Abstract
Albinism is a common problem encountering breeding and interspecific crosses. Arabidopsis thaliana chyB (AtchyB) gene encodes for ß-carotene hydroxylase. We generated transgenic plant over-expressing AtchyB in A. thaliana and compared to wild-type (WT) plants in response to light stress. We tested whether the over-expression of AtchyB gene can affect the green and albino leaf ultrastructure in A. thaliana transgenic lines. In this study, over-expression of AtchyB cDNA governed by Cauliflower Mosaic_Virus_35S (CaMV 35S) promoter showed a progressive yellow coloration in primary leaves and ultrastructural changes to albino and green leaves of transgenic A. thaliana plant in comparison to wild type (WT). Leaf albinism causes dilatation of both the palisade parenchyma and the secretory cells, enlargement of plastoglobules and increased cuticle thickness. In addition, the presence of low number of chloroplasts and/or starch grains is associated with leaf albinism phenomenon. Altogether, this suggests that A. thaliana 35S:AtchyB transgenic lines induce leaf albinism which affects the leaves ultrastructure with retrograde signaling, defects in chlorophyll biosynthesis and chloroplast dysfunction.