Arabidopsis NF-YCs play dual roles in repressing brassinosteroid biosynthesis and signaling during light-regulated hypocotyl elongation

2021 ◽  
Author(s):  
Wenbin Zhang ◽  
Yang Tang ◽  
Yilong Hu ◽  
Yuhua Yang ◽  
Jiajia Cai ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Signaling Pathway ◽  
Growth Regulators ◽  
Nuclear Factor ◽  
Loss Of Function ◽  
Hypocotyl Growth ◽  
Dual Roles ◽  
Environmental Stimulus ◽  
Biosynthesis Gene

Abstract Light functions as the primary environmental stimulus and brassinosteroids (BRs) as important endogenous growth regulators throughout the plant lifecycle. Photomorphogenesis involves a series of vital developmental processes that require the suppression of BR-mediated seedling growth, but the mechanism underlying the light-controlled regulation of the BR pathway remain unclear. Here, we reveal that nuclear factor YC proteins (NF-YCs) function as essential repressors of the BR pathway during light-controlled hypocotyl growth in Arabidopsis thaliana. In the light, NF-YCs inhibit BR biosynthesis by directly targeting the promoter of the BR biosynthesis gene BR6ox2 and repressing its transcription. NF-YCs also interact with BIN2, a critical repressor of BR signaling, and facilitate its stabilization by promoting its Tyr200 autophosphorylation, thus inhibiting the BR signaling pathway. Consistently, loss-of-function mutants of NF-YCs show etiolated growth and constitutive BR responses, even in the light. Our findings uncover a dual role of NF-YCs in repressing BR biosynthesis and signaling, providing mechanistic insights into how light antagonizes the BR pathway to ensure photomorphogenic growth in Arabidopsis.

scholarly journals ATANN3 is involved in extracellular ATP-regulated auxin transport and distribution in Arabidopsis thaliana seedlings

2021 ◽  
Author(s):  
Lijuan Han ◽  
Shuyan Xia ◽  
Jiawei Xu ◽  
Ruojia Zhu ◽  
Zhonglin Shang ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Stress Responses ◽  
Auxin Transport ◽  
Inhibitory Effect ◽  
Extracellular Atp ◽  
Root Tip ◽  
Asymmetric Distribution ◽  
Loss Of Function ◽  
Hypocotyl Growth

Abstract Background Extracellular ATP (eATP) exists in the apoplast of plants and plays multiple roles in growth, development, and stress responses. It has been reported that eATP stimulation suppresses growth rate and alters growth orientation of root and hypocotyls of Arabidopsis thaliana seedlings by affecting auxin accumulation and transport in these organs. However, the mechanism of eATP-stimulated vegetative organ growth remains unclear. Annexins are involved in multiple aspects of plant cellular metabolism, while the role of annexins in response to apoplast signal remains unclear. Here, by using loss-of-function mutants, we investigated the role of several annexins in eATP-regulated root and hypocotyl growth. Since mutant of AtANN3 did not respond to eATP sensitively, the role of AtANN3 in eATP regulated auxin transport was intensively investigated. Results First, the inhibitory effect of eATP on root or hypocotyl elongation was weakened or impaired in AtANN3 null mutants (atann3). Meanwhile, single-, double- or triple-null mutant of AtANN1, AtANN2 or AtANN4 responded to eATP stimulation in same manner and degree with Col-0. The abundance and distribution of Dr5-GUS and Dr5-GFP indicated that eATP-induced accumulation and asymmetric distribution of auxin in root tip or hypocotyl cells, which appeared in wild type controls, were lacking in atann3 seedlings. Further, eATP-induced accumulation and asymmetric distribution of PIN2-GFP in root tip cells or PIN3-GFP in hypocotyl cells were reduced in atann3 seedlings. Conclusions AtANN3 may be involved in eATP-regulated seedling growth through regulating auxin transport and accumulation in vegetative organs.

Role of melatonin in UV‐B signaling pathway and UV‐B stress resistance in Arabidopsis thaliana

2020 ◽  
Vol 44 (1) ◽  
pp. 114-129
Author(s):  
Jing‐Wen Yao ◽  
Zheng Ma ◽  
Yan‐Qin Ma ◽  
Ying Zhu ◽  
Meng‐Qi Lei ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Signaling Pathway ◽  
Stress Resistance

scholarly journals Role of Nuclear Factor Kappa B (NF-κB) Signalling in Neurodegenerative Diseases: An Mechanistic Approach

