XVI International Botanical Congess

In the Red Queen model, sexual reproduction can be advantageous under antagonistic coevolution of hosts and parasites. However, empirical evidence supproting this model is still limited. To test this model, a series of comparative studies on sexual and asexual populations of Eupatorium makinoi are on-going. Previous studies showed that (1) incidence of geminivirus infection is much higher in asexual populations, (2) geminivirus infection markedly decreases host's fitness, and (3) host-range determinant genes evolves faster in sexual host populations. Recently, we succeeded in isolating and sequencing homologues of LRR-type plant resistance genes from sexual and asexual plants of E. makinoi. A result of phylogenetic analysis of these sequences and homologous sequences from other flowering plants will be reported.