Abstract
Since the recovery of the first transgenic plant in the early 1980s, plant transformation technologies have enabled advances in many aspects of basic plant science, including nitrogen-fixing root endosymbioses. Using the biological vectors Agrobacterium tumefaciens and A. rhizogenes, gene constructs have been successfully introduced in the actinorhizal tree species Casuarina glauca, thereby paving the way for functional analysis of the key genes involved in the symbiotic process with the actinobacterium Frankia. In recent years, not only studies of gene promoters in transgenic Casuarinaceae, but also the use of RNA interference to down-regulate genes of interest, have provided new insights into the early stages of the interaction between the root system and the actinobacterium. Opportunities offered by recent developments in genome editing technologies based on the engineered nucleases ZFNs (zinc-finger nucleases), TALENs (transcription activator-like effector nucleases) and RNA-guided CRISPR-Cas (clustered regularly interspaced short palindromic repeats-associated protein/Cas) will be briefly presented.