A new study shows that plant hormone strigolactone could make it possible to encourage plant growth in space. With weak gravity and scarce nutrients, growing plants on moon or on other planets may have been unimaginable but scientists from University of Zurich have developed a solution. According to them, strigolactone fosters plant-fungal symbiosis and stimulates growth of plant, even in unfavorable environment found in space.
The idea of establishing lives on other planets has been discussed around for long, while entrepreneurs such as Elon Musk and Jeff Bezos have also showed huge interest in such vision. In addition, the prospects of long-term human space expedition in the future have raised the need to find ways to sustainably provide food for the people in space.
Previous studies have suggested cultivation of crop in situ but soil on other planets contain relatively low nutrients as compared to earth’s agricultural land. Further, transportation of high-nutrient soil and fertilizers up into the space comes with high economic and ecological cost.
In search of possible solution, the research team focused their study on a symbiotic association between fungus and roots of vascular plants such as mycorrhiza. According to the plant biologists, in such symbiotic relationship, the fungal filaments supply the plant roots with additional water and macronutrients such as nitrogen and phosphates plus trace elements from the ground. In exchange, the fungi receive sugar and fat from the plant. Such plant-fungal symbiosis is facilitated by hormones of strigolactone family, secreted by most plants into the soil. The mycorrhization process can greatly influence the plant growth, thereby significantly improving crop yields, especially in low-nutrient soil.
Major Challenges in Space Farming
One of the challenges faced in space-crop production is not just low nutrient but also the conditions of microgravity or altered gravity environments. To analyze the impact of such environment on plant growth, the research team cultivated petunias and mycorrhizal fungi, under mimicked microgravity conditions. Petunias were used in the experiment as they provide a model organism for plants belonging to Solanaceae or nightshade family including potatoes, tomatoes, and eggplants.
The plant biologists found that the low gravity conditions impede the mycorrhization process which decreased the petunias’ uptake of nutrients from the soil. However, the plant hormone strigolactone can oppose this negative effect. Synthetic strigolactone-treated fungi along with plants that secrete high levels of the hormone were able to grow significantly in the soil with lower nutrient despite the microgravity conditions.
According to Lorenzo Borghi of the University of Zurich, to grow crops such as potatoes and tomatoes in challenging conditions of space, it is necessary to encourage plant-fungal symbiosis which is possible by using the plant hormone strigolactone. Thus, the research pave the way for successful crop cultivation in space.