Up-regulated expression of AOS-LOXa and increased eicosanoid synthesis in response to coral wounding

PLoS One. 2014 Feb 14;9(2):e89215. doi: 10.1371/journal.pone.0089215. eCollection 2014.

Abstract

In octocorals, a catalase-like allene oxide synthase (AOS) and an 8R-lipoxygenase (LOX) gene are fused together encoding for a single AOS-LOX fusion protein. Although the AOS-LOX pathway is central to the arachidonate metabolism in corals, its biological function in coral homeostasis is unclear. Using an acute incision wound model in the soft coral Capnella imbricata, we here test whether LOX pathway, similar to its role in plants, can contribute to the coral damage response and regeneration. Analysis of metabolites formed from exogenous arachidonate before and after fixed time intervals following wounding indicated a significant increase in AOS-LOX activity in response to mechanical injury. Two AOS-LOX isoforms, AOS-LOXa and AOS-LOXb, were cloned and expressed in bacterial expression system as active fusion proteins. Transcription levels of corresponding genes were measured in normal and stressed coral by qPCR. After wounding, AOS-LOXa was markedly up-regulated in both, the tissue adjacent to the incision and distal parts of a coral colony (with the maximum reached at 1 h and 6 h post wounding, respectively), while AOS-LOXb was stable. According to mRNA expression analysis, combined with detection of eicosanoid product formation for the first time, the AOS-LOX was identified as an early stress response gene which is induced by mechanical injury in coral.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Anthozoa / enzymology*
  • Anthozoa / genetics*
  • Arachidonic Acid / metabolism
  • Chromatography, High Pressure Liquid
  • Chromatography, Reverse-Phase
  • Gene Expression Regulation, Enzymologic
  • Intramolecular Oxidoreductases / genetics*
  • Intramolecular Oxidoreductases / metabolism
  • Lipoxygenase / metabolism
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism
  • Real-Time Polymerase Chain Reaction
  • Sequence Analysis, Protein
  • Stress, Physiological*
  • Up-Regulation*

Substances

  • RNA, Messenger
  • Arachidonic Acid
  • Lipoxygenase
  • Intramolecular Oxidoreductases
  • hydroperoxide isomerase

Grants and funding

This work was supported by the Estonian Science Foundation Grant 9410 and the Estonian Ministry of Education and Research Grant 0140010s08 (both to NS). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.