A Region on the Upper Arm of Chromosome 5 of Medicago truncatula is Highly Syntenic to the SYM2 Region of PEA

The long history of pea (Pisum sativum) genetics has resulted in many symbiotic mutants. Molecular characterization of the genes involved is important for a better understanding of plant processes involved in the nodulation process. However, none of the genetically identified SYM genes have been cloned, mainly due to the size of the pea genome, which is relatively large basepairs per haploid genome). A few model legume plant species with a small genome have been selected, namely Lotus japonicus and Medicago truncatula. For both species a collection of symbiotic mutants will be isolated. However, up to now in pea, there are several mutants available which show a unique phenotype not yet identified either in L. japonicus or in M. truncatula. As examples of such mutants we like to mention NOD3 and SYM2.