Nitric oxide function in plant abiotic stress Fancy, Nurun Nahar; Bahlmann, Ann‐Kathrin; Loake, Gary J.
Plant, cell and environment,
April 2017, Letnik:
40, Številka:
4
Journal Article
Recenzirano
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Abiotic stress is one of the main threats affecting crop growth and production. An understanding of the molecular mechanisms that underpin plant responses against environmental insults will be ...crucial to help guide the rational design of crop plants to counter these challenges. A key feature during abiotic stress is the production of nitric oxide (NO), an important concentration dependent, redox‐related signalling molecule. NO can directly or indirectly interact with a wide range of targets leading to the modulation of protein function and the reprogramming of gene expression. The transfer of NO bioactivity can occur through a variety of potential mechanisms but chief among these is S‐nitrosylation, a prototypic, redox‐based, post‐translational modification. However, little is known about this pivotal molecular amendment in the regulation of abiotic stress signalling. Here, we describe the emerging knowledge concerning the function of NO and S‐nitrosylation during plant responses to abiotic stress.
In this manuscript, we focus on the current state‐of‐the‐art regarding the role of nitric oxide (NO) and S‐nitrosylation during abiotic stress responses in plants. This is significant because NO and S‐nitrosylation are emerging as important players in plant abiotic stress signalling. The paper should be of interest to readers in the areas of plant abiotic stress, signalling, redox regulation, NO function and S‐nitrosylation.
Nitric oxide (NO), a gaseous, redox-active small molecule, is gradually becoming established as a central regulator of growth, development, immunity and environmental interactions in plants. A major ...route for the transfer of NO bioactivity is S-nitrosylation, the covalent attachment of an NO moiety to a protein cysteine thiol to form an S-nitrosothiol (SNO). This chemical transformation is rapidly emerging as a prototypic, redox-based post-translational modification integral to the life of plants. Here we review the myriad roles of NO and SNOs in plant biology and, where known, the molecular mechanisms underpining their activity.
In eukaryotes, bursts of reactive oxygen and nitrogen species mediate cellular responses to the environment by modifying cysteines of signaling proteins. Cysteine reactivity toward nitric oxide (NO) ...leads to formation of S-nitrosothiols (SNOs) that play important roles in pathogenesis and immunity. However, it remains poorly understood how SNOs are employed as specific, reversible signaling cues. Here we show that in plant immunity the oxidoreductase Thioredoxin-h5 (TRXh5) reverses SNO modifications by acting as a selective protein-SNO reductase. While TRXh5 failed to restore immunity in gsnor1 mutants that display excessive accumulation of the NO donor S-nitrosoglutathione, it rescued immunity in nox1 mutants that exhibit elevated levels of free NO. Rescue by TRXh5 was conferred through selective denitrosylation of excessive protein-SNO, which reinstated signaling by the immune hormone salicylic acid. Our data indicate that TRXh5 discriminates between protein-SNO substrates to provide previously unrecognized specificity and reversibility to protein-SNO signaling in plant immunity.
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•Immune-induced TRXh5 displays denitrosylation activity in plants•Denitrosylation by TRXh5 regulates salicylic-acid-dependent plant immunity•TRX selectively denitrosylate protein-SNO distinct from those regulated by GSNOR
Protein S-nitrosothiols (SNOs) play important roles in pathogenesis and immunity, but how SNOs are employed as signaling cues remains poorly understood. Kneeshaw et al. demonstrate in plant immunity that Thioredoxin-h5 acts as a selective SNO reductase that discriminates between protein-SNO substrates to provide specificity and reversibility to protein-SNO signaling.
In plants, programed cell death (PCD) is an important mechanism to regulate multiple aspects of growth and development, as well as to remove damaged or infected cells during responses to ...environmental stresses and pathogen attacks. Under biotic and abiotic stresses, plant cells exhibit a rapid synthesis of nitric oxide (NO) and a parallel accumulation of reactive oxygen species (ROS). Frequently, these responses trigger a PCD process leading to an intrinsic execution of plant cells. The accumulating evidence suggests that both NO and ROS play key roles in PCD. These redox active small molecules can trigger cell death either independently or synergistically. Here we summarize the recent progress on the cross-talk of NO and ROS signals in the hypersensitive response, leaf senescence, and other kinds of plant PCD caused by diverse cues.
