Insight into the evolutionary history of symbiotic genes of Robinia pseudoacacia rhizobia deriving from Poland and Japan
- PDF / 639,368 Bytes
- 10 Pages / 595 x 791 pts Page_size
- 57 Downloads / 197 Views
ORIGINAL PAPER
Insight into the evolutionary history of symbiotic genes of Robinia pseudoacacia rhizobia deriving from Poland and Japan Borena Mierzwa · Sylwia Wdowiak-Wróbel · Michai Kalita · Sebastian Gnat · Wanda Maiek
Received: 30 November 2009 / Revised: 25 January 2010 / Accepted: 2 March 2010 / Published online: 20 March 2010 © Springer-Verlag 2010
Abstract The phylogeny of symbiotic genes of Robinia pseudoacacia (black locust) rhizobia derived from Poland and Japan was studied by comparative sequence analysis of nodA, nodC, nodH, and nifH loci. In phylogenetic trees, black locust symbionts formed a branch of their own suggesting that the spread and maintenance of symbiotic genes within Robinia pseudoacacia rhizobia occurred through vertical transmission. There was 99–100% sequence similarity for nodA genes of Robinia pseudoacacia nodulators, 97–98% for nodC, and 97–100% for nodH and nifH loci. A considerable sequence conservation of sym genes shows that the symbiotic apparatus of Robinia pseudoacacia rhizobia might have evolved under strong host plant constraints. In the nodA and nodC gene phylograms, Robinia pseudoacacia rhizobia grouped with Phaseolus sp. symbionts, although they were not closely related to our isolates based on 16S rRNA genes, and with Mesorhizobium amorphae. nifH gene phylogeny of our isolates followed the evolutionary history of 16S rDNA and Robinia pseudoacacia rhizobia grouped with Mesorhizobium genus species. Nodulation assays revealed that Robinia pseudoacacia rhizobia eVectively nodulated their native host and also Amorpha fruticosa and Amorpha californica resulting in a signiWcant enhancement of plant growth. The black locust root nodules are shown to be of indeterminate type.
Communicated by Ursula Priefer. B. Mierzwa · S. Wdowiak-Wróbel · M. Kalita · S. Gnat · W. Maiek (&) Department of Genetics and Microbiology, M. Curie-Skiodowska University, Akademicka 19 St., 20-033 Lublin, Poland e-mail: [email protected]
Keywords Robinia pseudoacacia rhizobia · Phylogeny of sym genes · Nodule structure
Introduction Soil bacteria collectively called rhizobia are able to induce nitrogen-Wxing symbiotic association with roots of leguminous plants. An eVective symbiosis requires several bacterial genes, including nitrogen-Wxation (nif) genes that encode nitrogenase responsible for N2 reduction and nodulation (nod) genes that encode Nod factors which trigger root hair deformations and cortical cell divisions (Debelle et al. 2001; Perret et al. 2000). Nod factors consist of -1,4-linked N-acetyl glucosamine oligosaccharide backbone ranging in length from 3 to 5 residues that are substituted by an N-acyl chain on the non-reducing end and other chemical groups on the glucosamine residues. The backbone of the Nod factors is synthesized under control of the common nod genes, nodA (acyl transferase), nodB (deacetylase), and nodC (N-acetylglucosaminyl transferase), and next it is modiWed by diVerent chemical groups (sulfate, fucosyl) that determine the speciWcity of rhizobium–legu
Data Loading...
