AgZDS, a gene encoding ζ-carotene desaturase, increases lutein and β-carotene contents in transgenic Arabidopsis and celery

zeta-Carotene desaturase (ZDS) is one of the key enzymes regulating carotenoids biosynthesis and accumulation. Celery transgenic efficiency is low and it is difficult to obtain transgenic plants. The study on ZDS was limited in celery. Here, the AgZDS gene was cloned from celery and overexpressed in Arabidopsis thaliana and celery to verify its function. The AgZDS has typical characteristic of ZDS protein and is highly conserved in higher plants. Phylogenetic analysis showed that AgZDS has the closest evolutionary relationship with ZDSs from Solarium lycopersicum, Capsicum annuum and Tagetes erecta. Overexpression of AgZDS gene in A. thaliana and celery resulted in increased accumulations of lutein and beta-carotene and up-regulated the expression levels of the genes involved in camtenoids biosynthesis. The contents of lutein and beta-carotene in two lines, AtL1 and AgL5, were the highest in transgenic A. thaliana and celery, respectively. The relative expression levels of 5 genes (AtPDS, AtZISO, AtZEP, AtNCED3, and AtCCD4) were up-regulated compared to the wild type plants. The relative expression levels of most genes in camtenoids biosynthesis pathway, such as AgPDS, AgCRTISO1, and AgZISO, were up-regulated in transgenic celery plants. The antioxidant capacity of A. thaliana and photosynthetic capacity of celery were also enhanced. This research is the first report on the function of structure gene related to carotenoid biosynthesis in transgenic celery plants. The findings in this study demonstrated the roles of AgZDS in regulating carotenoids metabolism of celery, which laid a potential foundation for quality improvement of celery.

Automated summary

The overexpression of AgZDS gene in Arabidopsis thaliana and celery resulted in increased accumulation of lutein and beta-carotene and up-regulated expression levels of genes involved in carotenoid biosynthesis. Additionally, the antioxidant capacity of A. thaliana and photosynthetic capacity of celery were enhanced in transgenic plants.