scholarly journals Integration of light and hormone signaling pathways in the regulation of plant shade avoidance syndrome

aBIOTECH ◽  
2021 ◽  
Author(s):  
Yang Liu ◽  
Feresheeh Jafari ◽  
Haiyang Wang
Keyword(s):  
Signaling Pathways ◽  
Molecular Mechanisms ◽  
Stem Elongation ◽  
Molecular Genetic ◽  
Red Light ◽  
High Density ◽  
Light Signaling ◽  
Shade Avoidance ◽  
Hormone Signaling ◽  
Shade Avoidance Syndrome

AbstractAs sessile organisms, plants are unable to move or escape from their neighboring competitors under high-density planting conditions. Instead, they have evolved the ability to sense changes in light quantity and quality (such as a reduction in photoactive radiation and drop in red/far-red light ratios) and evoke a suite of adaptative responses (such as stem elongation, reduced branching, hyponastic leaf orientation, early flowering and accelerated senescence) collectively termed shade avoidance syndrome (SAS). Over the past few decades, much progress has been made in identifying the various photoreceptor systems and light signaling components implicated in regulating SAS, and in elucidating the underlying molecular mechanisms, based on extensive molecular genetic studies with the model dicotyledonous plant Arabidopsis thaliana. Moreover, an emerging synthesis of the field is that light signaling integrates with the signaling pathways of various phytohormones to coordinately regulate different aspects of SAS. In this review, we present a brief summary of the various cross-talks between light and hormone signaling in regulating SAS. We also present a perspective of manipulating SAS to tailor crop architecture for breeding high-density tolerant crop cultivars.

scholarly journals UVR8 disrupts stabilisation of PIF5 by COP1 to inhibit plant stem elongation in sunlight

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Ashutosh Sharma ◽  
Bhavana Sharma ◽  
Scott Hayes ◽  
Konstantin Kerner ◽  
Ute Hoecker ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Light Quality ◽  
Stem Elongation ◽  
Red Light ◽  
Ubiquitin Proteasome System ◽  
Shade Avoidance ◽  
In Planta ◽  
Plant Growth And Development ◽  
Ubiquitin Proteasome ◽  
Plant Stem

Abstract Alterations in light quality significantly affect plant growth and development. In canopy shade, phytochrome photoreceptors perceive reduced ratios of red to far-red light (R:FR) and initiate stem elongation to enable plants to overtop competitors. This shade avoidance response is achieved via the stabilisation and activation of PHYTOCHROME INTERACTING FACTORs (PIFs) which elevate auxin biosynthesis. UV-B inhibits shade avoidance by reducing the abundance and activity of PIFs, yet the molecular mechanisms controlling PIF abundance in UV-B are unknown. Here we show that the UV-B photoreceptor UVR8 promotes rapid PIF5 degradation via the ubiquitin-proteasome system in a response requiring the N terminus of PIF5. In planta interactions between UVR8 and PIF5 are not observed. We further demonstrate that PIF5 interacts with the E3 ligase COP1, promoting PIF5 stabilisation in light-grown plants. Binding of UVR8 to COP1 in UV-B disrupts this stabilisation, providing a mechanism to rapidly lower PIF5 abundance in sunlight.

scholarly journals Phytochrome A elevates plant circadian-clock components to suppress shade avoidance in deep-canopy shade

2021 ◽  
Vol 118 (27) ◽  
pp. e2108176118
Author(s):  
Donald P. Fraser ◽  
Paige E. Panter ◽  
Ashutosh Sharma ◽  
Bhavana Sharma ◽  
Antony N. Dodd ◽  
...  
Keyword(s):  
Circadian Clock ◽  
Molecular Mechanisms ◽  
Response Regulator ◽  
Stem Elongation ◽  
Red Light ◽  
Canopy Cover ◽  
Shade Avoidance ◽  
Phytochrome A ◽  
Plant Survival ◽  
Light Foraging

