Utilization of a recombinant defensin from Maize (Zea mays L.) as a potential antimicrobial peptide

Najla Amin T Al Kashgry,Reda Salem,Mahmoud S M Mohamed,Yaser A Almaroai,Ismail Mohamed,Hussein H Abulreesh,Fatma R Waly,Gamal Osman,Iman A El-Sheikh

doi:10.1186/s13568-020-01146-9

Abstract

The search for effective and bioactive antimicrobial molecules to encounter the medical need for new antibiotics is an encouraging area of research. Plant defensins are small cationic, cysteine-rich peptides with a stabilized tertiary structure by disulfide-bridges and characterized by a wide range of biological functions. The heterologous expression of Egyptian maize defensin (MzDef) in Escherichia coli and subsequent purification by glutathione affinity chromatography yielded 2 mg/L of recombinant defensin peptide. The glutathione-S-transferase (GST)-tagged MzDef of approximately 30 kDa in size (26 KDa GST + ~ 4 KDa MzDef peptide) was immunodetected with anti-GST antibodies. The GST-tag was successfully cleaved from the MzDef peptide by thrombin, and the removal was validated by the Tris-Tricine gel electrophoresis. The MzDef induced strong growth inhibition of Rhizoctonia solani, Fusarium verticillioides, and Aspergillus niger by 94.23%, 93.34%, and 86.25%, respectively, whereas relatively weak growth inhibitory activity of 35.42% against Fusarium solani was recorded. Moreover, strong antibacterial activities were demonstrated against E. coli and Bacillus cereus and the moderate activities against Salmonella enterica and Staphylococcus aureus at all tested concentrations (0.1, 0.2, 0.4, 0.8, 1.6, and 3.2 µM). Furthermore, the in vitro MTT assay exhibited promising anticancer activity against all tested cell lines (hepatocellular carcinoma, mammary gland breast cancer, and colorectal carcinoma colon cancer) with IC50 values ranging from 14.85 to 29.85 µg/mL. These results suggest that the recombinant peptide MzDef may serve as a potential alternative antimicrobial and anticancer agent to be used in medicinal application.

Highlights

The higher plants are experiencing a diverse array of biotic stresses such as insects, herbivores as well as diseases caused by phytopathogenic bacteria and fungi throughout their lives in the natural environment
The α-defensins, one group of plant defensins, are small cationic peptides with a molecular weight of approximately 5 kDa, which belong to the family of antimicrobial peptides (AMP) and adopt an amphipathic structure with a wide range of biological functions such as antibacterial, antifungal, antiviral, and anticancer activity without toxicity to mammalian cells
Heterologous expression, and purification of Mz‐Def In this study, a defensin coding sequence was PCR amplified from total genomic DNA isolated from Gz 168 hybrid cultivar of maize (Zea mays L.)

Summary

Introduction

The higher plants are experiencing a diverse array of biotic stresses such as insects, herbivores as well as diseases caused by phytopathogenic bacteria and fungi throughout their lives in the natural environment. These different factors decrease plant productivity due to physical damages and physiological and molecular changes they cause on the growth and development of plants (Singh et al 2020). The β-defensins are involved in the defense system of vertebrates, exhibit a wide range of antimicrobial activities and share similar structures, α-helix, and β-sheet, but with a different topology compared to α-defensins (Montero-Alejo et al 2012; Shafee et al 2016)

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Results

Conclusion