Stressed-out plants pass down “memories” to make offspring stronger

Like any good parent, it turns out that plants can use their own experience to teach their offspring about how to overcome tough times. Geneticists at Penn State University have manipulated the expression of one gene in a plant that makes them more resilient to environmental change – and this is passed down to future generations.

Environmental factors are what guide evolution, so it makes sense that plants would not only be able to adapt to changing conditions themselves, but can pass those strategies down to give the next generation a head start.

A gene called MSH1 has long been known to play a key role in plant resilience. On the new study, the team found that deactivating it in Arabidopsis plants helped them react to times of stress, such as drought or heat waves. These plants used several coping strategies, including adjusting their growth, limiting how much biomass grew above ground, changing how their roots grew, and delaying when they flowered, among other things.

But perhaps the most interesting find was that these responses could be passed down to as many as five future generations. The team found that if a parent plant had gone through stressful conditions, the same coping behaviors could show up in some (but not all) of their offspring.

Left: a wild-type plant that hadn't been epigenetically tweaked. Right: a plant that retained the "memory" of its parents' struggles
Left: a wild-type plant that hadn’t been epigenetically tweaked. Right: a plant that retained the “memory” of its parents’ struggles

Sally Mackenzie Research Group/Penn State

“In our research, we show that this memory condition is heritable by progeny but occurs in only a proportion of the progeny – so that there are memory and non-memory full siblings,” says Sally Mackenzie, lead researcher on the study. “That results in definable gene expression changes that impact a plant’s phenotypic ‘plasticity.’ We suggest that all plants have this capacity, and that the condition that we describe is likely to be an important part of how plants transmit memory of their environment to precondition progeny.”

The team used different methods to disable the MSH1 gene. In some, they chose plants that already had natural mutations inactivating the gene. In others, they switched it off using RNA interference. However it’s done, the results are usually similar.

Importantly, the researchers say that epigenetics could be an important way to bypass concerns about genetically modified organisms (GMOs) as food. While modified crops have been largely found to be safe for consumption, there’s still controversy surrounding them.

But epigenetics doesn’t involve adding new genes, which is usually considered the problematic part of genetic engineering. Instead, scientists are just controlling the expression of genes. In the past, researchers have argued that genetically-edited cabbage and salmon aren’t classed as GMOs because they’re mimicking natural genetic variations rather than creating new ones. That means it’s no different to the selective breeding humans have been doing for millennia. And the US Department of Agriculture agrees.

The researchers on the new study say that they’ve already moved onto follow-up research, switching off MSH1 in tomato, soybean and canola plants. So far, the early results of these, and grafting experiments, have increased yields.

The research was published in the journal Nature Communications.

Source: Penn State University

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