scholarly journals RNA degradomes reveal substrates and importance for dark and nitrogen stress responses of Arabidopsis XRN4

2019 ◽  
Author(s):  
Vinay K Nagarajan ◽  
Patrick M Kukulich ◽  
Bryan von Hagel ◽  
Pamela J Green
Keyword(s):  
Stress Responses ◽  
Lateral Root ◽  
Nitrogen Stress ◽  
Degradome Analysis ◽  
Nonsense Mediated Decay ◽  
Whole Plant ◽  
Major Player ◽  
Plant Level ◽  
The Impact ◽  
Dark Stress

Abstract XRN4, the plant cytoplasmic homolog of yeast and metazoan XRN1, catalyzes exoribonucleolytic degradation of uncapped mRNAs from the 5′ end. Most studies of cytoplasmic XRN substrates have focused on polyadenylated transcripts, although many substrates are likely first deadenylated. Here, we report the global investigation of XRN4 substrates in both polyadenylated and nonpolyadenylated RNA to better understand the impact of the enzyme in Arabidopsis. RNA degradome analysis demonstrated that xrn4 mutants overaccumulate many more decapped deadenylated intermediates than those that are polyadenylated. Among these XRN4 substrates that have 5′ ends precisely at cap sites, those associated with photosynthesis, nitrogen responses and auxin responses were enriched. Moreover, xrn4 was found to be defective in the dark stress response and lateral root growth during N resupply, demonstrating that XRN4 is required during both processes. XRN4 also contributes to nonsense-mediated decay (NMD) and xrn4 accumulates 3′ fragments of select NMD targets, despite the lack of the metazoan endoribonuclease SMG6 in plants. Beyond demonstrating that XRN4 is a major player in multiple decay pathways, this study identified intriguing molecular impacts of the enzyme, including those that led to new insights about mRNA decay and discovery of functional contributions at the whole-plant level.

scholarly journals Increased oxidative stress tolerance of a spontaneously-occurring perR gene mutation in Streptococcus mutans UA159

2020 ◽  
Author(s):  
Jessica K. Kajfasz ◽  
Peter Zuber ◽  
Tridib Ganguly ◽  
Jacqueline Abranches ◽  
José A. Lemos
Keyword(s):  
Oxidative Stress ◽  
Streptococcus Mutans ◽  
Stress Responses ◽  
Transcriptional Repressor ◽  
Loss Of Function ◽  
Coding Region ◽  
Major Player ◽  
The Impact ◽  
Peroxide Stress

AbstractThe ability of bacteria such as the dental pathogen Streptococcus mutans to coordinate a response against damage-inducing oxidants is a critical aspect of their pathogenicity. The oxidative stress regulator SpxA1 has been proven to be a major player in the ability of S. mutans to withstand both disulfide and peroxide stresses. While studying spontaneously-occurring variants of an S. mutans ΔspxA1 strain, we serendipitously discovered that our S. mutans UA159 host strain bore a single nucleotide deletion within the coding region ofperR, resulting in a premature truncation of the encoded protein. PerR is a metal-dependent transcriptional repressor that senses and responds to peroxide stress such that loss of PerR activity results in activation of oxidative stress responses. To determine the impact of loss of PerR regulation, we obtained a UA159 isolated bearing an intact perR copy and created a clean perR deletion mutant. Our findings indicate that loss of PerR activity results in a strain that is primed to tolerate oxidative stresses in the laboratory setting. Interestingly, RNA-Seq and targeted transcriptional expression analyses reveal that PerR has a minor contribution to the ability of S. mutans to orchestrate a transcriptional response to peroxide stress. Furthermore, we detected loss-of-function perR mutations in two other commonly used laboratory strains of S. mutans suggesting that this may be not be an uncommon occurrence. This report serves as a cautionary warning regarding the so-called domestication of laboratory strains and advocates for the implementation of more stringent strain authentication practices.ImportanceA resident of the human oral biofilm, Streptococcus mutans is one of the major bacterial pathogens associated with dental caries. This report highlights a spontaneously-occurring mutation within the laboratory strain S. mutans UA159, found in the coding region of perR, a gene encoding a transcriptional repressor associated with peroxide tolerance. Though perR mutant strains of S. mutans showed a distinct growth advantage and enhanced tolerance toward H2O2, a ΔperR deletion strain showed a small number of differentially expressed genes as compared to the parent strain, suggesting few direct regulatory targets. In addition to characterizing the role of PerR in S. mutans, our findings serve as a warning to laboratory researchers regarding bacterial adaptation to in vitro growth conditions.

