nifH pyrosequencing reveals the potential for location-specific soil chemistry to influence N2-fixing community dynamics

COLLAVINO M.M; H JAMES TRIPP; ILDIKO E FRANK; MARÍA L VIDOZ; PRISCILA A CALDEROLI; MARIANO DONATO; JONATHAN P ZEHR; O MARIO AGUILAR

ENVIRONMENTAL MICROBIOLOGY

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2014 vol. 16 p. 3211 - 3223

1462-2912

A dataset of 87020 nifH reads and 16782 unique nifH protein sequences obtained over two years from four locations across a gradient of agricultural soil types in Argentina were analysed to provide a detailed and comprehensive picture of the diversity, abundance, and responses of the N2-fixing community in relation to differences in soil chemistry and agricultural practices. Phylogenetic analysis revealed an expected high proportion of Alpha-, Beta- and Delta-proteobacteria, mainly relatives to Bradyrhizobium and Methylosinus/Methylocystis, but a surprising paucity of Gamma-proteobacteria. ANOVA and stepwise regression modelling suggested location and treatment-specific influences of soil type on diazotrophic community composition and organic carbon concentrations on nifH diversity. nifH gene abundance, determined by qPCR, was higher in agricultural soils than in non-agricultural soils, and was influenced by soil chemistry under intensive crop rotation but not under monoculture. At some locations, sustainable increased crop yields might be possible through the management of soil chemistry to improve the abundance and diversity of N2-fixing bacteria.