NEW INSIGHTS INTO LIPID METABOLISM OF Haematococcuspluvialis IN RESPONSE TO HIGH-LIGHT STRESS

SCODELARO BILBAO, PAOLA G.; SALVADOR GABRIELA; LEONARDI, P

Parana

Congreso; LIV Reunión Anual de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular (SAIB), 5 al 8 de noviembre de 2018, Paraná, Entre Ríos, Argentina; 2018

SAIB

The oleaginous unicellular microalga Haematococcuspluvialis is being intensely studied as a source of carotenoids and lipids with potentialbiotechnological and biomedical applications. The aim of this study was to analyze the effect of high-light stress on the regulation oftriacylglyceride (TAG) and sterol synthesis in H. pluvialis UTEX 2505. After 24 hours of high-light exposure, both lipid classes significantlyincreased compared to the control condition. As expected, the use of inhibitors cerulenin, propranolol, xanthohumol and A922500 significantlydecreased TAG synthesis under high-light stress, while mevastatin and 25-hydroxycholesterol reduced sterol content. These results together withqPCR and Western blot analyses revealed some of the enzymes of H. pluvialis involved in lipid synthesis in response to high-light. In addition,we observed that TAG inhibitors also reduced sterol content while sterol inhibitors diminished TAG production, denoting coordination betweenboth synthesis pathways. Fosmidomycin, a specific inhibitor of the non-mevalonate pathway of isoprenoid biosynthesis, reduced total carotenoidcontent and antioxidant capacity together with TAG and sterol content. Finally, inhibition of carotenoid, TAG and sterol synthesis significantlyreduced cell viability suggesting their participation in H. pluvialis survival and adaption to high irradiance. These findings reveal features of lipidsynthesis and function of H. pluvialis under high-light stress, and points towards new possible molecular targets to enhance lipid production inmicroalgae