Effects of nanoplastic on fungal fitness

Background/Question/Methods

Micro- and nanoplastic has been identified as an increasing and major threat for organisms, species communities and ecosystem processes. However, our knowledge how plastic affects organisms and subsequent ecological processes is extremely limited, particularly for terrestrial ecosystems. Fungi are extremely divers and due to their lifestyles among the most important agents driving ecosystem processes. However, we have yet no understanding how nanoplastic affects the fitness of fungi and how possible fitness reduction translates into assemblages and related ecosystem processes. To gain first insights into the response of nanoplastic on fungal performance, we set up a lab experiment using the saprotrophic model species Cyclocybe aegerita and exposed individuals to two polystyren (PS) concentrations (5 vs. 100 mg/l) using two particle sizes (25 nm vs. 50 nm). As fitness measure, we used mycelial growth rate, mycelial biomass, and reproductive biomass.

Results/Conclusions

The experiment revealed that the fitness response of the fungi individuals depends on the nanoplastic concentration and the particle size. High concentration (100 mg/l) and small particle size (25nm) reduced mycelial growth rate by almost 100%. We found substantial mycelial growth rate and mycelial weight reduction under the high concentration treatment and large particle size (50nm) compared to the control. By contrast, the experiment did not reveal significant differences between the low concentration treatment (5 mg/l) and the control, irrespective of particle size. Our results suggest that fungal physiology and hence fitness is highly sensitive to nanoplastic contamination, particularly if high concentrations prevail. Further studies are needed to better understand the underlying cellular mechanisms and how fungal fitness reduction affects species communities and related ecosystem processes in the real world.