Expression of Chlamydomonas reinhardtii chloroplast diacylglycerol acyltransferase-3 is induced by light in concert with triacylglycerol accumulation.

CARRO, M.M.; GONORAZKY, G.; SOTO, D.; MAMONE, L.; BAGNATO, C; PAGNUSSAT, L.A.; BELIGNI, MV

PLANT JOURNAL

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2022

0960-7412

Considerable progress has been made towards the understanding of triacylglycerol (TAG) accumulation in algae. One key aspect is finding conditions that trigger TAG production without reducing cell division. Previously, we identified a soluble diacylglycerol acyltransferase (DGAT), related to plant DGAT3, with heterologous DGAT activity. In this work, we demonstrate that Chlamydomonas reinhardtii DGAT3 localizes to the chloroplast and that its expression is induced by light, in correspondence with TAG accumulation. Dgat3 mRNAs and TAGs increase in both wild type and starch-deficient cells grown with acetate upon transferring them from dark or low light to higher light, albeit affected by the particularities of each strain. The response of dgat3 mRNAs and TAGs to light depends on the preexisting levels of TAGs, suggesting the existence of a negative regulatory loop on the synthesis pathway, although an effect on TAG turnover cannot be ruled out. Altogether, these results hint toward a possible role of DGAT3 in light-dependent TAG accumulation in C. reinhardtii.