The regulation of photosynthesis in response to varying light conditions is primarily controlled through the phosphorylation of thylakoid proteins. This process is most extensively studied in the context of the phosphorylation of photosystem II (PSII) and light-harvesting complex II (LHCII) subunits. However, there is comparatively less understanding of the changes induced by light stress in photosystem I and light-harvesting complex I (LHCI). In this study, we examined the alterations in protein phosphorylation of PSI-LHCI in Chlorella ohadii, an extremely light-tolerant desert green alga, when grown under low light (LL) and high light (HL) conditions.