Covalently attaches a chromophore to Cys residue(s) of phycobiliproteins (By similarity). Required for plastid division, and involved in cell differentiation and regulation of the cell division plane. Maintenance of plastid homeostasis controls plant preconditioning to stress and stress acclimation. Confers sensitivity to cabbage leaf curl virus (CaLCuV), probably by supporting viral movement. Mostly expressed in shoot apices, to a lower extent, in leaves, inflorescence stems, buds and cotyledons, and, at low levels, in roots and siliques. Transient strong induction in response to cabbage leaf curl virus (CaLCuV) infection at an early stage. Abnormal organ morphology (e.g. pale green, reduced stature, crumpled and irregular margins in leaves and floral organs, and shorter roots) due to altered pattern of cell division and differentiation. Impaired plastid division leading to enlarged chloroplasts and the formation of cells lacking plastids. Reduced susceptibility to viral infection by cabbage leaf curl virus (CaLCuV). Belongs to the CpcT/CpeT biliprotein lyase family.