TY - JOUR AU - Harðardóttir, Sara AU - Wohlrab, Sylke AU - Hjort, Ditte Marie AU - Krock, Bernd AU - Nielsen, Torkel Gissel AU - John, Uwe AU - Lundholm, Nina PY - 2019 DA - 2019/02/26 TI - Transcriptomic responses to grazing reveal the metabolic pathway leading to the biosynthesis of domoic acid and highlight different defense strategies in diatoms JO - BMC Molecular Biology SP - 7 VL - 20 IS - 1 AB - A major cause of phytoplankton mortality is predation by zooplankton. Strategies to avoid grazers have probably played a major role in the evolution of phytoplankton and impacted bloom dynamics and trophic energy transport. Certain species of the genus Pseudo-nitzschia produce the neurotoxin, domoic acid (DA), as a response to the presence of copepod grazers, suggesting that DA is a defense compound. The biosynthesis of DA comprises fusion of two precursors, a C10 isoprenoid geranyl pyrophosphate and l-glutamate. Geranyl pyrophosphate (GPP) may derive from the mevalonate isoprenoid (MEV) pathway in the cytosol or from the methyl-erythritol phosphate (MEP) pathway in the plastid. l-glutamate is suggested to derive from the citric acid cycle. Fragilariopsis, a phylogenetically related but nontoxic genus of diatoms, does not appear to possess a similar defense mechanism. We acquired information on genes involved in biosynthesis, precursor pathways and regulatory functions for DA production in the toxigenic Pseudo-nitzschia seriata, as well as genes involved in responses to grazers to resolve common responses for defense strategies in diatoms. SN - 1471-2199 UR - https://doi.org/10.1186/s12867-019-0124-0 DO - 10.1186/s12867-019-0124-0 ID - Harðardóttir2019 ER -