Can plants adapt to thrive in space?

People in space have to eat. In the early days of space exploration, they had to eat paste and drink Tang (or so the legends tell us). Not a good long term diet at all. The plants should be in there too. And, astronauts on the ISS have been growing gardens in space for years.

So, what else should we know about farming in space? Well, as it turns out, quite a few. That’s why NASA is sending a plant habitat to the ISS. It is part of a program called Epigenetic Adaptation to the Spaceflight Environment—Cumulative Genomic Change Induced by Generations in Space (Plant Habitat-03). The idea is to follow successive generations of plants as they grow, develop, live and die in a microgravity environment. This experiment will fly to the ISS on Northrup Grumman Commercial Resupply Services Mission 18, scheduled for November 6, 2022.

Growing green in low gravity

While low gravity may seem like a pretty relaxing place to live and work, for plants, it’s actually stressful. Like humans, plants evolved in Earth’s gravity and soil-based environments. Exposure to the stress of spaceflight shows that things like an arabidopsis plant (previously grown on the station) actually change their genetics. It’s not a mutation like we see in SF movies. It’s more like the plant adds a little something extra to its DNA to affect gene expression. This is the process where a gene is stimulated or activated in a cell to produce RNA and other proteins. Living in space changes this a bit, but understanding this process and how extensive it is requires time and multiple experiments. That’s where Plant Habitat-03 comes in.

“Plant Habitat-03 will provide a better understanding of how the epigenome contributes to an organism’s ability to adapt to environmental stress, both in the current and future generations,” said Sharmila Bhattacharya, a space biology program scientist in the Dept. of Biological and Natural Sciences at NASA. Headquarters in Washington. “This is an important insight into how astronauts could potentially grow repeated generations of crops in orbit as well as on the Moon or Mars to provide food and other services for future space missions. The results can also support the development of strategies to adapt crops for growth in extreme environments on Earth.”

Plants that adapt to space

Plants are constantly evolving. We see it on Earth, where farmers and researchers are genetically modifying them. In nature, the same processes take thousands of years. The Habitat-3 plant will put them in microgravity and then watch them adjust to life in space. What epigenetic changes (ie, changes in gene expression) will occur? Will they be passed on to future generations? Or, will each set have to be “relearned” from scratch in new generations? These are the questions the research team wants to answer. So, what is the experimental procedure?

As part of the project, the experiment will grow seeds in a special unit on the ISS. Once the plants reach maturity, the astronauts will harvest them and return the harvested plants back to Earth. Their seeds will return to space, along with new seeds on their first “mission” to the ISS. Ultimately, the idea is to learn how much plant epigenetics change from samples affected by spaceflight and compare them to new generations of plants flown into space.

Plant Habitat-03 is one of several projects studying how living things respond to life in space. Previous ISS studies have looked at growing plants in space, for example, by studying how best to provide water and aeration in microgravity gardens. Human studies are of course well known. However, if we are going to put humans in space for long periods of time, understanding their space food sources is also important. Clearly, as NASA prepares for future human exploration, including the ambitious Artemis missions, a good understanding of the food these humans will need is a huge part of the effort.

Studies in space benefit the Earth

In addition to the space applications of the Plant Habitat-03 flight, there are benefits on Earth. First, our planet has areas under pressure from climate change. Discovering how stress affects genetic expression in food crops could help farmers on Earth adapt crops as conditions change across continents.

Surviving Space: Extreme Plant Adaptation
Epigenetic Adaptation to the Spaceflight Environment – ​​Cumulative Genomic Change Caused by Generations in Space (Plant Habitat-03)