Paper Title
Role of the GRP RNA Binding Proteins in Stress Adaptation in Chlamydomonasreinhardtii

Abstract
The class IV proteins are a distinct subgroup within the very heterogenous superfamily of glycine-rich proteins (GRPs), exemplified by the well-studied Arabidopsis thaliana protein (atGRP7). They are distinguished by the presence of an RNA-binding domain in the N-terminus, generally in the form of an RNA Recognition Motif (RRM) or a cold-shock domain (CSD) followed by a glycine-rich domain. These proteins play key roles in the adaptation to biotic and abiotic stresses that include pathogens, osmotic and salt stress, oxidative stress, and cold stress. This project aims to investigate the expression and function of the class IV GRP gene CrGRP1 in stress adaptation in the unicellular flagellate alga Chlamydomonasreinhardtii. Mid log-phase cultures of C. reinhardtii were subjected to oxidative stress.RT-PCR analysis of cells treated with 0.1�M to 1mM H2O2suggested a reduction in CrGRP1 expression. Next we examined whether or not CrGRP1 is expressed in a Circadian manner, similar its Arabidopsis thaliana orthologue atGRP7. This appeared to be the case as CrGRP1 was mostly highly expressed during day time. We then investigated the effect of abscisic acid (ABA) on the motility of C.reinhardtii.ABA treatment (50�M) appeared to reduce the motility and growth rate ofC. reinhardtii. ABA also significantly decreased the ability of C. reinhardtii to move away from an excessively strong light source. Together these results indicate that CrGRP1 is involved in adaptation to a biotic stress but also in developmental processes. In the long term, it may be possible to manipulate GRPs to improve the use of C.reinhardtii as a potentialbiofuel.