Multi-omics resources for the Australian stuttering frog (Mixophyes balbus) reveal assorted antimicrobial peptides

Type: Journal Article

Reference: Tang, S., Peel, E., Belov, K., Hogg, C. J., & Farquharson, K. A. (2024). Multi-omics resources for the Australian southern stuttering frog (Mixophyes australis) reveal assorted antimicrobial peptides. Scientific Reports, 14(1), 3991.


The number of genome-level resources for non-model species continues to rapidly expand. However, frog species remain underrepresented, with up to 90% of frog genera having no genomic or transcriptomic data. Here, we assemble the first genomic and transcriptomic resources for the recently described southern stuttering frog (Mixophyes australis). The southern stuttering frog is ground-dwelling, inhabiting naturally vegetated riverbanks in south-eastern Australia. Using PacBio HiFi long-read sequencing and Hi-C scaffolding, we generated a high-quality genome assembly, with a scaffold N50 of 369.3 Mb and 95.1% of the genome contained in twelve scaffolds. Using this assembly, we identified the mitochondrial genome, and assembled six tissue-specific transcriptomes. We also bioinformatically characterised novel sequences of two families of antimicrobial peptides (AMPs) in the southern stuttering frog, the cathelicidins and β-defensins. While traditional peptidomic approaches to peptide discovery have typically identified one or two AMPs in a frog species from skin secretions, our bioinformatic approach discovered 12 cathelicidins and two β-defensins that were expressed in a range of tissues. We investigated the novelty of the peptides and found diverse predicted activities. Our bioinformatic approach highlights the benefits of multi-omics resources in peptide discovery and contributes valuable genomic resources in an under-represented taxon.

ABC Radio: The race to save Australia’s dirty frogs

Simon Tang (2022 Honours Student) joined producer Shelby Traynor (ABC Radio) and Dr Jodi Rowley (Curator of Amphibian & Reptile Conservation Biology at the Australian Museum and UNSW) to talk about the pathogen-fighting peptides of frogs.

Listen to the full broadcast here:


The Secret Superpower of Frogs

by Simon Tang (2022 Honours Student) 

An intense, murky river. Densely packed trees, twisting into each other and Mother Earth below. Decaying detritus scattered throughout the landscape. This pulsating ecosystem is not the most welcoming of places. Many dare not to stay for too long, to avoid angering an infected mosquito, or brushing too close to a leech. In such a disease-riddled habitat, where bacteria and fungi fester and multiply, what thrives?

In the distance, the unperturbed croak of a frog, lazily perched atop a stone, reminds us of who prevails in these lands.

The frog is an enigmatic creature. While seemingly unassuming in appearance, they secretly walk a fine line between survival and destruction. This balancing act exists only as a result of their skin, a paradoxical blessing and curse. Frogs bear primitive, inefficient lungs, and so rely on their skin as a secondary respiratory organ to absorb enough oxygen. To sufficiently compensate for their lungs, their skin must be moist at all times, as water allows for more air to permeate into the skin. As a result, they are perpetually married to rivers and ponds, spending nearly their entire lives around them. While these water bodies are intrinsically life-giving, the enemy is never too far. Armies of hostile diseases lie beneath the water surface, primed to usurp the delicate skin that awaits them.

Fortunately, this is no new foe for the frog. Over millions of years of evolution, frogs have accrued an impressive catalogue of chemical weapons tailored to neutralise these microbes. When the microscopic enemies begin their attack, the frog secretes a powerful, antimicrobial serum from their skin. Like waves of infantry soldiers, these secretions are efficient, and leave little in their way. After a tough battle, the enemy side has been defeated. The frog can rest easy, and breathe for another day.


In some ways, the chemical warfare between the frog and diseases reflects our own battle with pathogens. Over hundreds of years of research, we have developed our own chemical fleet of medicines and therapeutics to treat a range of diseases. When we are being overwhelmed by infections and illness, a simple pill can turn the tide.

However, the tide is turning back. Over the past few years, we have become intimately aware of how bacteria and viruses can impact our lives, and the devastating effects they can have on society. Diseases that were once thought to be controlled are now coming back, stronger than ever. Many animal diseases are also crossing the species barrier to infect humans, exposing us to diseases we have never experienced before. We are currently facing a pathogenic assault on all fronts, and our weapons are dwindling.

To help better treat diseases, my honours project is taking a closer look at the frogs around us. Through identifying the specific, bioactive peptides in the skin secretions of frogs, I am discovering unique molecules with disease-killing properties that have never been exploited before. These compounds have the potential to help inform better drug design, or even to be directly translated into novel treatments for human diseases.  

In a world where infectious diseases threaten to take over, our unlikely superhero might be hidden in a riverbank, sunbathing on a stone.


Simon Tang (2022 Honours Student) is creating a reference genome for the stuttering frog (Mixophyes balbus) for the purpose of characterising novel antimicrobial peptides.