In most plants, sucrose, a major storage sugar, is transported into sink organs to support their growth. This key physiological process is dependent on the function of sucrose transporters. Sucrose ...export from source tissues is predominantly controlled through the activity of SUCROSE TRANSPORTER 2 (SUC2), required for the loading of sucrose into the phloem of Arabidopsis plants. However, how SUC2 activity is controlled to support root growth remains unclear. Glucose is perceived via the function of HEXOKINASE 1 (HXK1), the only known nuclear glucose sensor. HXK1 negatively regulates the stability of ETHYLENE-INSENSITIVE3 (EIN3), a key ethylene/glucose interaction component. Here we show that HXK1 functions upstream of EIN3 in the regulation of root sink growth mediated by glucose signaling. Furthermore, the transcription factor EIN3 directly inhibits SUC2 activity by binding to the SUC2 promoter, regulating glucose signaling linked to root sink growth. We demonstrate that these molecular components form a HXK1-EIN3-SUC2 module integral to the control of root sink growth. Also, we demonstrate that with increasing age, the HXK1-EIN3-SUC2 module promotes sucrose phloem loading in source tissues thereby elevating sucrose levels in sink roots. As a result, glucose signaling mediated-sink root growth is facilitated. Our findings thus establish a direct molecular link between the HXK1-EIN3-SUC2 module, the source-to sink transport of sucrose and root growth.
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Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Cauliflower mosaic virus (CaMV) encodes a multifunctional protein P6 that is required for translation of the 35S RNA and also acts as a suppressor of RNA silencing. Here we demonstrate that P6 ...additionally acts as a pathogenicity effector of an unique and novel type, modifying NPR1 (a key regulator of salicylic acid (SA)- and jasmonic acid (JA)-dependent signaling) and inhibiting SA-dependent defence responses We find that that transgene-mediated expression of P6 in Arabidopsis and transient expression in Nicotiana benthamiana has profound effects on defence signaling, suppressing expression of representative SA-responsive genes and increasing expression of representative JA-responsive genes. Relative to wild-type Arabidopsis P6-expressing transgenics had greatly reduced expression of PR-1 following SA-treatment, infection by CaMV or inoculation with an avirulent bacterial pathogen Pseudomonas syringae pv tomato (Pst). Similarly transient expression in Nicotiana benthamiana of P6 (including a mutant form defective in translational transactivation activity) suppressed PR-1a transcript accumulation in response to Agrobacterium infiltration and following SA-treatment. As well as suppressing the expression of representative SA-regulated genes, P6-transgenic Arabidopsis showed greatly enhanced susceptibility to both virulent and avirulent Pst (titres elevated 10 to 30-fold compared to non-transgenic controls) but reduced susceptibility to the necrotrophic fungus Botrytis cinerea. Necrosis following SA-treatment or inoculation with avirulent Pst was reduced and delayed in P6-transgenics. NPR1 an important regulator of SA/JA crosstalk, was more highly expressed in the presence of P6 and introduction of the P6 transgene into a transgenic line expressing an NPR1:GFP fusion resulted in greatly increased fluorescence in nuclei even in the absence of SA. Thus in the presence of P6 an inactive form of NPR1 is mislocalized in the nucleus even in uninduced plants. These results demonstrate that P6 is a new type of pathogenicity effector protein that enhances susceptibility to biotrophic pathogens by suppressing SA- but enhancing JA-signaling responses.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
S-nitrosylation, the addition of a nitric oxide (NO) moiety to a reactive protein cysteine (Cys) thiol, to form a protein S-nitrosothiol (SNO), is emerging as a key regulatory post-translational ...modification (PTM) to control the plant immune response. NO also S-nitrosylates the antioxidant tripeptide, glutathione, to form S-nitrosoglutathione (GSNO), both a storage reservoir of NO bioactivity and a natural NO donor. GSNO and, by extension, S-nitrosylation, are controlled by GSNO reductase1 (GSNOR1). The emerging data suggest that GSNOR1 itself is a target of NO-mediated S-nitrosylation, which subsequently controls its selective autophagy, regulating cellular protein SNO levels. Recent findings also suggest that S-nitrosylation may be deployed by pathogen-challenged host cells to counteract the effect of delivered microbial effector proteins that promote pathogenesis and by the pathogens themselves to augment virulence. Significantly, it also appears that S-nitrosylation may regulate plant immune functions by controlling SUMOylation, a peptide-based PTM. In this context, global SUMOylation is regulated by S-nitrosylation of SUMO conjugating enzyme 1 (SCE1) at Cys139. This redox-based PTM has also been shown to control the function of a key zinc finger transcriptional regulator during the establishment of plant immunity. Here, we provide an update of these recent advances.
