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International Journal of Molecular... Apr 2020Ten articles published in the "Special Issue: Salicylic Acid Signalling in Plants" are summarized, in order to get a global picture about the mode of action of salicylic...
Ten articles published in the "Special Issue: Salicylic Acid Signalling in Plants" are summarized, in order to get a global picture about the mode of action of salicylic acid in plants, and about its interaction with other stress-signalling routes. Its ecological aspects and possible practical use are also discussed.
Topics: Acclimatization; Plant Development; Plant Growth Regulators; Plants; Salicylic Acid; Signal Transduction; Stress, Physiological
PubMed: 32290350
DOI: 10.3390/ijms21072655 -
Current Opinion in Virology Jun 2020The small phenolic compound salicylic acid (SA) is a phytohormone that regulates many biological processes, although it is most well-known for its role in plant defense.... (Review)
Review
The small phenolic compound salicylic acid (SA) is a phytohormone that regulates many biological processes, although it is most well-known for its role in plant defense. SA is an important regulator of systemic acquired resistance (SAR), a type of systemic immunity that protects uninfected parts of the plant against secondary infections by a broad spectrum of pathogens. SAR involves the generation of mobile signal(s) at the primary infection site, which translocate to distal uninfected portions and activate systemic disease resistance. Although, SA was considered to not constitute the mobile SAR signal, it is preferentially transported from pathogen-infected to uninfected parts via the apoplast. Further investigations have revealed that distal transport of SA is indeed essential for SAR. The apoplastic SA transport is regulated by the transpirational pull and partitioning of SA between the symplast and cuticle.
Topics: Biological Transport; Disease Resistance; Plant Diseases; Plants; Salicylic Acid; Signal Transduction
PubMed: 32544865
DOI: 10.1016/j.coviro.2020.05.008 -
International Journal of Molecular... Sep 2019Salicylic acid (SA) is a phytohormone that plays important roles in many aspects of plant life, notably in plant defenses against pathogens. Key mechanisms of SA signal... (Review)
Review
Salicylic acid (SA) is a phytohormone that plays important roles in many aspects of plant life, notably in plant defenses against pathogens. Key mechanisms of SA signal transduction pathways have now been uncovered. Even though details are still missing, we understand how SA production is regulated and which molecular machinery is implicated in the control of downstream transcriptional responses. The NPR1 pathway has been described to play the main role in SA transduction. However, the mode of SA perception is unclear. NPR1 protein has been shown to bind SA. Nevertheless, NPR1 action requires upstream regulatory events (such as a change in cell redox status). Besides, a number of SA-induced responses are independent from NPR1. This shows that there is more than one way for plants to perceive SA. Indeed, multiple SA-binding proteins of contrasting structures and functions have now been identified. Yet, all of these proteins can be considered as candidate SA receptors and might have a role in multinodal (decentralized) SA input. This phenomenon is unprecedented for other plant hormones and is a point of discussion of this review.
Topics: Metabolic Networks and Pathways; Plant Diseases; Plant Growth Regulators; Plant Proteins; Salicylic Acid; Signal Transduction; Stress, Physiological; Structure-Activity Relationship
PubMed: 31489905
DOI: 10.3390/ijms20184377 -
Plant Physiology and Biochemistry : PPB Mar 2023Salicylic acid (SA) is one of the potential plant growth regulators (PGRs) that regulate plant growth and development by triggering many physiological and metabolic... (Review)
Review
Salicylic acid (SA) is one of the potential plant growth regulators (PGRs) that regulate plant growth and development by triggering many physiological and metabolic processes. It is also known to be a crucial component of plant defense mechanisms against environmental stimuli. In stressed plants, it is documented that it can effectively modulate a myriad of metabolic processes including strengthening of oxidative defense system by directly or indirectly limiting the buildup of reactive nitrogen and oxygen radicals. Although it is well recognized that it performs a crucial role in plant tolerance to various stresses, it is not fully elucidated that whether low or high concentrations of this PGR is effective to achieve optimal growth of plants under stressful environments. It is also not fully understood that to what extent and in what manner it cross-talks with other potential growth regulators and signalling molecules within the plant body. Thus, this critical review discusses how far SA mediates crosstalk with other key PGRs and molecular components of signalling pathways mechanisms, particularly in plants exposed to environmental cues. Moreover, the function of SA exogenously applied in regulation of growth and development as well as reinforcement of oxidative defense system of plants under abiotic stresses is explicitly elucidated.