scholarly journals Strategies to Apply Water-Deficit Stress: Similarities and Disparities at the Whole Plant Metabolism Level in Medicago truncatula

2021 ◽  
Vol 22 (6) ◽  
pp. 2813
Author(s):  
Verónica Castañeda ◽  
Esther M. González
Keyword(s):  
Drought Stress ◽  
Water Deficit ◽  
Stress Responses ◽  
Carbon Metabolism ◽  
Crop Productivity ◽  
Invertase Activity ◽  
Water Deficit Stress ◽  
Plant Responses ◽  
Whole Plant ◽  
Plant Level

Water-deficit stresses such as drought and salinity are the most important factors limiting crop productivity. Hence, understanding the plant responses to these stresses is key for the improvement of their tolerance and yield. In this study M. truncatula plants were subjected to 250 mM NaCl as well as reduced irrigation (No-W) and 250 g/L polyethylene glycol (PEG)-6000 to induce salinity and drought stress, respectively, provoking a drop to −1.7 MPa in leaf water potential. The whole plant physiology and metabolism was explored by characterizing the stress responses at root, phloem sap and leaf organ level. PEG treatment led to some typical responses of plants to drought stress, but in addition to PEG uptake, an important impairment of nutrient uptake and a different regulation of carbon metabolism could be observed compared to No-W plants. No-W plants showed an important redistribution of antioxidants and assimilates to the root tissue, with a distinctive increase in root proline degradation and alkaline invertase activity. On the contrary, salinity provoked an increase in leaf starch and isocitrate dehydrogenase activity, suggesting key roles in the plant response to this stress. Overall, results suggest higher protection of salt-stressed shoots and non-irrigated roots through different mechanisms, including the regulation of proline and carbon metabolism, while discarding PEG as safe mimicker of drought. This raises the need to understand the effect at the whole plant level of the different strategies employed to apply water-deficit stress.

scholarly journals Response of grafting tobacco to low potassium stress

2020 ◽  
Author(s):  
Wei Hu ◽  
Qing Di ◽  
Jie Zhang ◽  
Jia Liu ◽  
Xiaojun Shi
Keyword(s):  
Root Surface ◽  
Potassium Content ◽  
K Channel ◽  
Whole Plant ◽  
Low Potassium ◽  
Stress Signals ◽  
Plant Level ◽  
Time Required ◽  
And Coping ◽  
The Impact

Abstract Background In the previous study, we investigated the alleviation effect of grafting on potassium uptake in roots and tobacco growth inhibition under low potassium stress. However, the effect of grafting on the low potassium stress perception and coping mechanism of tobacco at the whole plant level is not clear now. In order to clearly understand the impact of grafting on potassium deficit responding mechanism in tobacco, a mutual grafting experiment has been conducted in two varieties of tobacco (‘Wufeng No.2’ and ‘Yunyan 87’) in different K supply level (5mmol L -1 and 0.5 mmol L -1 K). Results The results show that compared with the self-rooted seedlings, grafting significantly increased the potassium content of the whole plant of Yunyan 87 (97.57% and 189.74% under normal potassium and low potassium conditions, respectively), and the increase in shoots was greater. The data of whole plant K content distribution and tobacco hypocotyls net K + flux demonstrates that potassium stress makes plants more inclined to maintain K + in the shoot rather than root. In addition, when K deficiency occurs, grafting could reduce the time required for downward net K + flux in tobacco hypocotyl to decrease to stable levels. The results of net K + flux in the roots indicated that K channel proteins and transporters play different roles in two rootstocks in terms of potassium tolerance. Transcription level analysis suggested that the increased circulating efficiency of K + between the shoots and roots in tobacco constitutes one means to low potassium stress adaptation. Conclusions Grafting can activate more K + channels in tobacco ‘Yunyan 87’, this means a more active K + cycle, higher potassium content in shoot and faster response to low potassium stress signals in grafting tobacco. In addition, grafting can also change the K + absorption mode of tobacco root from being dominated by HATS to being jointly responsible by HATS and LATS, greatly improving the ability of K + transmembrane transportation on root surface under low potassium stress. These are undoubtedly the reasons why grafting tobacco performs better in coping with low potassium stress.

