Phylogeny and characterization of endophytic bacteria isolated from the rhizosphere of pea seedlings (<i>Pisum sativum</i> L.)

We have previously shown the ability of endophytic bacteria to move out of the pea plant seedling roots (Pisum sativum L.) into the rhizosphere. In this study, six distinct bacterial strains were isolated from the root growth medium during the cultivation of seedlings in an aqueous medium. By analyzing the nucleotide sequence of 16S rRNA genes, the taxonomic position of these strains was established, their morphological and cultural parameters were assessed, the activity of hydrolytic enzymes (pectinase, cellulase, protease) and the IAA-producing capability were examined. It has been observed that the quantity of endophytic bacteria that appears on the root surface during the growth of pea seedlings significantly surpasses the quantity present in the root tissues. It is assumed that hydrolytic enzymes such as pectinase and cellulase are involved in the release of bacteria into the external environment, causing the destruction of carbohydrate structures in plant cell walls. The metabolic parameters established in the studied strains and the significance of these endophytic bacteria for the host plant after their exit from the roots into the rhizosphere are under discussion.