Table of Contents
ISRN Ecology
Volume 2011, Article ID 938546, 10 pages
http://dx.doi.org/10.5402/2011/938546
Research Article

Analysis of the Bacterial Diversity Associated with the Roots of Maize (Zea mays L.) through Culture-Dependent and Culture-Independent Methods

1Departamento de Microbiología e Inmunología, Facultad de Ciencias Exactas, Físico-Químicas y Naturales, Universidad Nacional de Río Cuarto, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Ruta Nac. 36 Km 601, Río Cuarto, 5800 Córdoba, Argentina
2Departamento de Ciencias Naturales, Facultad de Ciencias Exactas, Físico-Químicas y Naturales, Universidad Nacional de Río Cuarto, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Ruta Nac. 36 Km 601, Río Cuarto, 5800 Córdoba, Argentina
3Centro de Ciencias Genómicas, Programa de Ecología Genómica, Universidad Nacional Autónoma de México, Apartado Postal 565-A, Av. Universidad s/n., Col. Chamilpa, C.P. 62210, Cuernavaca, Morelos, Mexico

Received 19 January 2011; Accepted 24 February 2011

Academic Editor: M. A. Molina-Montenegro

Copyright © 2011 Paola Pereira et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The present study investigated bacterial diversity associated with the roots of maize through the use of culture-dependent and culture-independent methods. Bacterial 16S–23S rDNA internal transcribed spacer sequences (ITS) primers were used to amplify sequences obtained directly from the root matrix by Percoll gradient separation. This assay showed that γ-Proteobacteria within Enterobacter, Erwinia, Klebsiella, Pseudomonas, and Stenotrophomonas genera were predominant groups. The culturable component of the bacterial community was also assessed, revealing that the predominant group was Firmicutes, mainly of Bacillus genus, while Achromobacter, Lysinibacillus, and Paenibacillus genera were rarely found in association with the roots. Only two genera within γ-Proteobacteria, Enterobacter and Pseudomonas, were found in the culture collection. Differences in richness and diversity between the rhizospheric and endophytic bacterial communities were also evidenced. The spectrum of bacteria naturally associated with maize roots is wide and the magnitude of such diversity will depend on the methods chosen for analysis. The knowledge of this spectrum will facilitate the search of microorganisms capable of exerting antagonism to diverse pathogens or detecting plant growth enhancers.