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Antifungal RNA spray could help fight barley crop disease

Plant vascular system transports RNA from sprayed leaves to distant fungal infection sites

Date:
October 13, 2016
Source:
PLOS
Summary:
Spraying barley crops with RNA molecules that inhibit fungus growth could help protect the plants against disease, according to a new study. Plant diseases caused by fungi that grow on crops seriously threaten the world's food supply, and fungi can develop resistance to traditional pesticides.
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Do double stranded (ds)RNAs represent a new generation of environmentally-friendly fungicides? The figure shows accumulation of fluorescent-labelled dsRNA in the plant vascular system after spraying barley leaves with CYP3-dsRNAA488 that inhibits plant infection with Fusarium fungi.
Credit: Dr. Aline Koch, Justus Liebig University Giessen, using a LEICA TCS SP8 confocal microscope

Spraying barley crops with RNA molecules that inhibit fungus growth could help protect the plants against disease, according to a new study published in PLOS Pathogens.

Plant diseases caused by fungi that grow on crops seriously threaten the world's food supply, and fungi can develop resistance to traditional pesticides. To improve the antifungal arsenal, Aline Koch of Justus Liebig University, Germany, and colleagues are investigating RNA-based techniques that fight fungi at the genetic level.

In the new study, Koch's team sprayed a double-stranded RNA molecule called CYP3-dsRNA onto barley leaves and exposed the plants to a common disease-causing fungus known as F. graminearum. When absorbed by fungal cells, CYP3-dsRNA is known to target and silence the expression of three key F. graminearum genes, inhibiting the pathogen's growth.

The scientists found that CYP3-dsRNA inhibited fungus growth on sprayed plants but not on unsprayed plants. The researchers also found reduced F. graminearum growth on leaves that were not directly sprayed with CYP3-dsRNA, suggesting that the plant's vascular system can transport the RNA from sprayed leaves to distant infection sites. Further experiments demonstrated that a fungal protein known as DICER-LIKE 1 is important for CYP3-dsRNA to inhibit growth effectively.

These findings will help inform future research into RNA-based control of plant pathogens. Koch's team had previously shown that barley plants can be genetically modified to produce CYP3-dsRNA themselves. However, scientific and societal obstacles to genetic engineering pose challenges for this technique. Spraying RNA directly onto crops could be a more viable, sustainable, and environmentally friendly alternative.

"The discovery that spraying of small RNAs targeting essential genes of the fungus Fungus graminearum," the authors report, "reduced its plant infection adverts to a new generation of environmentally-friendly fungicides."


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Materials provided by PLOS. Note: Content may be edited for style and length.


Journal Reference:

  1. Aline Koch, Dagmar Biedenkopf, Alexandra Furch, Lennart Weber, Oliver Rossbach, Eltayb Abdellatef, Lukas Linicus, Jan Johannsmeier, Lukas Jelonek, Alexander Goesmann, Vinitha Cardoza, John McMillan, Tobias Mentzel, Karl-Heinz Kogel. 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. PLOS Pathogens, 2016; 12 (10): e1005901 DOI: 10.1371/journal.ppat.1005901

Cite This Page:

PLOS. "Antifungal RNA spray could help fight barley crop disease: Plant vascular system transports RNA from sprayed leaves to distant fungal infection sites." ScienceDaily. ScienceDaily, 13 October 2016. <www.sciencedaily.com/releases/2016/10/161013155130.htm>.
PLOS. (2016, October 13). Antifungal RNA spray could help fight barley crop disease: Plant vascular system transports RNA from sprayed leaves to distant fungal infection sites. ScienceDaily. Retrieved May 28, 2017 from www.sciencedaily.com/releases/2016/10/161013155130.htm
PLOS. "Antifungal RNA spray could help fight barley crop disease: Plant vascular system transports RNA from sprayed leaves to distant fungal infection sites." ScienceDaily. www.sciencedaily.com/releases/2016/10/161013155130.htm (accessed May 28, 2017).

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