Characterization and antifungal activity of a plant peptide expressed in the interaction between Capsicum annuum fruits and the anthracnose fungus.

Álan Chrisleyr Maracahipes,Gabriel Bonan Taveira,Olga Lima Tavares Machado,André Oliveira Carvalho,Rosana Rodrigues,Valdirene Moreira Gomes,Lorran Yves Sousa-Machado

doi:10.1042/bsr20192803

Álan Chrisleyr Maracahipes, Gabriel Bonan Taveira + Show 5 more

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https://doi.org/10.1042/bsr20192803

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Journal: Bioscience reports	Publication Date: Dec 20, 2019
Citations: 14	License type: CC BY 4.0

Affiliation: State University of Norte Fluminense

Abstract

Plant defensins are low molecular weight basic peptides ranging from 5 to 7 kDa, with capacity of inhibiting various pathogens, including fungi. They are present in different tissues of plants, including floral parts and fruits of Capsicum sp. The IIF48 extract, present in immature fruits of Capsicum annuum inoculated with C. gloeosporioides, was able to inhibit up to 100% growth ‘in vitro’ of the fungus Colletotrichum gloeosporioides. The main objective of this work was the purification and antifungal activity characterization of a defense-related plant defensin-like isolated of the IIF48 immature fruits extract. The IIF48 extract was subjected to HPLC purification and 13 fractions were obtained, followed by a tricine gel electrophoresis to obtain the protein profile. The different fractions were submitted to a growth inhibition assay against C. gloeosporioides fungus. Fraction 7 (F7) was the most active causing 73% inhibition. Because of the higher F7 activity and the presence of only a peptide of approximately 5 kDa this fraction was subjected to N-terminal sequencing. F7 fraction was carried out plasma membrane permeabilization assays, induction of intracellular ROS production analysis and investigated mitochondrial membrane potential. The F7 fraction showed significant inhibitory activity on the tested fungus, besides promoting membrane permeabilization, induction of endogenous ROS production in Colletotrichum cells and impairing mitochondrial functionality. The first 18 amino acid sequence of the F7 fraction peptide suggests homology to plant-like defensin and was named IIFF7Ca. We also concluded that IIFF7Ca peptide has an effective antimicrobial action against the fungus C. gloeosporioides.

Highlights

Plant defensins are basic low-molecular-weight peptides ranging from 5 to 6 kDa, have 45 to 55 amino acid residues, with eight conserved cysteine residues linked by four disulfide bonds that ensure increased strength and structural stability
The protein extract IIF48 that was previously described by our research group, presented low-molecular-weight bands ranging from 5 to 11 kDa and presented a band of 5 kDa that did not appear in the control treatment (CIF48 without inoculation) [7]
The IIF48 sample was subjected to reversed-phase chromatography, and after fractionation using

Summary

Introduction

Plant defensins are basic low-molecular-weight peptides ranging from 5 to 6 kDa, have 45 to 55 amino acid residues, with eight conserved cysteine residues linked by four disulfide bonds that ensure increased strength and structural stability. Studies have shown that plant defensins have inhibitory activity against fungal species of the genera Colletotrichum, Fusarium, Aspergillus, Alternaria, Nectria and Candida, among others. The inhibitory activity and the concentration required for inhibition were dependent upon the specific fungus and on the defensin [1]. Several of the plant defensins showed a constitutive expression pattern with up-regulation following pathogens attacks, and different biotic or abiotic stresses. The present study verified that the interaction of the defensins with the License 4.0 (CC BY)

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