Epigenetics CLASSICAL GENETICS has been with us for a long time, ever since Gregor Mendel put forward his laws on the basic mechanisms of heredity in the 19th century. Classical genetics has led to wondrous developments in the area of agriculture, including GM and gene editing technologies. And now, another area of study is on the cusp of changing our ideas about plant function even more. Epigenetics, although has existed as a concept for nearly eight decades, is becoming a new buzzword that’s causing lots of chatter in plant breeding and seed circles, and for good reason. “Epigenetic technologies are on the cusp of being industry-ready. Unlike techniques such as CRISPR, it’s not quite there yet — but very close,” says Michiel Van Lookeren Campagne, head of seeds research at Syngenta. A field like epigenetics holds great promise for companies like Syngenta, he says, which invests a lot of time and money in dealing with the regulatory hurdles that invariably come with breeding plants that have had their genetic codes altered in some way. Flipping Switches Epigenetics comes from the Greek root word epi, meaning “on” or “on top of.” “Epigenetics essentially sits on top of the layer of classical genetics, which has been the basis of all breeding programs,” says Van Lookeren Campagne. Epigenetics is the study of heritable changes in gene function that do not involve changes in the DNA sequence. Epigenetic changes in plants do not occur as a result of any changes to the plant’s DNA, but as a result of other factors like changes to chromosomes that affect gene activity and expression. For global researchers studying epigenetics, looking at the surface of the genome could be the key to discovering the next big thing in plant and seed engineering. Flipping the Switch Basically, Van Lookeren Campagne explains, epigenetic changes occur when various “switches” in DNA are flipped on and off, triggering different reactions within the plant. He notes that epigenetics as a field really took off in the 1990s when Dutch and American molecular biologists breeding purple petunias obtained a number of unexpected results that were difficult to explain. They were trying to increase the colour intensity of the petals in petunias by introducing a gene which causes the formation of red pigment in the flowers. But instead of intensifying the colour, this treatment led to a complete loss of colour and the petals turned white. The mechanism causing these effects remained elusive until Andrew Z. Fire and Craig C. Mello discovered the cause, earning them the Nobel Prize in Physiology for Medicine for 2006. Fire and Mello deduced that double- stranded RNA can silence genes, that this RNA interference is specific for the gene whose code matches that of the injected RNA molecule, and that RNA interference can spread between cells and even be inherited. In other words, genes can be turned on and off like light switches, producing different reactions within a plant without altering the plant’s genetic code in any way. New Frontier Those epigenetic changes are ushering in a new frontier for the seed industry as a result. In March, Epicrop Technologies Inc., a company co-founded by University of Nebraska-Lincoln professor and epigenetics pioneer Sally Mackenzie, announced it had secured US$3.2 million in funding. This funding will be used to further develop epigenetic technology with a focus on large increases in yield and stress tolerance in crops. “We’re very excited to have previous and new investors on board who Michiel Van Lookeren Campagne is head of seeds research at Syngenta. 64 www.seed.ab.ca | Advancing Seed in Alberta