Epiphytic microorganisms on strawberry plants (Fragaria ananassa cv. Elsanta): identification of bacterial isolates and analysis of their interaction with leaf surfaces

Abstract

Epiphytic bacteria were isolated from strawberry plants cultivated in the field or in the greenhouse in order to investigate their interaction with leaf-surface transport properties. Colonization of lower leaf sides was higher on field-grown plants, whereas upper leaf sides were more densely colonized on plants cultivated in the greenhouse. Fungal isolates significantly contributed to total microbial biomass on leaf surfaces of greenhouse-grown strawberry plants, whereas these organisms were rarely abundant on field-grown plants. Microscopic investigations of bacteria in the phyllosphere revealed that the highest densities of bacteria were observed on living trichomes, which obviously provide a source of nutrients. Isolated strains were characterized by colony morphology, microscopy and histochemistry. About 324 isolated bacterial strains were grouped into 38 morphotypes. Of the morphotypes, 12 were identified by 16S rRNA gene sequencing. Dominating bacteria belonged to the genus Pseudomonas, Stenotrophomonas, Bacillus and Arthrobacter. Cuticular water permeability of isolated cuticular membranes and intact leaf disks was measured before and after treatment with one of the most prominent epiphytic bacteria, Pseudomonas rhizosphaerae. Results showed that cuticular transpiration was significantly increased by P. rhizosphaerae. This shows that leaf-surface properties, such as cuticular water permeability, can be influenced by bacteria, leading to improved habitable conditions in the phyllosphere.

Phyllopshere Bacterial Community Structure of Spinach (Spinacia oleracea) as Affected by Cultivar and Environmental Conditions at Time of Harvest

“…The plant stage of development and leaf age may impact the bacterial community on the phyllopshere [9,11,28]. Previous studies indicate that microbial diversity patterns differed between immature and mature plants, with increased species richness seen in younger leaves of olive trees and on sugar beet leaves [11,13].…”

“…"Menorca" and "Unipak" had more anatomical leaf features such as glandular trichomes and stomata (Table 3, Figure 1), where microbial aggregates and bacteria were observed. Veins, hooked trichomes and glandular trichomes, have preferential distribution associated with bacterial aggregates on leaf surfaces of beans [32] and strawberry leaves [28]. Foodborne pathogens such as Listeria monocytogenes and E. coli O157:H7 associated with leaves of Arabidopsis thaliana and spinach, respectively, have also shown to be associated with these plant structures [7,33].…”

pH-dependent permeation of amino acids through isolated ivy cuticles is affected by cuticular water sorption and hydration shell size of the solute

“…In addition, the cuticle counteracts the leaching of nutrients and metabolites from the inner leaf tissues (Tukey, 1970). Leaf surfaces represent a habitat for consortia of epiphyllic micro-organisms (Krimm et al , 2005; Leveau, 2006) and the availability of nutrients is a prerequisite for colonization. Carbohydrates and amino acids are frequently found on leaf surfaces (Derridj, 1996).…”

Ice nucleation active bacteria from pistachio in Kerman Province, Iran

“…Phenotypic characteristics Fresh cultures were prepared from each strain and all were subjected to key phenotyping test (Krimm et al 2005). The KOH test was used to determine the Gram reaction.…”