Isolation of a cDNA encoding a homologue of ribosomal protein L36 in a marine green alga, Enteromorpha compressa.

The multicellular green alga Enteromorpha (Ulvales, Chlorophyta) includes some economically valuable species cultivated as "Aonori" (green laver) in Japan. The life cycle of the genus Enteromorpha consists of gametophytic and sporophytic foliaceous thalli, which are indistinguishable in appearance. Both male and female gametes of E. compressa can grow parthenogenetically and can be cloned into gametophytic thalli; thus, separate cultures of male and female gametophytes can be perpetuated from unfused gametes. It is possible to collect a quantity of these clonal gametophytic thalli for the experimental materials in only a few weeks; it completes its life cycle in laboratory culture within a few months and has a comparatively small number of chromosomes (n = 9) in the haploid phase. The haploid genome size of E. compressa (0.9 x 10 bp) is a little smaller than that of Arabidopsis thaliana (unpublished data). It is easy to induce gametogenesis in E. compressa artificially (Kuwano et al., to be published elsewhere), therefore, we can easily collect experimental materials at synchronized developmental stages. These characters of E. compressa indicate that it is advantageous to study for genetic analysis, including both classical and modern molecular investigations in marine sciences. According to phylogenetic analysis, sequence comparisons suggest that all living green plants belong to one of two major phyla: Streptophyta (land plants and their closest green algal relatives, the charophytes); and Chlorophyta (all other green algae). It should be noted that molecular biology studies of the development of Chlorophyta including Enteromorpha are quite limited, although its phylogenetic position, which is not linked directly with land plants, is very unique.