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HIGH‐LIGHT AND SODIUM CHLORIDE STRESS DIFFERENTIALLY REGULATE THE BIOSYNTHESIS OF ASTAXANTHIN IN CHLORELLA ZOFINGIENSIS (CHLOROPHYCEAE) 1
Author(s) -
Li Yantao,
Huang Junchao,
Sandmann Gerhard,
Chen Feng
Publication year - 2009
Publication title -
journal of phycology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.85
H-Index - 127
eISSN - 1529-8817
pISSN - 0022-3646
DOI - 10.1111/j.1529-8817.2009.00689.x
Subject(s) - astaxanthin , canthaxanthin , phytoene desaturase , biology , zeaxanthin , carotenoid , biosynthesis , chlorophyceae , biochemistry , lutein , gene , botany , algae , chlorophyta
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 1 O 2 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 .