Browsing by Author "Brillet-Gueguen, Loraine"

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    Herbivore-induced chemical and molecular responses of the kelps Laminaria digitata and Lessonia spicata
    (2017) Ritter, Andres; Cabioch, Lea; Brillet-Gueguen, Loraine; Corre, Erwan; Cosse, Audrey; Dartevelle, Laurence; Durufle, Harold; Fasshauer, Carina; Goulitquer, Sophie; Thomas, Francois; Correa, Juan A.; Potin, Philippe; Faugeron, Sylvain; Leblanc, Catherine
    Kelps are founding species of temperate marine ecosystems, living in intertidal coastal areas where they are often challenged by generalist and specialist herbivores. As most sessile organisms, kelps develop defensive strategies to restrain grazing damage and preserve their own fitness during interactions with herbivores. To decipher some inducible defense and signaling mechanisms, we carried out metabolome and transcriptome analyses in two emblematic kelp species, Lessonia spicata from South Pacific coasts and Laminaria digitata from North Atlantic, when challenged with their main specialist herbivores. Mass spectrometry based metabolomics revealed large metabolic changes induced in these two brown algae following challenges with their own specialist herbivores. Targeted metabolic profiling of L. spicata further showed that free fatty acid (FFA) and amino acid (AA) metabolisms were particularly regulated under grazing. An early stress response was illustrated by the accumulation of Sulphur containing amino acids in the first twelve hours of herbivory pressure. At latter time periods (after 24 hours), we observed FFA liberation and eicosanoid oxylipins synthesis likely representing metabolites related to stress. Global transcriptomic analysis identified sets of candidate genes specifically induced by grazing in both kelps. qPCR analysis of the top candidate genes during a 48-hours time course validated the results. Most of these genes were particularly activated by herbivore challenge after 24 hours, suggesting that transcriptional reprogramming could be operated at this time period. We demonstrated the potential utility of these genes as molecular markers for herbivory by measuring their inductions in grazed individuals of field harvested L. digitata and L. spicata. By unravelling the regulation of some metabolites and genes following grazing pressure in two kelps representative of the two hemispheres, this work contributes to provide a set of herbivore-induced chemical and molecular responses in kelp species, showing similar inducible responses upon specialist herbivores in their respective ecosystems.
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    The Rhodoexplorer Platform for Red Algal Genomics and Whole-Genome Assemblies for Several Gracilaria Species
    (2023) Lipinska, Agnieszka P.; Krueger-Hadfield, Stacy A.; Godfroy, Olivier; Dittami, Simon M.; Ayres-Ostrock, Ligia; Bonthond, Guido; Brillet-Gueguen, Loraine; Coelho, Susana; Corre, Erwan; Cossard, Guillaume; Destombe, Christophe; Epperlein, Paul; Faugeron, Sylvain; Ficko-Blean, Elizabeth; Beltran, Jessica; Lavaut, Emma; Le Bars, Arthur; Marchi, Fabiana; Mauger, Stephane; Michel, Gurvan; Potin, Philippe; Scornet, Delphine; Sotka, Erik E.; Weinberger, Florian; de Oliveira, Mariana Cabral; Guillemin, Marie-Laure; Plastino, Estela M.; Valero, Myriam
    Macroalgal (seaweed) genomic resources are generally lacking as compared with other eukaryotic taxa, and this is particularly true in the red algae (Rhodophyta). Understanding red algal genomes is critical to understanding eukaryotic evolution given that red algal genes are spread across eukaryotic lineages from secondary endosymbiosis and red algae diverged early in the Archaeplastids. The Gracilariales is a highly diverse and widely distributed order including species that can serve as ecosystem engineers in intertidal habitats and several notorious introduced species. The genus Gracilaria is cultivated worldwide, in part for its production of agar and other bioactive compounds with downstream pharmaceutical and industrial applications. This genus is also emerging as a model for algal evolutionary ecology. Here, we report new whole-genome assemblies for two species (Gracilaria chilensis and Gracilaria gracilis), a draft genome assembly of Gracilaria caudata, and genome annotation of the previously published Gracilaria vermiculophylla genome. To facilitate accessibility and comparative analysis, we integrated these data in a newly created web-based portal dedicated to red algal genomics (https://rhodoexplorer.sb-roscoff.fr). These genomes will provide a resource for understanding algal biology and, more broadly, eukaryotic evolution.