Lotus japonicus nodulates and fixes nitrogen with the broad host range Rhizobium sp NGR234

Lotus japonicus possesses major advantages as a model legume for the study of plant-microbe interactions. The relative absence of genetic information on its normal microbial partner (i.e., Mesophizobium loti) could limit its utility in research. Here we show for the first time that the broad host range Rhizobium strain NGR234 nodulates and fixes nitrogen in symbiosis with Lotus japonicus ecotypes "Gifu" and "Funakura". We demonstrate that bacterial mutants deficient in nodulation or nitrogen fixation possess the expected phenotype with L. japonicus. Nodulation of L,japonicus was sensitive to nitrate. Vermiculite was an efficient synthetic growth substrate, allowing axenic growth in Magenta jars. The genetic analysis of the Lotus japonicus-Mesorhizobium interaction should be accelerated through the use of this well-defined microsymbiont.