Hexbyte Glen Cove Resolute scientific work could eliminate wheat disease within 40 years

Hexbyte Glen Cove

Credit: CC0 Public Domain

Wheat and barley growers know the devastating effects of Fusarium head blight, or scab. The widespread fungal disease contaminates grain with toxins that cause illness in livestock and humans, and can render worthless an entire harvest. As Fusarium epidemics began to worsen across the eastern U.S. in the 1990s and beyond, fewer and fewer farmers were willing to risk planting wheat.

But the battle to eliminate Fusarium head blight never went away. Public breeding programs, with support from the USDA-supported Wheat and Barley Scab Initiative, have been doggedly tweaking soft red winter wheat lines in hopes of achieving greater resistance to the disease.

In a new analysis, University of Illinois researchers say those efforts have paid off. Over the past 20 years, critical resistance metrics have improved significantly. And, they say, if breeding efforts continue, vulnerability to Fusarium head blight could be eliminated within 40 years.

“I don’t think anybody realizes it’s possible we could eliminate Fusarium head blight as a problem. Forty years sounds like a long time, but by the time I’m retired, the threat of disease could be gone. That would make a huge difference,” says Jessica Rutkoski, assistant professor in the Department of Crop Sciences at Illinois and co-author on the new paper.

Rutkoski and her colleagues examined 20 years of data from nine university breeding programs spanning 40 locations in the eastern U.S. That’s a whopping 1,068 wheat genotypes.

In each year and each location, researchers inoculated wheat plants with Fusarium spores. They evaluated both test entries (novel wheat lines) and check cultivars (standard across all locations and years) for various resistance traits. The long-term check cultivars act as a kind of barometer, accounting for agronomic practices and environmental factors.

The researchers looked at disease incidence, severity, Fusarium-damaged kernels, and deoxynivalenol (also known as Vomitoxin) content—the main toxin of concern in Fusarium-contaminated grain. And over 20 years and 1,068 lines, all the resistance traits improved.

“The genetic gain in disease resistance was significant for each of those four traits. Most importantly, we saw a 0.11 parts-per-million decrease in deoxynivalenol per year. Just to see any significant favorable trend is really good,” Rutkoski says. “It basically shows that everyone’s making progress, and that the investment in public breeding programs is paying off.”

Rutkoski says breeders have thrown nearly every technique at wheat to try to improve resistance to Fusarium head blight. It’s a tough nut to crack because resistance is controlled by multiple interacting genes.

“It’s quantitative resistance. There isn’t just one gene that’s going to solve it. On the breeding side, people have looked at exotic sources of resistance, such as Chinese lines that have high resistance. Then they’ll map the genes and introgress them,” Rutkoski says. “That’s been successful to some degree, but those genes tend to be associated with unfavorable traits, like lower yield. So, there have been issues.”

When Rutkoski analyzed the impact of germplasm introductions from Chinese wheat lines, they weren’t responsible for boosting resistance. In other words, progress over the past 20 years was mostly due to breeders exploiting native resistance—the locally adapted ‘s inherent genetic capacity to resist disease—rather than introducing resistance from exotic sources.

That’s not to say novel genetic sources of resistance don’t have their place. Rutkoski notes it’s important to try to identify major-effect genes because often they can help breeders achieve their goals faster.

Ultimately, Rutkoski hopes her results justify and encourage investments in public breeding programs.

“Nobody really notices the progress that’s being made. I think there’s some skepticism and suspicion that breeding isn’t that important. Or people think we need to focus more on genome editing or finding more exotic sources of resistance,” she says. “A lot of public breeding programs are getting shut down, and we risk losing all that progress. So, I was gratified to show that the improvement is very consistent over time. And if you just stick to this kind of strategy, you will have guaranteed results. It’s not risky.”

The article is published in Plant Disease.

More information:
Rupesh Gaire et al, Genetic trends in Fusarium head blight resistance due to 20 years of winter wheat breeding and cooperative testing in the Northern US., Plant Disease (2021). DOI: 10.1094/PDIS-04-21-0891-SR

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Hexbyte Glen Cove Using virtual fluid for the description of interfacial effects in metallic materials

Hexbyte Glen Cove

Schematic representation of an imperfect metal on which ions and their smeared-out mirror charges are shown. Credit: University of Stuttgart / