Stress proteins and auxiliary anti stress compounds in intertidal macroalgae

Abstract

ABSTRACT. Intertidal macroalgae are exposed to strong variation in the physical environment and thus, diverse anti-stress mechanisms are displayed by these organisms. Stress proteins (also called heat shock proteins, HSPs) have been invoked as potential protective mechanism, especially during stressful action of temperature and solar radiation. Therefore, macroalgae have not normally been used as model organisms in studies of these molecules. The present study compiles the existing information from intertidal species in the context of major factors that have been reported to induce them, e.g. temperature, enhanced solar radiation, contaminants, etc. Additionally, in order to address the question whether the expression of these proteins operates in intertidal macroalgae complementarily with other protective mechanisms, a case study of induction of HSPs after exposure to UV radiation and high temperature in two upper littoral species, Ulva sp. and Porphyra columbina, from southern Chile is presented. In parallel, two well-known responses to stress, photoinhibition of photochemical reactions (F v /F m ) and ROS scavenging were measured. The results indicated that, although stress proteins were detected in a time span between 3 and 24 h, the responses were not correlated with photochemical and antioxidative response. Overall, the study outlines a potential role of stress proteins in ecophysiological responses developed to cope mainly with high temperature and UV radiation. However, other rapid metabolic adjustments (e.g. high thermo-tolerance of photosynthesis and efficient ROS scavenging), together with other biomolecules (mycosporines, phenols, polyamines, etc.) and morphofunctional adaptations to the intertidal life (e.g. small size, high area/volume ratio) are also important. Keywords: stress proteins, intertidal macroalgae, photosynthesis, ROS, UV radiation, photoprotection. Proteínas de estrés y compuestos anti-estrés auxiliares en algas marinas intermarealesRESUMEN. Las macroalgas marinas intermareales están expuestas a extrema variación en las condiciones ambientales y por ello desarrollan una serie de mecanismos anti-estrés. Las proteínas de estrés (HSPs) han sido consideradas como potenciales agentes protectores en respuesta a condiciones estresantes, especialmente durante la acción de elevada temperatura y alta radiación solar. Considerando que las macroalgas marinas no han sido usadas comúnmente como modelos de estudio para analizar estas moléculas, el presente trabajo compila la información existente sobre la inducción de proteínas de estrés en algas intermareales en el contexto de los principales factores hasta ahora reportados como inductores, e.g. temperatura, alta radiación solar, contaminantes, etc. Adicionalmente, mediante un estudio de caso usando dos especies del intermareal superior, Ulva sp. y Porphyra columbina colectadas en el sur de Chile, se examina si la inducción de proteínas de estrés ocurre de forma complementaria con otras respuestas anti-stress. Para ello, dos mecanismos bien conocid...

Interaction of Photoprotective and Acclimation Mechanisms in Ulva rigida (Chlorophyta) in Response to Diurnal Changes in Solar Radiation in Southern Chile

“…Likewise, in the genus Ulva , the carbon‐assimilation pathways also could play an important role in its acclimation to different light conditions (Cruces et al. 2012b, Gómez and Huovinen , Holzinger et al. , Zhao et al.…”

“…The acclimation of the photosynthetic apparatus to diurnal changes of light in Ulva are related to the efficiency of a series of mechanisms such as: (i) the dissipation of energy as heat via the xanthophyll cycle (Franklin et al 2003, Mou et al 2013), (ii) a reduction in the efficiency of energy transfer to PSII reaction centers (i.e., photoinhibition; Pescheck et al 2016), and (iii) changes in the size of the light-harvesting antennae through the reduction of photosynthetic and accessory pigments (Melis 2009). Likewise, in the genus Ulva, the carbon-assimilation pathways also could play an important role in its acclimation to different light conditions (Cruces et al 2012b, G omez and Huovinen 2012, Holzinger et al 2015, Zhao et al 2016. For example, studies have shown that the exposure of U. prolifera to light intensities >1,000 lmol photons Á m À2 Á s À1 triggered a decrease in the gene expression of key enzymes of C 4 metabolism and RuBisCO's large subunit (Xu et al 2012).…”

Efeito do estresse térmico sobre respostas fisiológicas, composição química e potencial antioxidante de Sargassum stenophyllum (Fucales, Ochrophyta) e Pyropia spiralis (Bangiales, Rhodophyta)

“…O estudo de Zou et al (2017) reportou para S. polycystum Agardh tolerância a diferentes condições de temperatura ( A macroalga verde Ulva prolifera Müller, quando analisada a diferentes temperaturas (5,10,15,20,25,30, 35 e 40 °C) após 3, 6 e 24 h, apresentou indução de proteínas de choque térmico (HSP; Heat Shock Protein) sob temperaturas de 5 e 15 °C e em altas temperaturas acima de 30 °C . Cruces et al (2012) ex. aminoácidos tipo micosporinas, substâncias fenólicas, poliaminas, entre outras) (Cruces et al, 2012).…”

“…Cruces et al (2012) ex. aminoácidos tipo micosporinas, substâncias fenólicas, poliaminas, entre outras) (Cruces et al, 2012).…”

Fenologia e ecofisiologia das macroalgas Porphyra spp. (Bangiales, Rhodophyta) e Lessonia spp. (Laminariales, Phaeophyceae) na costa norte e central do Chile: variações latitudinais e sazonais

“…Seaweeds are also capable to produce chemical compounds in response to various environmental stresses such as e.g. mycosporine-like amino acids (MAAs), phenolic compounds, polyamines, and stress proteins Hoyer et al, 2001;Houvinen et al, 2004;Cruces et al, 2012). The efficiency to absorb-dissipate energy and the acclimation responses to fluctuating environmental factors, reflect a wide range of adaptive abilities and tolerances in macroalga species across their range of distribution.…”