Topics: Plant Growth Regulators; Salicylic Acid; Plant Development; Plants; Signal Transduction; Stress, Physiological
PubMed: 36758290
DOI: 10.1016/j.plaphy.2023.02.006 -
Journal of Integrative Plant Biology Jun 2011The small phenolic compound salicylic acid (SA) plays an important regulatory role in multiple physiological processes including plant immune response. Significant... (Review)
Review
The small phenolic compound salicylic acid (SA) plays an important regulatory role in multiple physiological processes including plant immune response. Significant progress has been made during the past two decades in understanding the SA-mediated defense signaling network. Characterization of a number of genes functioning in SA biosynthesis, conjugation, accumulation, signaling, and crosstalk with other hormones such as jasmonic acid, ethylene, abscisic acid, auxin, gibberellic acid, cytokinin, brassinosteroid, and peptide hormones has sketched the finely tuned immune response network. Full understanding of the mechanism of plant immunity will need to take advantage of fast developing genomics tools and bioinformatics techniques. However, elucidating genetic components involved in these pathways by conventional genetics, biochemistry, and molecular biology approaches will continue to be a major task of the community. High-throughput method for SA quantification holds the potential for isolating additional mutants related to SA-mediated defense signaling.
Topics: Plant Growth Regulators; Plant Immunity; Salicylic Acid; Signal Transduction
PubMed: 21535470
DOI: 10.1111/j.1744-7909.2011.01043.x -
Tuberculosis (Edinburgh, Scotland) May 2023Tuberculosis (TB), caused by Mycobacterium tuberculosis (Mtb) is a leading cause of infectious disease mortality. The salicylic acid derived small molecule siderophores...
Tuberculosis (TB), caused by Mycobacterium tuberculosis (Mtb) is a leading cause of infectious disease mortality. The salicylic acid derived small molecule siderophores known as mycobactins are essential in vivo for iron acquisition of Mtb where iron is restricted in the host. Herein, we synthesize and explore the mechanism of action of polyfluorinated salicylic acid derivates, which were previously reported to possess potent antimycobacterial activity. We hypothesized fluorinated salicylic acid derivates may inhibit mycobactin biosynthesis through initial bioactivation and conversion to downstream metabolites that block late steps in assembly of the mycobactins. Enzymatic studies demonstrated that some of the fluorinated salicylic acid derivatives compounds were readily activated by the bifunctional adenylating enzyme MbtA, responsible for incorporation of salicylic acid into the mycobactin biosynthetic pathway; however, they did not inhibit mycobactin biosynthesis as confirmed by LS-MS/MS using an authentic synthetic mycobactin standard. Further mechanistic analysis of the most active derivative (Sal-4) using an MbtA-overexpressing Mtb strain as well as complementation studies with iron and salicylic acid revealed Sal-4 cannot be antagonized by overexpression of MbtA or through supplementation with iron or salicylic acid. Taken together, our results indicate the observed antimycobacterial activity of polyfluorinated salicylic acid derivative is independent of mycobactin biosynthesis.
Topics: Siderophores; Mycobacterium tuberculosis; Salicylic Acid; Tandem Mass Spectrometry; Iron
PubMed: 37119793
DOI: 10.1016/j.tube.2023.102346 -
Molecules (Basel, Switzerland) Jan 2020Salicylic acid (SA) is a very simple phenolic compound (a CHO compound composed of an aromatic ring, one carboxylic and a hydroxyl group) and this simplicity contrasts... (Review)
Review
Salicylic acid (SA) is a very simple phenolic compound (a CHO compound composed of an aromatic ring, one carboxylic and a hydroxyl group) and this simplicity contrasts with its high versatility and the involvement of SA in several plant processes either in optimal conditions or in plants facing environmental cues, including heavy metal (HM) stress. Nowadays, a huge body of evidence has unveiled that SA plays a pivotal role as plant growth regulator and influences intra- and inter-plant communication attributable to its methyl ester form, methyl salicylate, which is highly volatile. Under stress, including HM stress, SA interacts with other plant hormones (e.g., auxins, abscisic acid, gibberellin) and promotes the stimulation of antioxidant compounds and enzymes thereby alerting HM-treated plants and helping in counteracting HM stress. The present literature survey reviews recent literature concerning the roles of SA in plants suffering from HM stress with the aim of providing a comprehensive picture about SA and HM, in order to orientate the direction of future research on this topic.
