Anti-fungal RNA spray developed to combat barley crop disease

A further concern with current anti-fungicides is with some fungi developing resistance to the active ingredients in the sprays. Resistance arises because many fungicides, usually systemics, have very specific modes of action. It is possible for fungi to develop resistance, such as by blocking the path that the anti-fungicide might take. Some fungi are also able to detoxify foreign compounds by metabolizing them.

Research into new anti-fungicides aimed at protecting crops is important given the adverse impact that fungi can have on fields and the associated impact upon the world’s food supply.

It is hoped, based on new research, that the RNA molecules can provided protection to barley (and other crops) against fugal disease. This is the approach taken by Professor Aline Koch, who works at Justus Liebig University, Germany. The use of RNA molecules takes the fight against fungi to the genetic level.

The research is based in the spraying a double-stranded RNA molecule termed CYP3-dsRNA onto barley leaves. In trials, Phys.org reports, barley leaves exposed to the new compound were purposefully infected with a common disease-causing fungus — Fusarium graminearum. F. Graminearum infected grains have been discovered in a broad range of environments. The fungus forms a scab-like structure on the grains.

These cultured Fusarium species are commonly found in home, business and public bathroom sink drains, according to Penn State University researchers.

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With the fungal-stopping process, the RNA molecules area absorbed into the fungal cells; here they target the expression of three important F. graminearum genes. In turn this inhibits the pathogen’s growth.

Successful trials showed that CYP3-dsRNA inhibited fungal growth. Further study suggests the plant’s vascular system transports the RNA from sprayed leaves to distant infection sites.

As a future research developed it is hoped the trial provides the basis for dispensing with anti-fungicides altogether. The longer-term aim is to genetically modify barley plants to produce CYP3-dsRNA through ‘normal’ growth.

The research is published in the journal PLOS Pathogens. The research paper is titled “An RNAi-Based Control of Fusarium graminearum Infections Through Spraying of Long dsRNAs Involves a Plant Passage and Is Controlled by the Fungal Silencing Machinery.”