2020 ◽  
Vol 18 (10) ◽  
pp. 918-935 ◽  
Author(s):  
Shareen Singh ◽  
Thakur Gurjeet Singh
Keyword(s):  
Neurodegenerative Diseases ◽  
Signaling Pathway ◽  
Nuclear Factor Kappa B ◽  
Autoimmune Disorder ◽  
Nuclear Factor ◽  
Human Beings ◽  
Inhibitor Molecule ◽  
Nuclear Factor Kappa ◽  
Iκb Kinase

A transcriptional regulatory nuclear factor kappa B (NF-κB) protein is a modulator of cellular biological activity via binding to a promoter region in the nucleus and transcribing various protein genes. The recent research implicated the intensive role of nuclear factor kappa B (NF-κB) in diseases like autoimmune disorder, inflammatory, cardiovascular and neurodegenerative diseases. Therefore, targeting the nuclear factor kappa B (NF-κB) protein offers a new opportunity as a therapeutic approach. Activation of IκB kinase/NF-κB signaling pathway leads to the development of various pathological conditions in human beings, such as neurodegenerative, inflammatory disorders, autoimmune diseases, and cancer. Therefore, the transcriptional activity of IκB kinase/NF- κB is strongly regulated at various cascade pathways. The nuclear factor NF-kB pathway plays a major role in the expression of pro-inflammatory genes, including cytokines, chemokines, and adhesion molecules. In response to the diverse stimuli, the cytosolic sequestered NF-κB in an inactivated form by binding with an inhibitor molecule protein (IkB) gets phosphorylated and translocated into the nucleus further transcribing various genes necessary for modifying various cellular functions. The various researches confirmed the role of different family member proteins of NF-κB implicated in expressing various genes products and mediating various cellular cascades. MicroRNAs, as regulators of NF- κB microRNAs play important roles in the regulation of the inflammatory process. Therefore, the inhibitor of NF-κB and its family members plays a novel therapeutic target in preventing various diseases. Regulation of NF- κB signaling pathway may be a safe and effective treatment strategy for various disorders.

scholarly journals Heat-induced transposition leads to rapid drought resistance of Arabidopsis thaliana

2021 ◽  
Author(s):  
Michael Thieme ◽  
Arthur Brêchet ◽  
Yann Bourgeois ◽  
Bettina Keller ◽  
Etienne Bucher ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Drought Resistance ◽  
Phenotypic Diversity ◽  
Plant Evolution ◽  
Loss Of Function ◽  
Copy Numbers ◽  
Drastic Increase ◽  
In The Wild ◽  
Rate Of Photosynthesis

Plant genomes comprise a vast diversity of transposable elements (TEs) (Tenaillon et al. 2010)⁠. While their uncontrolled proliferation can have fatal consequences for their host, there is strong evidence for their importance in fueling genetic diversity and plant evolution (Baduel et al. 2021)⁠. However, the number of studies addressing the role of TEs in this process is limited. Here we show that the heat-induced burst of a low-copy TE increases phenotypic diversity and leads to the rapid emergence of more drought-resistant individuals of Arabidopsis thaliana. We exposed TE-high-copy-(hc)lines (Thieme et al. 2017)⁠ with up to ~8 fold increased copy numbers of the heat-responsive ONSEN-TE (AtCOPIA78) (Ito et al. 2011; Cavrak et al. 2014; Tittel-Elmer et al. 2010)⁠ in the wild type background to desiccation as a straightforward and highly relevant selection pressure. We found evidence for a drastic increase of drought resistance in five out of the 23 tested hc-lines and further pinpoint one of the causative mutations to an exonic ONSEN-insertion in the ribose-5-phosphate-isomerase 2 gene. This loss-of-function mutation resulted in a decreased rate of photosynthesis and water consumption. This is one of the rare examples (Esnault et al. 2019)⁠ experimentally demonstrating the adaptive potential of mobilized stress-responsive TEs in eukaryotes. Our results further shed light on the complex relationship between mobile elements and their hosts and substantiate the importance of TE-mediated loss-of-function mutations in stress adaptation, particularly with respect to global warming.

scholarly journals Silencing of SPARC represses heterotopic ossification via inhibition of the MAPK signaling pathway

2019 ◽  
Vol 39 (11) ◽  
Author(s):  
Qianjun Wang ◽  
Qianqian Yang ◽  
Ali Zhang ◽  
Zhiqiang Kang ◽  
Yingsheng Wang ◽  
...  
Keyword(s):  
Heterotopic Ossification ◽  
Signaling Pathway ◽  
Molecular Mechanisms ◽  
Mapk Signaling ◽  
Mapk Signaling Pathway ◽  
Mitogen Activated Protein Kinase ◽  
Loss Of Function ◽  
Alp Activity ◽  
Mechanistic Investigation

