Martian soil is generally poor for growing plants, but researchers have used CRISPR to create gene-edited rice that might be able to germinate and grow despite the hostile habitat.
Gene-edited rice plants may be able to grow on Mars. Researchers have now identified a gene that, when modified, seems to give rice plants a better chance of surviving in harsh Martian soil.
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| Modified rice plants could better handle Martian soil Antony Ratcliffe / Alamy Stock Photo |
Martian soil, or regolith, has fewer nutrients than Earth soil and contains compounds that can be toxic to some plants. To see how well rice can handle such conditions, Abhilash Ramachandran at the University of Arkansas and his colleagues grew rice seeds in a series of mixtures of regular potting soil and an artificial Mars regolith called MMS-1, ranging from all potting soil to all MMS-1. The researchers found that rice could grow in mixtures with as little as 25 per cent potting soil almost as well as rice grown in 100 per cent potting soil.
However, the rice grown in all artificial regolith had much shorter shoots and longer roots than the rice grown with any potting soil. “The longer the root, the less nutrient [the soil] is,” said Ramachandran in the presentation. “The root will go deep into the soil looking for nutrients, but there are no nutrients.” The regolith-grown rice had fewer roots, as well. When the researchers added perchlorates – toxic chemicals found across the Martian surface – to the regolith, the plants fared even worse. Some of the seeds were unable to germinate, let alone grow and thrive, indicating that perchlorates are the main obstacle to growing rice in Martian soil.
When the researchers analysed the genetics of the rice plants, they found one gene that had an outsized effect on the plants’ reaction to bad soil, a gene called OsSnRK1. They used the gene-editing technique CRISPR to create rice seeds with mutated OsSnRK1 genes, and found that those seeds were able to germinate even with small amounts of perchlorates added to the soil. The mutant strains of rice also began to develop both roots and shoots in conditions with too much perchlorate for the original strain to grow at all.
These were only preliminary tests, and the researchers plan to test seeds with further mutations to adapt to Martian soil, as well as additional changes to adapt to the tenuous carbon dioxide atmosphere of Mars, which is so thin it will probably pose more problems for the plants. “It is very challenging to grow plants on Mars, but it is not impossible,” said Ramachandran. “Growth of plants is not a luxury… it’s very important for the survival of humankind on Mars.”
Ramachandran and his colleagues presented the work at the Lunar and Planetary Science Conference in Texas on 13 March.