scholarly journals Heat Stress Targeting Individual Organs Reveals the Central Role of Roots and Crowns in Rice Stress Responses

2022 ◽  
Vol 12 ◽  
Author(s):  
Sylva Prerostova ◽  
Jana Jarosova ◽  
Petre I. Dobrev ◽  
Lucia Hluskova ◽  
Vaclav Motyka ◽  
...  
Keyword(s):  
Heat Stress ◽  
Ascorbate Peroxidase ◽  
Peroxidase Activity ◽  
Stress Responses ◽  
Plant Stress ◽  
Growth Strategy ◽  
Whole Plant ◽  
Whole Plants ◽  
Induced Changes ◽  
The Impact

Inter-organ communication and the heat stress (HS; 45°C, 6 h) responses of organs exposed and not directly exposed to HS were evaluated in rice (Oryza sativa) by comparing the impact of HS applied either to whole plants, or only to shoots or roots. Whole-plant HS reduced photosynthetic activity (Fv/Fm and QY_Lss), but this effect was alleviated by prior acclimation (37°C, 2 h). Dynamics of HSFA2d, HSP90.2, HSP90.3, and SIG5 expression revealed high protection of crowns and roots. Additionally, HSP26.2 was strongly expressed in leaves. Whole-plant HS increased levels of jasmonic acid (JA) and cytokinin cis-zeatin in leaves, while up-regulating auxin indole-3-acetic acid and down-regulating trans-zeatin in leaves and crowns. Ascorbate peroxidase activity and expression of alternative oxidases (AOX) increased in leaves and crowns. HS targeted to leaves elevated levels of JA in roots, cis-zeatin in crowns, and ascorbate peroxidase activity in crowns and roots. HS targeted to roots increased levels of abscisic acid and auxin in leaves and crowns, cis-zeatin in leaves, and JA in crowns, while reducing trans-zeatin levels. The weaker protection of leaves reflects the growth strategy of rice. HS treatment of individual organs induced changes in phytohormone levels and antioxidant enzyme activity in non-exposed organs, in order to enhance plant stress tolerance.

scholarly journals Interaction of Nitric Oxide with Phytohormones under Drought Stress

2017 ◽  
Vol 6 (1) ◽  
pp. 58 ◽  
Author(s):  
Srivani S. Adimulam ◽  
Bhatnagar-Mathur Pooja ◽  
Santisree Parankusam
Keyword(s):  
Nitric Oxide ◽  
Heavy Metals ◽  
Drought Stress ◽  
Stress Responses ◽  
Extreme Temperatures ◽  
Abiotic And Biotic Stresses ◽  
Biotic Stresses ◽  
Whole Plant ◽  
Plant Level ◽  
Open Question

Plants are often exposed to a plethora of stress conditions such as salinity, extreme temperatures, drought, and heavy metals that can greatly impact farmer’s income. Nitric oxide (NO) has been implicated in resistance to various plant stresses and hence gaining increasing attention from plant researchers. NO mediate various abiotic and biotic stresses in plants including drought stress. However, it is still unclear about the actual involvement of NO in drought stress responses at a whole plant level. Whether NO act alone or in coherence with other phytohormones and signaling molecules is an open question till now. Here we summarized the interaction of NO with the well-known phytohormones in coping with the drought stress.

scholarly journals Increased oxidative stress tolerance of a spontaneously-occurring perR gene mutation in Streptococcus mutans UA159

2021 ◽  
Author(s):  
Jessica K. Kajfasz ◽  
Peter Zuber ◽  
Tridib Ganguly ◽  
Jacqueline Abranches ◽  
José A. Lemos
Keyword(s):  
Oxidative Stress ◽  
Streptococcus Mutans ◽  
Stress Responses ◽  
Transcriptional Repressor ◽  
Loss Of Function ◽  
Coding Region ◽  
Major Player ◽  
The Impact ◽  
Peroxide Stress

