Promotes chlorophyll degradation in leaves. May be involved in LHCI proteins degradation, regulating the balance between LHCI and LHCII. Strongly expressed in leaves, stems and panicles, and at lower levels in roots and seeds. Higher expression in young leaves. Down-regulated during dark-induced and natural senescence. Down-regulated by dark-induced senescence. Circadian-regulation with a strong expression during the transition from dark to light. Belongs to the staygreen family.