Table 3.
Emergence of novel symbionts of legumes by transfer of sym genes to local bacteria from rhizobia migrated to the novel ecological areas with the help of plant vectors.
| Migrated rhizobia | Transferred genomic elements | Newly emerged symbionts | Plant vectors | Direction of migration (its tentative age in years is given in parenthesis) | References |
|---|---|---|---|---|---|
| Mesorhizobium loti | Chromosomal islands | Mesorhizobium spp. | Lotus corniculatus | Europe → New Zeeland (7) | Sullivan et al. (1995; 2002) |
| Biserrula pelecinus | Mediterranean area → Australia (12) | Nandasena et al. (2006) | |||
| Mesorhizobium spp., Rhizobium spp. | Amorpha fruticosa | North America → China (50) | Wang et al. (1999) | ||
| Robinia pseudoacacia | North America → Europe (300) | Ulrich and Zaspel (2000) | |||
| Rhizobium tropici, R. etli | Sym plasmids | R. leguminosarum bv. phaseoli, R. gallicum, R. giardinii | Phaseolus vulgaris | South and Central America → Europe (500) | Laguerre et al. (1993); Bernal and Graham (2001); Laguerre et al. (2001); Brom et al. (2002) |