Research project: Seipin mutation in the model diatom Phaeodactylum tricornutum leads to altered lipid droplet composition: quantitative proteomics and lipidomics based approach

Supervisors: Dr. Mara Cucinotta (UNIMI) and Dr. Juliette Salvaing (LPCV)
Lab: LPCV, LIPID team
Year: 2022-2023

Diatoms, as a result of their independent evolutionary origin, exhibit a peculiar architecture  and some unique physiological characteristics that allow them to thrive in worldwide ecosystems. Among those, diatoms can accumulate higher amounts of lipids compared to cyanobacteria and filamentous green algae, holding potential for biotechnological applications. The accumulation of oil bodies is enhanced upon stress, due to the reorganising carbon flow towards the synthesis of lipids. Seipin is a transmembrane protein determinant for lipid droplets (LDs) biogenesis, and its depletion is observed to drive aberrant phenotypes due to disrupted LDs biogenesis in yeasts, drosophila, plants and humans.

The host laboratory aims to investigate the regulatory mechanisms underlying the involvement of Seipin in LDs biogenesis in the model diatom Phaeodactylum tricornutum. Starting from the acquisition of a stable PtSeipin knockout mutant line, previous work showed that Seipin depletion alters LDs dynamics and lipid metabolism in the diatom species. The present study focused on alterations of the LD composition in PtSeipin KO. Proteomic and lipidomic profiles of LDs purified under both nitrogen starvation and high light conditions pointed out that the LDs composition is peculiar to the culturing condition and significantly altered by PtSeipin depletion.

Francesca will now start working on a PhD project that will take place in both Montpellier and Marseille.