Author(s): Jesus, Tiago Filipe Salgueiro de, 1987-
Date: 2017
Persistent ID: http://hdl.handle.net/10451/34057
Origin: Repositório da Universidade de Lisboa
Project/scholarship: info:eu-repo/grantAgreement/FCT/SFRH/SFRH%2FBD%2F73801%2F2010/PT;
Subject(s): Teses de doutoramento - 2017; Domínio/Área Científica::Ciências Naturais::Ciências Biológicas
Tese de doutoramento, Biologia (Biologia Evolutiva), Universidade de Lisboa, Faculdade de Ciências, 2017
Climate changes are exposing freshwater sh to higher water temperatures and acidi cation. Once studies evaluating freshwater sh responses to these challenges are scarce, the main objective of this thesis is to comprehend how two Iberian freshwater sh species cope with future climate change. Squalius carolitertii and Squalius torgalensis, which are endemic of two distinct regions of the Iberian Peninsula, live in different environmental conditions. Herein, their thermal stress responses were rstly accessed by the expression of two genes involved in the heat shock response (HSR) (hsp70 and hsc70 ). Afterwards, we conducted a transcriptome-wide study of sh exposed to acute thermal stress. Results suggest that S. torgalensis handled with stressing thermal conditions differently than S. carolitertii. While S. torgalensis redirects resources from cell division and growth processes to the HSR, the induction of genes involved in the HSR was lower in S. carolitertii, which presented no re-adjustment of other energy consumption mechanisms. The long-term responses on gene expression and physiology of these two species to future warming (plus 3 °C) and acidi cation ( pH=-0.4) were evaluated herein, alongside with protein modeling of fourteen target genes. Findings suggest that S. torgalensis is better suited to cope with the projected climate change conditions, once it presents fewer changes in gene expression and in the physiological markers involved in the HSR and energy metabolism than S. carolitertii. Also, the HSP90 and GBP1 proteins of S. torgalensis have higher thermostability, suggesting that they function in a wider range of temperatures. Instead, S. carolitertii presents many changes in gene expression, including in genes involved in the thermal stress response as well as in energy metabolism, and a decrease in the aerobic metabolism coupled with an increase in the anaerobic metabolism. Remarkably, the projected climatic conditions elicit severe changes in the circadian (cry1aa and per1a) and immune (gpb1 ) related genes, as well as an increase in HSP70 protein content, which may hinder the survival of both species. This work provide the rst assessment of the ability of Iberian freshwater sh to deal with future climate change and shall be considered for conservation actions, particularly for the critically endangered S. torgalensis.
