Analyses of one T-DNA insertion mutant (cgl160-1), which is completely devoid of the CGL160 protein (Fig. 2B), and a second mutant (cgl160-2), which suffers from an 80% reduction in CGL160 protein content (Fig. 2C), revealed identical photosynthetic defects: Under long-day growth conditions, both T-DNA insertion lines hardly show a growth retardation,while under short-day and especially under fluctuating light conditions, the phenotype is more pronounced, and biomass accumulation is reduced (Fig. 4A-C, S2 Fig.).