Present adress: Department of Applied Biological Sciences, Arizona State University at the Polytechnic Campus, 7001 E. Williams Field Road, Mesa, Arizona 85212, USA.
HIGH-LIGHT AND SODIUM CHLORIDE STRESS DIFFERENTIALLY REGULATE THE BIOSYNTHESIS OF ASTAXANTHIN IN CHLORELLA ZOFINGIENSIS (CHLOROPHYCEAE)1
Article first published online: 1 JUN 2009
© 2009 Phycological Society of America
Journal of Phycology
Volume 45, Issue 3, pages 635–641, June 2009
How to Cite
Li, Y., Huang, J., Sandmann, G. and Chen, F. (2009), HIGH-LIGHT AND SODIUM CHLORIDE STRESS DIFFERENTIALLY REGULATE THE BIOSYNTHESIS OF ASTAXANTHIN IN CHLORELLA ZOFINGIENSIS (CHLOROPHYCEAE). Journal of Phycology, 45: 635–641. doi: 10.1111/j.1529-8817.2009.00689.x
Received 18 July 2008. Accepted 28 January 2009.
- Issue published online: 5 JUN 2009
- Article first published online: 1 JUN 2009
- carotenoid hydroxylase;
- carotenoid ketolase;
- Chlorella zofingiensis;
- high-light stress;
- NaCl stress;
- reactive oxygen species
Although light and salt stresses are known to enhance the biosynthesis of astaxanthin in certain green algae, the mechanism of their action remains largely unknown. Here we report the regulation of the genes encoding phytoene desaturase (PDS), carotenoid hydroxylase (CHYb), and carotenoid ketolase (BKT) in the green alga Chlorella zofingiensis Dönz under light or sodium chloride (NaCl) stress. High-light illumination (150 μmol photons · m−2 · s−1) up-regulated the transcripts of PDS, CHYb, and BKT and greatly enhanced the biosynthesis of zeaxanthin, canthaxanthin, and astaxanthin. In contrast, sodium chloride stress only up-regulated the transcript of BKT and enhanced the biosynthesis of canthaxanthin and astaxanthin. High-light and NaCl stresses were revealed to result in an increase in the intracellular reactive oxygen species (ROS) level. By applying chemically generated ROS to the algal cells, we determined that 1O2 specifically up-regulated the CHYb gene, whereas •OH up-regulated the PDS and BKT genes. We suggest that high-light and NaCl stresses may stimulate the generation of different ROS, which in turn trigger the up-regulation of specific carotenogenic genes and the enhanced biosynthesis of carotenoids in C. zofingiensis.