Transgenic oilseed crops

Apart from the above mentioned enzymes, there also exist a few enzymes involved in PUFA metabolic pathways that have recently been found. One of them is a novel n-3 fatty acid desaturase, isolated from an EPA-rich fungus, Saprolegnia diclina [248]. The gene was isolated by PCR amplification from a fungus cDNA library and then, expressed in S. cerevisiae, which was cultured in the presence of several FA as substrates. The study showed that the recombinant protein could exclusively desaturase C20 n-6 PUFAs, with preference for AA which was converted into EPA. This represents a completely novel and different activity from any organism previously described, and its potential for use in EPA production in transgenic oilseed crops has been outlined. 

M. Lassner, Transgenic oilseed crops a transition from basic research to product development. Lipid Technology, 1997, 9, 5-9. V.C. Knauf and A.J. Del Vecchio, Food Lipids Chemistry, Nutrition, and Biotechnology, (ed. C.C. Akoh and D.B. Min) Marcel Dekker, New York (1998) pp.779-805. 

Green, A.G., Chen, Y, Singh, S.P., Dribnenki, 2008. Flax. In Chittaranjan, K., Hall, T.C. (Eds.), Compendium of Transgenic Crop Plants Transgenic Oilseed Crops. Blackwell Publishing Ltd, Chicester, UK, pp. 200-226. 

Ruiz-Lopez, N., Haslam, R.P., Napier, J.A., Sayanova, O., 2014. Successful high-level accumulation of fish oil omega-3 long-chain polyunsaturated fatty adds in a transgenic oilseed crop. Plant . 77,198-208. 

TABLE 14.1 List of Selected Examples of Oil Modifications in Transgenic Oilseed Crops... 

The first transgenic (across genera) oilseed crops were planted in the United States and... 

One inhibiting factor in commercial development of transgenic oilseeds with novel traits is public acceptance. The primary principle upon which approval has been based is known as substantial equivalence, which means that aside from any introduced changes, the composition of the plant or seed remains essentially unchanged. However, the concept of unintended consequences expands the scope of substantial equivalence, which establishes criteria that must be examined and met. Satisfying the concern for unintended consequences broadened the concept of substantial equivalence to include transcripts, the proteome, metabolome, and even genome sameness (43). In the approval process for a transgenic plant, these issues become a key part of the risk assessment both for food crops (44) and for industrial crops (45). 

Most transgenic oilseeds with altered fatty acid composition remain research subjects, with commercial introduction limited to two crops, neither of which have yet achieved success in the marketplace. The expected benefits from transgenic crops with altered fatty acid composition include improved stability properties enhanced nutritive value expanded use of renewable resources to replace petroleum derived materials replacement of chemical processes, such as epoxidation of fatty acid double bonds and gradual expansion of agriculture as a chemical industry, a concept long ago known as chemurgy. It is possible to predict some issues that... 

Freyssinet, M., P. Creange, M. Renard, P.B.E. McVetty, P. Derose, and G. Freyssinet. 1996. Development of transgenic oilseed rape resistant to oxynil herbicides. In Crop Protection Forecasting and Chemical Control. International Rapeseed Congress, pp. 974-976. 

DuPont scientists were the first to clone FAD2 and FADS genes from the soybean (2). They also provided conclusive evidence for the mechanism of polyunsaturated fatty acid biosynthesis, when antisense or cosuppression of the FAD2 gene led to lower n-6 desaturase activity, and the accumulation of oleic acid in glycerolipids. This was demonstrated not only in soybeans, but also in other oilseed crops, such as canola and sunflower (Table 1). These transgenic events... 

Lu, C., Kang, J., 2008. Generation of transgenic plants of a potential oilseed crop Camelina saliva by Agrobacterium-mediatod transformation. Plant Cell Rep. 27, ITi-ZlZ. 

Coriander (Coriandrum sativum L.) is an herbaceous crop widely grown for the herb cilantro and for coriander seed, a common spice (Evangelista et al., 2015). The seed contains oil consisting of 57-75% petroselinic acid (Fig. 11.11.1), 6-cw-octadecenoic acid (Isbell, 2009). Ozonolysis of petrosele-nic acid would produce lauric acid (C12 0) for use in surfactants and adipic acid for Nylon 6,6 (Millam et al., 1997). The seed produces 12.8-30.2% oil with yields averaging 900-1120 up to 2800 kg/ha but has yet to achieve success as an oilseed crop (Isbell, 2009). Attempts to engineer petroselinic acid production in transgenic crops have also proven problematic (Suh et al., 2002). 

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