Plant Defensins from a Structural Perspective

Kovaleva, Valentina; Bukhteeva, Irina; Kit, Oleg; Nesmelova, Irina V.

doi:10.3390/ijms21155307

Cited by 59 publications

(55 citation statements)

References 135 publications

(328 reference statements)

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“…The different composition of the nematode and fungi epidermis suggests that the recognition mechanisms of the innate immunity system must be unrelated. Indeed, differential activation is confirmed for different groups of defensin peptides [ 11 ]. These mechanisms, however, are more compound than simple membrane permeabilization prompted by several small antimicrobial peptides.…”

Section: Discussionmentioning

confidence: 99%

“…Plant defensins are characterized as small, highly stable, cysteine-rich cationic peptides possessing a characteristic cysteine-stabilized alpha-beta protein fold [ 10 ]. Despite their structural similarities, plant defensins show great amino acid diversity, while minor structural modifications can dramatically modify activity spectra [ 11 ].…”

Section: Introductionmentioning

confidence: 99%

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Structural Diversity and Highly Specific Host-Pathogen Transcriptional Regulation of Defensin Genes Is Revealed in Tomato

Nikoloudakis

Pappi²,

Markakis³

et al. 2020

IJMS

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Defensins are small and rather ubiquitous cysteine-rich anti-microbial peptides. These proteins may act against pathogenic microorganisms either directly (by binding and disrupting membranes) or indirectly (as signaling molecules that participate in the organization of the cellular defense). Even though defensins are widespread across eukaryotes, still, extensive nucleotide and amino acid dissimilarities hamper the elucidation of their response to stimuli and mode of function. In the current study, we screened the Solanum lycopersicum genome for the identification of defensin genes, predicted the relating protein structures, and further studied their transcriptional responses to biotic (Verticillium dahliae, Meloidogyne javanica, Cucumber Mosaic Virus, and Potato Virus Y infections) and abiotic (cold stress) stimuli. Tomato defensin sequences were classified into two groups (C8 and C12). Our data indicate that the transcription of defensin coding genes primarily depends on the specific pathogen recognition patterns of V. dahliae and M. javanica. The immunodetection of plant defensin 1 protein was achieved only in the roots of plants inoculated with V. dahliae. In contrast, the almost null effects of viral infections and cold stress, and the failure to substantially induce the gene transcription suggest that these factors are probably not primarily targeted by the tomato defensin network.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Structural Diversity and Highly Specific Host-Pathogen Transcriptional Regulation of Defensin Genes Is Revealed in Tomato

Nikoloudakis

Pappi²,

Markakis³

et al. 2020

IJMS

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“…These peptides comprise a diverse group of short, cysteinerich proteins, some of which are also known as Pathogenesis-Related (PR) proteins. AMPs, which are ubiquitous in higher plants, are characterized by a remarkable primary sequence variation and high stability of their three-dimensional protein structure maintained by disulfide bonds formed by highly conserved cysteine residues (Campos et al, 2018;Kovaleva et al, 2020). Based on their tertiary structure, AMPs are classified into defensins, thionins, lipid-transfer proteins, heveins, and other multigene families.…”

Section: Antimicrobial Peptides As Potential Markers For the Early Dementioning

confidence: 99%

Plant Defense Proteins as Potential Markers for Early Detection of Forest Damage and Diseases

Nosenko

Hanke-Uhe

Heine

et al. 2021

Front. For. Glob. Change

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“…Plant defensins are approximately 50 residues in length and contain eight conserved cysteine residues forming four disulfide bonds that increase stability against proteases, temperature and pH [ 11 – 14 ]. Plant defensins belong to the cis-defensin superfamily that have a characteristic antiparallel β-sheet bound to an α-helix by two disulfide bonds (Fig.…”

Section: Introductionmentioning

confidence: 99%

Proteomic response of Escherichia coli to a membrane lytic and iron chelating truncated Amaranthus tricolor defensin

et al. 2021

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Background Plant defensins are a broadly distributed family of antimicrobial peptides which have been primarily studied for agriculturally relevant antifungal activity. Recent studies have probed defensins against Gram-negative bacteria revealing evidence for multiple mechanisms of action including membrane lysis and ribosomal inhibition. Herein, a truncated synthetic analog containing the γ-core motif of Amaranthus tricolor DEF2 (Atr-DEF2) reveals Gram-negative antibacterial activity and its mechanism of action is probed via proteomics, outer membrane permeability studies, and iron reduction/chelation assays. Results Atr-DEF2(G39-C54) demonstrated activity against two Gram-negative human bacterial pathogens, Escherichia coli and Klebsiella pneumoniae. Quantitative proteomics revealed changes in the E. coli proteome in response to treatment of sub-lethal concentrations of the truncated defensin, including bacterial outer membrane (OM) and iron acquisition/processing related proteins. Modification of OM charge is a common response of Gram-negative bacteria to membrane lytic antimicrobial peptides (AMPs) to reduce electrostatic interactions, and this mechanism of action was confirmed for Atr-DEF2(G39-C54) via an N-phenylnaphthalen-1-amine uptake assay. Additionally, in vitro assays confirmed the capacity of Atr-DEF2(G39-C54) to reduce Fe3+ and chelate Fe2+ at cell culture relevant concentrations, thus limiting the availability of essential enzymatic cofactors. Conclusions This study highlights the utility of plant defensin γ-core motif synthetic analogs for characterization of novel defensin activity. Proteomic changes in E. coli after treatment with Atr-DEF2(G39-C54) supported the hypothesis that membrane lysis is an important component of γ-core motif mediated antibacterial activity but also emphasized that other properties, such as metal sequestration, may contribute to a multifaceted mechanism of action.

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Plant Defensins from a Structural Perspective

Cited by 59 publications

References 135 publications

Structural Diversity and Highly Specific Host-Pathogen Transcriptional Regulation of Defensin Genes Is Revealed in Tomato

Structural Diversity and Highly Specific Host-Pathogen Transcriptional Regulation of Defensin Genes Is Revealed in Tomato

Plant Defense Proteins as Potential Markers for Early Detection of Forest Damage and Diseases

Proteomic response of Escherichia coli to a membrane lytic and iron chelating truncated Amaranthus tricolor defensin

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