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 (pCAMBIA 1304) harboring green fluorescent protein and β‐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.