ARS | Publication request: Disruption of the Arabidopsis CGI-58 homologue produces Chanarin-Dorfman-like lipodystrophy in plants

Submitted to: Proceedings of the National Academy of Sciences
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 7, 2010
Publication Date: October 12, 2010
Citation: James, C.N., Horn, P.J., Case, C.R., Gidda, S.K., Zhang, D., Mullen, R.T., Dyer, J.M., Anderson, R.G., and Chapman, K.D. 2010. Disruption of the Arabidopsis CGI-58 homologue produces Chanarin-Dorfman-like lipodystrophy in plants. Proceedings of the National Academy of Sciences of the United States of America. 107:17833-17838.

Interpretive Summary: The seed oils of plants represent outstanding renewable sources of fuel and chemical feedstocks for industry, but the size of these markets and demand for oil in these various applications is far greater than the amount of oil that can be supplied by traditional oilseed crops. To help meet the burgeoning need for renewable, alternative fuels and chemicals, scientists at the ARS lab in Maricopa, University of North Texas, University of Guelph, and University of Texas Southwestern Medical Center in Dallas have teamed up to investigate the possibility of producing oils in the vegetative parts of plants (e.g., leaves and stems), in addition to seeds. The vegetative parts of plants have significantly greater biomass in comparison to seeds, and producing even modest amounts of oils in these tissues may significantly increase the amount of oil obtained from a given are of land. Recently, the gene responsible for a rare human genetic disorder was identified whose mutation results in abnormal accumulation of large amounts of oil in tissues that do not normally store lipids. In research described here, the scientists reveal that disruption of the plant version of this gene had a similar effect in plants, with a significant increase in the amount of oil present in the leaves of the model plant Arabidopsis. These results provide insight to a previously unknown aspect of plant lipid metabolism that is fundamentally conserved between plants and humans. Although a significant amount of work is required to further elucidate the underlying mechanisms, the results provide clear evidence that it is possible to significantly increase the amount of oil present in the biomass of plants.

Technical Abstract: CGI-58 is the defective gene in the human neutral lipid storage disease called Chanarin-Dorfman syndrome. This disorder causes intracellular lipid droplets to accumulate in nonadipose tissues, such as skin and blood cells. Here, disruption of the homologous CGI-58 gene in Arabidopsis thaliana resulted in the accumulation of neutral lipid droplets in mature leaves. Mass spectroscopy of isolated lipid droplets from cgi-58 loss-of-function mutants showed they contain triacylglycerols with common leaf-specific fatty acids. Leaves of mature cgi-58 plants exhibited a marked increase in absolute triacylglycerol levels, more than 10-fold higher than in wild-type plants. Lipid levels in the oil-storing seeds of cgi-58 loss-of-function plants were unchanged, and unlike mutations in ß-oxidation, the cgi-58 seeds germinated and grew normally, requiring no rescue with sucrose. We conclude that the participation of CGI-58 in neutral lipid homeostasis of nonfat-storing tissues is similar, although not identical, between plant and animal species. This unique insight may have implications for designing a new generation of technologies that enhance the neutral lipid content and composition of crop plants.