Algal Gene Boosts Leaf Oil Content in Arabidopsis Plants

A team of scientists from the Michigan State University and University of Wisconsin have enhanced the leaf triacylglycerol (TAG) content in Arabidopsis thaliana plant using a gene from a green alga. This breakthrough is an important advance in plant genetic engineering that may boost biofuel production.

TAG is the predominant component of oil found in seeds or fruits of oil-producing plants. The possibility of producing high levels of TAG in the leaves of high biomass-producing plants has been thought as a potential approach to significantly increase biofuel production without compromising the availability of seed oils for food and feed. However, very few studies have been done to investigate this. The recent successful modification of leaf TAG content in Arabidopsis plant, reported in the journal The Plant Cell, provides a proof-of-concept that could be used for this purpose.

The key to this oil enhancement is an enzyme specifically known as diacylglycerol acyltransferase type two (DGTT2) which is responsible for catalyzing the transfer of fatty acyl group and formation of TAG from diacylglycerol and acyl-CoA substrates. The DGTT2 enzyme used in the study was encoded by a gene from the photosynthetic green alga Chlamydomonas reinhardtii. The expression of DGTT2 in Arabidopsis plant increased TAG content in vegetative tissues by altering the acyl carbon partitioning through a broad range of acyl-CoA substrates. The gain in energy density of the transgenic leaves was evident from the gain in weight of caterpillar larvae that were allowed to feed on them.

 According to Prof. Christoph Benning, the lead investigator, this proof-of-concept could be used to boost plants' oil production for biofuel use as well as improve the nutrition levels of animal feed.