RESUMO
Casuarina glauca is a fast-growing multipurpose tree belonging to the Casuarinaceae family and native to Australia. It requires limited use of chemical fertilizers due to the symbiotic association with the nitrogen-fixing actinomycete Frankia and with mycorrhizal fungi, which help improve phosphorous and water uptake by the root system. C. glauca can grow in difficult sites, colonize eroded lands and improve their fertility, thereby enabling the subsequent growth of more demanding plant species. As a result, this tree is increasingly used for reforestation and reclamation of degraded lands in tropical and subtropical areas such as China and Egypt. Many tools have been developed in recent years to explore the molecular basis of the interaction between Frankia and C. glauca. These tools include in vitro culture of the host and genetic transformation with Agrobacterium, genome sequencing of Frankia and related studies, isolation of plant symbiotic genes combined with functional analyses (including knock-down expression based on RNA interference), and transcriptome analyses of roots inoculated with Frankia or Rhizophagus irregularis. These efforts have been fruitful since recent results established that many common molecular mechanisms regulate the nodulation process in actinorhizal plants and legumes, thus providing new insights into the evolution of nitrogen-fixing symbioses.
RESUMO
A strain FCg77 was isolated from root nodule of Casuarina glauca by the squashing. The biological characteristics experiments demonstrated that the optimum culture medium was BAP, and the optimum carbon and nitrogen sources were tween-80 and beef. Strain FCg77 could endure 5% salinity. The strain was divided into physiological group AB, and the cell wall chemical composition was type III strain. And combined with the results of back inoculation tests, the strain of FCg77 was preliminary identified as a member of Frankia.