Biodiversity, the variety of life on Earth, is essential for maintaining healthy ecosystems and ensuring human well-being. While animals and plants are commonly highlighted when discussing biodiversity, fungi are often overlooked. With an estimated five million species, fungi represent the second-largest kingdom of organisms on Earth, surpassed only by animals. However, we are still in the early stages of exploring the extensive diversity of fungi, with numerous species remaining undiscovered and awaiting documentation.
In recent years, the interconnectedness of ecosystems and human health has become increasingly apparent, particularly in the context of emerging infectious diseases. A rich biodiversity plays a crucial role in mitigating the transmission of diseases from animals to humans, known as zoonotic disease transmission. Biodiversity acts as a buffer against the spread of diseases, where many species interact in ways that usually suppress disease outbreaks. Predators and competitors, for instance, can regulate the population size of disease-carrying species that typically serve as reservoirs for microbial pathogens, thereby reducing the risk of transmission to humans. When biodiversity is declined, the balance of ecosystems is weakened as well, creating opportunities for pathogens to thrive. For example, when natural enemies or competitors of disease vectors are reduced or absent in an area, outbreaks of infectious diseases may occur. Conversely, predation on disease vectors can effectively prevent or at least slow the spread of a pathogen. Additionally, deforestation or anthropogenic disturbance can harm biodiversity by disrupting the natural habitats of organisms and increasing the likelihood of human-animal interactions, which raises the risk of disease transmission as well.
Fungi, renowned for their diversity and ecological importance, play multifaceted and indispensable roles in the intricate web of life. Beyond being mushrooms that sprout after rain or yeasts that help ferment food and drinks, fungi also serve as decomposers, symbionts, and pathogens, all of which are essential for a healthy ecosystem. As a notable example of the significant impact of fungi on human health, the discovery of penicillin, an antibiotic derived from the mold Penicillium, have saved millions of lives from severe infection. The recent rise of superbugs and their antibiotic resistance has renewed our interest in discovering novel antibiotics from unexplored fungal species. Furthermore, the emergence of diseases like Dengue, Yellow Fever, and Zika virus has highlighted the urgency to mitigate the spillover of pathogens from animals to humans. While insect vectors like mosquitoes receive much attention, fungi are being explored as biocontrol agents to curb the spread of these infectious diseases. The insect-associated fungi, such as those historically used for medicines or immune system boosters (e.g., Cordyceps), have recently inspired multiple science fiction TV shows, like "The Last of Us."
Fungal species have pioneered multiple biocontrol strategies to manage adult mosquitoes in Africa, where Malaria are prevalent . A research group at the University of Toronto has been utilizing aquatic fungi as innovative biocontrol agents to target the larval stages of mosquitoes. They have identified these aquatic fungi as obligate symbionts of mosquito larvae for over hundreds of millions of years. The diversity observed in this group of fungi is thus believed to be a result of their long-term interaction with insect hosts. For instance, one species found in Australia, has demonstrated the ability to kill mosquito larvae by penetrating the gut lining, thereby hindering their molting process and emergence from water. Additionally, another species within the same group has exhibited the ability to steal genes from mosquito hosts for its own benefits within the gut environment. The research group is currently spearheading a project to survey the diversity of these fungi across Canada and beyond, aiming to establish an atlas system to evaluate their host specificity towards a precise biocontrol method that is friendly to non-targeted organisms and the environment. The first version of the online system, which showcases the diversity of these fungi, has been published and is now fully accessible to the public Database 1, Database 2.
In the increasingly interlinked world, preserving biodiversity is not just about saving species from extinction, more importantly, it's about protecting the delicate balance of life on Earth and the multitude of unidentified organisms. Healthy and sustainable ecosystems depend on this balance, where fungi play a variety of roles through their associations with other organisms. As we celebrate the International Day for Biological Diversity, it is imperative to recognize the crucial roles fungi play in our ecosystems and their potential in mitigating disease transmission. By ensuring their conservation, we can protect these vital resources for generations to come.
About the author
Assistant Professor Yan Wang started his lab in January 2020 at UTSC. He completed his BSc in Life Science at Shanxi University, China, followed by his MSc in Mycology and Molecular Systematics at Boise State University, and his PhD at the University of Toronto. He was a postdoc in the Stajich Laboratory for Fungal Evolutionary Genomics from 2017-2019 working on the ZyGoLife project and Anaerobic Gut Fungi (Neocallomastigomycota) systematics project.
Professor Wang and his lab study the ecology and evolution of fungus. Unlike the large mushroom fungi that we often think about when we read or hear the word 'fungus', the Wang Lab studies microbial fungi found in the gut of insects. They are interested in learning more about the ecology, evolution and genomics of the interactions between the microbial fungi and their insect hosts, the evolution of microbial fungi and their phylogeny, and the host specificity of the gut-dwelling fungi.