"Stress memory" helps plants become more resilient

The manipulation of a single gene can help plants pass on valuable information to their offspring, making them tougher and more productive. Experts at Penn State discovered that switching off the expression of one gene induced a type of “stress memory” in plants that is inherited by some of their descendants. 

According to the researchers, this discovery has significant implications for plant breeding. Furthermore, the changes are epigenetic and do not require material from another plant, which means that crops bred with this technology would not be included in the controversial “genetically modified” category of foods. 

“One gene, MSH1, gives us access to what is controlling a broad array of plant resiliency networks,” said Professor Sally Mackenzie, director of the Plant Institute at Penn State.

“When a plant experiences a stress such as drought or prolonged extreme heat, it has the ability to adjust quickly to its environment to become phenotypically ‘plastic’ – or flexible.”

The researchers explained that there are many ways to inactivate the MSH1 gene and they all have similar outcomes.

“When plants are modified epigenetically, they can modify many genes in as simple a manner as possible,” said Professor Mackenzie. Such modifications can be used to trigger growth, reproduction, and resiliency among plants. 

By silencing the MSH1 gene, the plants are able to detect stress and know how to respond to environmental stimuli. For example, the plants can change their root configuration, limit above-ground biomass, or delay flowering time.

According to the researchers, these responses are remembered, and can be passed down to many generations through selective breeding. 

“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,” said Professor Mackenzie. “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.”

Professor Mackenzie explained that by adjusting the epigenetic architecture of a plant, the researchers were able to access its resiliency network and see how genes are expressed quickly and broadly to adjust the plant’s growth to its environment.

The experts can identify pathways that enhance root growth and plant vigor, which increases crop yield. When an MSH1-modified plant is crossed or grafted, the plant vigor becomes even more pronounced.

In follow-up research that is currently underway, Professor Mackenzie’s team has suppressed MSH1 genes in tomato and soybean plants, and grafting experiments have shown excellent yield results. 

The study is published in the journal Nature Communications.

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By Chrissy Sexton, Earth.com Staff Writer