title: Molecular physiology of adventitious root formation in Petunia hybrida cuttings: involvement of wound response and primary metabolism.
abstract: Adventitious root formation (ARF) in the model plant Petunia hybrida cv. Mitchell has been analysed in terms of anatomy, gene expression, enzymatic activities and levels of metabolites. This study focuses on the involvement of wound response and primary metabolism. Microscopic techniques were complemented with targeted transcript, enzyme and metabolite profiling using real time polymerase chain reaction (PCR), Northern blot, enzymatic assays, chromatography and mass spectrometry. Three days after severance from the stock plants, first meristematic cells appeared which further developed into root primordia and finally adventitious roots. Excision of cuttings led to a fast and transient increase in the wound-hormone jasmonic acid, followed by the expression of jasmonate-regulated genes such as cell wall invertase. Analysis of soluble and insoluble carbohydrates showed a continuous accumulation during ARF. A broad metabolite profiling revealed a strong increase in organic acids and resynthesis of essential amino acids. Substantial changes in enzyme activities and metabolite levels indicate that specific enzymes and metabolites might play a crucial role during ARF. Three metabolic phases could be defined: (i) sink establishment phase characterized by apoplastic unloading of sucrose and being probably mediated by jasmonates; (ii) recovery phase; and (iii) maintenance phase, in which a symplastic unloading occurs.
authors.affiliation: Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Gatersleben, Germany.
authors.forename: Amir H
authors.initials: AH
authors.lastname: Ahkami
authors.forename: Sandra
authors.initials: S
authors.lastname: Lischewski
authors.forename: Klaus-T
authors.initials: KT
authors.lastname: Haensch
authors.forename: Svetlana
authors.initials: S
authors.lastname: Porfirova
authors.forename: Joerg
authors.initials: J
authors.lastname: Hofmann
authors.forename: Hardy
authors.initials: H
authors.lastname: Rolletschek
authors.forename: Michael
authors.initials: M
authors.lastname: Melzer
authors.forename: Philipp
authors.initials: P
authors.lastname: Franken
authors.forename: Bettina
authors.initials: B
authors.lastname: Hause
authors.forename: Uwe
authors.initials: U
authors.lastname: Druege
authors.forename: Mohammad R
authors.initials: MR
authors.lastname: Hajirezaei
mesh_terms: D000596:Amino Acids / Q000378:metabolism; D050260:Carbohydrate Metabolism / Q000235:genetics; D019069:Cell Respiration; D002952:Citric Acid Cycle; D003517:Cyclopentanes / Q000378:metabolism; D005231:Fatty Acids, Unsaturated / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D006019:Glycolysis; D054883:Oxylipins / Q000378:metabolism; D032306:Petunia / Q000166:cytology / Q000201:enzymology / Q000235:genetics / Q000378:metabolism*; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D018517:Plant Roots / Q000166:cytology / Q000201:enzymology / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism
chemical_list: D000596:Amino Acids; D003517:Cyclopentanes; D005231:Fatty Acids, Unsaturated; D054883:Oxylipins; D010940:Plant Proteins; D012333:RNA, Messenger; C025999:12-oxophytodienoic acid; C011006:jasmonic acid