Improvement of Lotus japonicus hairy root induction and development of a mycorrhizal symbiosis system

PREMISE OF THE STUDY: We describe a highly efficient in vitro Lotus japonicus hairy root transformation system that is useful for the investigation of mycorrhizal symbiosis. METHODS AND RESULTS: The Agrobacterium rhizogenes-mediated transformation method was improved based on the binary plasmid (pCAMBIA1304) harboring green fluorescent protein and beta-glucuronidase genes for rapid detection. Transgenic hairy roots were grown within 13 days. These in vitro-cultured hairy roots can be inoculated with Rhizophagus irregularis, thus facilitating the investigation of the symbiosis between L. japonicus and arbuscular mycorrhizal fungi. CONCLUSIONS: Compared with existing techniques, our protocol provides a simple and efficient A. rhizogenes-mediated transformation system for L. japonicus. The rapid induction of hairy roots can shorten the experimental time by at least one week.