The Microbiome of the ‘Williams’ Pear Variety Grown in the Organic Orchard and Antifungal Activity by the Autochthonous Bacterial and Yeast Isolates

Abstract

The total diversity of bacterial and fungal communities associated with the phyllosphere (fruits and leaves) of the ‘Williams’ pear variety was analyzed in two phenological stages during fruit development and maturation. The antagonistic potential of autochthonous bacterial and yeast isolates against phytopathogenic fungi was also evaluated. A metabarcoding approach revealed Pantoea, Sphingomonas, Hymenobacter, Massilia, and Pseudomonas as dominant bacterial constituents of the pear phyllosphere, whilst most abundant among the fungal representatives identified were Metschnikowia, Filobasidium, Aureobasidiumpullulans, Botrytis cinerea, and Taphrina. The traditional culturable approach revealed that the Pseudomonas genus with P. graminis, P. putida, and P. congelans was most prevalent. The most frequently cultivated fungal representatives belonged to the genus Fusarium with six identified species. A broad range of the antagonistic activity was detected for the Hannaella luteola and Metschnikowia pulcherrima yeasts, significantly affecting the growth of many fungal isolates in the range of 53–70%. Fusarium sporotrichioides was the most susceptible fungal isolate. The autochthonous antagonistic yeasts H. luteola and M. pulcherrima might be powerful biological control agents of postharvest diseases caused by Fusarium spp. and common pathogens like Monilinia laxa, Botrytis cinerea, Alternaria tenuissima, and Cladosporium cladosporioides.

Tillandsia landbeckii phyllosphere and laimosphere as refugia for bacterial life in a hyperarid desert environment

“…Likewise, several of the dominant genera (> 10% relative abundance in a phyllosphere sample; Figure S3) are well-known phyllosphere colonizers. This applies to all dominant Gammaproteobacteria, i.e., Pseudomonas, Massilia, and Ralstonia, as well as Hymenobacter (class Bacteroidia), which have all been reported to occur prominently or as part of a phyllosphere core microbiota on other plants (e.g., [14,51,[60][61][62][63][64][65][66]). Similarly, dominant genera within the class Actinobacteria, i.e., Modestobacter and Kineococcus, are known as phyllosphere colonizers [51,61].…”

Phytostimulation and Synergistic Antipathogenic Effect of Tagetes erecta Extract in Presence of Rhizobacteria

“…The use of a biological control is considered an environmentally friendly alternative for the treatment of phytopathogens [65]. According to Janakiev et al [66], phytopathogenic fungi reduce up to 80% of crop yield, as well as the quality of the crops; the pathogens responsible are fungi from the Fusarium and Monilinia genus [66]. The Fusarium genus representatives are the responsible agents that generate the most significant diseases of the culture worldwide, causing production losses up to 50%.…”

“…Phyllosphere microorganisms play an important role in a plant's health, such as nutrient acquisition, plant growth hormone production, abiotic stress tolerance, and biocontrol abilities of plant pathogens. Biocontrol as a strategy for the suppression of phytopathogens by beneficial microorganisms of the phyllosphere is based on many mechanisms, such as competition, antibiosis, and induction of the host's immune response [66].…”

The Metschnikowia pulcherrima Clade as a Model for Assessing Inhibition of Candida spp. and the Toxicity of Its Metabolite, Pulcherrimin

“…Metschnikowia spp. are mainly isolated from the phyllosphere (flowers, fruits, leaves, and nectars) [ 19 , 20 ]. However, strains belonging to the Metschnikowia genus have also been found in gut mycobiota [ 21 ].…”