The effect of nitrogen limitation on acetyl-CoA carboxylase expression and fatty acid content in Chromera velia and Isochrysis aff. galbana (TISO)

Huerlimann, Roger, Steinig, Eike J., Loxton, Heather, Zenger, Kyall, Jerry, Dean R., and Heimann, Kirsten (2014) The effect of nitrogen limitation on acetyl-CoA carboxylase expression and fatty acid content in Chromera velia and Isochrysis aff. galbana (TISO). Gene, 543 (2). pp. 204-211.

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Abstract

Lipids from microalgae have become a valuable product with applications ranging from biofuels to human nutrition. While changes in fatty acid (FA) content and composition under nitrogen limitation are well documented, the involved molecular mechanisms are poorly understood. Acetyl-CoA carboxylase (ACCase) is a key enzyme in the FA synthesis and elongation pathway. Plastidial and cytosolic ACCases provide malonyl-CoA for de novo FA synthesis in the plastid and FA elongation in the endoplasmic reticulum, respectively. The present study aimed at investigating the expression of plastidial and cytosolic ACCase in Chromera velia and Isochrysis aff. galbana (TISO) and their impact on FA content and elongation level when grown under nitrogen-deplete conditions. In C. velia, plastidial ACCase was significantly upregulated during nitrogen starvation and with culture age, strongly correlating with increased FA content. Conversely, plastidial ACCase of I. aff. galbana was not differentially expressed in nitrogen-deplete cultures, but upregulated during the logarithmic phase of nitrogen-replete cultures. In contrast to plastidial ACCase, the cytosolic ACCase of C. velia was downregulated with culture age and nitrogen-starvation, strongly correlating with an increase in medium-chain FAs. In conclusion, the expression of plastidial and cytosolic ACCase changed with growth phase and nutrient status in a species-specific manner and nitrogen limitation did not always result in FA accumulation.

Item ID: 32791
Item Type: Article (Refereed Research - C1)
Keywords: differential expression; elongation; homomeric; plastidial; cytosolic
ISSN: 1879-0038
Funders: James Cook University (JCU), Advanced Manufacturing Cooperative Research Centre (AMCRC)
Projects and Grants: AMCRC Project 2.3.2
Date Deposited: 21 May 2014 02:01
FoR Codes: 06 BIOLOGICAL SCIENCES > 0604 Genetics > 060405 Gene Expression (incl Microarray and other genome-wide approaches) @ 50%
06 BIOLOGICAL SCIENCES > 0607 Plant Biology > 060701 Phycology (incl Marine Grasses) @ 25%
06 BIOLOGICAL SCIENCES > 0606 Physiology > 060604 Comparative Physiology @ 25%
SEO Codes: 85 ENERGY > 8505 Renewable Energy > 850501 Biofuel (Biomass) Energy @ 50%
82 PLANT PRODUCTION AND PLANT PRIMARY PRODUCTS > 8299 Other Plant Production and Plant Primary Products > 829999 Plant Production and Plant Primary Products not elsewhere classified @ 50%
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