The ability of bacteria such as the dental pathogen Streptococcus mutans to coordinate a response against damage-inducing oxidants is a critical aspect of their pathogenicity. The oxidative stress regulator SpxA1 has been demonstrated to be a major player in the ability of S. mutans to withstand both disulfide and peroxide stresses. While studying spontaneously-occurring variants of an S. mutans ΔspxA1 strain, we serendipitously discovered that our S. mutans UA159 host strain bore a single nucleotide deletion within the coding region of perR, resulting in a premature truncation of the encoded protein. PerR is a metal-dependent transcriptional repressor that senses and responds to peroxide stress such that loss of PerR activity results in activation of oxidative stress responses. To determine the impact of loss of PerR regulation, we obtained a UA159 isolate bearing an intact perR copy and created a clean perR deletion mutant. Our findings indicate that loss of PerR activity results in a strain that is primed to tolerate oxidative stresses in the laboratory setting. Interestingly, RNA-Seq and targeted transcriptional expression analyses reveal that PerR offers a minor contribution to the ability of S. mutans to orchestrate a transcriptional response to peroxide stress. Furthermore, we detected loss-of-function perR mutations in two other commonly used laboratory strains of S. mutans suggesting that this may be not be an uncommon occurrence. This report serves as a cautionary tale regarding the so-called domestication of laboratory strains and advocates for the implementation of more stringent strain authentication practices. Importance: A resident of the human oral biofilm, Streptococcus mutans is one of the major bacterial pathogens associated with dental caries. This report highlights a spontaneously-occurring mutation within the laboratory strain S. mutans UA159, found in the coding region of perR, a gene encoding a transcriptional repressor associated with peroxide tolerance. Though perR mutant strains of S. mutans showed a distinct growth advantage and enhanced tolerance toward H2O2, a ΔperR deletion strain showed a small number of differentially expressed genes as compared to the parent strain, suggesting few direct regulatory targets. In addition to characterizing the role of PerR in S. mutans, our findings serve as a warning to laboratory researchers regarding bacterial adaptation to in vitro growth conditions.

scholarly journals The impact of stomatal kinetics on diurnal photosynthesis and water use efficiency under fluctuating light

2020 ◽  
Author(s):  
David Eyland ◽  
Jelle van Wesemael ◽  
Tracy Lawson ◽  
Sebastien Carpentier
Keyword(s):  
Light Intensity ◽  
Water Use Efficiency ◽  
Water Use ◽  
Light Conditions ◽  
Fluctuating Light ◽  
Whole Plant ◽  
Intrinsic Water Use Efficiency ◽  
Use Efficiency ◽  
Plant Level ◽  
The Impact

AbstractDynamic light conditions require continuous adjustments of stomatal aperture. As stomatal conductance (gs) kinetics are a magnitude slower than photosynthesis (A), they are hypothesized to be key to plant productivity and water use efficiency. Using step-changes in light intensity, we studied the diversity of light-induced gs kinetics in relation to stomatal anatomy in five banana genotypes (Musa spp.) and modelled the impact on A and intrinsic water use efficiency (iWUE). Banana generally exhibited a strong limitation of A by gs, indicating a priority for water saving. Significant genotypic differences in gs kinetics and gs-based limitations of A were observed. For two contrasting genotypes the impact of differential gs kinetics on A and iWUE was further investigated under realistic diurnally fluctuating light conditions and at whole-plant level. Genotype-specific stomatal kinetics observed at the leaf level were corroborated at whole-plant level, suggesting that despite differences in gs control at different locations in the leaf and across leaves, genotype-specific responses are still maintained. However, under diurnally fluctuating light conditions gs speediness had only a momentary impact on the diurnal iWUE and carbon gain. During the afternoon there was a setback in kinetics: the absolute gs and the gs responses to light were damped, strongly limiting A and the diurnal iWUE. We conclude that the impact of the differential gs kinetics on the limitation of A was dependent on the target light intensity, the magnitude of change, the gs prior to the intensity change and particularly the time of the day.One sentence summaryGenotype-specific stomatal rapidity is for the first time validated at whole-plant level, but under fluctuating light the impact of stomatal dynamics depends on other factors like the time of the day.

