The variation of actinobacteria species from a vicia sativa cultivated soil microhabitat

Abstract

Actinobacteria is a fairly complex group, intermediate between bacteria and filamentous fungi involved in
producing some infection, in the case of pathogenic strains and recycling of organic matter, as in the case of
nonpathogenic actinobacteria. Literature data have surprised many plant-microorganism interaction, on the one
hand making reference to the mineralization processes involving microorganisms by whom plants necessary
nutrients are released, and on the other hand underlines the influence of plants on the quantity and quality of
microbial population in root area as a result of exudates removed in the natural environment.
Actinobacteria from Frankia genus are counted among bacteria being able to fix nitrogen, and those from the
genus Streptomyces are major producers of antibiotics and numerous secondary metabolites. This paper presents
the study of the composition of Streptomyces genus actinobacteria community from a moderately gleyed
eutricambosoil, grown with vetch (Vicia sativa). The soil is located in the western part of Romania. Biological
material sampling was conducted in October, the depth of 0-20 cm. Isolation and studies of this bacterial group
were performed "in vitro", on Gause 1 culture media. Actinobacteria were collected from four areas (biotopes):
the plot uncultivated with Vicia sativa (control variant), the far rhizospheric area, the hairy root and root areas of vetch plant. Based on effectuated observations, it was noticed that soil microhabitats contain a variety of
actinobacteria and S. albosporeus, S. aureus, S. griseus, S.albus, S. nigrescens, S. lavenduleroseus, S. helvolus.
Numerically dominant species in tested soil samples are: S. griseus, S. albus and S. albosporeus.