Pseudomonas fluorescens: Prospective green antimicrobial for crops cultivation

Resumen

Background: Throughout the 20th century, pesticides were ubiquitous in agriculture and food production as a method of controlling pest populations and maintaining high yields of crops. However, after decades of uncontrolled pesticide use, their hazardous properties were discovered by scientists. Thus, in the 21st century, the urgency of discovering a form of ecologically safe functional food production has become evident, as it is closely linked to the development of green agriculture. As a result, recent innovations in biological protection of crops have become highly relevant. In this regard, bioactive compounds produced by non-pathogenic Pseudomonas fluorescens, found in soil, may become a prospective bio-control agent of complex influence with potential in the targeted functionalization of crops.

Objectives: Current research is devoted to investigation of the effect of P. fluorescens against the Pectobacterium carotovorum phytopathogen, which significantly reduces the yields of crops. Non-cellular extracts obtained from certain bacteria have been successfully tested against multi-drug-resistant strains of P. carotovorum.

Results: Bactericidal and bacteriostatic activities of lipoprotein and lipopeptide complexes within non-cellular extracts of P. fluorescens were detected. The majority of the studied strains were antibiotic-resistant and produced extracellular proteases, lipases, and polyphenol oxidases (PPOs). Proteases and PPOs are encoded by the bacterial chromosome, while lipases can be plasmid-encoded. They are associated with the resistance and biodegradation in both bacteria but are not transmissible.

Conclusions: Within P. fluorescens samples, 20 strains exhibit antimicrobial activity and contain a wide variety of extracellular enzymes. According to the literature data, the presence of P. fluorescens in environment can enhance the antioxidant status of fruits, stimulate plant growth, boost their immunity and enhance stress tolerance. Based on all of this, P. fluorescens may be considered as a prospective complex biocontrol agent with potential in the functionalization of fruits and vegetables. Further research is recommended to investigate its potential as a green alternative for pesticide-free crop cultivation and soil remediation.

Keywords: Pseudomonas fluorescens, Pectobacterium carotovorum, phytopathogen, crops biological protection, pesticide-free cultivation, food functionalization