Sexual Reproduction of a Unicellular Charophycean Alga, Closterium peracerosum-strogosum-littorale Complex

The genus Closterium is the best characterized charophycean green alga with respect to the process of sexual reproduction. Two sex pheromones , named PR-IP Inducer and PR-IP , that are involved in the progress of these processes were physiologically and biochemically characterized and the corresponding genes were cloned. These pheromones function in most steps of sexual reproduction. The timing after mixing, appropriate concentrations of the pheromones, and conditions of the cells are all essential for pheromones to be functional. To elucidate the molecular mechanisms of sexual reproduction in detail, molecular tools such as expressed sequence tag (EST), microarray analysis, and genetic transformation systems have been established. These methods will enable us to clarify the details of sexual reproduction in the near future.