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.Methodology/Principal FindingsEarly 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 ([Ca2+]cyt) and H2O2 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 [Ca2+]cyt and H2O2. 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/SignificanceBy 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.

Extracellular Self-DNA (esDNA), but Not Heterologous Plant or Insect DNA (etDNA), Induces Plasma Membrane Depolarization and Calcium Signaling in Lima Bean (Phaseolus lunatus) and Maize (Zea mays)

“…In most of our Vm experiments, Vm values did not recover the initial value after washing the system with fresh buffer. This effect has been already observed in other plant species like tomato [9], Ginkgo biloba [33], and Arabidopsis thaliana [34]. Since changes in the Vm imply changes in the flux of ions across the plasma membrane, this observation suggests that the interaction with putative membrane receptors might not be fully reversible and that some ion channels might remain open even after the removal of the molecule.…”

Advances in Ginkgo biloba research: Genomics and metabolomics perspectives

“…Data analysis and its validation demonstrated significant up and down regulation of different genes involved in plant stress response, including transcription factor regulator (Mohanta et al, 2012). Some other study includes phenylpropanoid metabolism pathway and reactive oxygen species scavenging system.…”

“…Usually, they play important role as antioxidant, anti-feeding, antinutritive agent against insect herbivores. It has been demonstrated that upon feeding G. biloba to Spodoptera littoralis, significant differential levels of quercetin and kaempferol were observed, compared to mechanically damaged G. biloba (Mohanta et al, 2012). Tanaka et al (2011) reported the role of bilobol and found that it plays significant role in plant stress response.…”

Structure and function of the tentpole in the reproductive process of Ginkgo biloba L.

“…Thus, G. biloba is believed to be one of the most primitive extant seed plants. 2 Many botanists have studied the primitive characteristics of G. biloba in terms of its morphology and anatomy. There are a number of characteristics of the reproductive process that are considered to be ancestral in G. biloba, including the structure of the archegonium, pollen chamber, tentpole, and haustorial pollen tubes.…”