Antifungal proteins: targets, mechanisms and prospective applications

Theis, Torsten; Ståhl, Ulf

doi:10.1007/s00018-003-3231-4

Cited by 192 publications

(141 citation statements)

References 164 publications

(191 reference statements)

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“…Locked in an arms race, avr and R-genes are under strong pressure to evade and reestablish detection. Arabidopsis (Arabidopsis thaliana) has more than 150 of the nucleotide-bindingsite/Leu-rich-repeat (NBS/LRR) class of R-genes (Baumgarten et al, 2003;Meyers et al, 2003).Considerable effort has been made to elucidate the prevalence and activity of pathogenesis-related proteins such as antimicrobial peptides (AMPs; Broekaert et al, 1997;Garcia-Olmedo et al, 1998;Theis and Stahl, 2004). AMPs are widespread throughout the plant kingdom and include thionins, defensins, lipid transfer proteins, knottins, heveins, and snakins.…”

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Genome Organization of More Than 300 Defensin-Like Genes in Arabidopsis

et al. 2005

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Defensins represent an ancient and diverse set of small, cysteine-rich, antimicrobial peptides in mammals, insects, and plants. According to published accounts, most species' genomes contain 15 to 50 defensins. Starting with a set of largely nodulespecific defensin-like sequences (DEFLs) from the model legume Medicago truncatula, we built motif models to search the nearcomplete Arabidopsis (Arabidopsis thaliana) genome. We identified 317 DEFLs, yet 80% were unannotated at The Arabidopsis Information Resource and had no prior evidence of expression. We demonstrate that many of these DEFL genes are clustered in the Arabidopsis genome and that individual clusters have evolved from successive rounds of gene duplication and divergent or purifying selection. Sequencing reverse transcription-PCR products from five DEFL clusters confirmed our gene predictions and verified expression. For four of the largest clusters of DEFLs, we present the first evidence of expression, most frequently in floral tissues. To determine the abundance of DEFLs in other plant families, we used our motif models to search The Institute for Genomic Research's gene indices and identified approximately 1,100 DEFLs. These expressed DEFLs were found mostly in reproductive tissues, consistent with our reverse transcription-PCR results. Sequence-based clustering of all identified DEFLs revealed separate tissue-or taxon-specific subgroups. Previously, we and others showed that more than 300 DEFL genes were expressed in M. truncatula nodules, organs not present in most plants. We have used this information to annotate the Arabidopsis genome and now provide evidence of a large DEFL superfamily present in expressed tissues of all sequenced plants.Organisms are constantly confronted with potentially pathogenic microorganisms. Yet, few encounters result in disease, due to the multilayered lines of defense each organism possesses. In vertebrates, adaptive immunity has long held center stage because of its ability to recognize almost any foreign antigen. The ancient innate immune system is equally important and provides a critical line of defense in vertebrates, invertebrates, plants, and insects (Thomma et al., 2002;Beutler, 2004;Bulet et al., 2004;Finlay and Hancock, 2004).In plants, innate immunity occurs via elaborate mechanisms (Dangl and Jones, 2001;Veronese et al., 2003). The plant cell wall serves as a barrier to microbial penetration. Antimicrobial compounds deter would-be invaders. Should penetration occur, recognition leads to the production of reactive oxygen intermediates, cell wall strengthening, activation of protein kinase pathways, and the production of signaling intermediates. Signaling events lead to localized responses such as a hypersensitive response (programmed cell death) or to the release of antimicrobial compounds. The plant is also immunized against unrelated pathogens via systemic acquired resistance (Delaney, 1997;Dong, 2001;Gozzo, 2003).Much attention has focused on the interaction of plant resistance genes (R-genes) and pathoge...

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Genome Organization of More Than 300 Defensin-Like Genes in Arabidopsis

et al. 2005

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“…One of the physiological roles of plant chitinases is to protect plants against fungal pathogens by degrading chitin, a major component of the cell walls of many fungi, 2,3) but researchers poorly understand what characters of chitinases have high antifungal activity. 4) In this study, we attempted to determine both the biochemical characters and the antifungal abilities of chitinases derived from a tropical plant, and we discuss the relationship.…”

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Purification, Characterization, and Antifungal Activity of Chitinases from Pineapple (Ananas comosus) Leaf

Taira¹,

Toma²,

Ishihara³

2005

Bioscience, Biotechnology, and Biochemistry

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Three chitinases, designated pineapple leaf chitinase (PL Chi)-A, -B, and -C were purified from the leaves of pineapple (Ananas comosus) using chitin affinity column chromatography followed by several column chromatographies. PL Chi-A is a class III chitinase having a molecular mass of 25 kDa and an isoelectric point of 4.4. PL Chi-B and -C are class I chitinases having molecular masses of 33 kDa and 39 kDa and isoelectric points of 7.9 and 4.6 respectively. PL Chi-C is a glycoprotein and the others are simple proteins. The optimum pHs of PL Chi-A, -B, and -C toward glycolchitin are pH 3, 4, and 9 respectively. The chitin-binding ability of PL Chi-C is higher than that of PL Chi-B, and PL Chi-A has lower chitin-binding ability than the others. At low ionic strength, PL Chi-B exhibits strong antifungal activity toward Trichoderma viride but the others do not. At high ionic strength, PL Chi-B and -C exhibit strong and weak antifungal activity respectively. PL Chi-A does not have antifungal activity.

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“…Papaya (Carica papaya) and rubber trees make latex and produce a large amount of chitinases in it. [4][5][6] Considering that several plant chitinases exhibit antifungal activity in vivo and/or in vitro, [7][8][9][10] chitinases in latex appear to play an important role in defense against fungal pathogens, but there is little information on the antifungal activity of chitinases in latex. We screened various tropical plants that produce latex for chitinase activity.…”

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confidence: 99%

“…One of the physiological roles of plant chitinases is to protect plants against fungal pathogens by degrading chitin, a major component of the cell walls of many fungi, 9,10) but researchers poorly understand what characteristics of chitinases have high antifungal activity. These enzymes have been grouped into different classes on the basis of their amino acid sequences: class I chitinases, consisting of an N-terminal chitin-binding domain and a catalytic domain linked by a flexible hinge region; class II chitinases, having a catalytic domain homologous to that of class I chitinases but lacking the chitin-binding domain and hinge; and class III chitinases, sharing no homology with class I or class II chitinases.…”

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confidence: 99%