Shade-avoiding plants can detect the presence of neighboring vegetation and evoke escape responses before canopy cover limits photosynthesis. Rapid stem elongation facilitates light foraging and enables plants to overtop competitors. A major regulator of this response is the phytochrome B photoreceptor, which becomes inactivated in light environments with a low ratio of red to far-red light (low R:FR), characteristic of vegetational shade. Although shade avoidance can provide plants with a competitive advantage in fast-growing stands, excessive stem elongation can be detrimental to plant survival. As such, plants have evolved multiple feedback mechanisms to attenuate shade-avoidance signaling. The very low R:FR and reduced levels of photosynthetically active radiation (PAR) present in deep canopy shade can, together, trigger phytochrome A (phyA) signaling, inhibiting shade avoidance and promoting plant survival when resources are severely limited. The molecular mechanisms underlying this response have not been fully elucidated. Here, we show that Arabidopsis thaliana phyA elevates early-evening expression of the central circadian-clock components TIMING OF CAB EXPRESSION 1 (TOC1), PSEUDO RESPONSE REGULATOR 7 (PRR7), EARLY FLOWERING 3 (ELF3), and ELF4 in photocycles of low R:FR and low PAR. These collectively suppress stem elongation, antagonizing shade avoidance in deep canopy shade.

scholarly journals RNA sequencing-based exploration of the effects of far-red light on lncRNAs involved in the shade-avoidance response of D. officinale

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e10769
Author(s):  
Hansheng Li ◽  
Wei Ye ◽  
Yaqian Wang ◽  
Xiaohui Chen ◽  
Yan Fang ◽  
...  
Keyword(s):  
Avoidance Response ◽  
Rna Sequencing ◽  
Production Efficiency ◽  
Stem Elongation ◽  
Red Light ◽  
Differentially Expressed ◽  
Control Group ◽  
Shade Avoidance ◽  
Biochemical Analyses ◽  
Experimental Group

Dendrobium officinale (D. officinale) is a valuable medicinal plant with a low natural survival rate, and its shade-avoidance response to far-red light is as an important strategy used by the plant to improve its production efficiency. However, the lncRNAs that play roles in the shade-avoidance response of D. officinale have not yet been investigated. This study found that an appropriate proportion of far-red light can have several effects, including increasing the leaf area and accelerating stem elongation, in D. officinale. The effects of different far-red light treatments on D. officinale were analysed by RNA sequencing technology, and a total of 69 and 78 lncRNAs were differentially expressed in experimental group 1 (FR1) versus the control group (CK) (FR1-CK) and in experimental group 4 (FR4) versus the CK (FR4-CK), respectively. According to GO and KEGG analyses, most of the differentially expressed lncRNA targets are involved in the membrane, some metabolic pathways, hormone signal transduction, and O-methyltransferase activity, among other functions. Physiological and biochemical analyses showed that far-red light promoted the accumulation of flavonoids, alkaloids, carotenoids and polysaccharides in D. officinale. The effect of far-red light on D. officinalemight be closely related to the cell membrane and Ca2+ transduction. Based on a Cytoscape analysis and previous research, this study also found that MSTRG.38867.1, MSTRG.69319.1, and MSTRG.66273.1, among other components, might participate in the far-red light signalling network through their targets and thus regulate the shade-avoidance response of D. officinale. These findings will provide new insights into the shade-avoidance response of D. officinale.

scholarly journals Genome-wide expression and network analyses of mutants in key brassinosteroid signaling genes

BMC Genomics ◽  
2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Razgar Seyed Rahmani ◽  
Tao Shi ◽  
Dongzhi Zhang ◽  
Xiaoping Gou ◽  
Jing Yi ◽  
...  
Keyword(s):  
Signaling Pathways ◽  
Signaling Pathway ◽  
Molecular Mechanisms ◽  
Differential Expression Analysis ◽  
Transcriptional Level ◽  
Partial Recovery ◽  
Hormone Signaling ◽  
Loss Of Function ◽  
Altered Expression ◽  
Network Analyses

Abstract Background Brassinosteroid (BR) signaling regulates plant growth and development in concert with other signaling pathways. Although many genes have been identified that play a role in BR signaling, the biological and functional consequences of disrupting those key BR genes still require detailed investigation. Results Here we performed phenotypic and transcriptomic comparisons of A. thaliana lines carrying a loss-of-function mutation in BRI1 gene, bri1–5, that exhibits a dwarf phenotype and its three activation-tag suppressor lines that were able to partially revert the bri1–5 mutant phenotype to a WS2 phenotype, namely bri1–5/bri1–1D, bri1–5/brs1–1D, and bri1–5/bak1–1D. From the three investigated bri1–5 suppressors, bri1–5/bak1–1D was the most effective suppressor at the transcriptional level. All three bri1–5 suppressors showed altered expression of the genes in the abscisic acid (ABA signaling) pathway, indicating that ABA likely contributes to the partial recovery of the wild-type phenotype in these bri1–5 suppressors. Network analysis revealed crosstalk between BR and other phytohormone signaling pathways, suggesting that interference with one hormone signaling pathway affects other hormone signaling pathways. In addition, differential expression analysis suggested the existence of a strong negative feedback from BR signaling on BR biosynthesis and also predicted that BRS1, rather than being directly involved in signaling, might be responsible for providing an optimal environment for the interaction between BRI1 and its ligand. Conclusions Our study provides insights into the molecular mechanisms and functions of key brassinosteroid (BR) signaling genes, especially BRS1.

