title: The decision to germinate is regulated by divergent molecular networks in spores and seeds.
abstract: Dispersal is a key step in land plant life cycles, usually via formation of spores or seeds. Regulation of spore- or seed-germination allows control over the timing of transition from one generation to the next, enabling plant dispersal. A combination of environmental and genetic factors determines when seed germination occurs. Endogenous hormones mediate this decision in response to the environment. Less is known about how spore germination is controlled in earlier-evolving nonseed plants. Here, we present an in-depth analysis of the environmental and hormonal regulation of spore germination in the model bryophyte Physcomitrella patens (Aphanoregma patens). Our data suggest that the environmental signals regulating germination are conserved, but also that downstream hormone integration pathways mediating these responses in seeds were acquired after the evolution of the bryophyte lineage. Moreover, the role of abscisic acid and diterpenes (gibberellins) in germination assumed much greater importance as land plant evolution progressed. We conclude that the endogenous hormone signalling networks mediating germination in response to the environment may have evolved independently in spores and seeds. This paves the way for future research about how the mechanisms of plant dispersal on land evolved.
authors.affiliation: School of Biosciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK.
authors.forename: Eleanor F
authors.initials: EF
authors.lastname: Vesty
authors.affiliation: School of Biosciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK.
authors.forename: Younousse
authors.initials: Y
authors.lastname: Saidi
authors.affiliation: School of Biosciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK.
authors.forename: Laura A
authors.initials: LA
authors.lastname: Moody
authors.affiliation: School of Biosciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK.
authors.forename: Daniel
authors.initials: D
authors.lastname: Holloway
authors.affiliation: School of Biosciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK.
authors.forename: Amy
authors.initials: A
authors.lastname: Whitbread
authors.affiliation: School of Biosciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK.
authors.forename: Sarah
authors.initials: S
authors.lastname: Needs
authors.affiliation: School of Biosciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK.
authors.forename: Anushree
authors.initials: A
authors.lastname: Choudhary
authors.affiliation: School of Biosciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK.
authors.forename: Bethany
authors.initials: B
authors.lastname: Burns
authors.affiliation: School of Biosciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK.
authors.forename: Daniel
authors.initials: D
authors.lastname: McLeod
authors.affiliation: School of Biosciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK.
authors.forename: Susan J
authors.initials: SJ
authors.lastname: Bradshaw
authors.affiliation: Department of Systems Biology, Technical University of Denmark, Søltofts Plads, 2800 Kgs, Lyngby, Denmark.
authors.forename: Hansol
authors.initials: H
authors.lastname: Bae
authors.affiliation: Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, Frederiksberg C, 1871, Denmark.
authors.forename: Brian Christopher
authors.initials: BC
authors.lastname: King
authors.affiliation: School of Biosciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK.
authors.forename: George W
authors.initials: GW
authors.lastname: Bassel
authors.affiliation: Department of Systems Biology, Technical University of Denmark, Søltofts Plads, 2800 Kgs, Lyngby, Denmark.
authors.forename: Henrik Toft
authors.identifier: 0000-0003-3070-807X
authors.initials: HT
authors.lastname: Simonsen
authors.affiliation: School of Biosciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK.
authors.forename: Juliet C
authors.identifier: 0000-0002-2381-0298
authors.initials: JC
authors.lastname: Coates
mesh_terms: D000040:Abscisic Acid / Q000096:biosynthesis / Q000494:pharmacology; D019068:Bryopsida / Q000187:drug effects / Q000196:embryology* / Q000235:genetics* / Q000528:radiation effects; D003080:Cold Temperature; D004224:Diterpenes / Q000494:pharmacology; D045786:Diterpenes, Kaurane / Q000096:biosynthesis; D004777:Environment; D018506:Gene Expression Regulation, Plant / Q000187:drug effects / Q000528:radiation effects; D053263:Gene Regulatory Networks / Q000187:drug effects / Q000528:radiation effects; D017343:Genes, Plant; D018525:Germination / Q000187:drug effects / Q000235:genetics* / Q000528:radiation effects; D006358:Hot Temperature; D007783:Lactones / Q000494:pharmacology; D008027:Light; D057445:Plant Dormancy / Q000187:drug effects / Q000235:genetics / Q000528:radiation effects; D012639:Seeds / Q000187:drug effects / Q000196:embryology* / Q000235:genetics* / Q000528:radiation effects; D015398:Signal Transduction / Q000187:drug effects / Q000235:genetics / Q000528:radiation effects; D013170:Spores / Q000187:drug effects / Q000235:genetics / Q000528:radiation effects; D013395:Sucrose / Q000494:pharmacology
chemical_list: D004224:Diterpenes; D045786:Diterpenes, Kaurane; D007783:Lactones; D013395:Sucrose; D000040:Abscisic Acid
keywords: Physcomitrella; abscisic acid (ABA); ent-kaurenes; ethylene; high temperature; light; spore germination; strigolactones