A new study, published in January in eLife, a peer-reviewed open access journal, showed that epigenetic modifications passed along to plant offspring can instil disease resistance ― importantly, without decreasing the amount and quality of food produced (1).
When plants are repeatedly attacked by particular pathogens, they are ‘primed’ with a memory of the event so that the immune system can respond to the attack more efficiently the next time. But more intriguing, this memory can also be passed along to the next generation of plants ― via the epigenetic phenomena ― thus, presenting a potential new way of preventing disease in crops.
What is epigenetics?
Epigenetics refers to changes in gene expression achieved by so-called DNA methylation, which essentially attaches a ‘tag’ onto certain regions of DNA, allowing plants to inherit new traits much more quickly than typical evolutionary changes ― which also means plants can adapt to environmental stresses and respond to diseases much more quickly.
This is in contrast to changes in the underlying DNA structure itself that are typically associated with evolution. Evolutionary changes take millions of years to appear, whereas epigenetic changes can occur much faster ― within one generation. When DNA is passed along to the subsequent generations, the epigenetic information is also be passed along.
Plants can inherit disease resistance
In the recent study, the international team of researchers, led by Prof Jurriaan Ton P3 Plant Production and Protection Centre of the University of Sheffield, examined how DNA methylation affects the disease resistance of a small weed known as Arabidopsis thaliana.
The scientists identified four specific locations on the plant’s chromosome with the ability to transfer immunity to their offspring. Interestingly, they discovered that reduced ― not increased ― methylation at these specific DNA regions led to faster and stronger responses against downy mildew, a plant disease caused by several different types of fungus ― something the authors refer to as “heritable DNA hypomethylation.”
In other words, crops with lower levels of methylation at specific DNA locations exhibited improved disease resistance, without any negative effects on plant growth or resistance against other environmental stresses.
Potential opportunities for farmers
The recent findings pave the way for further research on whether epigenetics can improve the resilience of food crops by priming them with disease resistance. The researchers hope to translate these findings into crops vital to food worldwide food supplies. But first, they will need to understand exactly how epigenetics controls a plant’s defences against disease.
Moreover, new strategies for preventing disease in crops could reduce the global reliance on harmful pesticides. Reducing pesticides could improve plant growth while lessening chemical pollution and the environmental impacts of agriculture, such as the detrimental effects on insects.
(1) Furci, L. et al. Identification and characterisation of hypomethylated DNA loci controlling quantitative resistance in Arabidopsis. eLife (2019). DOI: 10.7554/eLife.40655.001