In:
Journal of Phycology, Wiley, Vol. 53, No. 2 ( 2017-04), p. 405-414
Abstract:
Under nutrient deplete conditions, diatoms accumulate between 15% to 25% of their dry weight as lipids, primarily as triacylglycerols ( TAG s). As in most eukaryotes, these organisms produce TAG s via the acyl‐CoA dependent Kennedy pathway. The last step in this pathway is catalyzed by diacylglycerol acyltransferase ( DGAT ) that acylates diacylglycerol ( DAG ) to produce TAG . To test our hypothesis that DGAT plays a major role in controlling the flux of carbon towards lipids, we overexpressed a specific type II DGAT gene, DGAT 2D , in the model diatom Phaeodactylum tricornutum . The transformants had 50‐ to 100‐fold higher DGAT 2D mRNA levels and the abundance of the enzyme increased 30‐ to 50‐fold. More important, these cells had a 2‐fold higher total lipid content and incorporated carbon into lipids more efficiently than the wild type ( WT ) while growing only 15% slower at light saturation. Based on a flux analysis using 13 C as a tracer, we found that the increase in lipids was achieved via increased fluxes through pyruvate and acetyl‐CoA. Our results reveal overexpression of DAGT 2D increases the flux of photosynthetically fixed carbon towards lipids, and leads to a higher lipid content than exponentially grown WT cells.
Type of Medium:
Online Resource
ISSN:
0022-3646
,
1529-8817
DOI:
10.1111/jpy.2017.53.issue-2
Language:
English
Publisher:
Wiley
Publication Date:
2017
detail.hit.zdb_id:
281226-5
detail.hit.zdb_id:
1478748-9
SSG:
12
Bookmarklink