Sorghum – the new late night servo. Fill up your car and get a feed at the same time.
There are few people in history credited with saving billions of lives. Perhaps Alexander Fleming and the discovery of penicillin or Marie Curie discovering X-Rays and their use in medicine to diagnose injuries, tumours and for irradiating cancers. Another man, Norman Borlaug is credited with preventing the death of over a billion people in Africa, avoiding severe famine and widespread malnutrition. He managed to accomplish this by manipulating the genetics of wheat, increasing its resistance to a disastrous disease called rust and by reducing the height of the plant with dwarfing genes. The dwarf varieties were more robust and higher yielding, owing to their stature and the reallocation of nutrients into the grain rather than the useless stem and leaves.
Now genes can be manipulated in a number of different ways. In our own bodies for example, carcinogens (cancer causing substances) such as asbestos, smoking and radiation exposure can damage the DNA within cells and cause detrimental mutations. The mutations cause the cell to rapidly divide and result in a cancerous tumour.
However, mutations are the fundamental component of evolution. Without random changes in the genetics of an organism and consequently the change in the observed characteristics there is no change in the survival rate. Now obviously beneficial mutations are incredibly rare but are present nonetheless.
Many plant breeders go in search of these benevolent mutations by applying plant-specific carcinogens or radiation doses to large numbers of seeds or plants. Seedless watermelons are one indirect example using a chemical that interrupts cell division and hence the number of genes in the seed. Atomic Gardening is another example of mutation breeding, whereby a strongly radioactive source (typically cobalt-60) is raised out of the ground and irradiates a whole orchard of trees or plants for a short period of time. Large chunks of DNA are mutated and eventually they managed to find a change with potentially marketable or beneficial characteristic. These products are all labeled GMO-free.
Of course the genetic make-up is also created by the mix of genes from the parent. That’s why we look half like our mum/dad, a quarter like our siblings and one eighth like our 1st cousins. The same goes for plants too. Plant breeders find wild types of the same species and incorporate traits such as hardiness, early vigour or disease resistance into the old line of plants.
Now on a brief side note, I’m sure many of us will appreciate that sweet taste that often accompanies chewing white bread. Now that is the remnant of an ancient virus that infected our ancestors when we were in a period of environmental change. Our diet was changing from tree based to open savannah and grain based foods with lots of starch. Those infected with the virus, known as an endogenous retrovirus, were able to pre-digest the starches and hence had an improved survivability than those without, even in the face of an infection. The viral DNA, like all endogenous retroviruses incorporated itself into the human genome and remains there today – digesting starch in the mouth into sugars, otherwise known as salivary amylase. Fun fact – rats are the only other mammal to also have salivary amylase. So why does this matter?
Well in plant breeding this concept of endogenous retroviruses is also used. Agrobacterium, a bacteria (not a virus but the principle remains) specific to plants is able to incorporate itself into the genome (in a modified fashion – a little like a vaccine), without disrupting the plant too much at all. In fact, much of plant DNA is made up of Agrobacterium DNA owing to the co-development arms race of plant and pathogen. This means that scientists can take advantage of this natural carrier and incorporate particular genes that are transferred into the cells and rearrange themselves into the DNA. Plant geneticists are able to insert really specific portions of DNA as opposed to the mass mutation in the prior example. They know exactly what is being adjusted and can observe the exact effect of any such change.
These insertions or deletions have paved the way for up to 95% reductions in pesticide usage in the Australian cotton industry, and within the next year or two we will be able to grow plants capable of producing highly potent omega three fatty acids, industrial-grade machine and hydraulic oil, and the co production of food and biofuel! All these discoveries are patented by the CSIRO too – not large chemical, or biotechnology companies. These plants will be able to mitigate the impacts of climate change, prevent further removal of fossil fuels whilst also providing us with nutritious energy and food. So if you had the option of digging up farming land for coal, destroying the seabed and high risk of oil spill or growing a field of yellow flowering plants (with the option of using chemicals or just tillage) producing both food and oil, which one would you choose?