Functional Interaction of DMC1 and RAD51 during Meiotic Recombination in Arabidopsis

Meiotic recombination is required for the proper chromosome segregation and plant fertility. The eukaryotic RAD51 gene family has seven ancient paralogs conserved between plants and animals and plays important roles in homologous recombination and/or DNA repair. The Arabidopsis DMC1, RAD51, RAD51C and XRCC3 genes have non-redundant roles in meiotic recombination and are required for normal fertility. However, relationship of these genes is quietly unclear. Here, we show that sufficient amount of RAD51 protein is necessary for meiotic recombination and fertility, with the formation of reduced number of crossovers when RAD51 loci decreased significantly. In addition, the distribution of DMC1 foci is altered. The results suggest distinct role in RAD51 and DMC1 function during meiotic recombination, consistent with previous reports. Together, our results support the hypothesis that sufficient RAD51 is necessary for normal DMC1 function. Given the high degree of conservation of the RAD51-assocaited meiotic recombination, we hypothesize that maintenance of DMC1 function requires sufficient RAD51 in eukaryotes in general.