Adsorption of Recombinant Human β-Defensin 2 and Two Mutants on Mesoporous Silica Nanoparticles and Its Effect against Clavibacter michiganensis subsp. michiganensis

Abstract

Solanum lycopersicum L. is affected among other pests and diseases, by the actinomycete Clavibacter michiganensis subsp. michiganensis (Cmm), causing important economic losses worldwide. Antimicrobial peptides (AMPs) are amphipathic cationic oligopeptides with which the development of pathogenic microorganisms has been inhibited. Therefore, in this study, we evaluate antimicrobial activity of mesoporous silica nanoparticles (MSN5.4) loaded with human β-defensin-2 (hβD2) and two mutants (TRX-hβD2-M and hβD2-M) against Cmm. hβD2, TRX-hβD2-M and hβD2-M presented a half-maximum inhibitory concentration (IC50) of 3.64, 1.56 and 6.17 μg/mL, respectively. MSNs had average particle sizes of 140 nm (SEM) and a tunable pore diameter of 4.8 up to 5.4 nm (BJH). AMPs were adsorbed more than 99% into MSN and a first release after 24 h was observed. The MSN loaded with the AMPs inhibited the growth of Cmm in solid and liquid media. It was also determined that MSNs protect AMPs from enzymatic degradation when the MSN/AMPs complexes were exposed to a pepsin treatment. An improved AMP performance was registered when it was adsorbed in the mesoporous matrix. The present study could expand the applications of MSNs loaded with AMPs as a biological control and provide new tools for the management of phytopathogenic microorganisms.

Bacillus Strains as Effective Biocontrol Agents Against Phytopathogenic Bacteria and Promoters of Plant Growth

“…This may include the use of genetically edited plants with reduced water consumption or increased drought tolerance via CRISPR/Cas9 gene editing, without compromising yield [ 50 ], or the engineering of plants to resist pathogen attacks, as seen in the case of Huanglongbing affecting citrus worldwide [ 51 ]. Other options include the use of nanoparticles loaded with antimicrobials for controlling various phytopathogens [ 52 ]. These alternatives should be considered part of integrated crop management.…”

An Update on the Therapeutic Potential of Antimicrobial Peptides against Acinetobacter baumannii Infections

“…HBD-2 and HBD-3 are human β-defensins found on the epithelial lining of respiratory and urinary tracts. Interestingly, they appear more effective against MDR clinical isolates [ 237 ]. The other β-defensin, HBD-3, combines an α-helical segment with a β strand and can kill non-MDR and MDR A. baumannii isolates in serum-free conditions [ 238 ].…”

Delivery of Therapeutic Biopolymers Employing Silica-Based Nanosystems

“…To conclude with the silica-based delivery of antibacterial proteins, it is noteworthy to highlight, too, the potential of human proteins for antibacterial therapies on other species. Along this line, Marcelino-Pérez et al reported the effect of a recombinant human β-defensin 2 onto mesoporous silica nanoparticles as phytosanitary against Clavibacter michiganensis subspecies michiganensis [ 135 ]. In this work the authors obtained the human β-defensin 2 upon transfection of the engineered plasmid in E. coli .…”