SYM82 of Lotus japonicus is required for symbiosis of rhizobia and arbuscular mycorrhizal fungi

Abstract

Legume plants establish symbiosis with rhizobia and arbuscular mycorrhizal fungi in root. In this study, we have analyzed Ljsym82, a symbiotic mutant of Lotus japonicus acc. Gifu. When rhizobia were infected with Ljsym82, this mutant formed many bumps, but failed to develop mature nodules. Infection thread growth was arrested in the root hair. When arbuscular mycorrhizal fungi were infected, their internal hyphae could invade in cortical cells, but early senescence of arbuscules was induced. By mapping analysis, it was suggested that this gene was located at the linkage group 2. After the locus was narrowed to roughly 20 kbp, Mutation point was identified by sequence analysis of candidate genes. Putative protein consisted of 518 amino acid residues. In this mutant, nonsense mutation was occurred at 107th amino acid. This gene did not possess any known domain.