scholarly journals Genome-Wide Expression and Network Analyses of Mutants in Key Brassinosteroid Signaling Genes

2020 ◽  
Author(s):  
Razgar Seyed Rahmani ◽  
Tao Shi ◽  
Dongzhi Zhang ◽  
Xiaoping Gou ◽  
Jing Yi ◽  
...  
Keyword(s):  
Signaling Pathways ◽  
Signaling Pathway ◽  
Molecular Mechanisms ◽  
Differential Expression Analysis ◽  
Transcriptional Level ◽  
Partial Recovery ◽  
Hormone Signaling ◽  
Loss Of Function ◽  
Altered Expression ◽  
Network Analyses

Abstract BackgroundBrassinosteroid (BR) signaling regulates plant growth and development in concert with other signaling pathways. Although many genes have been identified that play a role in Brassinosteroid (BR) signaling, the biological and functional consequences of disrupting those key BR genes still requires detailed investigation.ResultsHere we performed phenotypic and transcriptomic comparisons of A. thaliana lines carrying a loss-of-function mutation in BRI1 gene, bri1-5, that exhibits a dwarf phenotype along with its three activation-tag suppressor lines that were able to partially revert the bri1-5 mutant phenotype to a WT phenotype, namely bri1-5/bri1-1D, bri1-5/brs1-1D, bri1-5/bak1-1D. From the three investigated bri1-5 suppressors, bri1-5/bak1-1D was the most effective suppressor at the transcriptional level. All three bri1-5 suppressors showed altered expression of the genes in the abscisic acid (ABA signaling) pathway, indicating that ABA likely contributes to the partial recovery of the wild type phenotype in these bri1-5 suppressors. Network analysis revealed crosstalk between BR and other phytohormone signaling pathways, suggesting that interference with one hormone signaling pathway affects other hormone signaling pathways. In addition, differential expression analysis suggested the existence of a strong negative feedback from BR signaling on BR biosynthesis and also predicted that BRS1, rather than being directly involved in signaling, is likely responsible for providing an optimal environment for the interaction between BRI1 and its ligand. ConclusionsOur study provides insights into the molecular mechanisms and functions of key brassinosteroid (BR) signaling genes, especially BRS1.

scholarly journals Rapid metabolite response in leaf blade and petiole as a marker for shade avoidance syndrome

Plant Methods ◽  
2020 ◽  
Vol 16 (1) ◽  
Author(s):  
Benny Jian Rong Sng ◽  
Gajendra Pratap Singh ◽  
Kien Van Vu ◽  
Nam-Hai Chua ◽  
Rajeev J. Ram ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Plant Species ◽  
Plant Density ◽  
Morphological Changes ◽  
High Density ◽  
Carotenoid Content ◽  
Shade Avoidance ◽  
Shade Avoidance Syndrome ◽  
High Plant Density ◽  
Short Term Exposure

Abstract Background Shade avoidance syndrome (SAS) commonly occurs in plants experiencing vegetative shade, causing morphological and physiological changes that are detrimental to plant health and consequently crop yield. As the effects of SAS on plants are irreversible, early detection of SAS in plants is critical for sustainable agriculture. However, conventional methods to assess SAS are restricted to observing for morphological changes and checking the expression of shade-induced genes after homogenization of plant tissues, which makes it difficult to detect SAS early. Results Using the model plant Arabidopsis thaliana, we introduced the use of Raman spectroscopy to measure shade-induced changes of metabolites in vivo. Raman spectroscopy detected a decrease in carotenoid contents in leaf blades and petioles of plants with SAS, which were induced by low Red:Far-red light ratio or high density conditions. Moreover, by measuring the carotenoid Raman peaks, we were able to show that the reduction in carotenoid content under shade was mediated by phytochrome signaling. Carotenoid Raman peaks showed more remarkable response to SAS in petioles than leaf blades of plants, which greatly corresponded to their morphological response under shade or high plant density. Most importantly, carotenoid content decreased shortly after shade induction but before the occurrence of visible morphological changes. We demonstrated this finding to be similar in other plant species. Comprehensive testing of Brassica vegetables showed that carotenoid content decreased during SAS, in both shade and high density conditions. Likewise, carotenoid content responded quickly to shade, in a manner similar to Arabidopsis plants. Conclusions In various plant species tested in this study, quantification of carotenoid Raman peaks correlate to the severity of SAS. Moreover, short-term exposure to shade can induce the carotenoid Raman peaks to decrease. These findings highlight the carotenoid Raman peaks as a biomarker for early diagnosis of SAS in plants.

