Evaluation of Three Antimicrobial Peptides Mixtures to Control the Phytopathogen Responsible for Fire Blight Disease

Abstract

Fire blight is a severe bacterial plant disease that affects important chain-of-value fruit trees such as pear and apple trees. This disease is caused by Erwinia amylovora, a quarantine phytopathogenic bacterium, which, although highly distributed worldwide, still lacks efficient control measures. The green revolution paradigm demands sustainable agriculture practices, for which antimicrobial peptides (AMPs) have recently caught much attention. The goal of this work was to disclose the bioactivity of three peptides mixtures (BP100:RW-BP100, BP100:CA-M, and RW-BP100:CA-M), against three strains of E. amylovora representing distinct genotypes and virulence (LMG 2024, Ea 630 and Ea 680). The three AMPs’ mixtures were assayed at eight different equimolar concentrations ranging from 0.25 to 6 μM (1:1). Results showed MIC and MBC values between 2.5 and 4 μM for every AMP mixture and strain. Regarding cell viability, flow cytometry and alamarBlue reduction, showed high reduction (>25%) of viable cells after 30 min of AMP exposure, depending on the peptide mixture and strain assayed. Hypersensitive response in tobacco plants showed that the most efficient AMPs mixtures and concentrations caused low to no reaction of the plant. Altogether, the AMPs mixtures studied are better treatment solutions to control fire blight disease than the same AMPs applied individually.

Exploring Active Peptides with Antimicrobial Activity In Planta against Xylella fastidiosa

“…Moreover, some of these AMPs have been successfully expressed in grapevines to control Xf in greenhouses [ 34 , 35 , 36 ]. Thus, AMPs are considered to be promising candidates for controlling this plant pathogen because of their antibacterial activity, low toxicity to the host plants, low propensity to incite bacteria-acquired resistance, and ability to be expressed in plants [ 37 , 38 ]. To search and explore whether there are more effective AMPs against Xf infection, this study has examined for the first time the efficiency of a set of nine potential peptides reported in the literature for their antimicrobial activity against Gram-negative and Gram-positive bacteria with biofilm activity [ 24 , 39 ], contrasting Xf in planta.…”

Wild Malus niedzwetzkyana Dieck ex Koehne as a Genetic Resource for Fire Blight Resistance

“…Eight 5-month-old apple tree saplings were inoculated on 30 June 2021. Phenotypic fire blight responses of the regenerants were evaluated under glasshouse conditions and scored using a categorical scale of severity of infection (0 to 5) [32,33]…”

Host-Defense Peptides as New Generation Phytosanitaries: Low Toxicity and Low Induction of Antimicrobial Resistance

“…A recent report described the activity of three peptide mixtures against three strains of Erwinia amylovora with different genotypes and virulence (LMG 2024, Ea 630 and Ea 680) [68]. This pathogen causes the fire blight disease that affects different plants, including fruit (pear, apple) trees.…”