New findings indicate gene-edited rice might survive in Martian soil

Hardin Young

FAYETTEVILLE, ARKANSAS

 Weir’s bestselling 2011 book, “The Martian,” features botanist Mark Watney’s efforts to grow food on Mars after he becomes stranded there. While Watney’s initial efforts focus on growing potatoes, new research presented at the 54th Lunar and Planetary Science Conference by a team of interdisciplinary researchers from the University of Arkansas suggests future Martian botanists like Watney may have a better option: growing rice.

As outlined in the team’s abstract, “Rice Can Grow and Survive in Martian Regolith with Challenges That Could be Overcome Through Control of Stress-Related Genes,” one of the biggest challenges to growing food on Mars is the presence of perchlorate salts, which have been detected in the planet’s soil and are generally considered to be toxic for plants.

Vibha Srivastava, professor of plant biotechnology with the Arkansas Agricultural Experiment Station within the crop, soil and environmental sciences department, served as mentor for the team of University of Arkansas researchers, which includes Peter James Gann, a doctoral student in cell and molecular biology; Abhilash Ramachandran, a post-doctoral fellow at the Arkansas Center for Space and Planetary Sciences; Yheni Dwiningsih, a post-doctoral associate in plant sciences; and Dominic Dharwadker, an undergraduate student in the Honors College.

The experiment station is the research arm of the University of Arkansas System Division of Agriculture. 

The team of researchers were able to simulate Martian soil using basaltic-rich soil mined from the Mojave Desert, called the Mojave Mars Simulant, or MMS, which was developed by scientists from NASA and the Jet Propulsion Laboratory. 

The team then grew three varieties of rice, including one wild-type and two gene-edited lines with genetic mutations that better enable them to respond to stress, such as drought, sugar starvation or salinity. These varieties were grown in the MMS, as well as a regular potted mix and a hybrid of the two. While plants were able to grow in the Martian simulant, they were not as developed as those grown in the potting soil and hybrid mix. Replacing just a quarter of the Martian simulant with potting soil resulted in improved development.

The team also experimented with the amount of perchlorate in the soil, finding that 3 grams per kilogram was the threshold beyond which nothing would grow, while mutant strains could still root in 1 gram per kilogram.

Their findings suggest that there might be a way forward for genetically modified rice to find purchase in Martian soil. 

Next steps will include experimenting with a newer Martian soil simulant called the Mars Global Simulant, as well as other rice strains that have increased tolerance for higher salt concentrations. An important part of the research will be determining to what degree perchlorate may be leeching into the plant from the soil. Farther down the road, the researchers would like to introduce rice into a closed habitat chamber and place it in a Mars simulation chamber that replicates the temperature and atmosphere of the planet.

Whether humans ever colonize Mars, the team’s research could have applications here on Earth. Ramachandran noted that he spoke with an Australian researcher from an area where the soil had high salinity and saw their work as a potential way to grow food there. He added, “We could use Earth as a terrestrial analog before the seeds ever get sent to Mars.”

Gann said that the project began when he met Ramachandran for coffee in the student union. 

“He was new here at the university, and we shared the things we were doing in our respective laboratories,” Gann said. “Since he works on planetary science, and I specialize in cell and molecular biology, we decided to try out plants.”

They were joined by co-authors Dwiningsih, Dharwadker, and Srivastava, who has a joint appointment with the University of Arkansas System Division of Agriculture.

“From my first talk with Abhi, we came to a consensus that Dr. Srivastava would be the most appropriate and best mentor for this work with her extensive experience in plant biotechnology and deep understanding of gene editing,” Gann said. “In her laboratory, where I am currently working towards my doctoral degree, they have developed multiple mutant rice plants that can perform better under several environmental stresses.”

Since conditions on Mars are known to be stressful for living organisms like rice plants, Gann said the resources available in Srivastava's lab were their best asset to move forward with the work.

"Dr. Vibha's wisdom in conducting research assured us that she can lead us in the right direction to come up with meaningful and useful results,” Gann said. 

Srivastava said she was initially “hands off” in the research but became involved when she learned that rice would have to overcome salt stress to be able to germinate in Martian soil.

“We have gene-edited rice lines in our lab that are either more sensitive, or tolerant, to environmental stresses and I suggested it would be interesting to test their performance in the Martian soil,” Srivastava said. “I am happy to work with them and very proud that they came together to work on this very interesting project. My focus is to develop better rice for the earth, but if our rice could also be used for space agriculture, that’s nice!”

Gann is also pleased with how his initial conversation with Ramachandran has turned out.

“Relevant and interesting research can emanate from talking to strangers over a cup of coffee or a glass of beer,” he said, before adding: “Ain't that cool?” ∆