Regulation of carotenoid biosynthetic genes expression and carotenoid accumulation in the green alga Haematococcus pluvialis under nutrient stress conditions

Vidhyavathi, Raman and Venkatachalam, Lakshmanan and Sarada, Ravi and Ravishankar, G. A. (2008) Regulation of carotenoid biosynthetic genes expression and carotenoid accumulation in the green alga Haematococcus pluvialis under nutrient stress conditions. Journal of Experimental Botany, 59 (6). pp. 1409-1418. ISSN 1460-2431

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Abstract

Haematococcus pluvialis, a green alga, accumulates carotenoids, predominantly astaxanthin, when exposed to stress conditions. In the present work, changes in the pigment profile and expression of carotenogenic genes under various nutrient stress conditions and their regulation were studied. Nutrient stress and higher light intensity in combination with NaCl/sodium acetate (SA) enhanced total carotenoid and total astaxanthin content to 32.0 and 24.5 mg g(-1) of dry biomass, respectively. Expression of carotenogenic genes, phytoene synthase (PSY), phytoene desaturase (PDS), lycopene cyclase (LCY), beta-carotene ketolase (BKT), and beta-carotene hydroxylase (CHY) were up-regulated under all the stress conditions studied. However, the extent of expression of carotenogenic genes varied with stress conditions. Nutrient stress and high light intensity induced expression of astaxanthin biosynthetic genes, BKT and CHY, transiently. Enhanced expression of these genes was observed with SA and NaCl/SA, while expression was delayed with NaCl. The maximum content of astaxanthin recorded in cells grown in medium with SA and NaCl/SA correlated with the expression profile of the astaxanthin biosynthetic genes. Studies using various inhibitors indicated that general carotenogenesis and secondary carotenoid induction were regulated at both the transcriptional and the cytoplasmic translational levels. The induction of general carotenoid synthesis genes was independent of cytoplasmic protein synthesis while BKT gene expression was dependent on de novo protein synthesis.

Item Type:	Article
Uncontrolled Keywords:	Astaxanthin, carotenoid, Haematococcus pluvialis, NaCl, nutrient stress, sodium acetate.
Subjects:	500 Natural Sciences and Mathematics > 07 Life Sciences > 04 Microbiology > 01 Algae 500 Natural Sciences and Mathematics > 04 Chemistry and Allied Sciences > 14 Carotenoid Chemistry
Divisions:	Plant Cell Biotechnology
Depositing User:	Food Sci. & Technol. Information Services
Date Deposited:	08 Jun 2009 09:03
Last Modified:	28 Dec 2011 09:35
URI:	http://ir.cftri.res.in/id/eprint/1804

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