A symbiotic partnership between plant and fungus could offer a farming fix in space

With plant hormone strigolactone, scientists grew a petunia-fungi network in simulated microgravity.

A new study has found what could be missing ingredients from farming plans made for outer space so far — symbiotic fungi and a hormone supplement.

Researchers studied a particular category of fungi, known a mycorrhiza, which is often found tightly linked to the roots of certain plants. This symbiotic relationship involves tiny, thread-like connections between the plant and fungus. These can spread over large areas underground and form a network, linking multiple plants indirectly to one another.

What the researchers grew interested in about such associations is how the fungus interacts with the plants — specifically, its barter system.

The fungus supplies the plant with water, nitrogen and phosphates from the soil that the plant cannot acquire otherwise, and the plant in return sustains the fungus by sharing the energy it produces — as sugar.

A symbiotic partnership between plant and fungus could offer a farming fix in space

A still from the movie Martian, where Matt Damon checks on the health of his potato farm on Mars. Image courtesy: Twentieth Century Fox Film Corporation

Using simulated microgravity, scientists successfully grew a network of petunia plants and mycorrhiza. Petunias have a lot in common with common no-fuss plants like potatoes and eggplants, which could be the likely choice for the first farms set up on Mars.

Microgravity did affect the interaction, they found. The network didn’t grow as well in low gravity, and the amount of the protein the petunia could take up was lower.

A natural hormone in plants called strigolactone was supplemented to the soil to encourage more interaction between fungus and plant. The petunias bloomed and grew without the challenges posed by low gravity after the strigolactone was enhanced artificially.

“Our findings may… pave the way for the successful cultivation in space of the types of plants that we grow on Earth,” Lorenzo Borghi, author of the study, said to the university press.

The study's results were published in NPJ Microgravity on 17 October.

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