Abstract Heterotopic ossification (HO), the pathologic formation of extraskeletal bone, can be disabling and lethal. However, the underlying molecular mechanisms were largely unknown. The present study aimed to clarify the involvement of secreted protein acidic and rich in cysteine (SPARC) and the underlying mechanism in rat model of HO. The mechanistic investigation on roles of SPARC in HO was examined through gain- and loss-of-function approaches of SPARC, with alkaline-phosphatase (ALP) activity, mineralized nodules, and osteocalcin (OCN) content measured. To further confirm the regulatory role of SPARC, levels of mitogen-activated protein kinase (MAPK) signaling pathways-related proteins (extracellular signal-regulated kinase (ERK), c-jun N-terminal kinase (JNK), p38, nuclear factor κ-B (NF-κB), and IkB kinase β (IKKβ)) were determined. Bone marrow mesenchymal stem cells were treated with pathway inhibitor to investigate the relationship among SPARC, MAPK signaling pathway, and HO. The results suggested that SPARC expression was up-regulated in Achilles tendon tissues of HO rats. Silencing of SPARC could decrease phosphorylation of ERK, JNK, p38, NF-κB, and IKKβ. Additionally, silencing of SPARC or inhibition of MAPK signaling pathway could reduce the ALP activity, the number of mineralized nodules, and OCN content, thus impeding HO. To sum up, our study identifies the inhibitory role of SPARC gene silencing in HO via the MAPK signaling pathway, suggesting SPARC presents a potential target for HO therapy.

scholarly journals The Boundary-Expressed EPIDERMAL PATTERNING FACTOR-LIKE2 Gene Encoding a Signaling Peptide Promotes Cotyledon Growth during Arabidopsis thaliana Embryogenesis

2021 ◽  
Author(s):  
Rina Fujihara ◽  
Naoyuki Uchida ◽  
Toshiaki Tameshige ◽  
Nozomi Kawamoto ◽  
Yugo Hotokezaka ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Plant Growth ◽  
Mutant Embryo ◽  
Loss Of Function ◽  
Auxin Response ◽  
Gene Encoding ◽  
Late Embryogenesis ◽  
Signaling Center ◽  
Epidermal Patterning

AbstractThe shoot organ boundaries have important roles in plant growth and morphogenesis. It has been reported that a gene encoding a cysteine-rich secreted peptide of the EPIDERMAL PATTERNING FACTOR-LIKE (EPFL) family, EPFL2, is expressed in the boundary domain between the two cotyledon primordia of Arabidopsis thaliana embryo. However, its developmental functions remain unknown. This study aimed to analyze the role of EPFL2 during embryogenesis. We found that cotyledon growth was reduced in its loss-of-function mutants, and this phenotype was associated with the reduction of auxin response peaks at the tips of the primordia. The reduced cotyledon size of the mutant embryo recovered in germinating seedlings, indicating the presence of a factor that acted redundantly with EPFL2 to promote cotyledon growth in late embryogenesis. Our analysis indicates that the boundary domain between the cotyledon primordia acts as a signaling center that organizes auxin response peaks and promotes cotyledon growth.

scholarly journals P2K1 Receptor, Heterotrimeric Gα Protein and CNGC2/4 Are Involved in Extracellular ATP-Promoted Ion Influx in the Pollen of Arabidopsis thaliana

Plants ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 1743
Author(s):  
Yansheng Wu ◽  
Hongmin Yin ◽  
Xinyue Liu ◽  
Jiawei Xu ◽  
Baozhi Qin ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Pollen Grains ◽  
Extracellular Atp ◽  
Loss Of Function ◽  
Promoting Effect ◽  
Α Subunit ◽  
Tobacco Pollen ◽  
Ion Influx ◽  
Signaling Components

As an apoplastic signal, extracellular ATP (eATP) is involved in plant growth and development. eATP promotes tobacco pollen germination (PG) and pollen tube growth (PTG) by stimulating Ca2+ or K+ absorption. Nevertheless, the mechanisms underlying eATP-stimulated ion uptake and their role in PG and PTG are still unclear. Here, ATP addition was found to modulate PG and PTG in 34 plant species and showed a promoting effect in most of these species. Furthermore, by using Arabidopsis thaliana as a model, the role of several signaling components involved in eATP-promoted ion (Ca2+, K+) uptake, PG, and PTG were investigated. ATP stimulated while apyrase inhibited PG and PTG. Patch-clamping results showed that ATP promoted K+ and Ca2+ influx into pollen protoplasts. In loss-of-function mutants of P2K1 (dorn1-1 and dorn1-3), heterotrimeric G protein α subunit (gpa1-1, gpa1-2), or cyclic nucleotide gated ion channel (cngc2, cngc4), eATP-stimulated PG, PTG, and ion influx were all impaired. Our results suggest that these signaling components may be involved in eATP-promoted PG and PTG by regulating Ca2+ or K+ influx in Arabidopsis pollen grains.

