Space agriculture review shortlists fungi to unlock 3 scarce nutrients in Martian and lunar regolith

Growing crops on the Moon or Mars will depend on solving a nutrient problem that fertilizer agronomists know well: nitrogen, phosphorus and potassium that are scarce or locked in forms plants cannot use. A review by researchers in Brazil and the United States argues that beneficial fungi are among the strongest tools for making space agriculture work in local regolith rather than in soil shipped from Earth.

The paper, Selection of beneficial fungi for plants with the potential to metabolize lunar and Martian regolith, was published online in Frontiers in Astronomy and Space Sciences on February 28, 2026, and in the journal’s April 17 issue. It drew new attention on September 25, when ScienceDaily ran a summary. The authors are from the Federal University of the State of Rio de Janeiro (UNIRIO), Winston-Salem State University and the Florida Institute of Technology. It is a literature review, not a new experiment.

Why space agriculture struggles in regolith

Regolith is the loose mineral layer covering the Moon and Mars. It contains no organic matter and no living microbes, which the authors see as its defining difference from even the poorest soil on Earth. It is also typically alkaline, which cuts the solubility of phosphorus and potassium. It carries potentially toxic levels of aluminum and manganese, and Martian material adds perchlorate salts.

Composition data for widely used simulants show the scale of the challenge. The Martian simulant MGS-1 contains just 0.29% K₂O and 0.17% P₂O₅, against 12.84% aluminum oxide. The lunar highlands simulant LHS-1 has 0.34% K₂O, 0.17% P₂O₅ and 26.29% aluminum oxide. Nitrogen has been detected on both bodies only in trace amounts. Potassium on Mars exists, but no reserve large enough to supply farming has been identified. Phosphorus is relatively abundant on Mars and at least partly extractable by plants.

Micronutrients run in the opposite direction. Martian regolith holds about 12.4% iron, according to studies the review cites. That is more than 1,000 times the roughly 0.01% most crops need, and most of it is bound in insoluble oxides.

Which fungi the review puts forward

The review groups candidate fungi by what they do. Penicillium and Aspergillus strains solubilize phosphate through organic acid production, the same mechanism behind commercial phosphorus-solubilizing biologicals on Earth. Siderophore-producing fungi such as Beauveria bassiana chelate iron into more available forms. Other species remove or immobilize aluminum. In one cited study, Aspergillus tubingensis released metals from the Martian simulant MMS-1, producing oxalic acid that rapidly lowered pH within five days.

Trichoderma, already widely sold as a biostimulant and biocontrol agent, gets particular attention. In a lunar simulant, Trichoderma viride taken from cactus roots significantly improved seed germination compared with other fungi. Trichoderma longibrachiatum spores survived almost two years of exposure outside the International Space Station when shielded from radiation, with about 30% remaining viable.

The authors place their strongest bet on arbuscular mycorrhizal fungi (AMF) from the phylum Glomeromycota. These fungi act as microscopic extensions of plant roots, and on Earth they improve iron uptake, reduce oxidative stress and bind soil particles through the glycoprotein glomalin. The early evidence is limited but encouraging. Chickpeas grown in lunar simulant amended with AMF and vermicompost flowered and set seed. In an older test, marigolds inoculated with a bacterial consortium and Glomus flowered after 54 days, while uninoculated controls died within three to four weeks.

The cost argument for in-situ fertility

The economic logic is freight. Under NASA pricing first released in 2019, delivering cargo to the International Space Station was estimated at about USD 20,000 per kilogram. Shipping soil or conventional fertilizer beyond low Earth orbit would cost far more. The review argues that fungal biostimulants could offer a lighter, self-replicating way to build fertility on site.

Gaps before mycorrhizal fungi can farm Mars

The authors list four open problems. Fungi have not been grown with crops under combined microgravity, cosmic radiation, extreme temperatures and altered CO₂. There are no standard protocols for testing symbiosis in high-fidelity simulants. Biosafety is a concern, because the most promising genera also contain pathogens; some Trichoderma species caused up to 92% disease severity in corn cobs in one study. Inoculation methods for closed systems also still need to be developed. Almost all work to date has used simulants rather than real lunar or Martian material.

What it means for fertilizer and biologicals on Earth

The review is explicit that its findings apply to degraded and nutrient-poor soils on Earth as well. The same phosphate-solubilizing, iron-mobilizing and metal-tolerant strains are the ones biological input makers are commercializing today. Mycorrhizal products are also moving into mainstream distribution, as seen in Syngenta’s partnership with Groundwork BioAg on mycorrhizal biologicals. Regolith is an extreme test case for how far fungi can stretch scarce nutrients.

The next step, the authors say, is a staged research program: screen fungal inoculants in high-fidelity simulants, pair them with bacterial consortia, and then add simulated extraterrestrial conditions before anything is written into mission plans.

Source: ScienceDaily