Isolation of Rhizobia from roots of some legumes and identification using biochemical tests, artificial infection, and molecular test

Abstract

The research was conducted in the Biodiversity Laboratory and the Greenhouse of Syrian National 47 Commission for Biotechnology in Damascus during the years 2019 and 2020 with the aim of isolating and identifying rhizobia from the roots of some wild and culivated legumes.

Samples of leguminous plants (beans, chickpeas, peas, chicory, alfalfa, trifolium, soybeans, vetch, and lentils) were collected from several governorates of the Syrian Arab Republic (Damascus countryside, Homs, Daraa, As-Suwayda, Lattakia, Hama, and Raqqa). 109 bacterial strains were isolated from the root nodules of these plants on Yeast mannitol agar medium. 5 isolates that appeared red on YMA medium with Congo red, and 44 Gram positive isolates were excluded, while the results of biochemical, molecular, and synthetic infection tests showed that 42 isolates belonged to rhizobia, which grew on the nutrient media in the form of creamy, convex, well-edged, and mucous colonies, characterized as positive for catalase, oxidase, BTB, and sugars metabolism (glucose, lactose, maltose), and were negative for MR and gram test, and formed nitrogenous nodules on the roots of the host plants, while 19 isolates showed characteristics contrary to the previously mentioned and therefore they do not belong to the root nodules bacteria