Functional analysis of drought and salt tolerance mechanisms of mulberry RACK1 gene

2019 ◽  
Vol 39 (12) ◽  
pp. 2055-2069 ◽  
Author(s):  
Changying Liu ◽  
Panpan Zhu ◽  
Wei Fan ◽  
Yang Feng ◽  
Min Kou ◽  
...  
Keyword(s):  
Abiotic Stress ◽  
G Proteins ◽  
Stress Responses ◽  
Molecular Mechanisms ◽  
Guanine Nucleotide Binding Protein ◽  
Expression Levels ◽  
Drought And Salt Tolerance ◽  
Drought And Salt Stresses ◽  
Guanine Nucleotide Binding ◽  
Eukaryotic Organisms

Abstract The receptor for activated C kinase 1 (RACK1) protein acts as a central hub for the integration of many physiological processes in eukaryotic organisms. Plant RACK1 is implicated in abiotic stress responses, but the underlying molecular mechanisms of stress adaptation remain largely unknown. Here, the overexpression of the mulberry (Morus alba L.) RACK1 gene in Arabidopsis decreased tolerance to drought and salt stresses and MaRACK1 overexpression changed expression levels of genes in response to stress and stimuli. We developed a simple and efficient transient transformation system in mulberry, and the mulberry seedlings transiently expressing MaRACK1 were hypersensitive to drought and salt stresses. The expression levels of guanine nucleotide-binding protein (G-protein) encoding genes in mulberry and Arabidopsis were not affected by MaRACK1 overexpression. The interactions between RACK1 and G-proteins were confirmed, and the RACK1 proteins from mulberry and Arabidopsis could not interact with their respective G-proteins, which indicated that RACK1 may regulate stress responses independently of G-proteins. Additionally, MaRACK1 may regulate drought and salt stress tolerances by interacting with a fructose 1, 6-bisphosphate aldolase. Our findings provide new insights into the mechanisms underlying RACK1 functions in abiotic stress responses and important information for their further characterization.

scholarly journals Ectopic Expression of Mulberry G-Proteins Alters Drought and Salt Stress Tolerance in Tobacco

2018 ◽  
Vol 20 (1) ◽  
pp. 89 ◽  
Author(s):  
Changying Liu ◽  
Yazhen Xu ◽  
Yang Feng ◽  
Dingpei Long ◽  
Boning Cao ◽  
...  
Keyword(s):  
Abiotic Stress ◽  
Stress Tolerance ◽  
G Protein ◽  
G Proteins ◽  
Stress Responses ◽  
Molecular Mechanisms ◽  
Abiotic Stress Tolerance ◽  
Ectopic Expression ◽  
Protein Subunit ◽  
Guanine Nucleotide Binding

Heterotrimeric guanine-nucleotide-binding proteins (G-proteins) play key roles in responses to various abiotic stress responses and tolerance in plants. However, the detailed mechanisms behind these roles remain unclear. Mulberry (Morus alba L.) can adapt to adverse abiotic stress conditions; however, little is known regarding the associated molecular mechanisms. In this study, mulberry G-protein genes, MaGα, MaGβ, MaGγ1, and MaGγ2, were independently transformed into tobacco, and the transgenic plants were used for resistance identification experiments. The ectopic expression of MaGα in tobacco decreased the tolerance to drought and salt stresses, while the overexpression of MaGβ, MaGγ1, and MaGγ2 increased the tolerance. Further analysis showed that mulberry G-proteins may regulate drought and salt tolerances by modulating reactive oxygen species’ detoxification. This study revealed the roles of each mulberry G-protein subunit in abiotic stress tolerance and advances our knowledge of the molecular mechanisms underlying G-proteins’ regulation of plant abiotic stress tolerance.

scholarly journals Heterologous Expression of Dehydration-Inducible MfWRKY17 of Myrothamnus Flabellifolia Confers Drought and Salt Tolerance in Arabidopsis

2020 ◽  
Vol 21 (13) ◽  
pp. 4603
Author(s):  
Zhuo Huang ◽  
Han-Du Guo ◽  
Ling Liu ◽  
Si-Han Jin ◽  
Pei-Lei Zhu ◽  
...  
Keyword(s):  
Abiotic Stress ◽  
Salt Tolerance ◽  
Stress Tolerance ◽  
Stress Responses ◽  
Molecular Mechanisms ◽  
Wrky Transcription Factor ◽  
Resurrection Plant ◽  
Drought And Salt Tolerance ◽  
High Degree

