title: Ginkgo biloba responds to herbivory by activating early signaling and direct defenses.
abstract: BACKGROUND
  Ginkgo biloba (Ginkgoaceae) is one of the most ancient living seed plants and is regarded as a living fossil. G. biloba has a broad spectrum of resistance or tolerance to many pathogens and herbivores because of the presence of toxic leaf compounds. Little is known about early and late events occurring in G. biloba upon herbivory. The aim of this study was to assess whether herbivory by the generalist Spodoptera littoralis was able to induce early signaling and direct defense in G. biloba by evaluating early and late responses.
  
  
  RESULTS
  Early and late responses in mechanically wounded leaves and in leaves damaged by S. littoralis included plasma transmembrane potential (Vm) variations, time-course changes in both cytosolic calcium concentration ([Ca(2+)](cyt)) and H(2)O(2) production, the regulation of genes correlated to terpenoid and flavonoid biosynthesis, the induction of direct defense compounds, and the release of volatile organic compounds (VOCs). The results show that G. biloba responded to hebivory with a significant Vm depolarization which was associated to significant increases in both [Ca(2+)](cyt) and H(2)O(2). Several defense genes were regulated by herbivory, including those coding for ROS scavenging enzymes and the synthesis of terpenoids and flavonoids. Metabolomic analyses revealed the herbivore-induced production of several flavonoids and VOCs. Surprisingly, no significant induction by herbivory was found for two of the most characteristic G. biloba classes of bioactive compounds; ginkgolides and bilobalides.
  
  
  CONCLUSIONS
  By studying early and late responses of G. biloba to herbivory, we provided the first evidence that this "living fossil" plant responds to herbivory with the same defense mechanisms adopted by the most recent angiosperms.
authors.affiliation: Plant Physiology Unit, Department of Life Sciences and Systems Biology, Innovation Centre, University of Turin, Turin, Italy.
authors.forename: Tapan Kumar
authors.initials: TK
authors.lastname: Mohanta
authors.forename: Andrea
authors.initials: A
authors.lastname: Occhipinti
authors.forename: Simon
authors.initials: S
authors.lastname: Atsbaha Zebelo
authors.forename: Maria
authors.initials: M
authors.lastname: Foti
authors.forename: Judith
authors.initials: J
authors.lastname: Fliegmann
authors.forename: Simone
authors.initials: S
authors.lastname: Bossi
authors.forename: Massimo E
authors.initials: ME
authors.lastname: Maffei
authors.forename: Cinzia M
authors.initials: CM
authors.lastname: Bertea
mesh_terms: D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D002118:Calcium / Q000378:metabolism; D003600:Cytosol / Q000378:metabolism; D005247:Feeding Behavior; D005419:Flavonoids / Q000378:metabolism; D020869:Gene Expression Profiling; D017343:Genes, Plant; D020441:Ginkgo biloba / Q000378:metabolism*; D006861:Hydrogen Peroxide / Q000378:metabolism; D008564:Membrane Potentials; D020411:Oligonucleotide Array Sequence Analysis; D010936:Plant Extracts / Q000494:pharmacology; D018515:Plant Leaves / Q000378:metabolism* / Q000469:parasitology*; D012333:RNA, Messenger / Q000235:genetics; D018749:RNA, Plant / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction; D018411:Spodoptera / Q000502:physiology*; D055549:Volatile Organic Compounds / Q000378:metabolism
chemical_list: D015415:Biomarkers; D005419:Flavonoids; D010936:Plant Extracts; D012333:RNA, Messenger; D018749:RNA, Plant; D055549:Volatile Organic Compounds; D006861:Hydrogen Peroxide; D002118:Calcium