A diatom gene regulating nitric-oxide signaling and susceptibility to diatom-derived aldehydes

A Vardi, KD Bidie, C Kwityn, DJ Hirsh, Stephanie Thompson, James Callow, P Falkowski, C Bowler

Research output: Contribution to journalArticle

98 Citations (Scopus)


Diatoms are unicellular phytoplankton accounting for similar to 40% of global marine primary productivity [1], yet the molecular mechanisms underlying their ecological success are largely unexplored. We use a functional-genomics approach in the marine diatom Phaeodactylum tricomutum to characterize a novel protein belonging to the widely conserved YqeH subfamily [2] of GTP-binding proteins thought to play a role in ribosome biogenesis [3], sporulation [4], and nitric oxide (NO) generation [5). Transgenic diatoms overexpressing this gene, designated PtNOA, displayed higher NO production, reduced growth, impaired photosynthetic efficiency, and a reduced ability to adhere to surfaces. A fused YFP-PtNOA protein was plastid localized, distinguishing it from a mitochondria-localized plant ortholog. PtNOA was upregulated in response to the diatom-derived unsaturated aldehyde 2E,4E/Z-decadienal (DD), a molecule previously shown to regulate intercellular signaling, stress surveillance [6], and defense against grazers [7]. Overexpressing cell lines were hypersensitive to sublethal levels of this aldehyde, manifested by altered expression of superoxide dismutase and metacaspases, key components of stress and death pathways [8, 9]. NOA-like sequences were found in diverse oceanic regions, suggesting that a novel NO-based system operates in diatoms and may be widespread in phytoplankton, providing a biological context for NO in the upper ocean [10].
Original languageEnglish
Pages (from-to)895-899
Number of pages5
JournalCurrent Biology
Issue number12
Publication statusPublished - 1 Jan 2008


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