title: Expression profile of desiccation tolerance factors in intertidal seaweed species during the tidal cycle.
abstract: The transcriptional modulation of desiccation tolerance factors in P. orbicularis explains its successful recuperation after water deficit. Differential responses to air exposure clarify seaweed distribution along intertidal rocky zones. Desiccation-tolerant seaweed species, such as Pyropia orbicularis, can tolerate near 96% water loss during air exposure. To understand the phenotypic plasticity of P. orbicularis to desiccation, several tolerance factors were assessed by RT-qPCR, Western-blot analysis, and enzymatic assays during the natural desiccation-rehydration cycle. Comparative enzymatic analyses were used to evidence differential responses between P. orbicularis and desiccation-sensitive species. The results showed that during desiccation, the relative mRNA levels of genes associated with basal metabolism [trehalose phosphate synthase (tps) and pyruvate dehydrogenase (pdh)] were overexpressed in P. orbicularis. Transcript levels related to antioxidant metabolism [peroxiredoxin (prx); thioredoxin (trx); catalase (cat); lipoxygenase (lox); ferredoxin (fnr); glutathione S-transferase (gst)], cellular detoxification [ABC transporter (abc) and ubiquitin (ubq)], and signal transduction [calmodulin (cam)] increased approximately 15- to 20-fold, with the majority returning to basal levels during the final hours of rehydration. In contrast, actin (act) and transcription factor 1 (tf1) transcripts were down-regulated. ABC transporter protein levels increased in P. orbicularis during desiccation, whereas PRX transcripts decreased. The antioxidant enzymes showed higher specific activity in P. orbicularis under desiccation, and sensitive species exhibited enzymatic inactivation and scarce ABC and PRX protein detection following prolonged desiccation. In conclusion, the reported findings contribute towards understanding the ecological distribution of intertidal seaweeds at the molecular and functional levels.
authors.affiliation: Departamento de Ecología y Biodiversidad, Facultad de Ecología y Recursos Naturales, Universidad Andres Bello, República 440, Santiago, Chile.
authors.forename: Camila
authors.initials: C
authors.lastname: Fierro
authors.affiliation: Departamento de Biología Evolutiva, Ecología y Ciencias Ambientales, Facultad de Biología, Universidad de Barcelona, Diagonal 643, 08028, Barcelona, Spain.
authors.forename: Camilo
authors.initials: C
authors.lastname: López-Cristoffanini
authors.affiliation: Departamento de Ecología y Biodiversidad, Facultad de Ecología y Recursos Naturales, Universidad Andres Bello, República 440, Santiago, Chile.
authors.forename: Andrés
authors.initials: A
authors.lastname: Meynard
authors.affiliation: Departamento de Ecología y Biodiversidad, Facultad de Ecología y Recursos Naturales, Universidad Andres Bello, República 440, Santiago, Chile.
authors.forename: Carlos
authors.initials: C
authors.lastname: Lovazzano
authors.affiliation: Departamento de Ecología y Biodiversidad, Facultad de Ecología y Recursos Naturales, Universidad Andres Bello, República 440, Santiago, Chile.
authors.forename: Francisco
authors.initials: F
authors.lastname: Castañeda
authors.affiliation: Departamento de Ecología y Biodiversidad, Facultad de Ecología y Recursos Naturales, Universidad Andres Bello, República 440, Santiago, Chile.
authors.forename: Eduardo
authors.initials: E
authors.lastname: Guajardo
authors.affiliation: Departamento de Ecología y Biodiversidad, Facultad de Ecología y Recursos Naturales, Universidad Andres Bello, República 440, Santiago, Chile. lorettocontreras@unab.cl.|Center of Applied Ecology and Sustainability (CAPES), Pontificia Universidad Católica de Chile, Avda. Bernardo O'Higgins 340, Santiago, Chile. lorettocontreras@unab.cl.
authors.forename: Loretto
authors.identifier: http://orcid.org/0000-0002-6511-2244
authors.initials: L
authors.lastname: Contreras-Porcia
mesh_terms: D015153:Blotting, Western; D002374:Catalase / Q000235:genetics / Q000378:metabolism; D003890:Desiccation; D005288:Ferredoxins / Q000235:genetics / Q000378:metabolism; D005982:Glutathione Transferase / Q000235:genetics / Q000378:metabolism; D008084:Lipoxygenase / Q000235:genetics / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D012624:Seaweed / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction; D013879:Thioredoxins / Q000235:genetics / Q000378:metabolism
chemical_list: D005288:Ferredoxins; D010940:Plant Proteins; D013879:Thioredoxins; D002374:Catalase; D008084:Lipoxygenase; D005982:Glutathione Transferase
keywords: Desiccation stress; Intertidal distribution; Pyropia; Seaweeds