How does space radiation affect plants?

From food and water purification to oxygen production and CO2 removal, plants are essential for life on Earth. Now, with technological advancements such as rockets and other exploratory devices, astronauts can reach the moon and beyond.

However, as NASA explores the potential for longer space flights, prolonged stays on the International Space Station, or even the future colonization of the moon or planets such as Mars, scientists are well-aware that plants are needed for survival in outer space too. Yet, it is still unclear how exposure to extreme environmental factors related to space travel, such as microgravity or space radiation, may impact biological systems such as plants.

In a new research project led by the Texas A&M University and funded by NASA, a team of researchers will explore how radiation exposure in space impacts plant telomeres, which are the basic building blocks in their DNA, located at the very end of chromosomes, and have a crucial role in keeping the chromosomes healthy and stable. However, telomeres are far from static. In fact, they continually contract and expand due to environmental stressors, and if they get outside of their normal range, they frequently lose their protective function.

“Plants are obviously very important for space travel, and so from a practical point of view we want to understand how we can help them survive the extreme conditions of space,” said project leader Dorothy Shippen, a professor of Biochemistry and Biophysics at Texas A&M. “There is so much we don’t know, but this telomere research will answer some of the basic questions we have related to plants and space radiation.” 

“There is interest in telomeres because they are linked to survivability, and it turns out the environment can influence the size of telomeric DNA tract. The telomeres are like a reporter for the physiological health of organisms and a biomarker for their ability to be healthy. We are interested in understanding how plants respond to the stress of space radiation and then figure out how to protect them,” she explained.

The researchers hypothesize that exposure to space radiation may trigger genome oxidation and an increase in the activity of telomerase, a specialized enzyme that plays a crucial role in maintaining telomeric DNA. Preliminary data from plant seedlings sent into low Earth orbit on a previous space flight have shown that, while the telomere lengths of the plants did not change, telomerase activity increased 150-fold.

“This is all very new, and we need to understand how this exposure to radiation plays out,” said Borja Barbero Barcenilla, a postdoctoral fellow in Biochemistry and Biophysics at Texas A&M, who will also be involved in the project. “Right now, the level of radiation these samples were exposed to in our preliminary experiments in low Earth orbit aboard the International Space Station are much less than what they will suffer on the moon or Mars. The radiation exposure will exponentially increase on those missions, so we need to understand how plants will react to the much higher levels of radiation.”

During the following years, the scientists aim to comprehensively investigate how space radiation impacts plants from seed to flower, as well as across generations. “I think we are in a really good position to deliver some interesting data. We have the right collaborators, and we feel privileged that NASA sees the value in these experiments and trusts us with them,” Shippen concluded.

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By Andrei Ionescu, Earth.com Staff Writer

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