AUTHOR=Pajot Anne , Lavaud Johann , Carrier Gregory , Garnier Matthieu , Saint-Jean Bruno , Rabilloud Noémie , Baroukh Caroline , Bérard Jean-Baptiste , Bernard Olivier , Marchal Luc , Nicolau Elodie 

TITLE=The Fucoxanthin Chlorophyll a/c-Binding Protein in Tisochrysis lutea: Influence of Nitrogen and Light on Fucoxanthin and Chlorophyll a/c-Binding Protein Gene Expression and Fucoxanthin Synthesis

JOURNAL=Frontiers in Plant Science

VOLUME=Volume 13 - 2022

YEAR=2022

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2022.830069

DOI=10.3389/fpls.2022.830069

ISSN=1664-462X

ABSTRACT=We observed differences in lhc classification among Chromista. We proposed a classification of the lhcf family with two groups specific to haptophytes, one specific to diatoms, one specific to seaweeds. The identification and characterization of the fucoxanthin and chlorophyll a/c-binding protein (FCP) of the haptophyte microalgae Tisochrysis lutea was performed using similarity analysis. The FCP family contains 52 lhc genes in T. lutea. The FCP pigments binding sites were characterized on the Lhcf protein monomers of T. lutea, which possesses at least nine chlorophylls and five fucoxanthin molecules in average per monomer. The expression of T. lutea lhc genes was assessed during turbidostat and chemostat experiments, one with constant light and changing nitrogen phases, the second with a 12 h: 12 h (day:night) sinusoidal photoperiod and changing nitrogen phases. RNAseq analysis of the 52 lhc sequences revealed a dynamic decrease in the expression of genes with nitrogen depletion. The day:night cycle expression revealed T. lutea lhcx2 is only expressed at night, suggesting that its role is to protect the cells from the return of the light after a prolonged darkness exposure.