we will discuss the complex interactions between photoreceptor and auxin signalling, addressing both mechanisms and consequences of these highly interconnected pathways.
PubMed: 32722230
DOI: 10.3390/plants9080940 -
International Journal of Molecular... Mar 2023The root is an important organ for obtaining nutrients and absorbing water and carbohydrates, and it depends on various endogenous and external environmental... (Review)
Review
The root is an important organ for obtaining nutrients and absorbing water and carbohydrates, and it depends on various endogenous and external environmental stimulations such as light, temperature, water, plant hormones, and metabolic constituents. Auxin, as an essential plant hormone, can mediate rooting under different light treatments. Therefore, this review focuses on summarizing the functions and mechanisms of light-regulated auxin signaling in root development. Some light-response components such as phytochromes (PHYs), cryptochromes (CRYs), phototropins (PHOTs), phytochrome-interacting factors (PIFs) and constitutive photo-morphorgenic 1 (COP1) regulate root development. Moreover, light mediates the primary root, lateral root, adventitious root, root hair, rhizoid, and seminal and crown root development via the auxin signaling transduction pathway. Additionally, the effect of light through the auxin signal on root negative phototropism, gravitropism, root greening and the root branching of plants is also illustrated. The review also summarizes diverse light target genes in response to auxin signaling during rooting. We conclude that the mechanism of light-mediated root development via auxin signaling is complex, and it mainly concerns in the differences in plant species, such as barley ( L.) and wheat ( L.), changes of transcript levels and endogenous IAA content. Hence, the effect of light-involved auxin signaling on root growth and development is definitely a hot issue to explore in the horticultural studies now and in the future.
Topics: Indoleacetic Acids; Signal Transduction; Plant Growth Regulators; Phytochrome; Light Signal Transduction; Plant Roots; Gene Expression Regulation, Plant; Arabidopsis Proteins
PubMed: 36982350
DOI: 10.3390/ijms24065253 -
Ying Yong Sheng Tai Xue Bao = the... Mar 2024Insect visual electrophysiological techniques are important to study the electrical characteristics of photoreceptor cells and visual neurons in insects, including... (Review)
Review
Insect visual electrophysiological techniques are important to study the electrical characteristics of photoreceptor cells and visual neurons in insects, including electroretinography (ERG) and microelectrode intracellular recording (MIR). ERG records the changes of voltage or electric current in the retina of insects in response to different light stimuli, which occurs outside the cell. MIR records the changes in individual photoreceptor cells or visual neurons of an insect exposed to different lights, which occurs inside the cell. Insect visual electrophysiological techniques can explore the mechanism of electrophysiological response of insects' vision to light and reveal their sensitive light spectra and photoreceptor types. This review introduced the basic structure and the principle of ERG and MIR, and summarized their applications in insect researches in the past 20 years, which would provide references for elucidating the mechanism of light perception in insects and the use of insect phototropism to control pests.
Topics: Animals; Insecta; Electroretinography; Photoreceptor Cells, Invertebrate; Vision, Ocular; Microelectrodes; Electrophysiological Phenomena; Electrophysiology
PubMed: 38646774
DOI: 10.13287/j.1001-9332.202403.032 -
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 -
Annual Review of Microbiology Sep 2019The blast disease, caused by the ascomycete , poses a great threat to rice production worldwide. Increasing use of fungicides and/or blast-resistant varieties of rice ()... (Review)
Review
The blast disease, caused by the ascomycete , poses a great threat to rice production worldwide. Increasing use of fungicides and/or blast-resistant varieties of rice () has proved to be ineffective in long-term control of blast disease under field conditions. To develop effective and durable resistance to blast, it is important to understand the cellular mechanisms underlying pathogenic development in . In this review, we summarize the latest research in phototropism, autophagy, nutrient and redox signaling, and intrinsic phytohormone mimics in for cellular and metabolic adaptation(s) during its interactions with the host plants.
Topics: Adaptation, Physiological; Ascomycota; Autophagy; Biological Coevolution; Carbon; Circadian Clocks; Disease Resistance; Genes, Plant; Glucosyltransferases; Glycogen; Host-Pathogen Interactions; Magnaporthe; Nitrogen; Oryza; Oxidation-Reduction; Phototropism; Plant Diseases; Plant Growth Regulators; Plant Immunity; Reactive Oxygen Species; Signal Transduction
PubMed: 31283431
DOI: 10.1146/annurev-micro-020518-115810