Forging sustainability

HULK - Functional Chloroplasts inside Animal cells: cracking the puzzle
Coordinator - Sónia Marisa Gonçalves da Cruz
Programme - Projetos de Investigação Científica e Desenvolvimento Tecnológico - 2014 (PTDC/BIA-ANM/4622/2014)
Execution dates - 2016-06-01 - 2020-02-29 (45 Months)
Funding Entity - FCT - Fundação para a Ciência e a Tecnologia
Funding for CESAM - 153948 €
Total Funding - 183732 €
Proponent Institution - Universidade de Aveiro
Participating Institutions
Universidade de Lisboa
Cooperativa de Formação e Animação Cultural, CRL (COFAC)
Fundação da Faculdade de Ciências da Universidade de Lisboa (FFCUL)
Institut of Chemical Sciences and Engineering - Ecole Polytechnique Fédérale de Lausanne (ISIC-EPFL), Swiss
Muséum National d'Histoire Naturelle de Paris (MNHN), France
Marine Biological Laboratory (MBL), University of Copenhagen, Denmark

Sacoglossa sea slugs feed on algae and sequester chloroplasts (kleptoplasts), which can be maintained photosynthetically active inside tubule cells of their digestive diverticula for different periods of time. This unique animal-plant association is far from being understood. It has been assumed that kleptoplast photosynthesis act as a nutritional source during food depletion, though little evidence exists on the putative translocation of photosynthates between plastids and host. Recent research has shown that photosynthesis might not be essential for animal survival in the absence of food, speculating that kleptoplasts act as food depots. Photosynthesis in kleptoplasts can be sustained for several months after separation from its algal nucleus. Maintenance of functional plastids inside metazoan cells in the absence of the algal nucleus is puzzling, as several photosynthetic components display short lifespan. It has been hypothesized that algal nuclear genes transferred to the animal would support photosynthesis, but recent reports contradict this theory. Alternative hypotheses rely mostly on chloroplast robustness. Retention of functional kleptoplasts possibly results from a combination of several physical and molecular non-described mechanisms. In marine symbioses, the efficient possibly results from a combination of several physical and molecular non-described mechanisms. In marine symbioses, the efficient use of light play a major role in keeping healthy associations. In Sacoglossa sea slugs, recent evidence indicates a major contribution of photoprotection mechanisms in the maintenance of photosynthetic activity in kleptoplasts. Further investigation addressing these issues is required.

We aim to understand role of kleptoplast in host metabolism and to determine what are the mechanisms responsible for kleptoplast survival inside the animal cell. We will address the following questions: 1) what is the fate of photosynthetically fixed carbon inside animal cells? Do species retaining photosynthetically active kleptoplasts for longer periods show a higher degree of photosynthetic carbon acquisition? 2) can photoprotective processes mitigate kleptoplast oxidative stress in Sacoglossa sea slugs thus contributing to kleptoplast longevity?

Members on this project
Felisa Rey Eiras

CESAM Funding: