Changes in microbial community structure and increased metal bioavailability in a metal-contaminated soil and in the rhizosphere of corn (Zea mays)

• Published in: Rhizosphere Vol. 11; p. 100169
• Main Authors: Mahrous, Nahed N., Columbus, Melanie P., Southam, Gordon, Macfie, Sheila M.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.09.2019
• Subjects: Ecoplate; Metal bioavailability; Microbial community; Rhizosphere; Zea mays; Metal bioavailability; Rhizosphere; Zea mays; Ecoplate; Microbial community
• ISSN: 2452-2198; 2452-2198
• DOI: 10.1016/j.rhisph.2019.100169

Metal-contaminated soils are common in many urban areas and are potentially toxic to plants and microorganisms. This study investigated metal bioavailability as well as the microbial (i.e., Bacteria and Archaea) functional and structural diversity in the bulk soil and rhizosphere of corn, Zea mays, grown in two metal-contaminated urban soils. The concentrations of bioavailable metals varied between the two soils and increased over time in bulk soil and in the rhizosphere of Zea mays. The microbial communities in bulk and rhizospheric soils metabolized nearly all of the carbon sources on the Ecoplates™ (including amino acids and amines, carbohydrates, carboxylic acids and polymeric compounds), indicating broad degradative capabilities. Terminal restriction fragment length polymorphism (TRFLP) analysis indicated that the two soils contained very different microbial communities and that at day 30 microbial diversity increased in the rhizosphere of both soils. While the presence of Zea mays roots enhanced microbial community diversity in most cases, the physiological potential of the community in the rhizosphere decreased over time in one of the metal-contaminated soils.