A forward genetic screen in the marine planktonic diatom Pseudo-nitzschia multistriata
The GyPSy project is a Marie Curie Career Integration Grant (CIG) focused on a marine diatom, a unicellular alga called Pseudo-nitzschia multistriata. We plan to use this species as a genetic model system to study the function of algal genes involved in important processes such as lipid biosynthesis. This will be achieved by the generation of mutant clones. An important part of this project is the sequencing of the genome of this alga in collaboration with The Genome Analysis Centre in Norwich, UK; its final goal is to consolidate a new model organism to explore the molecular mechanisms underlying the biology of diatoms.
Diatoms carry out one fifth of the photosynthesis on Earth and are essential to aquatic ecosystems. In addition to their fundamental role in carbon fixation, they play a key role in the biogeochemical cycle of nitrate and silica, have other complex metabolic abilities, such as the urea cycle and fatty acid metabolism, and developed several strategies for the adaptation to different, sometimes extreme, environments. An improved knowledge of diatom biology is crucial for understanding the basis of their ecological success, for predicting their capability to adapt to a rapidly changing environment, including climatic changes due to greenhouse gasses, and for industrial exploitation of their biological properties.
The aim of project is to generate a collection of stable mutants for diatoms through random chemical mutagenesis. Specifically, we want to isolate mutants with altered production of fatty acids, oxylipins and domoic acid, both to characterise the molecular pathways involved and to obtain clones of potential interest to industry. So far, genomics and functional data are available for less than 10 of the 200.000 known species, the project team aims at generating a tool that will facilitate molecular studies in these organisms. For these studies, the species selected is Pseudo-nitzschia multistriata, for its ecological relevance in Mediterranean ecosystems and forits controllable life cycle with known sexual stages.
As a preliminary step to this study the project plans to exploit new sequencing technologies to sequence the genome of the selected diatom, this will allow to undertake positional cloning once mutants have been isolated and will represent per se a valuable resource. The project will contribute to establish a Pseudo-nitzschia multistriata as a model organism and to develop molecular biology and functional genomic resources for diatoms. Ultimately, the objective is to allow a better comprehension of the data and observations that will come from the sea.