scholarly journals Insights into the Transcriptional Regulation of Branching Hormonal Signaling Pathways Genes under Drought Stress in Arabidopsis

Genes ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 298
Author(s):  
Nkulu Kabange Rolly ◽  
Bong-Gyu Mun ◽  
Byung-Wook Yun

A large number of hormonal biosynthetic or signaling pathways genes controlling shoot branching are widely known for their roles in regulating plant growth and development, operating in synergetic or antagonistic manner. However, their involvement in abiotic stress response mechanism remains unexplored. Initially, we performed an in silico analysis to identify potential transcription binding sites for the basic leucine zipper 62 transcription factor (bZIP62 TF) in the target branching related genes. The results revealed the presence of cis-regulatory elements specific to two bZIP TFs, AtbZIP18 and AtbZIP69, rather than AtbZIP62. Interestingly, these bZIP TFs were previously proposed to be negatively regulated by the AtbZIP62 TF under salinity in Arabidopsis. Therefore, we investigated the transcriptional regulation of more axillary branching (MAX, strigolactone), PIN-FORMED (PINs, auxin carriers), gibberellic acid (GA)-biosynthetic genes as well as isopentenyltransferase (IPT, cytokinin biosynthesis pathway) genes in response to drought stress in Arabidopsis Col-0 wild type. In addition, in the perspective of exploring the transcriptional interplay of the selected genes with the AtbZIP62, we measured their expression by qPCR in the atbzip62 (lacking the AtbZIP62 gene) background under the same conditions. Our findings revealed that the expression of AtMAX2, AtMAX3, and AtMAX4 was differentially regulated by drought stress between the atbzip62 and Col-0 wild type, but not AtMAX1. Similarly, the transcripts accumulation of AtPIN3 and AtPIN7 (known as auxin efflux carriers), and that of the AtAXR1 showed similar regulation patterns in atbzip62. However, AtPIN1 expression was downregulated in Col-0, but no change was observed in atbzip62. Furthermore, AtIPT5 and AtIPT7 exhibited a differential transcripts accumulation pattern in atbzip62 and Col-0 wild type (WT). In the same way, the expression of the GA biosynthetic genes AtGA2ox1 and AtGA20ox2, and that of AtRGA1 were differentially regulated in atbzip62 compared to the Col-0. Meanwhile, AtGA2ox1 showed a similar expression pattern with Col-0. Therefore, all results suggest PIN, MAX, IPT, and GA-biosynthetic genes, which are differentially regulated by AtbZIP62 transcription factor, as emerging candidate genes that could be involved in drought stress response mechanism in Arabidopsis.

2018 ◽  
Vol 19 (9) ◽  
pp. 2580 ◽  
Author(s):  
Chang-Tao Wang ◽  
Jing-Na Ru ◽  
Yong-Wei Liu ◽  
Jun-Feng Yang ◽  
Meng Li ◽  
...  

Abiotic stresses restrict the growth and yield of crops. Plants have developed a number of regulatory mechanisms to respond to these stresses. WRKY transcription factors (TFs) are plant-specific transcription factors that play essential roles in multiple plant processes, including abiotic stress response. At present, little information regarding drought-related WRKY genes in maize is available. In this study, we identified a WRKY transcription factor gene from maize, named ZmWRKY40. ZmWRKY40 is a member of WRKY group II, localized in the nucleus of mesophyll protoplasts. Several stress-related transcriptional regulatory elements existed in the promoter region of ZmWRKY40. ZmWRKY40 was induced by drought, high salinity, high temperature, and abscisic acid (ABA). ZmWRKY40 could rapidly respond to drought with peak levels (more than 10-fold) at 1 h after treatment. Overexpression of ZmWRKY40 improved drought tolerance in transgenic Arabidopsis by regulating stress-related genes, and the reactive oxygen species (ROS) content in transgenic lines was reduced by enhancing the activities of peroxide dismutase (POD) and catalase (CAT) under drought stress. According to the results, the present study may provide a candidate gene involved in the drought stress response and a theoretical basis to understand the mechanisms of ZmWRKY40 in response to abiotic stresses in maize.


2019 ◽  
Author(s):  
Sarah M. Ryan ◽  
Kaitie Wildman ◽  
Briseida Oceguera-Perez ◽  
Scott Barbee ◽  
Nathan T. Mortimer ◽  
...  

AbstractAs organisms are constantly exposed to the damaging effects of oxidative stress through both environmental exposure as well as internal metabolic processes, they have evolved a variety of mechanisms to cope with this stress. One such mechanism is the highly conserved p38 MAPK (p38K) pathway, which is known to be to post-translationally activated in response to oxidative stress resulting in the activation of downstream antioxidant targets. However, little is known about the role of p38K transcriptional regulation in response to oxidative stress. Therefore, we analyzed the p38K gene family across the genus Drosophila to identify conserved regulatory elements. We find that oxidative stress exposure results in increased p38K protein levels in multiple Drosophila species and is associated with increased oxidative stress resistance. We also find that the p38Kb genomic locus includes conserved binding sites for the AP-1 and lola-PT transcription factors. Accordingly, over-expression of these transcription factors in D. melanogaster is sufficient to induce transcription of p38Kb and enhances resistance to oxidative stress. We further find that the presence of a lola-PT binding site in the p38Kb locus of a given species is predictive of the species’ survival in response to oxidative stress. Through our comparative genomics approach, we have identified biologically relevant transcription factor binding sites that regulate the expression of p38Kb and are associated with resistance to oxidative stress. These findings reveal a novel mode of regulation for p38K genes and suggests that transcription may play as important a role in p38K mediated stress responses as post-translational modifications.Significance StatementOrganisms encounter a variety of environmental stresses such as oxidative stress throughout their lifetime. Therefore, organisms have evolved a number of mechanisms to combat these stresses. In order to understand how these mechanisms evolved, we have compared the genomes of a diverse set of species across the genus Drosophila to examine the p38 MAPK stress response gene family. Our analysis was able to successfully predict transcription factors that not only regulate our target gene, p38Kb, but do so under different conditions to ensure an appropriate stress response. Therefore, we find that in addition to post-translational regulation, transcriptional regulation of signaling pathways may also play an important role in how organisms are able to adapt to stressful environments or respond to stress conditions as they arise. Furthermore, our comparative genomics approach may be utilized to identify transcriptional regulators of other highly conserved signaling pathways.


Author(s):  
Ai-Hua Wang ◽  
Lan Yang ◽  
Xin-Zhuan Yao ◽  
Xiao-Peng Wen

AbstractPhosphoethanolamine N-methyltransferase (PEAMTase) catalyzes the methylation of phosphoethanolamine to produce phosphocholine and plays an important role in the abiotic stress response. Although the PEAMT genes has been isolated from many species other than pitaya, its role in the drought stress response has not yet been fully elucidated. In the present study, we isolated a 1485 bp cDNA fragment of HpPEAMT from pitaya (Hylocereus polyrhizus). Phylogenetic analysis showed that, during its evolution, HpPEAMT has shown a high degree of amino acid sequence similarity with the orthologous genes in Chenopodiaceae species. To further investigate the function of HpPEAMT, we generated transgenic tobacco plants overexpressing HpPEAMT, and the transgenic plants accumulated significantly more glycine betaine (GB) than did the wild type (WT). Drought tolerance trials indicated that, compared with those of the wild-type (WT) plants, the roots of the transgenic plants showed higher drought tolerance ability and exhibited improved drought tolerance. Further analysis revealed that overexpression of HpPEAM in Nicotiana tabacum resulted in upregulation of transcript levels of GB biosynthesis-related genes (NiBADH, NiCMO and NiSDC) in the leaves. Furthermore, compared with the wild-type plants, the transgenic tobacco plants displayed a significantly lower malondialdehyde (MDA) accumulation and higher activities of the superoxide dismutase (SOD) and peroxidase (POD) antioxidant enzymes under drought stress. Taken together, our results suggested that HpPEAMT enhanced the drought tolerance of transgenic tobacco.


2021 ◽  
Vol 22 (13) ◽  
pp. 6952
Author(s):  
Mingxin Yu ◽  
Junling Liu ◽  
Bingshuai Du ◽  
Mengjuan Zhang ◽  
Aibin Wang ◽  
...  

