Ice-binding proteins (IBPs) in cold-adapted diatoms – implications for survival under freezing temperatures


The ocean harbours the largest untapped resource for novel products used in biotechnology, agriculture and medicine. Many valuable products with great potential have been isolated from cold-adapted marine microbes as they occupy extreme environments, which require proteins to function at low temperatures.

The ubiquitous family of ice-binding proteins (IBPs) helps cold-adapted organisms to survive at lower temperatures by reducing ice-crystal formation, and in case of microbes by reshaping their icy surroundings. Potential applications include controlling ice-crystal formation in food, growing frost-resistant crops and improving preservation of cells and tissues for medical applications. However, as IBPs are diverse, the function of different isoforms needs to be determined, which will define their applications in biotechnology.

To address this question, this PhD studentship will determine the function of representative IBPs in the cold-adapted model diatom Fragilariopsis cylindrus through reverse genetics and biochemical characterisation. The genome of this prolific diatom encodes several IBP genes, which are differentially expressed, and preliminary data based on targeting signals imply that their proteins are localised in different parts of the cell, which suggests that they perform different roles.

The student will fluorescently tag IBPs for their subcellular localisation and assess their effects on growth and ice-structure. Furthermore, genome editing will be used to remove IBP genes from the genome of F. cylindrus for their characterisation through loss of function. Thus, data from this project will lay the foundation for a biotechnology platform to characterise cold-adapted proteins for providing new insights into the biology of polar organisms and to test and produce novel cold-adapted proteins.


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