Molecular diversity of rhizobia nodulating the invasive legume Cytisus scoparius in Australia.
OBJECTIVE
To contribute to the understanding of Cytisus scoparius success at invading and establishing itself in Australia.


RESULTS
Root-nodule bacteria isolated from C. scoparius, growing on five different sites and originally introduced to Australia, were compared with isolates from indigenous plants growing in France and isolates from native legumes growing on the same Australian sites as C. scoparius. Small-subunit rDNA from 251 isolates were analysed by PCR-RFLP and representatives from different genospecies were selected for sequencing. Phylogenetic analyses revealed a great diversity of lineages belonging to Bradyrhizobium, with one genospecies being specific for Cytisus both in Australia and in France, Rhizobium and Mesorhizobium and one falling outside the described genera of legume-nodulating bacteria. Principal component analysis showed that the Cytisus Australian rhizobial communities are more similar to each other than to their co-occurring native partners.


CONCLUSIONS
Early established rhizobial symbionts may have an increased probability to contribute inoculum for the development of further nodules.


CONCLUSIONS
This is a first report comparing rhizobia nodulating C. scoparius in its native and exotic environments. Cytisus scoparius symbionts were identified outside the Bradyrhizobium genus and a new lineage of legume-nodulating bacteria was identified.
Lafay
B
B
CSIRO Plant Industry, PO Box 1600, Canberra ACT 2601, Australia. lafay@mpl.ird.fr
Burdon
J J
JJ
D001315:Australia; D001483:Base Sequence; D029865:Cytisus / Q000382:microbiology*; D004269:DNA, Bacterial / Q000032:analysis; D005516:Food Microbiology; D014644:Genetic Variation; D008969:Molecular Sequence Data; D010802:Phylogeny; D018517:Plant Roots / Q000382:microbiology; D012231:Rhizobium / Q000235:genetics* / Q000302:isolation & purification; D017422:Sequence Analysis, DNA; D013559:Symbiosis
D004269:DNA, Bacterial