Study discovers novel chemistry to fight against fungal disease in crops

Pathogenic fungi are a major and ever-increasing threat to global food security.

Image Credit: aleori/Shutterstock.com

At present, anti-fungal chemical agents, also called fungicides, are sprayed on crops, protecting them against fungal disease. However, the growing challenge of microbial resistance against these chemicals necessitates new fungicides to be constantly developed.

Led by Professor Gero Steinberg, a research team at the University of Exeter put their expertise together to combat against plant pathogenic fungi.

In a study published recently in the renowned scientific journal Nature Communications, the researchers identified new mono-alkyl chain lipophilic cations (MALCs) that protect crops from Septoria tritici blotch in rice and wheat blast disease.

These diseases pose a threat to temperate-grown rice and wheat, respectively, and are a risk to the security of the two main calorie crops. The researchers started by discovering MALCs that block the activity of fungal mitochondria.

Mitochondria also called the “power-house” of cells, are essential to provide fuel for all vital processes in the pathogen. MALCs block an essential pathway in mitochondria, thereby preventing the supply of cellular energy, which ultimately kills the pathogen.

Steinberg and the team demonstrate that this “mode of action” is common to several MALCs investigated and was found to be effective against plant pathogenic fungi. One MALC they produced and termed C18-SMe2+ exhibited unpredicted additional modes of action.

First, C18-SMe2+ produces aggressive molecules within the mitochondria that target fungal proteins essential to thrive, in turn triggering a self-destruction program that eventually leads to cellular suicide of the fungus.

Then, upon application to crop plants, C18-SMe2+ provides a signal to the defense system of the plants, thus preparing the crop for subsequent attack and enhancing the armory of the plant against the intruder.

The researchers at Exeter University showed that C18-SMe2+  exhibited no toxicity to plants and was found to be less toxic for human cells and aquatic organisms than existing fungicides used in the field at present.

It is the combined approach of Exeter scientists, providing skills in fungal cell biology (myself, Dr Martin Schuster), fungal plant pathology (Professor Sarah J. Gurr), human cell biology (Professor Michael Schrader) and synthetic chemistry (Dr Mark Wood) that enabled us to develop and characterise this potent chemistry.”

Gero Steinberg, Professor, University of Exeter

Steinberg added, “The University has filed a patent (GB 1904744.8) in recognition of the potential of this novel chemistry in our perpetual fight against fungi. “We now seek partners/investors to take this development to the field and prove its usefulness under ‘real agricultural conditions’. Our long-term aim is to foster greater food security, in particular in developing nations.”

I always wanted to apply my research outside of the ivory tower of academia and combine the fundamental aspects of my work with a useful application. The visionary approach of the Biological Sciences Research Council (BBSRC) provided me with this opportunity, for which I am very grateful. In my mind, this project is a strong example of translational research that benefits the public.”

Gero Steinberg, Professor, University of Exeter

According to Professor Sarah Gurr, “This is such a timely and important study. We are increasingly aware of the growing burden of plant disease caused by fungi and of our need to safeguard our calorie and commodity crops better.”

The challenge is not only to discover and describe the mode of action of new antifungals but to ensure that chemistries potent against fungi do not harm plants, wildlife or human health. This new antifungal is thus an exciting discovery and its usefulness may extend beyond crops into the realms of fungal disease in humans and, indeed to various applications in the paint and preservative industries. This merits investment!”

Sarah Gurr, Professor, University of Exeter