TY - JOUR

T1 - Changes in lipid and carotenoid metabolism in Chlamydomonas reinhardtii during induction of CO2-concentrating mechanism

T2 - Cellular response to low CO2 stress

AU - Abreu, Ilka N.

AU - Aksmann, Anna

AU - Bajhaiya, Amit K.

AU - Benlloch, Reyes

AU - Giordano, Mario

AU - Pokora, Wojciech

AU - Selstam, Eva

AU - Moritz, Thomas

PY - 2020

Y1 - 2020

N2 - Photosynthetic organisms strictly depend on CO2 availability and the CO2:O2 ratio, as both CO2/O2 compete for catalytic site of Rubisco. Green alga Chlamydomonas reinhardtii, can overcome CO2 shortage by inducing CO2-concentrating mechanism (CCM). Cells transferred to low-CO2 are subjected to light-driven oxidative stress due to decrease in the electron sink. Response to environmental perturbations is mediated to some extent by changes in the lipid and carotenoid metabolism. We thus hypothesize that when cells are challenged with changes in CO2 availability, changes in the lipidome and carotenoids profile occur. These changes expected to be transient, when CCM is activated, CO2 limitation will be substantially ameliorated. In our experiments, cells were transferred from high (5%) to low (air equilibrium) CO2. qPCR analysis of genes related to CCM and lipid metabolism was carried out. Lipidome was analyzed both in whole cells and in isolated lipid droplets. We characterized the changes in polar lipids, fatty acids and ketocarotenoids. In general, polar lipids significantly and transiently increased in lipid droplets during CCM. Similar pattern was observed for xanthophylls, ketocarotenoids and their esters. The data supports our hypothesis about the roles of lipids and carotenoids in tackling the oxidative stress associated with acclimation to sub-saturating CO2.

AB - Photosynthetic organisms strictly depend on CO2 availability and the CO2:O2 ratio, as both CO2/O2 compete for catalytic site of Rubisco. Green alga Chlamydomonas reinhardtii, can overcome CO2 shortage by inducing CO2-concentrating mechanism (CCM). Cells transferred to low-CO2 are subjected to light-driven oxidative stress due to decrease in the electron sink. Response to environmental perturbations is mediated to some extent by changes in the lipid and carotenoid metabolism. We thus hypothesize that when cells are challenged with changes in CO2 availability, changes in the lipidome and carotenoids profile occur. These changes expected to be transient, when CCM is activated, CO2 limitation will be substantially ameliorated. In our experiments, cells were transferred from high (5%) to low (air equilibrium) CO2. qPCR analysis of genes related to CCM and lipid metabolism was carried out. Lipidome was analyzed both in whole cells and in isolated lipid droplets. We characterized the changes in polar lipids, fatty acids and ketocarotenoids. In general, polar lipids significantly and transiently increased in lipid droplets during CCM. Similar pattern was observed for xanthophylls, ketocarotenoids and their esters. The data supports our hypothesis about the roles of lipids and carotenoids in tackling the oxidative stress associated with acclimation to sub-saturating CO2.

KW - Betaine lipids

KW - Carotenogenesis

KW - CCM

KW - Chlamydomonas

KW - Lipid droplets

KW - Low-CO stress

U2 - 10.1016/j.algal.2020.102099

DO - 10.1016/j.algal.2020.102099

M3 - Journal article

AN - SCOPUS:85092778428

VL - 52

JO - Algal Research

JF - Algal Research

SN - 2211-9264

M1 - 102099

ER -