Progress 07/01/06 to 06/30/08
Outputs
OUTPUTS: Continuing work on this project has focused on three areas; 1) identification of genes involved in the complex multi-step oil biosynthesis pathways, 2) development of genetic engineering technology that will enable the introduction of multistep biosynthetic pathways into plants, and 3) the ultimate production of seed crops expressing novel high value oils. During the past year substantial progress was made in the first two areas. Progress includes the first analysis of a 12 member gene family in Arabidopsis which is related to the jojoba was synthase gene. This gene family was discovered via bioinformatic analysis of the Arabidopsis genome sequence. The role of these genes in the life cycle of Arabidopsis is unknown. During the past year we completed the first spatial, temporal, and developmental analysis of expression for all of these genes. Our results show that several members are not expressed and are likely pseudo genes while others show complex developmentally regulated expression patterns with many of the genes being expressed specifically in reproductive tissues. Continuing work will use biochemical approaches and mutant analysis to begin deciphering what oil / wax products these enzymes help synthesize. Since Arabidopsis makes small amounts of high value oils like jojoba wax the members of this gene family involved in these biosynthetic pathways are likely to be strong candidates for engineering plants for production of high value oil products. Further, since Arabidopsis is closely related to commercial oilseed crops and readily amenable to experimental analysis, this should be a system where identification of other genes in these complex pathways, and their transfer to commercial oil crops, is highly feasible and not encumbered by the problems associated with distantly related species such as jojoba. In addition to the gene identification progress outlined above, we continued to make progress in development of technology for transferring multi-gene pathways into plants. This is an extremely important aim for this project because the ability to manipulate oil biosynthesis will require transfer of multi-step biochemical pathways into plants. During the past year we continued our progress in developing systems which allow polycistronic gene expression in plants by characterizing an internal ribosome entry site from potato virus Y. Our results demonstrated that this sequence facilitated efficient internal initiation of translation and allowed efficient expression of two genes from a single cassette. Using this technology along with other multi-gene expression technology we have developed previously it will be possible to mobilize multi-gene biochemical pathways into plants in single rounds of transformation. PARTICIPANTS: Not relevant to this project. TARGET AUDIENCES: Not relevant to this project. PROJECT MODIFICATIONS: Not relevant to this project.
Impacts
The impact of this project derives from the potential to develop clean and renewable domestic sources of valuable industrial and commercial oil products while taking advantage of existing agricultural resources to produce alternative crops (non food crops). Prior attempts to produce high value oils, such as jojoba wax, in conventional oil crops have seen modest success but have reached production levels that are economically feasible. Further research aimed at understanding the complex interactions involved in the multistep biosynthesis of these compounds will lead to improved efficiency and an expanded repertoire of products that can be produced. This is likely due to incompatibility between synthetic enzymes from widely diverse sources. Identification of oil synthetic enzymes from Arabidopsis, which is closely related to conventional oil crops such as rapeseed, should enable creation of plants that produce economically viable amounts of high value oils. This project is also well positioned to integrate with recent efforts to expand biodiesel as a domestic energy source. In particular, integrating the ability to produce high value oils (developed in this work) into biodiesel crops and production systems will provide a value added component that will allow biodiesel to become an economically viable domestic energy solution.
Publications
- No publications reported this period
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Progress 07/01/06 to 06/30/07
Outputs
Continuing work on this project has focused on three areas; 1) identification of genes involved in the complex multi-step oil biosynthesis pathways, 2) development of genetic engineering technology that will enable the introduction of multistep biosynthetic pathways into plants, and 3) the ultimate production of seed crops expressing novel high value oils. During the past year substantial progress was made in the first two areas. Progress includes completion of the first analysis of a 12 member Arabidopsis thaliana gene family related to the jojoba was synthase gene. This gene family was discovered via bioinformatic analysis of the Arabidopsis genome sequence although the function and role of these genes in the life cycle of Arabidopsis is unknown. Detailed molecular and bioinformatic studies have shown that this is a diverse family of genes that likely have many roles, where most family members play an unexpected role in reproduction, and where few members are
actually involved in the synthesis of high value oils. Further analysis demonstrated that this complex family of genes is conserved among many, if not all, plant families including monocots and dicots. This analysis also demonstrated that one of the family members is a pseudogene and identified three of the twelve family members that are likely involved in the synthesis of high molecular weight waxes. A manuscript is describing these results is being prepared. Continuing work will use molecular and biochemical approaches to elucidate the functions of the three genes identified as potential wax synthases and to evaluate their potential for directing accumulation of high value oils in transgenic crops. In addition to the gene identification progress outlined above, we continued to make progress in development of technology for transferring multi-gene pathways into plants. This is an extremely important aim for this project because the ability to manipulate oil biosynthesis will require
transfer of multi-step biochemical pathways into plants. During the past year we continued our progress in developing systems which allow polycistronic gene expression in plants by furthering the characterization of genetic elements conferring cap independent translation activity. Past results on the IRES element of potato virus Y have been extended to include other elements and an analysis of physiological factors affecting IRES element activity. Interestingly, our results indicate that most of these elements are responsive to stress, especially heat stress and pathogen attack.
Impacts
The impact of this project derives from the potential to develop clean and renewable domestic sources of valuable industrial and commercial oil products while taking advantage of existing agricultural resources to produce alternative crops (non food crops). Prior attempts to produce high value oils, such as jojoba wax, in conventional oil crops have failed due to an inability to make economically viable amounts of product in the engineered crops. This is likely due to incompatibility between synthetic enzymes from widely diverse sources. Identification of oil synthetic enzymes from Arabidopsis, which is closely related to conventional oil crops such as rapeseed, should enable creation of plants that produce economically viable amounts of high value oils. This project is also well positioned to integrate with recent efforts to expand biodiesel as a domestic energy source. In particular, integrating the ability to produce high value oils (developed in this work) into
biodiesel crops and production systems will provide a value added component that will allow biodiesel to become an economically viable domestic energy solution.
Publications
- No publications reported this period
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