Variation in the active diazotrophic community in rice paddy - nifH PCR-DGGE analysis of rhizosphere and bulk soil
2008 (English)In: Applied Soil Ecology, Vol. 39, 65-75 p.Article in journal (Refereed) Published
Biological nitrogen ﬁxation (BNF) is an important source of nitrogen input in many natural ecosystems. The rice production today depends on large amounts of chemical nitrogen fertilizer, which is an environmental hazard in rice producing areas. Better exploitation of BNF is one way to reduce the use of chemical nitrogen fertilizer in the future. In this study the active diazotrophic community was investigated in nitrogen fertilized and un-fertilized rice ﬁeld soils in Fujian Province, southeast China by PCR-DGGE of nifH mRNA, and the potential community by PCR-DGGE of the nifH gene. A total of 45 sequences representing 33 different sequence types were recovered from the DGGE gels. The retrieved cDNA sequences representing the active population of diazotrophs both in fertilized and un-fertilized soils dispersed throughout the nifH clades (alpha-, beta- and gamma Proteobacteria, Firmicutes and Archaea). Thirteen of the sequence types were most closely related to Azoarcus endophytes indicating widespread associations between heterotrophic nitrogen ﬁxing bacteria and rice (Oryza sativa). The majority of the 13 sequence types were identiﬁed from the cDNA samples, showing that the Azoarcus might be an important active nitrogen ﬁxing diazotroph in the paddy ﬁeld. None of the sequence types were closely related to cyanobacteria, nevertheless previous studies from the same area had documented the presence of cyanobacteira in rice ﬁelds. The lack of identiﬁed cyanobacteria might be due to template discrimination in the PCR reactions, or low abundance of cyanobacteria compared to heterotrophic nitrogen ﬁxing bacteria.
Place, publisher, year, edition, pages
2008. Vol. 39, 65-75 p.
nifH, DGGE, Diazotroph, Community analysis, Gene activity
Ecology Botany Biological Systematics
IdentifiersURN: urn:nbn:se:su:diva-17424DOI: doi:10.1016/j.apsoil.2007.11.008ISI: 000253616800007OAI: oai:DiVA.org:su-17424DiVA: diva2:183945