Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
8354780 | Plant Physiology and Biochemistry | 2015 | 11 Pages |
Abstract
Fatty acids from dietary lipids can impart both beneficial and harmful health effects. The compositional balance between saturated and unsaturated fatty acids plays a decisive role in maintaining the physiological harmony, proper growth and development in the human system. In case of Brassica juncea seed oil, the level of saturated fatty acid, especially desirable stearate is very much lower than the recommended value, along with a high content of nutritionally undesirable erucic acid. Therefore, in order to shift the carbon flux towards the production of stearate at the expense of erucate, the MlFatB gene encoding a FatB thioesterase from Madhuca longifolia (latifolia) was expressed heterologously in seed tissues of B. juncea. The functional MlFatB competed with the highly active endogenous BjFatA thioesterase, and the transgenic B. juncea lines showed noteworthy changes in their seed fatty acid profiles. The proportion of stearate increased up to 16-fold, constituting almost 31% of the total fatty acids along with the production of arachidic acid in significant amount (up to â¼11%). Moreover, the content of erucate was reduced up to 71% in the seed oils of transgenic lines. Although a nutritionally desirable fatty acid profile was achieved, the transgenic seeds exhibit reduction or abolition of seed germination in addition to a decrease in seed lipid content. The findings of the present study revealing the stearoyl-ACP thioesterase-mediated enhancement of the stearate content that is associated with reduced germination frequency of transgenic B. juncea seeds, may explain why no natural or induced stearate-rich Brassica has been found or developed. Furthermore, this study also suggests that the newly characterized MlFatB is a potential candidate gene for refined metabolic engineering strategy in B. juncea or other plant species for increasing stearate content in seed oil.
Keywords
FAD2HDLVLCFAPUFAsPMSFSFAT-DNAACPPVDFFAE1transferred DNAFAD3BSENAPNOSCTABBSAMurashige and Skoog mediumflame ionization detectorbovine serum albuminEDTAEthylenediaminetetraacetic acidcetyl trimethylammonium bromideStearic acidErucic acidsaturated fatty acidPolyunsaturated fatty acidsfatty acid desaturase 2Very long chain fatty acidFatty acid biosynthesistriacylglycerolTAG یا triacylglycerols FIDNapinpolyvinylidene difluoridenopaline synthaseFAMEsphenylmethylsulfonyl fluoridehigh density lipoproteinlow density lipoproteinLDLfatty acid methyl estersMetabolic engineeringacyl carrier proteinFatGas chromatography
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Authors
Surajit Bhattacharya, Saheli Sinha, Natasha Das, Mrinal K. Maiti,