title: Regulation of the KNOX-GA gene module induces heterophyllic alteration in North American lake cress.
abstract: Plants show leaf form alteration in response to changes in the surrounding environment, and this phenomenon is called heterophylly. Although heterophylly is seen across plant species, the regulatory mechanisms involved are largely unknown. Here, we investigated the mechanism underlying heterophylly in Rorippa aquatica (Brassicaceae), also known as North American lake cress. R. aquatica develops pinnately dissected leaves in submerged conditions, whereas it forms simple leaves with serrated margins in terrestrial conditions. We found that the expression levels of KNOTTED1-LIKE HOMEOBOX (KNOX1) orthologs changed in response to changes in the surrounding environment (e.g., change of ambient temperature; below or above water) and that the accumulation of gibberellin (GA), which is thought to be regulated by KNOX1 genes, also changed in the leaf primordia. We further demonstrated that exogenous GA affects the complexity of leaf form in this species. Moreover, RNA-seq revealed a relationship between light intensity and leaf form. These results suggest that regulation of GA level via KNOX1 genes is involved in regulating heterophylly in R. aquatica. The mechanism responsible for morphological diversification of leaf form among species may also govern the variation of leaf form within a species in response to environmental changes.
authors.affiliation: Faculty of Life Sciences, Kyoto Sangyo University, Motoyama, Kamigamo, Kita-Ku, Kyoto 603-8555, Japan.
authors.forename: Hokuto
authors.identifier: http://orcid.org/0000-0002-5724-4861
authors.initials: H
authors.lastname: Nakayama
authors.affiliation: Institute of Molecular Plant Sciences, University of Edinburgh, Edinburgh EH9 3JH, United Kingdom.
authors.forename: Naomi
authors.initials: N
authors.lastname: Nakayama
authors.affiliation: Teacher Education Department, University of San Francisco, San Francisco, California 94117-1080.
authors.forename: Sumer
authors.initials: S
authors.lastname: Seiki
authors.affiliation: RIKEN Center for Sustainable Resource Science, Tsurumi, Yokohama 230-0045, Japan.
authors.forename: Mikiko
authors.initials: M
authors.lastname: Kojima
authors.affiliation: RIKEN Center for Sustainable Resource Science, Tsurumi, Yokohama 230-0045, Japan.
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Sakakibara
authors.affiliation: Department of Plant Biology, University of California, Davis, California 95616.
authors.forename: Neelima
authors.identifier: http://orcid.org/0000-0002-1494-7065
authors.initials: N
authors.lastname: Sinha
authors.affiliation: Faculty of Life Sciences, Kyoto Sangyo University, Motoyama, Kamigamo, Kita-Ku, Kyoto 603-8555, Japan seisuke@cc.kyoto-su.ac.jp.
authors.forename: Seisuke
authors.identifier: http://orcid.org/0000-0002-6796-3675
authors.initials: S
authors.lastname: Kimura
mesh_terms: D019607:Brassicaceae / Q000187:drug effects / Q000235:genetics* / Q000254:growth & development; D049109:Cell Proliferation; D004777:Environment; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D005875:Gibberellins / Q000494:pharmacology; D018398:Homeodomain Proteins / Q000235:genetics* / Q000378:metabolism / Q000502:physiology; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism / Q000502:physiology; D013696:Temperature
chemical_list: D005875:Gibberellins; D018398:Homeodomain Proteins; D010940:Plant Proteins