Towards a greener Mars

If you’ve seen the Hollywood blockbuster “The Martian” or read the book with the same name by Andy Weir, you would know that the protagonist Mark Watney, astronaut and botanist, stranded on the red planet, manages to grow his own food on the desolate Martian soil. Although still in the realm of science fiction, this possibility has been backed by recent experiments.

Now a team of researchers from LIST has confirmed the scenario in a study, published in the Science of The Total Environment journal, and picked up by Gene Lab, NASA’s open-access data repository.

Built on existent data, which have primarily shown that plants can grow on Martian soil but lack detailed molecular analyses, this study fills the gap by providing new understanding of the physiology and molecular biology of the plants.

Why turn the red planet green in the first place?

If it was Mark Watney’s will to survive that pushed him towards farming and producing food in space, for present-day researchers the challenge is fuelled by humanity’s quest for survival beyond our own planet. The study incidentally comes on the heels of the updated publication of the Global Exploration Roadmap, by the International Space Exploration Coordination Group whose long-term vision is to expand and sustain human presence in the solar system. Within this vision, it is possible to imagine crewed missions to Mars as early as 2040. If such human establishment in space were to become a reality, it is imperative that we find ways to use in situ or local resources to produce necessities such as food, construction materials or pharmaceuticals. This is where the role of plants becomes crucial.

Plants are a vital resource due to their ability to produce phytochemicals that are relevant to pharmaceuticals, their potential as a food source, and their ability to provide oxygen which is key in bioregenerative life support systems.

Growing ryegrass on Mars – the experiment and future perspectives

In their experiment, the group of researchers from the Plant Molecular Farming group at LIST, used ryegrass seeds – known for their ubiquitous nature and resilience – and Martian regolith simulants as soil. “We made sure to use distilled water in the soil in order to prevent any minerals from affecting the regolith,” said Roberto Berni, co-author. This was to observe the effect on plants of a simulant as close as possible to the real Martian soil, which is poor in important components for plants’ growth, such as reactive nitrogen.

The plants were grown for a period of 14 days. Midway through the experiment, some of the plants were cut in order to see if they were capable of regrowth. The cutting was performed to mimic a hypothetical scenario in which the grass is mown and regrown.

The results show plants, quite like humans, are capable of adapting to their surroundings, especially if it comes to a question of survival. Despite some visible signs of stress – such as chlorosis (yellowing of leaf tissue) or presence of lacunae (large unfilled spaces) at the root level – which the researchers attributed to lack of water and other essential minerals, the plants grew.

What is even more promising is that the ones harvested mid-way had no problem in growing back. “We also hypothesize that, in this process, the epigenome of the plants got altered,” added Berni, “The epigenome is a set of instructions that can be modified without changing the plant's DNA. The data suggest that plants put in place modifications of their epigenome in response to stress, which likely allows them to adapt to their environment.”
Berni believes that this experiment is only the beginning and can lead to various other research questions. One aspect worth investigating would be to see how the plants affect the alien soil. One way to explore this would be by analyzing the organic acids that the plants secrete via the roots. Additionally, it may be useful to mix the biomass produced with the soil to facilitate a second growth cycle.

“The research is still in its early stages,” concludes Berni, “Despite this, the findings will surely pave the way for further studies and collaboration across various sectors.”

The paper was co-authored by Roberto Berni, Céline C. Leclercq, Jean-Francois Hausman, Jenny Renaut and Gea Guerriero (Plant Molecular Farming research group and Biotechnologies and Environmental Analytics Platform at LIST) and Philippe Roux (TERRA Teaching and Research Centre, University of Liège).