Discovery and characterization of a new antifungal compound

Antimicrobial resistance has prompted scientists to search for novel compounds everywhere. A multinational group of European scientists reports the discovery of solanimycin, a novel antifungal antibiotic. The chemical, which was first discovered from a pathogenic bacterium that attacks potatoes, seems to be produced by a diverse range of plant pathogenic bacteria.

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The study was published in mBio.

According to scientists, solanimycin is effective against a vast spectrum of fungi known to infect and destroy agricultural crops. In laboratory tests, the chemical also inhibited Candida albicans, a fungus that naturally exists in the body but can cause serious infections. Solanimycin and similar chemicals may be effective in both agricultural and clinical settings, according to the research.

The majority of medicinal antibiotics used today are produced by soil microorganisms, particularly those of the Actinobacteria phylum. According to scientist Rita Monson PhD, of the University of Cambridge, the latest discovery shows that plant-based microbes are worth investigating further, particularly as crops acquire resistance to present treatments.

Rita Monson co-led the research with molecular microbiologist Miguel Matilla PhD, at the Estación Experimental del Zaidn of the Spanish Research Council in Granada.

We have to look more expansively across much more of the microbial populations available to us.”

Rita Monson, Scientist, University of Cambridge

Over 15 years ago, the pathogenic potato bacterium Dickeya solani, which produces solanimycin, was discovered. Around a decade ago, investigators in the laboratory of molecular microbiologist George Salmond PhD, at the University of Cambridge began researching its antibiotic potential.

These strains emerged rapidly, and now they are widely distributed.”

Miguel Matilla, Molecular Microbiologist, Estación Experimental del Zaidn, Spanish Research Council

Solanimycin is not the first antibiotic identified from the microorganism. Researchers have previously discovered that D. solani produces an antibiotic named oocydin A, which is very potent against a variety of fungal plant diseases.

These prior discoveries, along with an investigation of the bacterium’s genome, suggested that it could generate more antibiotics, possibly with antifungal properties, according to Matilla. Matilla, Monson, Salmond, and their colleagues discovered that when they suppressed the genes necessary for oocydin A production, the bacterium retained antifungal activity.

This insight led to the discovery of solanimycin as well as the gene clusters responsible for the proteins that synthesize the chemical.

The scientists found that the bacterium produces the chemical sparingly in proportion to cell density. The solanimycin gene cluster is also activated in an acidic pH environment, such as that seen in potatoes. According to Monson, it appears to be a clever protective mechanism.

It’s an antifungal that we believe that will work by killing fungal competitors, and the bacteria benefit so much from this. But you don’t turn it on unless you’re in a potato.”

Rita Monson, Scientist, University of Cambridge

Monson stated that the researchers have begun working with scientists to learn more about the chemical structure of solanimycin and precisely comprehend how it works. Then, she and Matilla expressed their desire for the drug to be tested further in plant and animal models.

Matilla says, “Our future steps are focused on trying to use this antibiotic antifungal for plant protection.”

The discovery, according to the researchers, is a hopeful hint that plant pathogens, such as D. solani, can be coaxed into producing compounds that can be utilized to treat plant and human diseases.

Matilla concludes, “We have to open to the exploration of everything that’s out there to find new antibiotics.”