Toward Systems Biology in Brown Algae to Explore Acclimation and Adaptation to the Shore Environment

Abstract

Brown algae belong to a phylogenetic lineage distantly related to land plants and animals. They are almost exclusively found in the intertidal zone, a harsh and frequently changing environment where organisms are submitted to marine and terrestrial constraints. In relation with their unique evolutionary history and their habitat, they feature several peculiarities, including at the level of their primary and secondary metabolism. The establishment of Ectocarpus siliculosus as a model organism for brown algae has represented a framework in which several omics techniques have been developed, in particular, to study the response of these organisms to abiotic stresses. With the recent publication of medium to high throughput profiling data, it is now possible to envision integrating observations at the cellular scale to apply systems biology approaches. As a first step, we propose a protocol focusing on integrating heterogeneous knowledge gained on brown algal metabolism. The resulting abstraction of the system will then help understanding how brown algae cope with changes in abiotic parameters within their unique habitat, and to decipher some of the mechanisms underlying their (1) acclimation and (2) adaptation, respectively consequences of (1) the behavior or (2) the topology of the system resulting from the integrative approach.

The effect of the algal microbiome on industrial production of microalgae

“…strain 371 from seawater to freshwater medium greatly depended on the associated bacterial community. Strain 371 is a small filamentous brown alga with broad range salinity tolerance that is mediated by adjusting cell wall structure and metabolism (Charrier et al, 2008;Ritter et al, 2010;Tonon et al, 2011). Cultures deprived of associated microbes were unable to survive a salinity change, while this capability could be restored by restoring their microbiota (Dittami et al, 2016).…”

Mass Spectrometry-Based Metabolomics to Elucidate Functions in Marine Organisms and Ecosystems

“…Targeted metabolite profiling was then continued in brown algae, and in particular in the model species Ectocarpus siliculosus , to analyze variations of some metabolites related to primary metabolism through the diurnal cycle [56], and under short-term non-lethal abiotic stress conditions [57]. In a recent review [58], Tonon et al described various approaches to integrate metabolomic results with genomic and transcriptomic data to move towards systems biology approaches in the context of studying acclimation and adaptation processes to abiotic factors in E. siliculosus . Furthermore, this alga represents a good candidate to foresee fluxomic studies in the near future, for instance by incorporating 13 C and 15 N in the culture media, and by subsequently analyzing the produced metabolites by MS approaches to elucidate the metabolic pathways involved in these biological processes.…”

“…Mathematical modeling has been used recently to infer the dynamics of starch content during the diurnal cycle in the model green alga Ostreococcus tauri [146]. In addition, application of systems biology to brown algae, and in particular for E. siliculosus , has been highlighted to explore acclimation and adaptation to the intertidal zone [58]. …”

Host–microbe interactions as a driver of acclimation to salinity gradients in brown algal cultures

“…Among brown algae, Ectocarpus is a cosmopolitan genus of small filamentous species with a long history of research (Charrier et al, 2008) and has recently been established as a genomic and genetic model for this lineage (Peters et al, 2004;Cock et al, 2010). One of the particularities of Ectocarpus is its high capacity to acclimate to different environments, which has led to the development of a range of new approaches to study stress tolerance in this organism (for example, Dittami et al, 2009;Ritter et al, 2010;Tonon et al, 2011;Billoud et al, 2014). A key advantage of Ectocarpus for this type of study is that a number of different strains and ecotypes with different tolerance ranges towards abiotic factors are available.…”