Comparative evolution of polar adaption in Antarctic Desmarestiales versus Arctic Laminariales (brown algae)
Final Report Abstract
Global change is intensely affecting polar regions and its effects are expected to be among the largest and most rapid of any region on Earth. Brown algae of the order Desmarestiales dominate rocky shores along the Antarctic Peninsula, where they form huge underwater forests providing habitat and nurseries for various marine organisms. Within the framework of this study, a comprehensive transcriptome of the brown alga Desmarestia anceps using MiSeq sequencing was generated and tested for differential gene expression in response to different photosynthetically active radiation (PAR), temperature, ultraviolet radiation (UVR) and CO2 conditions using HiSeq 2500 sequencing. A reference transcriptome consisting of 20.2 million paired end reads was established, out of this a total of 53,745 assembled transcripts were generated. Gene expression profiling showed that D. anceps responds to abiotic stress with a multitude of transcriptional changes. Antarctic D. anceps shows a high constitutive expression of genes coding for photosynthetic components and ROS scavenging enzymes, which was not observed in the Arctic kelp S. latissima. High temperatures had a stronger influence D. anceps on metabolic processes than different light conditions at low temperatures in. D. anceps features different mechanisms of heat acclimation, e.g. strong regulation of lipid metabolism, protein and membrane modification processes, which were not found to be part of the heat acclimation mechanisms of Arctic kelps. General stress responses observed in D. anceps sporophytes subjected to high PAR include regulation of photosynthetic components, induction of the nucleic acid metabolism and induction of antioxidant enzymes. The data suggests that D. anceps is more sensitive towards high temperature stress compared to the Arctic kelp S. latissima. Under high CO2 conditions growth and photosynthetic rates increased, however enhanced CO2 induced only few transcriptomic changes. High CO2 alone or in combination with light & moderate temperature stress does not affect D. anceps negatively. CO2 increase accompanied by a moderate temperature increase might allow D. anceps to maintain its productivity while tolerating higher irradiances than at present conditions.
Publications
- (2015): Transcriptomic acclimation in Desmarestia anceps, 6th European Phycological Congress, 23.08.2015 - 28.08.2015, London, UK
Heinrich, S., Harms, L. & Frickenhaus, S.
- (2016). Short term physiological response to light, UVR and temperature stress in Antarctic versus Arctic habitat structuring brown algae. Algological Studies, 151: 151-165
Heinrich, S.
(See online at https://doi.org/10.1127/algol_stud/2016/0274) - (2016): Transcriptomics of short term acclimation in Desmarestia anceps, 13. Wissenschaftliche Tagung der Sektion Phykologie, 06.03.2016-09.03.2016, Leipzig, Germany
Heinrich, S., Harms, L. & Frickenhaus, S.
- (2017). Increased temperature and CO2 alleviate photoinhibition in Desmarestia anceps: from transcriptomics to carbon utilisation. Journal of Experimental Botany
Iñiguez, C., Heinrich, S., Harms, L. & Gordillo, F.J.L.
(See online at https://doi.org/10.1093/jxb/erx164)