NAC (NAM, ATAF1/2, and CUC2) transcription factors are ubiquitously distributed in eukaryotes and play significant roles in stress response. However, the functional verifications of NACs in Picea (P.) wilsonii remain largely uncharacterized. Here, we identified the NAC transcription factor PwNAC11 as a mediator of drought stress, which was significantly upregulated in P. wilsonii under drought and abscisic acid (ABA) treatments. Yeast two-hybrid assays showed that both the full length and C-terminal of PwNAC11 had transcriptional activation activity and PwNAC11 protein cannot form a homodimer by itself. Subcellular observation demonstrated that PwNAC11 protein was located in nucleus. The overexpression of PwNAC11 in Arabidopsis obviously improved the tolerance to drought stress but delayed flowering time under nonstress conditions. The steady-state level of antioxidant enzymes’ activities and light energy conversion efficiency were significantly increased in PwNAC11 transgenic lines under dehydration compared to wild plants. PwNAC11 transgenic lines showed hypersensitivity to ABA and PwNAC11 activated the expression of the downstream gene ERD1 by binding to ABA-responsive elements (ABREs) instead of drought-responsive elements (DREs). Genetic evidence demonstrated that PwNAC11 physically interacted with an ABA-induced protein—ABRE Binding Factor3 (ABF3)—and promoted the activation of ERD1 promoter, which implied an ABA-dependent signaling cascade controlled by PwNAC11. In addition, qRT-PCR and yeast assays showed that an ABA-independent gene—DREB2A—was also probably involved in PwNAC11-mediated drought stress response. Taken together, our results provide the evidence that PwNAC11 plays a dominant role in plants positively responding to early drought stress and ABF3 and DREB2A synergistically regulate the expression of ERD1.


2021 ◽  
Author(s):  
Anindita Dutta ◽  
Apurba Das ◽  
Deep Bisht ◽  
Vijendra Arya ◽  
Rohini Muthuswami

Cells respond to oxidative stress by elevating the levels of antioxidants, signaling, and transcriptional regulation often implemented by chromatin remodeling proteins.  The study presented in this paper shows that the expression of PICH, an ATP-dependent chromatin remodeler, is upregulated during oxidative stress in HeLa cells. We also show that PICH regulates the expression of Nrf2, a transcription factor regulating antioxidant response, both in the absence and presence of oxidative stress. In turn, Nrf2 regulates the expression of PICH in the presence of oxidative stress. Both PICH and Nrf2 together regulate the expression of antioxidant genes and this transcriptional regulation is dependent on the ATPase activity of PICH. In addition, H3K27ac modification also plays a role in activating transcription in the presence of oxidative stress. Co-immunoprecipitation experiments show that PICH and Nrf2 interact with H3K27ac in the presence of oxidative stress. Mechanistically, PICH recognizes ARE sequences present on its target genes and introduces a conformational change to the DNA sequences leading us to hypothesize that PICH regulates transcription by remodeling DNA. PICH ablation leads to reduced expression of Nrf2 and impaired antioxidant response leading to increased ROS content, thus, showing PICH is essential for the cell to respond to oxidative stress.


Plants ◽  
2021 ◽  
Vol 10 (10) ◽  
pp. 2149
Author(s):  
Nkulu Kabange Rolly ◽  
Byung-Wook Yun

