Epiphytic microflora of poplar clones susceptible and resistant to infection by Dothichiza populea

Abstract

One-year-old poplar shoots (nodes, internodes and lenticels) of clones susceptible to infection by the pathogenic fungus Dothichiza populea, viz. Populus nigra Italica and P. Robusta, resistant ones, viz. P. Grandis and P. Hybrida 275, as well as a hybrid of a susceptible and a resistant clone, viz. P. maximowiczii x P. nigra (P. Kórnik 42), were used. The plate method was employed to determine: 1. the abundance of the epiphytic microflora on a mineral medium with glucose; 2. the quantitative composition of epiphytic communities by determining the numbers of typical bacteria (including rod-shaped, spherical and sporulating forms), actinomycetes and yeasts in microscopic preparations from epiphyte colonies; 3. the abundance and level of activity of epiphytes antagonistic towards Dothichiza populea. In all poplar clones the epiphytic microflora was most abundant on nodes and least abundant on lenticels. In the resistant clones epiphytes were 7 (P. Grandis) to as many as 84 times (P. Hybrida 275) less numerous than in the susceptible ones. In the microflora communities of the susceptible poplars, rod-shaped bacteria were the most abundant, and in the resistant ones and the hybrid, yeasts, which made up from 60% to 70% of the strains tested. Spherical and sporulating bacteria as well as actinomycetes were found in numbers not exceeding 4% of the total number of epiphytes. The proportion of antagonistic microflora in whole epiphytic communities was higher in the resistant clones and the hybrid than in the susceptible clones, with the microflora having a more restrictive effect on the development of the pathogen.

Template Preparation Affects 16S rRNA High-Throughput Sequencing Analysis of Phyllosphere Microbial Communities

“…The global population of phyllosphere microbes is estimated to be ∼10 26 cells ( Lindow and Brandl, 2003 ). Culture-based isolation studies have shown that phyllosphere microbial communities include many important taxa, including plant pathogens, ice nucleation-active bacteria ( Hirano and Upper, 2000 ), decomposers ( Hicks and Silvester, 1985 ), phytohormone producers ( Fett et al, 1987 ), nitrogen fixers ( Furnkranz et al, 2008 ), and antagonists of plant pathogens ( Weyman-Kaczmarkowa and Pedziwilk, 2001 ). Phototrophic microbes also colonize some plant leaves, including rhodopsin-based ones, absorbing different fractions of the light spectrum ( Atamna-Ismaeel et al, 2012b ).…”

Powdery Mildew-Infection Changes Bacterial Community Composition in the Phyllosphere

“…Epiphytic bacteria are the main inhabitants of the phyllosphere, and are estimated to have a density of 10 6 -10 7 CFU cm −2 on a typical leaf (20). Culture-based studies have shown that such bacteria may include plant pathogens, ice nucleation-active bacteria, decomposers, phytohormoneproducers, nitrogen fixers, and antagonists of plant pathogens (8,10,11,14,25,35). Traditionally, bacterial communities in the phyllosphere were thought to be highly variable in both quantity and quality (9, 13, 33).…”

A Direct Method to Isolate DNA from Phyllosphere Microbial Communities without Disrupting Leaf Tissues

“…Epiphytic bacteria are the main inhabitants of the phyllosphere, and are estimated to have a density of 10 6 to 10 7 CFU cm −2 on a typical leaf 14) . Traditional isolation studies have shown that such bacteria include plant pathogens, ice nucleation-active bacteria, decomposers, phytohormone producers, nitrogen fixers, and antagonists of plant pathogens 3,4,6,8,17,26) . However, recent studies have revealed that many microorganisms in this environment are non-culturable.…”