Internalization of a sunflower mannose-binding lectin into phytopathogenic fungal cells induces cytotoxicity

[Display omitted] Lectins are carbohydrate-affinity proteins with the ability to recognize and reversibly bind specific glycoconjugates. We have previously isolated a bioactive sunflower mannose-binding lectin belonging to the jacalin-related family called Helja. Despite of the significant number of...

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Bibliographic Details
Published in:Journal of plant physiology 2018-02, Vol.221, p.22-31
Main Authors: Del Rio, Marianela, de la Canal, Laura, Pinedo, Marcela, Regente, Mariana
Format: Article
Language:English
Subjects:
Antifungal
Antifungal activity
Binding
Biocompatibility
Carbohydrates
Cell death
Cytotoxicity
Flowers & plants
Fungi
Fungicides
Fusarium solani
Glycoconjugates
Helianthus
Helianthus annuus
Internalization
Jacalin-related lectin
Lectins
Mannose
Mannose-binding lectin
Oxidative stress
Pathogens
Plant defense
Plant diseases
Proteins
Sclerotinia sclerotiorum
Toxicity
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Summary:[Display omitted] Lectins are carbohydrate-affinity proteins with the ability to recognize and reversibly bind specific glycoconjugates. We have previously isolated a bioactive sunflower mannose-binding lectin belonging to the jacalin-related family called Helja. Despite of the significant number of plant lectins described in the literature, only a small group exhibits antifungal activity and the mechanism by which they kill fungi is still not understood. The aim of this work was to explore Helja activity on plant pathogenic fungi, and provide insights into its mechanism of action. Through cellular and biochemical experimental approaches, here we show that Helja exerts an antifungal effect on Sclerotinia sclerotiorum, a sunflower pathogen. The lectin interacts with the fungal spore surface, permeabilizes its plasma membrane, can be internalized into the cell and induces oxidative stress, finally leading to the cell death. On the other hand, Helja is inactive towards Fusarium solani, a non-pathogen of sunflower, showing the selective action of the lectin. The mechanistic basis for the antifungal activity of an extracellular jacalin lectin is presented, suggesting its initial interaction with fungal cell wall carbohydrates and further internalization. The implication of our findings for plant defense is discussed.
ISSN:0176-1617
1618-1328
DOI:10.1016/j.jplph.2017.12.001