To truly understand how spaceflight affects plant biology, researchers must look closer. We turn to molecular biology and genetics.
DNA is the blueprint for biological functions. Though your DNA codes every cell in your body, it is not concrete. Genes are expressed differently in different environments, through gene regulation, epigenetics, etc. Astrobotany researchers can look at how genes are expressed differently in spaceflight using molecular biology techniques. By understanding what is happening at the molecular level, we can gain a more thorough understanding of how spaceflight affects plant biology.
Below is a list of plant biology gene families that are regulated by spaceflight:
(this list is currently being expanded)
Peroxidases are a large family of enzymes that catalyze oxidative reactions. They are known to have a chemical relationship with reactive oxygen species (ROS). Two examples of ROS are hydrogen peroxide and superoxide anions. These are known to be implicated in cellular harm and are the cause of oxidative stress but interestingly also have a role in regulating cell elongation, division and aging. Peroxidases can use peroxides as a substrate and subsequently can “scavenge” ROS, but they can also produce ROS in environments where autoxidation is hindered. Focusing on plant biology, some studies conclude that peroxidases play a role in plant defense to environmental stress (cold and salt), and a spaceflight experiment concluded that peroxidases’ production of ROS leads to stunted growth in root hairs.
Transcriptional response of Arabidopsis seedlings during spaceflight reveals peroxidase and cell wall remodeling genes associated with root hair development.
The RBOH family of proteins that are involved in reactive oxygen species that are signaling molecules. RBOHs are a group of genes that are differentially expressed during spaceflight. This is based on data retrieved from BRIC 19 SpaceX CRS-4.
Strigolactone is a plant hormone that stimulates branching and helpful fungi growth in root systems. In October of 2018, a research paper from microgravity asserted that this chemical may help stop some of the negative effects of spaceflight microgravity and low nutrient environments. Read more.