Project description:The Streptophyta include unicellular and multicellular charophyte green algae and land plants. Colonization of the terrestrial habitat by land plants was a major evolutionary event that has transformed our planet. So far lack of genome information on unicellular charophyte algae hinders our understanding of the origin and the evolution from unicellular to multicellular life in Streptophyta. This work reports the high-quality reference genome and transcriptome of Mesostigma viride, a single-celled charophyte alga with a position at the base of Streptophyta. There are abundant segmental duplications and transposable elements in M. viride, which contribute to a relatively large genome with high gene content compared to other algae and early diverging land plants. This work identifies the origin of genetic tools that multicellular Streptophyta have inherited and key genetic innovations required for evolution of land plants from unicellular aquatic ancestors. The findings shed light on the age-old questions of the evolution of multicellularity and the origin of land plants.
Project description:The Streptophyta include unicellular and multicellular charophyte green algae and land plants. Colonization of the terrestrial habitat by land plants was a major evolutionary event that has transformed our planet. So far lack of genome information on unicellular charophyte algae hinders our understanding of the origin and the evolution from unicellular to multicellular life in Streptophyta. This work reports the high-quality reference genome and transcriptome of Mesostigma viride, a single-celled charophyte alga with a position at the base of Streptophyta. There are abundant segmental duplications and transposable elements in M. viride, which contribute to a relatively large genome with high gene content compared to other algae and early diverging land plants. This work identifies the origin of genetic tools that multicellular Streptophyta have inherited and key genetic innovations required for evolution of land plants from unicellular aquatic ancestors. The findings shed light on the age-old questions of the evolution of multicellularity and the origin of land plants.
Project description:The Streptophyta include unicellular and multicellular charophyte green algae and land plants. Colonization of the terrestrial habitat by land plants was a major evolutionary event that has transformed our planet. So far lack of genome information on unicellular charophyte algae hinders our understanding of the origin and the evolution from unicellular to multicellular life in Streptophyta. This work reports the high-quality reference genome and transcriptome of Mesostigma viride, a single-celled charophyte alga with a position at the base of Streptophyta. There are abundant segmental duplications and transposable elements in M. viride, which contribute to a relatively large genome with high gene content compared to other algae and early diverging land plants. This work identifies the origin of genetic tools that multicellular Streptophyta have inherited and key genetic innovations required for evolution of land plants from unicellular aquatic ancestors. The findings shed light on the age-old questions of the evolution of multicellularity and the origin of land plants.
Project description:The Streptophyta include unicellular and multicellular charophyte green algae and land plants. Colonization of the terrestrial habitat by land plants was a major evolutionary event that has transformed our planet. So far lack of genome information on unicellular charophyte algae hinders our understanding of the origin and the evolution from unicellular to multicellular life in Streptophyta. This work reports the high-quality reference genome and transcriptome of Mesostigma viride, a single-celled charophyte alga with a position at the base of Streptophyta. There are abundant segmental duplications and transposable elements in M. viride, which contribute to a relatively large genome with high gene content compared to other algae and early diverging land plants. This work identifies the origin of genetic tools that multicellular Streptophyta have inherited and key genetic innovations required for evolution of land plants from unicellular aquatic ancestors. The findings shed light on the age-old questions of the evolution of multicellularity and the origin of land plants.
Project description:Light control of motility behavior (phototaxis and photophobic responses) in green flagellate algae is mediated by sensory rhodopsins homologous to phototaxis receptors and light-driven ion transporters in prokaryotic organisms. In the phototaxis process, excitation of the algal sensory rhodopsins leads to generation of transmembrane photoreceptor currents. When expressed in animal cells, the algal phototaxis receptors function as light-gated cation channels, which has earned them the name "channelrhodopsins." Channelrhodopsins have become useful molecular tools for light control of cellular activity. Only four channelrhodopsins, identified in Chlamydomonas reinhardtii and Volvox carteri, have been reported so far. By screening light-induced currents among algal species, we identified that the phylogenetically distant flagellate Mesostigma viride showed photoelectrical responses in vivo with properties suggesting a channelrhodopsin especially promising for optogenetic use. We cloned an M. viride channelrhodopsin, MChR1, and studied its channel activity upon heterologous expression. Action spectra in HEK293 cells match those of the photocurrents observed in M. viride cells. Comparison of the more divergent MChR1 sequence to the previously studied phylogenetically clustered homologs and study of several MChR1 mutants refine our understanding of the sequence determinants of channelrhodopsin function. We found that MChR1 has the most red-shifted and pH-independent spectral sensitivity so far reported, matches or surpasses known channelrhodopsins' channel kinetics features, and undergoes minimal inactivation upon sustained illumination. This combination of properties makes MChR1 a promising candidate for optogenetic applications.
Project description:The Streptophyta include unicellular and multicellular charophyte green algae and land plants. Colonization of the terrestrial habitat by land plants is a major evolutionary event that has transformed the planet. So far, lack of genome information on unicellular charophyte algae hinders the understanding of the origin and the evolution from unicellular to multicellular life in Streptophyta. This work reports the high-quality reference genome and transcriptome of Mesostigma viride, a single-celled charophyte alga with a position at the base of Streptophyta. There are abundant segmental duplications and transposable elements in M. viride, which contribute to a relatively large genome with high gene content compared to other algae and early diverging land plants. This work identifies the origin of genetic tools that multicellular Streptophyta have inherited and key genetic innovations required for the evolution of land plants from unicellular aquatic ancestors. The findings shed light on the age-old questions of the evolution of multicellularity and the origin of land plants.
Project description:Digital gene expression analysis by Ht-SuperSAGE (Matsumura et al. 2011. High-Throughput SuperSAGE. Methods Mol Biol.) was carried out to compare gene expression between wild type and mutant cell lines of the green algae Dunaliella tertiolecta under different light levels.
Project description:We report the results of a genome-wide analysis of AS in Arabidopsis thaliana plants exposed to a 2h light pulse given in the middle of the night, a treatment that simulates the effects of early dawn or late dusk signals. This light affects the plant transcriptome at multiple regulatory layers, and that light regulation of mRNA levels of splicing regulatory factors is likely to mediate light effects on AS contributing to adjust plant physiological processes to the prevailing light environment.