Plants have evolved a vast chemical cornucopia to support their sessile lifestyles. Man has exploited this natural resource since Neolithic times and currently plant-derived chemicals are exploited ...for a myriad of applications. However, plant sources of most high-value natural products (NPs) are not domesticated and therefore their production cannot be undertaken on an agricultural scale. Further, these plant species are often slow growing, their populations limiting, the concentration of the target molecule highly variable and routinely present at extremely low concentrations. Plant cell and organ culture constitutes a sustainable, controllable and environmentally friendly tool for the industrial production of plant NPs. Further, advances in cell line selection, biotransformation, product secretion, cell permeabilisation, extraction and scale-up, among others, are driving increases in plant NP yields. However, there remain significant obstacles to the commercial synthesis of high-value chemicals from these sources. The relatively recent isolation, culturing and characterisation of cambial meristematic cells (CMCs), provides an emerging platform to circumvent many of these potential difficulties. BMB Reports 2016; 49(3): 149-158.
Traditional knowledge is a particular form of practice or skill set that was developed in ancient times and was sustained through generations via the passing of knowledge, essentially confined within ...a specific tribe, local people, or family lineages. Ethnodermatological use of medicinal plants in India is still a subject to conduct more studies to see if there is chemical, microbiological, and/or clinical evidence, from a scientific perspective, of their effectiveness for those skin disorders. Thus, this review can be the basis for further studies and may provide targets for drug development.
We compile and emphasize the most important part of ethnodermatology, namely, traditional knowledge of medicinal plants and their applications for several skin diseases in India. We also include a brief review and explanation on dermatology in Ayurvedic and Unani medicine. We review the pharmacological activity of extracts derived from some of the most cited plants against problem skin diseases as well.
Different kinds of key phrases such as “Indian traditional ethnodermatology”, “ethnodermatology”, “ethnobotany”, “skin diseases”, “Ayurveda dermatology”, “pharmacological activity” were searched in online search servers/databases such as Google Scholar (https://scholar.google.com/), ResearchGate (https://www.researchgate.net/), PubMed (https://pubmed.ncbi.nlm.nih.gov/), NISCAIR Online Periodicals Repository (NOPR) (http://nopr.niscair.res.in/). Based upon the analyses of data obtained from 178 articles, we formulated several important findings which are a summary shown in Tables. Tables. A total of 119 records of plants’ uses have been found across India against 39 skin diseases. These are depicted with their localities of report, parts used, and preparation and administration methods against particular skin diseases.
The knowledge and utilisation of herbal medicine in the Indian subcontinent has great potential to treat different kinds of human skin disorders. The administration of extracts from most of the plant species used is topical and few only are administrated orally. We also investigated the pharmacological activity of the extracts of the most cited plants against mice, bacterial and fungal pathogens, and human cells.
Complementary therapy for dermatological problems and treatment remains the main option for millions of people in the Indian subcontinent. This review on the practices of ethnobotanical dermatology in India confirms the belief that their analysis will accelerate the discovery of new, effective therapeutic agents for skin diseases. However, more studies and clinical evidence are still required to determine if the identified species may contribute to skin condition treatment, particularly in atopic eczema. Today, ethnodermatology is a well-accepted international discipline and many new practices have been initiated in numerous countries. We hope this article will further accelerate the development of this area to identify a new generation of natural human skin treatments that will help meet the growing consumer demand for safe, sustainable, and natural treatments. In this context, research on plants utilised in ethnodermatology in India and elsewhere should be intensified.
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•Skin diseases are a major public health concern worldwide.•The potential use of medicinal plants for the treatment of skin diseases and related problems in India were critically reviewed.•Ayurvedic formulations of medicinal plants for dermatology were evaluated.•Preclinical and clinical evidence, as well as cellular investigations, on the pharmacological activities of medicinal plants, were summarized.•Further research is needed to deeply understand the molecular mechanism of action of herbal compounds used in dermatology.
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