CASUARINACEAE-FRANKIA SYMBIOSIS - MOLECULAR STUDY OF THE HOST-PLANT

Casuarinas are actinorhizal tropical trees belonging to the family Cas uarinaceae and are capable of forming nitrogen fixing root nodules wit h an actinomycetal microorganism known as Frankia. In order to identif y genes involved in Casuarina-Frankia symbiosis, a Casuarina glauca ro ot nodule cDNAs library was constructed and screened differentially wi th root and nodule cDNA probes. Here, we present the characterization of several C. glauca transcripts identified by sequence analysis of cD NA clones. In order to study the symbiotic genes in Casuarina glauca r oot nodules, two genetic transformation systems were developed in Casu arinaceae using Agrobacterium rhizogenes and Agrobacterium tumefaciens . Expression of symbiotic genes was studied in transgenic root nodules .