scholarly journals Shade-induced nuclear localization of PIF7 is regulated by phosphorylation and 14-3-3 proteins in Arabidopsis

eLife ◽  
2018 ◽  
Vol 7 ◽  
Author(s):  
Xu Huang ◽  
Qian Zhang ◽  
Yupei Jiang ◽  
Chuanwei Yang ◽  
Qianyue Wang ◽  
...  
Keyword(s):  
Gene Expression ◽  
Transcription Factor ◽  
Nuclear Localization ◽  
Stem Elongation ◽  
Hypocotyl Elongation ◽  
Nuclear Accumulation ◽  
Shade Avoidance ◽  
Light Perception ◽  
Shade Avoidance Syndrome

Shade avoidance syndrome enables shaded plants to grow and compete effectively against their neighbors. In Arabidopsis, the shade-induced de-phosphorylation of the transcription factor PIF7 (PHYTOCHROME-INTERACTING FACTOR 7) is the key event linking light perception to stem elongation. However, the mechanism through which phosphorylation regulates the activity of PIF7 is unclear. Here, we show that shade light induces the de-phosphorylation and nuclear accumulation of PIF7. Phosphorylation-resistant site mutations in PIF7 result in increased nuclear localization and shade-induced gene expression, and consequently augment hypocotyl elongation. PIF7 interacts with 14-3-3 proteins. Blocking the interaction between PIF7 and 14-3-3 proteins or reducing the expression of 14-3-3 proteins accelerates shade-induced nuclear localization and de-phosphorylation of PIF7, and enhances the shade phenotype. By contrast, the 14-3-3 overexpressing line displays an attenuated shade phenotype. These studies demonstrate a phosphorylation-dependent translocation of PIF7 when plants are in shade and a novel mechanism involving 14-3-3 proteins, mediated by the retention of PIF7 in the cytoplasm that suppresses the shade response.

scholarly journals Comparative phenotypic and transcriptomic analyses unravel conserved and distinct mechanisms underlying shade avoidance syndrome in Brassicaceae vegetables

BMC Genomics ◽  
2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Nguyen Hoai Nguyen ◽  
Benny Jian Rong Sng ◽  
Hock Chuan Yeo ◽  
In-Cheol Jang
Keyword(s):  
Regulatory Networks ◽  
Agricultural Practices ◽  
High Density ◽  
Negative Regulator ◽  
Auxin Signaling ◽  
Shade Avoidance ◽  
Transcriptional Regulatory Networks ◽  
Shade Avoidance Syndrome ◽  
Primary Roots ◽  
Brassicaceae Species

