Editor: Yaacov Okon
Diversity of nifH gene pools in the rhizosphere of two cultivars of sorghum (Sorghum bicolor) treated with contrasting levels of nitrogen fertilizer
Article first published online: 7 DEC 2007
FEMS Microbiology Letters
Volume 279, Issue 1, pages 15–22, February 2008
How to Cite
Rodrigues Coelho, M. R., De Vos, M., Carneiro, N. P., Marriel, I. E., Paiva, E. and Seldin, L. (2008), Diversity of nifH gene pools in the rhizosphere of two cultivars of sorghum (Sorghum bicolor) treated with contrasting levels of nitrogen fertilizer. FEMS Microbiology Letters, 279: 15–22. doi: 10.1111/j.1574-6968.2007.00975.x
- Issue published online: 19 DEC 2007
- Article first published online: 7 DEC 2007
- Received 24 July 2007; accepted 27 September 2007.First published online 7 December 2007.
- nitrogen fixation;
- diazotrophic communities;
- nifH sequences;
- Sorghum bicolor
The diversity of nitrogen-fixing bacteria was assessed in the rhizospheres of two cultivars of sorghum (IS 5322-C and IPA 1011) sown in Cerrado soil amended with two levels of nitrogen fertilizer (12 and 120 kg ha−1). The nifH gene was amplified directly from DNA extracted from the rhizospheres, and the PCR products cloned and sequenced. Four clone libraries were generated from the nifH fragments and 245 sequences were obtained. Most of the clones (57%) were closely related to nifH genes of uncultured bacteria. NifH clones affiliated with Azohydromonas spp., Ideonella sp., Rhizobium etli and Bradyrhizobium sp. were found in all libraries. Sequences affiliated with Delftia tsuruhatensis were found in the rhizosphere of both cultivars sown with high levels of nitrogen, while clones affiliated with Methylocystis sp. were detected only in plants sown under low levels of nitrogen. Moreover, clones affiliated with Paenibacillus durus could be found in libraries from the cultivar IS 5322-C sown either in high or low amounts of fertilizer. This study showed that the amount of nitrogen used for fertilization is the overriding determinative factor that influenced the nitrogen-fixing community structures in sorghum rhizospheres cultivated in Cerrado soil.