scholarly journals Revisiting the Role of Ethylene and N-End Rule Pathway on Chilling-Induced Dormancy Release in Arabidopsis Seeds

2018 ◽  
Vol 19 (11) ◽  
pp. 3577 ◽  
Author(s):  
Xu Wang ◽  
Zhazira Yesbergenova-Cuny ◽  
Catherine Biniek ◽  
Christophe Bailly ◽  
Hayat El-Maarouf-Bouteau ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Signaling Pathway ◽  
Dormancy Release ◽  
Ethylene Signaling ◽  
Aba Signaling ◽  
Wild Type ◽  
Ethylene Signaling Pathway

Dormant Arabidopsis (Arabidopsis thaliana) seeds do not germinate easily at temperatures higher than 10–15 °C. Using mutants affected in ethylene signaling (etr1, ein2 and ein4) and in the N-end-rule pathway of the proteolysis (prt6 and ate1-ate2) we have investigated the effects of cold and ethylene on dormancy alleviation. Ethylene (10–100 ppm) and 2–4 days chilling (4 °C) strongly stimulate the germination of wild type (Col-0) seeds at 25 °C. Two to four days of chilling promote the germination at 25 °C of all the mutants suggesting that release of dormancy by cold did not require ethylene and did not require the N-end-rule pathway. One mutant (etr1) that did not respond to ethylene did not respond to GA3 either. Mutants affected in the N-end rule (prt6 and ate1-ate2) did not respond to ethylene indicating that also this pathway is required for dormancy alleviation by ethylene; they germinated after chilling and in the presence of GA3. Cold can activate the ethylene signaling pathway since it induced an accumulation of ETR1, EINI4, and EIN2 transcripts, the expression of which was not affected by ethylene and GA3. Both cold followed by 10 h at 25 °C and ethylene downregulated the expression of PRT6, ATE1, ATE2, and of ABI5 involved in ABA signaling as compared to dormant seeds incubated at 25 °C. In opposite, the expression of RGA, GAI, and RGL2 encoding three DELLAs was induced at 4 °C but downregulated in the presence of ethylene.

scholarly journals MIR822 modulates monosporic female gametogenesis through an ARGONAUTE9-dependent pathway in Arabidopsis thaliana

2021 ◽  
Author(s):  
ANDREA TOVAR AGUILAR ◽  
Daniel GRIMANELLI ◽  
Gerardo Acosta Garcia ◽  
Jean Philippe Vielle Calzada ◽  
Jesus Agustin Badillo-Corona ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Molecular Mechanisms ◽  
Target Genes ◽  
Flowering Plants ◽  
Loss Of Function ◽  
Genes Encoding ◽  
Functional Megaspore ◽  
Dependent Pathway ◽  
Female Gametogenesis

In the ovule of flowering plants, the establishment of the haploid generation occurs when a somatic cell differentiates into a Megaspore Mother Cell (MMC) and initiates meiosis. As most flowering plants, Arabidopsis thaliana undergoes a monosporic type of gametogenesis; three meiotically derived cells degenerate without further division, and a single one, the functional megaspore (FM), divides mitotically to form the female gametophyte. In Arabidopsis, the ARGONAUTE4 clade proteins are involved in the control of megasporogenesis. In particular, mutations in ARGONAUTE9 (AGO9) lead to the ectopic differentiation of gametic precursors that can give rise female gametophytes. However, the genetic basis and molecular mechanisms that control monosporic gametogenesis remain largely unknown. Here, we show that Arabidopsis plants carrying loss-of-function mutations in the AGO9-interacting miR822a give rise to extranumerary surviving megaspores that acquire a FM identity and divide without giving rise to differentiated female gametophytes. The overexpression of three miR822a target genes encoding Cysteine/Histidine-Rich C1 domain proteins (DC1) phenocopy mir822a plants. The miR822a targets are overexpressed in ago9 mutant ovules, confirming that miR822a acts through an AGO9-dependent pathway to negatively regulate DC1 domain proteins. Our results identify a new role of miRNAs in the most prevalent form of female gametogenesis in flowering plants

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