AEM
Home Help [Feedback] [For Subscribers] [Archive] [Search] [Contents]
This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrowReprints and Permissions
Right arrow Copyright Information
Right arrow Books from ASM Press
Right arrow MicrobeWorld
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Haukka, K.
Right arrow Articles by Young, J. P. W.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Haukka, K.
Right arrow Articles by Young, J. P. W.
Agricola
Right arrow Articles by Haukka, K.
Right arrow Articles by Young, J. P. W.

 Previous Article  |  Next Article 

Appl Environ Microbiol, February 1998, p. 419-426, Vol. 64, No. 2
0099-2240/98/$04.00+0
Copyright © 1998, American Society for Microbiology. All rights reserved.

Three Phylogenetic Groups of nodA and nifH Genes in Sinorhizobium and Mesorhizobium Isolates from Leguminous Trees Growing in Africa and Latin America

Kaisa Haukka,1,* Kristina Lindström,2 and J. Peter W. Young1

Department of Biology, University of York, York YO1 5YW, United Kingdom,1 and Department of Applied Chemistry and Microbiology, Biocenter 1A, FIN-00014 University of Helsinki, Helsinki, Finland2

Received 7 July 1997/Accepted 5 October 1997

The diversity and phylogeny of nodA and nifH genes were studied by using 52 rhizobial isolates from Acacia senegal, Prosopis chilensis, and related leguminous trees growing in Africa and Latin America. All of the strains had similar host ranges and belonged to the genera Sinorhizobium and Mesorhizobium, as previously determined by 16S rRNA gene sequence analysis. The restriction patterns and a sequence analysis of the nodA and nifH genes divided the strains into the following three distinct groups: sinorhizobia from Africa, sinorhizobia from Latin America, and mesorhizobia from both regions. In a phylogenetic tree also containing previously published sequences, the nodA genes of our rhizobia formed a branch of their own, but within the branch no correlation between symbiotic genes and host trees was apparent. Within the large group of African sinorhizobia, similar symbiotic gene types were found in different chromosomal backgrounds, suggesting that transfer of symbiotic genes has occurred across species boundaries. Most strains had plasmids, and the presence of plasmid-borne nifH was demonstrated by hybridization for some examples. The nodA and nifH genes of Sinorhizobium teranga ORS1009T grouped with the nodA and nifH genes of the other African sinorhizobia, but Sinorhizobium saheli ORS609T had a totally different nodA sequence, although it was closely related based on the 16S rRNA gene and nifH data. This might be because this S. saheli strain was originally isolated from Sesbania sp., which belongs to a different cross-nodulation group than Acacia and Prosopis spp. The factors that appear to have influenced the evolution of rhizobial symbiotic genes vary in importance at different taxonomic levels.

* Corresponding author. Present address: Department of Applied Chemistry and Microbiology, Division of Microbiology, P.O. Box 56, Biocenter 1A, FIN-00014 University of Helsinki, Helsinki, Finland. Phone: 358-9-708-59202. Fax: 358-9-708 59322. E-mail: Kaisa.Haukka{at}Helsinki.Fi.




This article has been cited by other articles:



Home Help [Feedback] [For Subscribers] [Archive] [Search] [Contents]
J. Bacteriol. Microbiol. Mol. Biol. Rev. Eukaryot. Cell All ASM Journals

Copyright © 1998 by the American Society for Microbiology. All rights reserved.