title: Profiling and Characterization of Small RNAs in the Liverwort, Marchantia polymorpha, Belonging to the First Diverged Land Plants.
abstract: MicroRNAs (miRNAs) have important roles in gene regulation during plant development. Previous studies revealed that some miRNAs are highly shared by most land plants. Recently, the liverwort, Marchantia polymorpha, has been studied by molecular genetic approaches, and sequencing of its genome is currently underway. The expression pattern and the detailed functions of miRNAs during Marchantia development are unknown. Here, we profiled the small RNAs expressed in thalli, antheridiophores and archegoniophores of M. polymorpha using high-throughput RNA sequencing. We revealed that a limited number of miRNAs are shared between M. polymorpha and the moss, Physcomitrella patens, and that a number of miRNAs are M. polymorpha specific. Like other land plants, cognate target genes corresponding to conserved miRNAs could be found in the genome database and were experimentally confirmed to guide cleavage of target mRNAs. The results suggested that two genes in the SPL (SQUAMOSA PROMOTER BINDING-LIKE) transcription factor family, which are regulated by miR156 in most land plants, were instead targeted by two distinct miRNAs in M. polymorpha. In order to demonstrate the physiological roles of miRNAs in M. polymorpha, we constructed an miRNA ectopic expression system to establish overexpression transformants for conserved miRNAs, miR166 and miR319. Ectopic expression of these miRNAs induced abnormal development of the thallus and gemma cups, suggesting that balanced expression of miRNA/target mRNAs has a crucial role in developmental regulation in M. polymorpha. Profiling data on miRNA together with the ectopic expression system would provide new information on the liverwort small RNA world and evolutionary divergence/conservation of small RNA function among land plants.
authors.affiliation: Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Tokyo, 153-8902 Japan.
authors.forename: Masayuki
authors.initials: M
authors.lastname: Tsuzuki
authors.affiliation: Graduate School of Biostudies, Kyoto University, Kyoto, 606-8502 Japan.
authors.forename: Ryuichi
authors.initials: R
authors.lastname: Nishihama
authors.affiliation: Graduate School of Science, Kobe University, Kobe, 657-8501 Japan.
authors.forename: Kimitsune
authors.initials: K
authors.lastname: Ishizaki
authors.affiliation: Synthetic Genomics Research Team, Biomass Engineering Program Cooperation Division, RIKEN Center for Sustainable Resource Science (CSRS), Yokohama, 230-0045 Japan.
authors.forename: Yukio
authors.initials: Y
authors.lastname: Kurihara
authors.affiliation: Synthetic Genomics Research Team, Biomass Engineering Program Cooperation Division, RIKEN Center for Sustainable Resource Science (CSRS), Yokohama, 230-0045 Japan.
authors.forename: Minami
authors.initials: M
authors.lastname: Matsui
authors.affiliation: School of Biological Sciences, Monash University, Melbourne, Victoria 3800, Australia Department of Plant Biology, UC Davis, Davis, CA 95616, USA.
authors.forename: John L
authors.initials: JL
authors.lastname: Bowman
authors.affiliation: Graduate School of Biostudies, Kyoto University, Kyoto, 606-8502 Japan.
authors.forename: Takayuki
authors.initials: T
authors.lastname: Kohchi
authors.affiliation: Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Tokyo, 153-8902 Japan.
authors.forename: Takahiro
authors.initials: T
authors.lastname: Hamada
authors.affiliation: Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Tokyo, 153-8902 Japan solan@bio.c.u-tokyo.ac.jp.
authors.forename: Yuichiro
authors.initials: Y
authors.lastname: Watanabe
mesh_terms: D001483:Base Sequence; D017124:Conserved Sequence; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant; D056426:Genetic Loci; D047008:Marchantia / Q000235:genetics*; D035683:MicroRNAs / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D018749:RNA, Plant / Q000235:genetics* / Q000378:metabolism; D034741:RNA, Small Interfering / Q000378:metabolism; D017423:Sequence Analysis, RNA
chemical_list: D035683:MicroRNAs; D018749:RNA, Plant; D034741:RNA, Small Interfering
keywords: Liverwort; Marchantia polymorpha; MicroRNA; RNA sequencing; Small RNA