Rhizobia associated with neotropical tree Centrolobium tomentosum used in riparian restoration

Abstract

Centroloblum tomentosum is a tropical legume tree indicated for functional and structural restoration of riparian areas. This study was conducted to characterize the rhizobia isolated from nodules of C. tomentosum in situ and to determine their capacity of renodulation, in an experimental area of land rehabilitation in the Rio Doce valley. Modulation potential to inoculation with 2 selected fast-growing Rhizobium strains separately and a mixed inoculum of arbuscular mycorrhizal fungi was evaluated by the use of antibiotics resistance. Flood disturbance were observed not to affect renodulation by fast-growing strains. DNA fingerprinting RAPD (random amplified polymorphic DNA) and lipopolysaccharides (LPS) profiles were used to examine molecular relationships among field isolates, inoculants and reference strains. Maximal renodulation was exhibited by strain BHCBAb1 after 24 months after transplantation. Centrolobium tomentosum forms symbiosis with fast- and slow-growing Rhizobium strains, and it is suggested that their nursery culture could be improved by inoculation of selected strain under low nitrogen-input conditions.