Upregulation of Lipid Biosynthesis Increases the Oil Content in Sorghum

Production of the storage lipid triacylglycerol in vegetative plant tissues has emerged as a promising strategy to meet the world's need for vegetable oil. Sorghum (Sorghum bicolor) is an attractive target crop due to its high biomass, drought resistance and C4 photosynthesis. While oilseed-like triacylglycerol levels have been engineered in the C3 model plant tobacco, progress in C4 monocot crops has been relatively slow. This prompted researchers from CSIRO Agriculture and Food in Australia to modify sorghum so its leaf tissues produce and accumulate triacylglycerol.

The team overexpressed the maize (Zea mays) WRI1 transcription factor gene, the UrDGAT2a acyltransferase gene from the fungus Umbelopsis ramanniana and Oleosin‐L oil body protein from sesame (Sesamum indicum). Overexpressing these three genes led to the upregulation of lipid synthesis in the transgenic sorghum. The resulting transgenics exhibited increased oil content, which was visible as lipid droplets in the leaf mesophyll cells.

 These results present the first step forward towards the development of sorghum as a biomass oil crop.

For more information, read the article in Plant Biotechnology Journal.