JSTの最近のニュースから

【研究成果】5種類の金属からナノ粒子を合成

【研究成果】次世代発光材料の新製法を開発　赤色ペロブスカイト量子ドットLEDで世界最高発光効率を実現

【研究成果】開花を誘導する遺伝子は朝に働くことを解明　作物の品種改良や収穫時期の制御が可能に

【開催報告】ICTの活用で学び方はどう変わるのか？　サイエンスアゴラ2018でセッションを開催

Marchantia polymorpha is a common species in liverwort (Marchantiophyta) that occupies the basalmost lineage of land plant evolution. M. polymorpha has a long history as a model plant, and the state-of-the-art drawings of those days were published for education in late 19th century. As the gametophyte generation (n) dominates over the sporophyte generation (2n) in the life cycle, it is simple and efficient to take genetic approaches with M. polymorpha. The genome project that is in progress in Joint Genome Institute, U.S.A., with international collaboration including Japanese laboratories. M. polymorpha has relatively a simple genome context with low genetic redundancy and with fewer repetitive sequences, but possesses most genes for genetic regulatory networks that are common to other groups of land plants. With rapid and efficient methods of Agrobacterium-mediated transformation to sporelings and thalli, various molecular approaches for functional analysis of genes, including T-DNA tagging, expression modification, homologous recombination, genome editing and conditional expression, are available for research. M. polymorpha should offer a unique experimental platform to study the evolution and logics of regulatory systems in land plants.

Plants regulate timing of phase transition in response to day length. Over the past 80 years a considerable number of studies have been done on photoreceptors and circadian clock to understand photoperiodism. Today, the factors mediating the physiological response have been examined extensively. However we could not achieve a comprehensive understanding yet, due to their complexity of signaling network. This review provides a brief overview of the current state of photoreceptors, circadian clock and photoperiodic flowering in Arabidopsis thaliana and addresses to the future issues of these research fields. Also we introduce a novel approach to understand a framework of entire signaling pathway from light input to physiological output by using species with low genetic redundancy. In particular, recent studies in the liverwort Marchantia polymorpha, one of emerging model plants in bryophytes, have revealed that it has the most simplified version with all required components for A. thaliana circadian clock and photoperiodic growth-phase regulation. Together with the phylogenetic position as basal land plants, studies with M. polymorpha provide us insights into the evolution of underlying mechanism regulating photoperiodic growth-phase transition.