The possibility of sustaining life on other planets, such as Mars, is of growing interest as space travel advances and issues such as climate change raise concerns about the future of life on Earth. However, there are many difficulties scientists will need to overcome to bring space colonization beyond the realm of science fiction; for example, the regolith of Mars is a poor environment for plant growth, in part due to the toxic perchlorate salts it contains. A group of researchers from the University of Arkansas has leveraged gene editing technology to explore the possibilities of extraterrestrial plant growth, demonstrating how genetically modified rice could potentially survive in Martian soil.
The researchers produced two gene-edited lines of rice designed to better respond to stress than wild-type rice; this includes better abilities to adapt to drought, sugar starvation and high soil salinity. The team attempted to grow these engineered plants in a type of soil known as the Mojave Mars Simulant (MMS) – a basaltic rich soil developed by NASA and the Jet Propulsion Laboratory to simulate Martian regolith. The edited and wild type strains were grown in MMS alone, regular potted mix, or a mixture of two. The team also experimented with different concentrations of perchlorate in the soil.
The team found that the mutant strains were able to grow in the MMS soil, though those grown in potting soil and hybrid mix were more developed. Replacing just a quarter of the MMS with potting soil was found to significantly improve the plants’ development. Additionally, the researchers observed that the mutant rice was capable of rooting in soil with a perchlorate concentration of 1 gram per kilogram, while 3 grams per kilogram was the threshold beyond which nothing could root. This data could not only bring scientists closer to the possibility of inhabiting plants beyond Earth, but aid in the growth of plants in regions on our own planet where conditions, such as high soil salinity, pose difficulties for farmers. The abstract, “Rice Can Grow and Survive in Martian Regolith with Challenges That Could be Overcome Through Control of Stress-Related Genes,” was recently presented at the 54th Lunar and Planetary Science Conference.
“We could use Earth as a terrestrial analog before the seeds ever get sent to Mars,” said second author Abhilash Ramachandran, a post-doctoral fellow at the Arkansas Center for Space and Planetary Sciences.
The research team plans to further their research by experimenting with a newer Martian soil simulant called the Mars Global Simulant, as well as study other rice strains with increased tolerance for higher salt concentrations. Additional experiments for the future include determining the degree to which perchlorate may leach from the soil to the growing plant, as well as testing the growth of plants in a closed simulation chamber that replicates the temperature and atmosphere of Mars.