Development of marker-free transgenic Jatrophaplants with increased levels of seed oleic acid
Abstract Background Jatropha curcas is recognized as a new energy crop due to the presence of the high amount of oil in its seeds that can be converted into biodiesel. The quality and performance of the biodiesel depends on the chemical composition of the fatty acids present in the oil. The fatty ac...
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Published in | Biotechnology for biofuels Vol. 5; no. 1 |
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Main Authors | , , , , , , , |
Format | Journal Article |
Language | English |
Published |
29.02.2012
|
Online Access | Get full text |
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Summary: | Abstract
Background
Jatropha curcas
is recognized as a new energy crop due to the presence of the high amount of oil in its seeds that can be converted into biodiesel. The quality and performance of the biodiesel depends on the chemical composition of the fatty acids present in the oil. The fatty acids profile of the oil has a direct impact on ignition quality, heat of combustion and oxidative stability. An ideal biodiesel composition should have more monounsaturated fatty acids and less polyunsaturated acids. Jatropha seed oil contains 30% to 50% polyunsaturated fatty acids (mainly linoleic acid) which negatively impacts the oxidative stability and causes high rate of nitrogen oxides emission.
Results
The enzyme 1-acyl-2-oleoyl-sn-glycero-3-phosphocholine delta 12-desaturase (FAD2) is the key enzyme responsible for the production of linoleic acid in plants. We identified three putative
delta
12
fatty acid desaturase
genes in
Jatropha
(
JcFAD2s
) through genome-wide analysis and downregulated the expression of one of these genes,
JcFAD2-1
, in a seed-specific manner by RNA interference technology. The resulting
JcFAD2-1
RNA interference transgenic plants showed a dramatic increase of oleic acid (> 78%) and a corresponding reduction in polyunsaturated fatty acids (< 3%) in its seed oil. The control
Jatropha
had around 37% oleic acid and 41% polyunsaturated fatty acids. This indicates that FAD2-1 is the major enzyme responsible for converting oleic acid to linoleic acid in
Jatropha
. Due to the changes in the fatty acids profile, the oil of the
JcFAD2-1
RNA interference seed was estimated to yield a cetane number as high as 60.2, which is similar to the required cetane number for conventional premium diesel fuels (60) in Europe. The presence of high seed oleic acid did not have a negative impact on other
Jatropha
agronomic traits based on our preliminary data of the original plants under greenhouse conditions. Further, we developed a marker-free system to generate the transgenic
Jatropha
that will help reduce public concerns for environmental issues surrounding genetically modified plants.
Conclusion
In this study we produced seed-specific
JcFAD2-1
RNA interference transgenic
Jatropha
without a selectable marker. We successfully increased the proportion of oleic acid versus linoleic in
Jatropha
through genetic engineering, enhancing the quality of its oil. |
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ISSN: | 1754-6834 1754-6834 |
DOI: | 10.1186/1754-6834-5-10 |