title: Endogenous rhythmic growth in oak trees is regulated by internal clocks rather than resource availability.
abstract: Common oak trees display endogenous rhythmic growth with alternating shoot and root flushes. To explore the mechanisms involved, microcuttings of the Quercus robur L. clone DF159 were used for (13)C/(15)N labelling in combination with RNA sequencing (RNASeq) transcript profiling of shoots and roots. The effect of plant internal resource availability on the rhythmic growth of the cuttings was tested through inoculation with the ectomycorrhizal fungus Piloderma croceum. Shoot and root flushes were related to parallel shifts in above- and below-ground C and, to a lesser extent, N allocation. Increased plant internal resource availability by P. croceum inoculation with enhanced plant growth affected neither the rhythmic growth nor the associated resource allocation patterns. Two shifts in transcript abundance were identified during root and shoot growth cessation, and most concerned genes were down-regulated. Inoculation with P. croceum suppressed these transcript shifts in roots, but not in shoots. To identify core processes governing the rhythmic growth, functions [Gene Ontology (GO) terms] of the genes differentially expressed during the growth cessation in both leaves and roots of non-inoculated plants and leaves of P. croceum-inoculated plants were examined. Besides genes related to resource acquisition and cell development, which might reflect rather than trigger rhythmic growth, genes involved in signalling and/or regulated by the circadian clock were identified. The results indicate that rhythmic growth involves dramatic oscillations in plant metabolism and gene regulation between below- and above-ground parts. Ectomycorrhizal symbiosis may play a previously unsuspected role in smoothing these oscillations without modifying the rhythmic growth pattern.
authors: Department of Soil Ecology, UFZ-Helmholtz Centre for Environmental Research, Theodor-Lieser-Str. 4, D-06120 Halle/Saale, Germany Department of Community Ecology, UFZ-Helmholtz Centre for Environmental Research,Theodor-Lieser-Str. 4, D-06120 Halle/Saale, Germany German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Deutscher Platz 5e, D-04103 Leipzig, Germany sylvie.herrmann@ufz.de.
authors: S
authors: S
authors: Herrmann
authors: Department of Soil Ecology, UFZ-Helmholtz Centre for Environmental Research, Theodor-Lieser-Str. 4, D-06120 Halle/Saale, Germany.
authors: S
authors: S
authors: Recht
authors: Department of Soil Ecology, UFZ-Helmholtz Centre for Environmental Research, Theodor-Lieser-Str. 4, D-06120 Halle/Saale, Germany.
authors: M
authors: M
authors: Boenn
authors: Department of Soil Ecology, UFZ-Helmholtz Centre for Environmental Research, Theodor-Lieser-Str. 4, D-06120 Halle/Saale, Germany.
authors: L
authors: L
authors: Feldhahn
authors: Section Pathology of Woody Plants, Technische Universität München, Hans-Carl-von-Carlowitz-Platz 2, D-85354 Freising, Germany Ecophysiology of Plants, Technische Universität München, Hans-Carl-von-Carlowitz-Platz 2, D-85354 Freising, Germany.
authors: O
authors: O
authors: Angay
authors: Section Pathology of Woody Plants, Technische Universität München, Hans-Carl-von-Carlowitz-Platz 2, D-85354 Freising, Germany.
authors: F
authors: F
authors: Fleischmann
authors: Department of Soil Ecology, UFZ-Helmholtz Centre for Environmental Research, Theodor-Lieser-Str. 4, D-06120 Halle/Saale, Germany German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Deutscher Platz 5e, D-04103 Leipzig, Germany.
authors: M T
authors: MT
authors: Tarkka
authors: Ecophysiology of Plants, Technische Universität München, Hans-Carl-von-Carlowitz-Platz 2, D-85354 Freising, Germany.
authors: T E E
authors: TE
authors: Grams
authors: Department of Soil Ecology, UFZ-Helmholtz Centre for Environmental Research, Theodor-Lieser-Str. 4, D-06120 Halle/Saale, Germany German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Deutscher Platz 5e, D-04103 Leipzig, Germany.
authors: F
authors: F
authors: Buscot
mesh_terms: D001487:Basidiomycota / Q000502:physiology; D001683:Biological Clocks / Q000235:genetics; D050260:Carbohydrate Metabolism; D002244:Carbon / Q000378:metabolism; D018744:DNA, Plant; D015536:Down-Regulation; D018506:Gene Expression Regulation, Plant; D009584:Nitrogen / Q000378:metabolism; D010937:Plant Growth Regulators / Q000235:genetics; D018515:Plant Leaves / Q000254:growth & development / Q000378:metabolism; D018517:Plant Roots / Q000254:growth & development; D029963:Quercus / Q000235:genetics / Q000254:growth & development* / Q000382:microbiology; D017422:Sequence Analysis, DNA; D015398:Signal Transduction
chemical_list: D018744:DNA, Plant; D010937:Plant Growth Regulators; D002244:Carbon; D009584:Nitrogen
keywords: Ectomycorrhiza; Piloderma croceum; Quercus robur; RNASeq; growth cessation; stable isotope labelling.