title: Structure and composition of bacterial and fungal community in soil under soybean monoculture in the Brazilian Cerrado.
abstract: Soybean is the most important oilseed cultivated in the world and Brazil is the second major producer. Expansion of soybean cultivation has direct and indirect impacts on natural habitats of high conservation value, such as the Brazilian savannas (Cerrado). In addition to deforestation, land conversion includes the use of fertilizers and pesticides and can lead to changes in the soil microbial communities. This study evaluated the soil bacterial and fungal communities and the microbial biomass C in a native Cerrado and in a similar no-tillage soybean monoculture area using PCR-DGGE and sequencing of bands. Compared to the native area, microbial biomass C was lower in the soybean area and cluster analysis indicated that the structure of soil microbial communities differed. 16S and 18S rDNA dendrograms analysis did not show differences between row and inter-row samples, but microbial biomass C values were higher in inter-rows during soybean fructification and harvest. The study pointed to different responses and alterations in bacterial and fungal communities due to soil cover changes (fallow x growth period) and crop development. These changes might be related to differences in the pattern of root exudates affecting the soil microbial community. Among the bands chosen for sequencing there was a predominance of actinobacteria, γ-proteobacteria and ascomycetous divisions. Even under no-tillage management methods, the soil microbial community was affected due to changes in the soil cover and crop development, hence warning of the impacts caused by changes in land use.
authors.affiliation: Universidade de Brasília , Brasília, DF , Brasil.
authors.forename: J D
authors.initials: JD
authors.lastname: Bresolin
authors.forename: M M C
authors.initials: MM
authors.lastname: Bustamante
authors.forename: R H
authors.initials: RH
authors.lastname: Krüger
authors.forename: M R S S
authors.initials: MR
authors.lastname: Silva
authors.forename: K S
authors.initials: KS
authors.lastname: Perez
keywords: Cropland; DGGE; Land use; Microbial Communities; Savanna
references.citation: J Bacteriol. 1996 Oct;178(19):5636-43
references.pmid: 8824607
references.citation: Appl Environ Microbiol. 2005 Oct;71(10):5710-8
references.pmid: 16204479
references.citation: Microb Ecol. 2005 Jan;49(1):50-62
references.pmid: 15690227
references.citation: Bioinformatics. 2004 Sep 22;20(14):2317-9
references.pmid: 15073015
references.citation: Appl Environ Microbiol. 2001 Feb;67(2):972-6
references.pmid: 11157271
references.citation: Environ Microbiol. 2004 Aug;6(8):769-79
references.pmid: 15250879
references.citation: Arch Microbiol. 2008 Aug;190(2):129-39
references.pmid: 18458875
references.citation: FEMS Microbiol Lett. 2005 Mar 15;244(2):385-90
references.pmid: 15766795
references.citation: Int Microbiol. 2005 Mar;8(1):13-21
references.pmid: 15906257
references.citation: Annu Rev Phytopathol. 2004;42:243-70
references.pmid: 15283667
references.citation: Appl Environ Microbiol. 2005 Nov;71(11):6784-92
references.pmid: 16269710
references.citation: Appl Environ Microbiol. 2001 Oct;67(10):4742-51
references.pmid: 11571180
references.citation: FEMS Microbiol Ecol. 2003 Jul 1;45(2):105-14
references.pmid: 19719621
references.citation: Microbiol Res. 2009;164(1):59-70
references.pmid: 17324564
references.citation: Appl Environ Microbiol. 2004 May;70(5):2692-701
references.pmid: 15128520
references.citation: Appl Environ Microbiol. 1999 Jun;65(6):2614-21
references.pmid: 10347051
references.citation: Appl Environ Microbiol. 2000 Jan;66(1):345-51
references.pmid: 10618246
references.citation: FEMS Microbiol Ecol. 2006 May;56(2):236-49
references.pmid: 16629753