Production of volatiles by the red seaweed Gelidium arbuscula (Rhodophyta): emission of ethylene and dimethyl sulfide

Abstract

The effects of different light conditions and exogenous ethylene on the emission of volatile compounds from the alga Gelidium arbuscula Bory de Saint-Vincent were studied. Special emphasis was placed on the possibility that the emission of ethylene and dimethyl sulfide (DMS) are related through the action of dimethylsulfoniopropionate (DMSP) lyase. The conversion of DMSP to DMS and acrylate, which is catalyzed by DMSP lyase, can indirectly support the synthesis of ethylene through the transformation of acrylate to ethylene. After mimicking the desiccation of G. arbuscula thalli experienced during low tides, the volatile compounds emitted were trapped in the headspace of 2 mL glass vials for 1 h. Two methods based on gas chromatography/mass spectrometry revealed that the range of organic volatile compounds released was affected by abiotic factors, such as the availability and spectral quality of light, salinity, and exogenous ethylene. Amines and methyl alkyl compounds were produced after exposure to white light and darkness but not after exposure to exogenous ethylene or red light. Volatiles potentially associated with the oxidation of fatty acids, such as alkenes and low-molecular-weight oxygenated compounds, accumu-lated after exposure to exogenous ethylene and red light. Ethylene was produced in all treatments, especially after exposure to exogenous ethylene. Levels of DMS, the most abundant sulfur-compound that was emitted in all of the conditions tested, did not increase after incubation with ethylene. Thus, although DMSP lyase is active in G. arbuscula, it is unlikely to contribute to ethylene synthesis. The generation of ethylene and DMS do not appear to be coordinated in G. arbuscula.

Producing the Ethylene Signal: Regulation and Diversification of Ethylene Biosynthetic Enzymes

“…In flowering plants and in all four gymnosperm groups (Osborne et al, 1996), feeding the biosynthetic intermediate ACC to whole plants or live tissue results in the production of ethylene, consistent with an ACO activity conserved throughout seed plants. Similarly, ACC treatment increases ethylene production in the charophyte Spirogyra pratensis, the chlorophytes Haematococcus pluvialis and Ulva intestinalis, and the red alga Pterocladiella capillacea, consistent with conservation throughout the plant kingdom (Maillard et al, 1993;Plettner et al, 2005;Garcia-Jimenez et al, 2013;Ju et al, 2015). However, treatment of liverworts, moss, and ferns with exogenous ACC does not yield increased ethylene production, despite detectable uptake and metabolism of labeled ACC (Osborne et al, 1996).…”

Occurrence of jasmonates during cystocarp development in the red alga Grateloupia imbricata

“…Evidence for the roles of volatiles and their involvement in seaweed development has increased over the last few years (Garcia‐Jimenez and Robaina , Garcia‐Jimenez et al. , Montero‐Fernández et al. ).…”

“…In addition, other volatiles in the red seaweed G. arbuscula were described as methyl transferase–like derivatives, with the most representative compound being MeJa (Garcia‐Jimenez et al. ).…”

“…Seaweeds emit a myriad of fatty acid derivatives, nitrogen‐containing compounds, organic halogen compounds, sulfur compounds, and compounds derived from transferases (Garcia‐Jimenez et al. ). Information on halogenated volatile compounds has been extensively reported (Roje , Laturnus et al.…”

“…In order to improve the comprehension of the role of the different volatile compounds in the physiology of the seaweeds, we have initially focused on compounds such as methyl esters that are generated by the activities of putative methyltransferases (Garcia‐Jimenez et al. ).…”