Peptidyl prolyl cis/trans isomerase from Pseudomonas fluorescens encapsulated into biodegradable natural polymers: A potential plant protection agent inducing plant resistance to fungal pathogens

Abstract

Intensive use of pesticides causes pollution of terrestrial and water ecosystems negatively influencing on the biodiversity and human health. Use of bioactive compounds, such as elicitors, able to boost non-specific plant immunity, is a promising alternative to chemical treatments of crops. MF3, a protein from Pseudomonas fluorescens , is able to induce resistance in various crops thus protecting them from a range of plant pathogens, but can be destroyed under field conditions by UV radiation and proteolytic enzymes of plant and microbial origin. MF3 encapsulation in biodegradable polymers, such as poly-3-hydroxybutyrate (PHB) and sodium alginate (ALG) has been shown earlier to shield it against adverse external factors. In this study, we examined the protecting efficiency of both MF3 complexes on three model plant–pathogen systems: “wheat – Parastagonospora nodorum ” (1), “rice – Magnaporthe oryzae ” (2), and “cucumber – Cladosporium cucumerinum ” (3). Both MF3-ALG and MF3-PHB complexes demonstrated a significant disease suppression level varying between 55–80 and 40–60 % in the models 1 and 3, respectively; in the model 2, they completely blocked disease development. A significant protective activity of ALG alone was observed in all three models. For the models 1 and 2, a synergistic interaction between MF3 and ALG in relation to the disease suppression was validated. In several cases (free and encapsulated MF3 in the model 1 and MF3-ALG complex in the model 2), a possible translaminar protective activity was shown. The obtained results confirmed a principal possibility to develop environmentally safe biopesticides based on the MF3 encapsulated in PHB or ALG. • MF3 protein encapsulation in sodium alginate and 3-PHB did not influence on its protecting activity. • Encapsulated MF3 protein improves resistance of wheat, rice, and cucumber against some fungi. • MF3 protein encapsulated in sodium alginate completely protect rice against rice blast. • MF3 and sodium alginate synergistically interacts in two model plant-pathogen systems. • For some cases, MF3 possesses a possible translaminar protecting activity.