People on low-fat diets generally think they can eat unlimited vegetables because plants are relatively low in fats. Yet plants actually produce lipids in abundance. In addition to providing us with calories, these lipids are the basis for soaps, lotions, lubricants, biodiesel and other fuel, insecticides, plastics, and paints.

Lipids have typically been difficult to study since they are not as stable in the lab as other, more popular biomolecules like proteins and DNA. But recent technical advances have started to reveal the breadth of their current and potential uses. This increased usefulness will only boost our demand for plant-based lipids.

Many commercially desirable lipids are produced by plants that are challenging to cultivate. Yet through the miracle of genetic modification, some of these lipids can now be generated in the seeds and leaves of domesticated crop species. Recently, a review of what has been accomplished was published in Science.

To wit: scientists have moved a gene that encodes an enzyme from the ornamental burning bush Euonymus alatus into a relative of canola (full disclosure—I think I may have a Euonymus alatus in my front yard). Once the gene is in the canola relative, it generates seeds rich in acetyl-triacylglycerols that can replace the diesel fuel now used by trains and ships.

Coconuts are a plant with "limited global distribution," but, through genetic modification, coconut oil can now be made in tobacco leaves. The writers in Science also report that castor oil, which is used as a lubricant in many settings and found in the seed of the toxic castor bean, can now be produced from the seeds of genetically modified Arabidopsis thaliana, a harmless mustard plant. (Arabidopsis has been the favored workhorse of plant geneticists for decades.)

Not only can we now make plants generate useful fatty acids that they otherwise would not, we can make them more efficient at generating the useful oils they already make. Lowland rainforests are currently being razed to keep abreast of the developed world’s suddenly insatiable appetite for palm oil. As a result, any increase in the seed oil content of crops like palm, soy, and canola could be a boon, although progress there hasn't been as impressive.

We can also get plants to make fatty acids that originate in other taxonomic kingdoms—like the fish oils that are so healthy for us. This way, we can eat our fish oil but still leave some fish in the sea.

This ability to have plants churn out tailor-made lipids on demand can help preserve fossil fuel and marine stocks, and it can help us get better bang for our buck in terms of cropland. Plants have always had, and will continue to have, an enormous impact on human health and the well-being of our planet; marrying their capacity to the promise of synthetic biology will only be the next chapter in their doing so.

Science, 2016. DOI: 10.1126/science.aaf6206 (About DOIs).