Emotions and health: The impact of emotions, emotions regulation, music, and acculturation on health

2008 ◽  
Vol 16 (3) ◽  
pp. 112-115 ◽  
Author(s):  
Stephan Bongard ◽  
Volker Hodapp ◽  
Sonja Rohrmann
Keyword(s):  
Stress Responses ◽  
Physiological Stress ◽  
Anger Expression ◽  
Domain Specific ◽  
Cardiovascular Stress ◽  
Expression Behavior ◽  
Cardio Vascular ◽  
And Coping ◽  
Relationship Of ◽  
The Impact

Abstract. Our unit investigates the relationship of emotional processes (experience, expression, and coping), their physiological correlates and possible health outcomes. We study domain specific anger expression behavior and associated cardio-vascular loads and found e.g. that particularly an open anger expression at work is associated with greater blood pressure. Furthermore, we demonstrated that women may be predisposed for the development of certain mental disorders because of their higher disgust sensitivity. We also pointed out that the suppression of negative emotions leads to increased physiological stress responses which results in a higher risk for cardiovascular diseases. We could show that relaxation as well as music activity like singing in a choir causes increases in the local immune parameter immunoglobuline A. Finally, we are investigating connections between migrants’ strategy of acculturation and health and found e.g. elevated cardiovascular stress responses in migrants when they where highly adapted to the German culture.

Childbirth and Posttraumatic Stress Responses

2006 ◽  
Vol 22 (4) ◽  
pp. 259-267 ◽  
Author(s):  
Eelco Olde ◽  
Rolf J. Kleber ◽  
Onno van der Hart ◽  
Victor J.M. Pop
Keyword(s):  
Posttraumatic Stress Disorder ◽  
Posttraumatic Stress ◽  
Stress Responses ◽  
Rating Scales ◽  
Rating Scale ◽  
Stress Disorder ◽  
Traumatic Experience ◽  
Event Scale ◽  
Self Rating ◽  
The Impact

Childbirth has been identified as a possible traumatic experience, leading to traumatic stress responses and even to the development of posttraumatic stress disorder (PTSD). The current study investigated the psychometric properties of the Dutch version of the Impact of Event Scale-Revised (IES-R) in a group of women who recently gave birth (N = 435). In addition, a comparison was made between the original IES and the IES-R. The scale showed high internal consistency (α = 0.88). Using confirmatory factor analysis no support was found for a three-factor structure of an intrusion, an avoidance, and a hyperarousal factor. Goodness of fit was only reasonable, even after fitting one intrusion item on the hyperarousal scale. The IES-R correlated significantly with scores on depression and anxiety self-rating scales, as well as with scores on a self-rating scale of posttraumatic stress disorder. Although the IES-R can be used for studying posttraumatic stress reactions in women who recently gave birth, the original IES proved to be a better instrument compared to the IES-R. It is concluded that adding the hyperarousal scale to the IES-R did not make the scale stronger.

scholarly journals Arginine Decarboxylase Is Essential for Pneumococcal Stress Responses

Pathogens ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 286
Author(s):  
Mary Frances Nakamya ◽  
Moses B. Ayoola ◽  
Leslie A. Shack ◽  
Mirghani Mohamed ◽  
Edwin Swiatlo ◽  
...  
Keyword(s):  
Stress Responses ◽  
Critical Role ◽  
Acid Stress ◽  
Arginine Decarboxylase ◽  
Arginine Deiminase ◽  
Dependent Manner ◽  
Cellular Processes ◽  
Opportunistic Human Pathogen ◽  
Thiol Peroxidase ◽  
The Impact

Polyamines such as putrescine, cadaverine, and spermidine are small cationic molecules that play significant roles in cellular processes, including bacterial stress responses and host–pathogen interactions. Streptococcus pneumoniae is an opportunistic human pathogen, which causes several diseases that account for significant morbidity and mortality worldwide. As it transits through different host niches, S. pneumoniae is exposed to and must adapt to different types of stress in the host microenvironment. We earlier reported that S. pneumoniae TIGR4, which harbors an isogenic deletion of an arginine decarboxylase (ΔspeA), an enzyme that catalyzes the synthesis of agmatine in the polyamine synthesis pathway, has a reduced capsule. Here, we report the impact of arginine decarboxylase deletion on pneumococcal stress responses. Our results show that ΔspeA is more susceptible to oxidative, nitrosative, and acid stress compared to the wild-type strain. Gene expression analysis by qRT-PCR indicates that thiol peroxidase, a scavenger of reactive oxygen species and aguA from the arginine deiminase system, could be important for peroxide stress responses in a polyamine-dependent manner. Our results also show that speA is essential for endogenous hydrogen peroxide and glutathione production in S. pneumoniae. Taken together, our findings demonstrate the critical role of arginine decarboxylase in pneumococcal stress responses that could impact adaptation and survival in the host.

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