SRA

Multicellular land plants evolved from charophyte green algae. Lacking the genome of unicellular charophyte green algae hindered the understanding of transition from unicellular to mutilcellular in Streptophyta. Here, we report the high quality reference genome of Mesostigma viride, a single celled charophyte alga with unique position at the base of Streptophyta. We find potential whole genome duplication and large number of transposable element contribute to a relative higher gene content and genome size. We identify the evolutionary novelties and the origin of genetic toolkits that multicellular Streptophyte plants inherited including genes for transcription regulation, phytohormone, epigenetics and photosynthesis. Transcriptomic analysis reveals that M. viride may possess conserved gene regulation and genetic pathway in response to different environmental changes. The genomic resources are an important first step towards the understanding the origin and evolution of Streptophyta.