As the only woody resurrection plant, Myrothamnus flabellifolia has a strong tolerance to drought and can survive long-term in a desiccated environment. However, the molecular mechanisms related to the stress tolerance of M. flabellifolia are largely unknown, and few tolerance-related genes previously identified had been functionally characterized. WRKYs are a group of unique and complex plant transcription factors, and have reported functions in diverse biological processes, especially in the regulation of abiotic stress tolerances, in various species. However, little is known about their roles in response to abiotic stresses in M. flabellifolia. In this study, we characterized a dehydration-inducible WRKY transcription factor gene, MfWRKY17, from M. flabellifolia. MfWRKY17 shows high degree of homology with genes from Vitis vinifera and Vitis pseudoreticulata, belonging to group II of the WRKY family. Unlike known WRKY17s in other organisms acting as negative regulators in biotic or abiotic stress responses, overexpression of MfWRKY17 in Arabidopsis significantly increased drought and salt tolerance. Further investigations indicated that MfWRKY17 participated in increasing water retention, maintaining chlorophyll content, and regulating ABA biosynthesis and stress-related gene expression. These results suggest that MfWRKY17 possibly acts as a positive regulator of stress tolerance in the resurrection plant M. flabellifolia.

Overexpression of a Malus baccata WRKY transcription factor gene (MbWRKY5) increases drought and salt tolerance in transgenic tobacco

2019 ◽  
Vol 99 (2) ◽  
pp. 173-183 ◽  
Author(s):  
Deguo Han ◽  
Yanjie Hou ◽  
Yufang Wang ◽  
Boxin Ni ◽  
Zitong Li ◽  
...  
Keyword(s):  
Transgenic Plants ◽  
Transgenic Tobacco ◽  
Stress Responses ◽  
Wrky Transcription Factor ◽  
Expression Levels ◽  
Drought And Salt Tolerance ◽  
Drought And Salt Stress ◽  
Drought And Salt Stresses ◽  
Stress Related Genes ◽  
Malus Baccata

WRKY transcription factors are widely involved in abiotic stress responses in plants. However, their roles in the abiotic stresses of Malus plants are still not well known. In this study, a WRKY gene is isolated from Malus baccata (L.) Borkh. and designated as MbWRKY5. MbWRKY5 contains two WRKY domains and one Cys2-His2 (C2H2) zinc-finger motif, and was localized in the nucleus. The expression levels of MbWRKY5 were up-regulated by salinity, heat, cold, drought, and abscisic acid treatments in M. baccata seedlings. When MbWRKY5 was introduced into tobacco, an improvement in tolerance to drought and salt was achieved in transgenic plants. Under drought and salt treatments, transgenic plants had higher contents of chlorophyll, proline, glutathione, and ascorbate, and increased activities of peroxidase (POD), superoxide dismutase (SOD), and catalase (CAT) than wild-type (WT) tobaccos. Compared with WT plants, overexpression of MbWRKY5 in transgenic tobacco also led to decreased levels of malondialdehyde and hydrogen peroxide (H2O2) under drought and salt stresses. Moreover, the MbWRKY5-OE tobaccos increased the expression levels of stress-related genes involved in oxidative stress response (NtPOD, NtSOD and NtCAT) and membrane protection (NtLEA5, NtERD10D, and NtP5CS), especially under drought and salt stresses. These results suggest that the MbWRKY5 gene plays a positive regulatory role in drought and salt stress responses.

scholarly journals Genome-wide promoter analysis, homology modeling and protein interaction network of Dehydration Responsive Element Binding (DREB) gene family in Solanum tuberosum

PLoS ONE ◽  
2021 ◽  
Vol 16 (12) ◽  
pp. e0261215
Author(s):  
Qurat-ul ain-Ali ◽  
Nida Mushtaq ◽  
Rabia Amir ◽  
Alvina Gul ◽  
Muhammad Tahir ◽  
...  
Keyword(s):  
Abiotic Stress ◽  
Gene Family ◽  
Stress Responses ◽  
Promoter Analysis ◽  
Molecular Mechanisms ◽  
Regulatory Elements ◽  
Start Codon ◽  
Gene Promoters ◽  
Responsive Element ◽  
Dreb Gene