Abstract Background Plants grown under shade are exposed to low red/far-red ratio, thereby triggering an array of altered phenotypes called shade avoidance syndrome (SAS). Shade negatively influences plant growth, leading to a reduction in agricultural productivity. Understanding of SAS is crucial for sustainable agricultural practices, especially for high-density indoor farming. Brassicaceae vegetables are widely consumed around the world and are commonly cultivated in indoor farms. However, our understanding of SAS in Brassicaceae vegetables and their genome-wide transcriptional regulatory networks are still largely unexplored. Results Shade induced common signs of SAS, including hypocotyl elongation and reduced carotenoids/anthocyanins biosynthesis, in two different Brassicaceae species: Brassica rapa (Choy Sum and Pak Choy) and Brassica oleracea (Kai Lan). Phenotype-assisted transcriptome analysis identified a set of genes induced by shade in these species, many of which were related to auxin biosynthesis and signaling [e.g. YUCCA8 (YUC8), YUC9, and INDOLE-3-ACETIC ACID INDUCIBLE (IAAs)] and other phytohormones signaling pathways including brassinosteroids and ethylene. The genes functioning in plant defense (e.g. MYB29 and JASMONATE-ZIM-DOMAIN PROTEIN 9) as well as in biosynthesis of anthocyanins and glucosinolates were repressed upon shade. Besides, each species also exhibited distinct SAS phenotypes. Shade strongly reduced primary roots and elongated petioles of B. oleracea, Kai Lan. However, these SAS phenotypes were not clearly recognized in B. rapa, Choy Sum and Pak Choy. Some auxin signaling genes (e.g. AUXIN RESPONSE FACTOR 19, IAA10, and IAA20) were specifically induced in B. oleracea, while homologs in B. rapa were not up-regulated under shade. Contrastingly, shade-exposed B. rapa vegetables triggered the ethylene signaling pathway earlier than B. oleracea, Kai Lan. Interestingly, shade induced the transcript levels of LONG HYPOCOTYL IN FAR-RED 1 (HFR1) homolog in only Pak Choy as B. rapa. As HFR1 is a key negative regulator of SAS in Arabidopsis, our finding suggests that Pak Choy HFR1 homolog may also function in conferring higher shade tolerance in this variety. Conclusions Our study shows that two Brassicaceae species not only share a conserved SAS mechanism but also exhibit distinct responses to shade, which will provide comprehensive information to develop new shade-tolerant cultivars that are suitable for high-density indoor farms.

scholarly journals Basic Protein Modules Combining Abscisic Acid and Light Signaling in Arabidopsis

2022 ◽  
Vol 12 ◽  
Author(s):  
Victor P. Bulgakov ◽  
Olga G. Koren
Keyword(s):  
Stem Cell ◽  
Abscisic Acid ◽  
Stem Elongation ◽  
Light Signal ◽  
Light Signaling ◽  
Shade Avoidance ◽  
Signaling System ◽  
Complex Signaling ◽  
Signaling Components ◽  
Protein Modules

It is generally accepted that plants use the complex signaling system regulated by light and abscisic acid (ABA) signaling components to optimize growth and development in different situations. The role of ABA–light interactions is evident in the coupling of stress defense reactions with seed germination and root development, maintaining of stem cell identity and stem cell specification, stem elongation and leaf development, flowering and fruit formation, senescence, and shade avoidance. All these processes are regulated jointly by the ABA–light signaling system. Although a lot of work has been devoted to ABA–light signal interactions, there is still no systematic description of central signaling components and protein modules, which jointly regulate plant development. New data have emerged to promote understanding of how ABA and light signals are integrated at the molecular level, representing an extensively growing area of research. This work is intended to fill existing gaps by using literature data combined with bioinformatics analysis.

Molecular Basis and Clinical Aspects of Hereditary Megakaryocyte and Platelet Membrane Glycoprotein Disorders

1996 ◽  
Vol 16 (02) ◽  
pp. 114-138 ◽  
Author(s):  
R. E. Scharf
Keyword(s):  
Genetic Basis ◽  
Molecular Mechanisms ◽  
Molecular Genetic ◽  
Platelet Membrane ◽  
Clinical Aspects ◽  
Membrane Glycoprotein ◽  
Membrane Glycoproteins ◽  
Membrane Expression ◽  
Receptor Complexes ◽  
Platelet Membrane Glycoprotein

SummarySpecific membrane glycoproteins (GP) expressed by the megakaryocyte-platelet system, including GPIa-lla, GPIb-V-IX, GPIIb-llla, and GPIV are involved in mediat-ing platelet adhesion to the subendothelial matrix. Among these glycoproteins, GPIIb-llla plays a pivotal role since platelet aggregation is exclusively mediated by this receptor and its interaction with soluble macromolecular proteins. Inherited defects of the GPIIb-llla or GPIb-V-IX receptor complexes are associated with bleeding disorders, known as Glanzmann's thrombasthenia, Bernard-Soulier syndrome, or platelet-type von Willebrand's disease, respectively. Using immuno-chemical and molecular biology techniques, rapid advances in our understanding of the molecular genetic basis of these disorders have been made during the last few years. Moreover, analyses of patients with congenital platelet membrane glycoprotein abnormalities have provided valuable insights into molecular mechanisms that are required for structural and functional integrity, normal biosynthesis of the glycoprotein complexes and coordinated membrane expression of their constituents. The present article reviews the current state of knowledge of the major membrane glycoproteins in health and disease. The spectrum of clinical bleeding manifestations and established diagnostic criteria for each of these dis-orders are summarized. In particular, the variety of molecular defects that have been identified so far and their genetic basis will be discussed.

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