Dr. Fatemeh Ghaderiardakani

Postdoctoral Researcher

Research Project:

Adaptation of the green seaweed Ulva and its microbiome to cold temperature in Antarctica (COLDULVA) funded by the DFG Priority Program 1158 "Antarctic Research" (Germany)

The project COLDULVA (read cold-ulva) investigates the cold adaptation of the green macroalga Ulva, also known as sea lettuce, which occurs worldwide in coastal areas. Ulva is characterised by excellent adaptability to changes in its environment. It is therefore often found in waters heavily polluted by humans, but also under extreme natural conditions such as in Antarctica. However, Ulva´s growth and morphogenesis depend on the associated bacteria releasing growth promoting compounds (morphogens). Under bacteria-free conditions, Ulva develops into a callus of non-differentiated cells.The project aims to identify stress-regulated genes and metabolites that are stimulated during the short-term cold response and acclimation under specific consideration of Ulva´s microbiome. Interestingly, cold-adapted (i.e. the Antarctic/cold temperate) Ulva species also grow at a higher temperature. However, the warm temperate U. mutabilis does not grow at low temperature, and neither do the associated essential bacteria. These observations pave the way to decipher the cold-responsive genes and metabolites in Ulva from the perspective of both intrinsic (algal metabolism) and extrinsic (microbiome) factors. COLDULVA will compare the warm temperate model system Ulva mutabilis with the Antarctic/cold temperate Ulva strains, U. compressa and U. bulbosa, which were previously collected on King Georg Island (Antarctica).We hypothesise that Ulva will react properly to stress if its microbiome also adapts to environmental changes to provide the necessary algal growth-promoting compounds. The following three approaches will be performed to address the key question “Are there key genes and metabolites for adaptation to Antarctic environmental conditions?”(1) Bacteria will be isolated from Antarctic temperate Ulva species to promote the growth of the warm temperate Ulva mutabilis at low temperature. (2) Changes of the algal metabolism due to differential gene expression and metabolite production will be investigated upon a shift to cold temperature in order to define the Ulva’s core stress-responsive genes and metabolites. (3) Ulva will be sampled again in the Potter Cove on King George Island (Carlini Station/Dallmann Laboratory, South Shetlands, Antarctica) to prove the ecological significance of the upregulated genes and biomarkers identified. Applying genome-wide transcriptome analysis and metabolite profile of macroalgae under standardised conditions and in their natural habitats will provide biological information regarding how Ulva optimise its metabolism to overcome environmental stresses. Overall, the insights which we gain on the ecology and physiology of macroalgae will shed light on how polar symbiotic communities are developing in response to global climatic changes in the ecosystem of Potter Cove. DFG-Project

Publications

Ghaderiardakani F., Califano G., Mohr J.F., Abreu M.H., Coates J.C., Wichard T* (2019) Analysis of algal growth- and morphogenesis-promoting factors in an integrated multi-trophic aquaculture system for farming the green seaweed Ulva spp. Aquaculture Environment Interactions 11: 375-391. https://doi.org/10.3354/aei00319

Ghaderiardakani, F., Coates, J.C., Wichard T.* (2017) Bacteria-induced morphogenesis of Ulva intestinalis and Ulva mutabilis (Chlorophyta): a contribution to the lottery theory. FEMS Microbiology Ecology 93(8):fix094

 

 

 

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