Dehydration Responsive Element Binding (DREB) regulates the expression of numerous stress-responsive genes, and hence plays a pivotal role in abiotic stress responses and tolerance in plants. The study aimed to develop a complete overview of the cis-acting regulatory elements (CAREs) present in S. tuberosum DREB gene promoters. A total of one hundred and four (104) cis-regulatory elements (CREs) were identified from 2.5kbp upstream of the start codon (ATG). The in-silico promoter analysis revealed variable sets of cis-elements and functional diversity with the predominance of light-responsive (30%), development-related (20%), abiotic stress-responsive (14%), and hormone-responsive (12%) elements in StDREBs. Among them, two light-responsive elements (Box-4 and G-box) were predicted in 64 and 61 StDREB genes, respectively. Two development-related motifs (AAGAA-motif and as-1) were abundant in StDREB gene promoters. Most of the DREB genes contained one or more Myeloblastosis (MYB) and Myelocytometosis (MYC) elements associated with abiotic stress responses. Hormone-responsive element i.e. ABRE was found in 59 out of 66 StDREB genes, which implied their role in dehydration and salinity stress. Moreover, six proteins were chosen corresponding to A1-A6 StDREB subgroups for secondary structure analysis and three-dimensional protein modeling followed by model validation through PROCHECK server by Ramachandran Plot. The predicted models demonstrated >90% of the residues in the favorable region, which further ensured their reliability. The present study also anticipated pocket binding sites and disordered regions (DRs) to gain insights into the structural flexibility and functional annotation of StDREB proteins. The protein association network determined the interaction of six selected StDREB proteins with potato proteins encoded by other gene families such as MYB and NAC, suggesting their similar functional roles in biological and molecular pathways. Overall, our results provide fundamental information for future functional analysis to understand the precise molecular mechanisms of the DREB gene family in S. tuberosum.

Role of G proteins and KCa channels in the muscarinic and beta-adrenergic regulation of airway smooth muscle

1995 ◽  
Vol 268 (2) ◽  
pp. L221-L229 ◽  
Author(s):  
H. Kume ◽  
K. Mikawa ◽  
K. Takagi ◽  
M. I. Kotlikoff
Keyword(s):  
Smooth Muscle ◽  
Adenylyl Cyclase ◽  
G Protein ◽  
Muscarinic Receptor ◽  
G Proteins ◽  
Isometric Tension ◽  
Guanine Nucleotide Binding Protein ◽  
Kca Channels ◽  
Stimulatory G Protein ◽  
Guanine Nucleotide Binding

We have examined the functional consequences of G protein coupling to calcium-activated potassium (KCa) channels using isometric tension records from guinea pig tracheal smooth muscle. After incubation with 1 microgram/ml pertussis toxin (PTX) for 6 h, the contraction response to 1 microM methacholine (MCh) was suppressed by 31.7 +/- 5.0% (n = 10). Similarly, the contraction was inhibited by 29.1 +/- 5.0% (n = 6) after application of 0.1 microM AF-DX 116, an M2-selective muscarinic receptor antagonist. Cholera toxin (CTX, 2.0 micrograms/ml for 6 h), which activates the stimulatory G protein of adenylyl cyclase (Gs), also suppressed contraction by 43.9 +/- 3.3% (n = 11). The inhibitory effects of PTX, AF-DX 116, or CTX were reversed in the presence of 100 nM charybdotoxin (ChTX), a selective KCa channel inhibitor. These findings suggest that disruption of inhibitory coupling between muscarinic receptor and KCa channels mediated by PTX-sensitive G proteins, or KCa channel activation induced by Gs/adenylyl cyclase-linked processes, antagonizes muscarinic contraction. The isoproterenol concentration-inhibition curves for precontracted trachea (1 microM MCh) were shifted to the left after perfusion with PTX or AF-DX 116, and the leftward shift of the curve was blocked by ChTX. Thus direct or indirect regulation of KCa channels mediated by the inhibitory guanine nucleotide binding protein (Gi) and Gs may play a functionally important role in the mechanical antagonism by the two receptor agonists.

scholarly journals Toward Understanding Molecular Mechanisms of Abiotic Stress Responses in Rice

Rice ◽  
2008 ◽  
Vol 1 (1) ◽  
pp. 36-51 ◽  
Author(s):  
Ji-Ping Gao ◽  
Dai-Yin Chao ◽  
Hong-Xuan Lin
Keyword(s):  
Abiotic Stress ◽  
Stress Responses ◽  
Molecular Mechanisms

scholarly journals Signal Integration in Plant Abiotic Stress Responses via Multistep Phosphorelay Signaling

2021 ◽  
Vol 12 ◽  
Author(s):  
Jan Skalak ◽  
Katrina Leslie Nicolas ◽  
Radomira Vankova ◽  
Jan Hejatko
Keyword(s):  
Abiotic Stress ◽  
Stress Responses ◽  
Environmental Conditions ◽  
Molecular Mechanisms ◽  
Geographical Location ◽  
Survival Strategies ◽  
Balance Growth ◽  
Adaptive Responses ◽  
Wide Range ◽  
Sensor Kinases