Nitrogen (N) is an essential macronutrient, which contributes substantially to the growth and development of plants. In the soil, nitrate (NO3) is the predominant form of N available to the plant and its acquisition by the plant involves several NO3 transporters; however, the mechanism underlying their involvement in the adaptive response under abiotic stress is poorly understood. Initially, we performed an in silico analysis to identify potential binding sites for the basic leucine zipper 62 transcription factor (AtbZIP62 TF) in the promoter of the target genes, and constructed their protein–protein interaction networks. Rather than AtbZIP62, results revealed the presence of cis-regulatory elements specific to two other bZIP TFs, AtbZIP18 and 69. A recent report showed that AtbZIP62 TF negatively regulated AtbZIP18 and AtbZIP69. Therefore, we investigated the transcriptional regulation of AtNPF6.2/NRT1.4 (low-affinity NO3 transporter), AtNPF6.3/NRT1.1 (dual-affinity NO3 transporter), AtNRT2.1 and AtNRT2.2 (high-affinity NO3 transporters), and AtGLU1 and AtGLU2 (both encoding glutamate synthase) in response to drought stress in Col-0. From the perspective of exploring the transcriptional interplay of the target genes with AtbZIP62 TF, we measured their expression by qPCR in the atbzip62 (lacking the AtbZIP62 gene) under the same conditions. Our recent study revealed that AtbZIP62 TF positively regulates the expression of AtPYD1 (Pyrimidine 1, a key gene of the de novo pyrimidine biosynthesis pathway know to share a common substrate with the N metabolic pathway). For this reason, we included the atpyd1-2 mutant in the study. Our findings revealed that the expression of AtNPF6.2/NRT1.4, AtNPF6.3/NRT1.1 and AtNRT2.2 was similarly regulated in atzbip62 and atpyd1-2 but differentially regulated between the mutant lines and Col-0. Meanwhile, the expression pattern of AtNRT2.1 in atbzip62 was similar to that observed in Col-0 but was suppressed in atpyd1-2. The breakthrough is that AtNRT2.2 had the highest expression level in Col-0, while being suppressed in atbzip62 and atpyd1-2. Furthermore, the transcript accumulation of AtGLU1 and AtGLU2 showed differential regulation patterns between Col-0 and atbzip62, and atpyd1-2. Therefore, results suggest that of all tested NO3 transporters, AtNRT2.2 is thought to play a preponderant role in contributing to NO3 transport events under the regulatory influence of AtbZIP62 TF in response to drought stress.


2001 ◽  
Vol 21 (4) ◽  
pp. 1207-1217 ◽  
Author(s):  
Michael J. McDonald ◽  
Michael Rosbash ◽  
Patrick Emery

ABSTRACT Transcriptional regulation plays an important role inDrosophila melanogaster circadian rhythms. The period promoter has been well studied, but the timeless promoter has not been analyzed in detail. Mutagenesis of the canonical E box in the timelesspromoter reduces but does not eliminate timeless mRNA cycling or locomotor activity rhythms. This is because there are at least two other cis-acting elements close to the canonical E box, which can also be transactivated by the circadian transcription factor dCLOCK. These E-box-like sequences cooperate with the canonical E-box element to promote high-amplitude transcription, which is necessary for wild-type rhythmicity.


Plant Science ◽  
2020 ◽  
Vol 301 ◽  
pp. 110689
Author(s):  
Xing-Long Ji ◽  
Hong-Liang Li ◽  
Zhi-Wen Qiao ◽  
Jiu-Cheng Zhang ◽  
Wei-Jian Sun ◽  
...  

2011 ◽  
Vol 111 (4) ◽  
pp. 1142-1149 ◽  
Author(s):  
Kazuyuki Yasuhara ◽  
Yoshitaka Ohno ◽  
Atsushi Kojima ◽  
Kenji Uehara ◽  
Moroe Beppu ◽  
...  

Effects of heat shock transcription factor 1 (HSF1) gene on the regrowth of atrophied mouse soleus muscles were studied. Both HSF1-null and wild-type mice were subjected to continuous hindlimb suspension for 2 wk followed by 4 wk of ambulation recovery. There was no difference in the magnitude of suspension-related decrease of muscle weight, protein content, and the cross-sectional area of muscle fibers between both types of mice. However, the regrowth of atrophied soleus muscle in HSF1-null mice was slower compared with that in wild-type mice. Lower baseline expression level of HSP25, HSC70, and HSP72 were noted in soleus muscle of HSF1-null mice. Unloading-associated downregulation and reloading-associated upregulation of HSP25 and HSP72 mRNA were observed not only in wild-type mice but also in HSF1-null mice. Reloading-associated upregulation of HSP72 and HSP25 during the regrowth of atrophied muscle was observed in wild-type mice. Minor and delayed upregulation of HSP72 at mRNA and protein levels was also seen in HSF1-null mice. Significant upregulations of HSF2 and HSF4 were observed immediately after the suspension in HSF1-null mice, but not in wild-type mice. Therefore, HSP72 expression in soleus muscle might be regulated by the posttranscriptional level, but not by the stress response. Evidence from this study suggested that the upregulation of HSPs induced by HSF1-associated stress response might play, in part, important roles in the mechanical loading (stress)-associated regrowth of skeletal muscle.


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