Radiation has been pictured as something special in the world of superheroes. Spiderman and his spider abilities, Hulk with his super strength, Daredevil with his super senses — all examples of beloved heroes that have evolved, seemingly instantaneously, from radiation. Evidently, this kind of effect would not just happen overnight, but rather, through generations of radiation breaking apart and rearranging genetic material. For the anther-smut fungi living near Chernobyl, this radiation-induced evolution has been far from super.
In 1986, Reactor 4 of the Chernobyl Nuclear Power Plant exploded, releasing an equivalent of 400 Hiroshima bombs worth of radiation into the environment. Many of the effects of this powerful ionizing radiation had been observed on the individuals involved in the incident and the organisms in the surrounding environment. Impacts of the disaster on health were very negative, from acute radiation poisoning to long-term mutagenic (mutagen-causing) effects.
Fungi in the Chernobyl exclusion zone have demonstrated a remarkable resistance to radiation due to a simple physical property — melanin. This natural pigment allowed some fungi to persist in highly stressful environments, while others were impacted negatively. Due to their melanin superpower, fungi remain one of the most radio-resistant organisms on Earth. Nevertheless, there is one pathogenic fungus that has suffered from long-term radiation exposure in Chernobyl.
Microbotryum lychnidis-dioicae, an anther-smut fungus that lives near Chernobyl lacks the typical melanized properties that allow most fungi to withstand heavy ionizing radiation. A recent study was conducted to assess the fungi’s overall fitness (ability to survive and reproduce) and toleration of high ionizing radiation doses. The anther-smut fungi’s fitness in this study was determined by its capacity to infect and castrate Silene latifolia (its host plant). Therefore, the amount of infected and/or castrated plants in highly contaminated areas were recorded and compared to that of areas with little to no contamination.
After collecting these results from the field and blasting the anther-smut fungus with a massive, controlled dose of ionizing radiation, it was concluded that its overall fitness was considerably weakened, and that the fungus did not show any resistance to radiation. Unsurprisingly, they also found significantly less infected host plants in contaminated areas in contrast to areas with less radioactive contamination from Chernobyl.
There are super-powered radiation-absorbing mushrooms with melanin, and there are mushrooms that are getting closer to extinction because they are radioactive, but why is this important? Well, these kinds of studies can lead us closer to answers regarding the effects of ionizing radiation on other living things. This is crucial, especially in a world where nuclear industrial activities are still ongoing. Tatiana Giraud, a researcher that worked on the study, commented on what these findings say about Chernobyl’s influence on other organisms. “There are many other studies showing effects of ionizing radiation in plants, fungi, animals… this adds to the general picture that Chernobyl is not a ‘heaven’ free of human disturbance,” she explained.
Every organism has a purpose, so if only one is negatively affected by an environmental stressor such as heavy radiation, the ecosystem can imbalance. However, Giraud emphasized that the anther-smut fungus would likely have little impact on the ecosystem. “Although this is a fungus castrating a plant, […]it may allow the plant to reproduce more, and maybe disturb other plants,” she stated. “There are other studies showing impacts of ionizing radiation on wood-degrading fungi and other organisms: this leads to dead wood accumulation, and more fires, and thereby more dispersal of ionizing radiation,” she continued. Just like that, an entire ecosystem can become susceptible to environmental disasters simply due to radiation’s impact on the fitness of one organism.
With the ongoing use of nuclear energy and hazardous industrial activities, studies like this should be acknowledged as it instigates further investigations into the impacts of ionizing radiation. Although highly unlikely, if a catastrophic nuclear event were to occur today, it is more likely that humans would experience serious health issues than get superpowers. That is why understanding the risks of these toxins on organisms and the environment is essential.