Plants growing in any particular geographical location are exposed to variable and diverse environmental conditions throughout their lifespan. The multifactorial environmental pressure resulted into evolution of plant adaptation and survival strategies requiring ability to integrate multiple signals that combine to yield specific responses. These adaptive responses enable plants to maintain their growth and development while acquiring tolerance to a variety of environmental conditions. An essential signaling cascade that incorporates a wide range of exogenous as well as endogenous stimuli is multistep phosphorelay (MSP). MSP mediates the signaling of essential plant hormones that balance growth, development, and environmental adaptation. Nevertheless, the mechanisms by which specific signals are recognized by a commonly-occurring pathway are not yet clearly understood. Here we summarize our knowledge on the latest model of multistep phosphorelay signaling in plants and the molecular mechanisms underlying the integration of multiple inputs including both hormonal (cytokinins, ethylene and abscisic acid) and environmental (light and temperature) signals into a common pathway. We provide an overview of abiotic stress responses mediated via MSP signaling that are both hormone-dependent and independent. We highlight the mutual interactions of key players such as sensor kinases of various substrate specificities including their downstream targets. These constitute a tightly interconnected signaling network, enabling timely adaptation by the plant to an ever-changing environment. Finally, we propose possible future directions in stress-oriented research on MSP signaling and highlight its potential importance for targeted crop breeding.

scholarly journals Overexpression of Arabidopsis OPR3 in Hexaploid Wheat (Triticum aestivum L.) Alters Plant Development and Freezing Tolerance

2018 ◽  
Vol 19 (12) ◽  
pp. 3989 ◽  
Author(s):  
Alexey Pigolev ◽  
Dmitry Miroshnichenko ◽  
Alexander Pushin ◽  
Vasily Terentyev ◽  
Alexander Boutanayev ◽  
...  
Keyword(s):  
Stress Responses ◽  
Molecular Mechanisms ◽  
Triticum Aestivum L ◽  
Transgenic Wheat ◽  
Environmental Stresses ◽  
Allene Oxide ◽  
Biosynthesis Pathway ◽  
Expression Levels ◽  
Pathway Gene ◽  
Developmental Traits

Jasmonates are plant hormones that are involved in the regulation of different aspects of plant life, wherein their functions and molecular mechanisms of action in wheat are still poorly studied. With the aim of gaining more insights into the role of jasmonic acid (JA) in wheat growth, development, and responses to environmental stresses, we have generated transgenic bread wheat plants overexpressing Arabidopsis 12-OXOPHYTODIENOATE REDUCTASE 3 (AtOPR3), one of the key genes of the JA biosynthesis pathway. Analysis of transgenic plants showed that AtOPR3 overexpression affects wheat development, including germination, growth, flowering time, senescence, and alters tolerance to environmental stresses. Transgenic wheat plants with high AtOPR3 expression levels have increased basal levels of JA, and up-regulated expression of ALLENE OXIDE SYNTHASE, a jasmonate biosynthesis pathway gene that is known to be regulated by a positive feedback loop that maintains and boosts JA levels. Transgenic wheat plants with high AtOPR3 expression levels are characterized by delayed germination, slower growth, late flowering and senescence, and improved tolerance to short-term freezing. The work demonstrates that genetic modification of the jasmonate pathway is a suitable tool for the modulation of developmental traits and stress responses in wheat.

scholarly journals Environment of the Active Site Region of RseP, an Escherichia coli Regulated Intramembrane Proteolysis Protease, Assessed by Site-directed Cysteine Alkylation

2006 ◽  
Vol 282 (7) ◽  
pp. 4553-4560 ◽  
Author(s):  
Kayo Koide ◽  
Saki Maegawa ◽  
Koreaki Ito ◽  
Yoshinori Akiyama
Keyword(s):  
Escherichia Coli ◽  
Stress Responses ◽  
Active Site ◽  
Molecular Mechanisms ◽  
Lipid Phase ◽  
Intramembrane Proteolysis ◽  
Regulated Intramembrane Proteolysis ◽  
Eukaryotic Organisms ◽  
Alkylating Reagents ◽  
Active Site Region

Regulated intramembrane proteolysis (RIP) plays crucial roles in both prokaryotic and eukaryotic organisms. Proteases for RIP cleave transmembrane regions of substrate membrane proteins. However, the molecular mechanisms for the proteolysis of membrane-embedded transmembrane sequences are largely unknown. Here we studied the environment surrounding the active site region of RseP, an Escherichia coli S2P ortholog involved in the σE pathway of extracytoplasmic stress responses. RseP has two presumed active site motifs, HEXXH and LDG, located in membrane-cytoplasm boundary regions. We examined the reactivity of cysteine residues introduced within or in the vicinity of these two active site motifs with membrane-impermeable thiol-alkylating reagents under various conditions. The active site positions were inaccessible to the reagents in the native state, but many of them became partially modifiable in the presence of a chaotrope, while requiring simultaneous addition of a chaotrope and a detergent for full modification. These results suggest that the active site of RseP is not totally embedded in the lipid phase but located within a proteinaceous structure that is partially exposed to the aqueous milieu.

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