Topics: Antioxidants; Environmental Exposure; Metabolic Networks and Pathways; Metals, Heavy; Molecular Structure; Oxidative Stress; Plants; Reactive Oxygen Species; Salicylic Acid; Stress, Physiological
PubMed: 31991931
DOI: 10.3390/molecules25030540 -
Essays in Biochemistry 2015The plant hormone salicylic acid (SA) plays an essential role in the regulation of diverse biological processes throughout the entire lifespan of the plant. Twenty-five... (Review)
Review
The plant hormone salicylic acid (SA) plays an essential role in the regulation of diverse biological processes throughout the entire lifespan of the plant. Twenty-five years ago, SA first emerged as an endogenous signal capable of inducing plant defence responses both at the site of infection and in the systemic tissue of the plant. Since then, SA-mediated signalling pathways have been extensively characterized and dissected using genetic and biochemical approaches. Current research is largely focused on the identification of novel SA downstream signalling genes, in order to understand their precise contributions to the phytohormonal cross-talk and signalling network. This will subsequently help us to identify novel targets that are important for plant health, and contribute to advances in modern agriculture. In this chapter we highlight recent advances in the field of SA biosynthesis and the discovery of candidates for systemic mobile signals. We also discuss the molecular mechanisms underlying SA perception. In addition, we review the novel SA signalling components that expand the scope of SA functions beyond plant immunity to include plant growth and development, endoplasmic reticulum (ER) stress, DNA repair and homologous recombination. Finally, we shed light on the roles of SA in epigenetically controlled transgenerational immune memory that has long-term benefits for plants.
Topics: Endoplasmic Reticulum Stress; Plant Proteins; Salicylic Acid; Signal Transduction
PubMed: 26374890
DOI: 10.1042/bse0580101 -
International Journal of Molecular... Oct 2021Salicylic acid (SA) is an important plant hormone with a critical role in plant defense against pathogen infection. Despite extensive research over the past 30 year or... (Review)
Review
Salicylic acid (SA) is an important plant hormone with a critical role in plant defense against pathogen infection. Despite extensive research over the past 30 year or so, SA biosynthesis and its complex roles in plant defense are still not fully understood. Even though earlier biochemical studies suggested that plants synthesize SA from cinnamate produced by phenylalanine ammonia lyase (PAL), genetic analysis has indicated that in Arabidopsis, the bulk of SA is synthesized from isochorismate (IC) produced by IC synthase (ICS). Recent studies have further established the enzymes responsible for the conversion of IC to SA in Arabidopsis. However, it remains unclear whether other plants also rely on the ICS pathway for SA biosynthesis. SA induces defense genes against biotrophic pathogens, but represses genes involved in growth for balancing defense and growth to a great extent through crosstalk with the growth-promoting plant hormone auxin. Important progress has been made recently in understanding how SA attenuates plant growth by regulating the biosynthesis, transport, and signaling of auxin. In this review, we summarize recent progress in the biosynthesis and the broad roles of SA in regulating plant growth during defense responses. Further understanding of SA production and its regulation of both defense and growth will be critical for developing better knowledge to improve the disease resistance and fitness of crops.
Topics: Indoleacetic Acids; Plant Development; Plant Immunity; Plants; Receptor Cross-Talk; Salicylic Acid; Stress, Physiological
PubMed: 34769103
DOI: 10.3390/ijms222111672 -
Current Opinion in Plant Biology Aug 2003Salicylic acid is an important signal molecule in plant defense. In the past two years, significant progress has been made in understanding the mechanism of... (Review)
Review
Salicylic acid is an important signal molecule in plant defense. In the past two years, significant progress has been made in understanding the mechanism of salicylic-acid biosynthesis and signaling in plants. A pathway similar to that found in some bacteria synthesizes salicylic acid from chorismate via isochorismate. Salicylic-acid signaling is mediated by at least two mechanisms, one requiring the NON-EXPRESSOR OF PR1 (NPR1) gene and a second that is independent of NPR1. Feedback loops involving salicylic acid modulate upstream signals. These feedback loops may provide a point for integrating developmental, environmental and other defense-associated signals, and thus fine-tune the defense responses of plants.
Topics: Arabidopsis Proteins; Plant Physiological Phenomena; Salicylic Acid
PubMed: 12873532
DOI: 10.1016/s1369-5266(03)00058-x