Characterization of genes which are induced under astaxanthin accumulated condition

Abstract

Unicellular green alga, Haematococcus pluvialis used as a biological production system for astaxanthin. Upon environmental stress such as strong irradiance or nitrogen deficiency unicellular green algae of the genus Haematococcus accumulate astaxanthin in the cytosol. To induce astaxanthin biosynthesis of H. pluvialis, cells were incubated in either nitrate free at 25℃ under continuous high light intensity (1000 ?Eㆍm-2ㆍs-1) for 2 day and cells were incubated with methyl viologen (MV). Under these stress conditions, pigment changes and photosynthetic capacity were monitored by using HPLC. We have cloned 5 different peroxiredoxin (Prx) genes of H. pluvialis, and several biosynthesis of astaxanthin genes such as carotenoid hydroxylase, phytoene desaturase, beta-carotene C-4 oxygenase, IPP isomerase and beta-carotene ketolase. When these genes are monitored their expression by using under different culture conditions, all astaxanthin biosynthesis genes were up-regulated under N depletion and highlight stress where total astaxanthin content started to accumulate. In addition, 4 among 5 Prx genes were up regulated under astaxanthin induction conditions, while most known other anti-oxidant protein were down regulated.