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Applied and Environmental Soil Science
Volume 2017 (2017), Article ID 2561428, 10 pages
https://doi.org/10.1155/2017/2561428
Research Article

Diazotrophic Bacterial Community of Degraded Pastures

1Microbial Genetics and Biotechnology Laboratory, Academic Unit of Garanhuns, Rural Federal University of Pernambuco, 55290-000 Garanhuns, PE, Brazil
2Department of Agricultural Microbiology, Superior School of Agriculture “Luiz de Queiroz”, University of São Paulo, 13418-900 Piracicaba, SP, Brazil
3Department of Agronomy, Rural Federal University of Pernambuco, 52171-900 Recife, PE, Brazil

Correspondence should be addressed to Fernando José Freire; rb.eprfu@erierf.odnanref

Received 5 April 2017; Revised 29 June 2017; Accepted 5 July 2017; Published 6 August 2017

Academic Editor: Amaresh K. Nayak

Copyright © 2017 João Tiago Correia Oliveira 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

Pasture degradation can cause changes in diazotrophic bacterial communities. Thus, this study aimed to evaluate the culturable and total diazotrophic bacterial community, associated with regions of the rhizosphere and roots of Brachiaria decumbens Stapf. pastures in different stages of degradation. Samples of roots and rhizospheric soil were collected from slightly, partially, and highly degraded pastures. McCrady’s table was used to obtain the Most Probable Number (MPN) of bacteria per gram of sample, in order to determine population density and calculate the Shannon-Weaver diversity index. The diversity of total diazotrophic bacterial community was determined by the technique of Denaturing Gradient Gel Electrophoresis (DGGE) of the nifH gene, while the diversity of the culturable diazotrophic bacteria was determined by the Polymerase Chain Reaction (BOX-PCR) technique. The increase in the degradation stage of the B. decumbens Stapf. pasture did not reduce the population density of the cultivated diazotrophic bacterial community, suggesting that the degradation at any degree of severity was highly harmful to the bacteria. The structure of the total diazotrophic bacterial community associated with B. decumbens Stapf. was altered by the pasture degradation stage, suggesting a high adaptive capacity of the bacteria to altered environments.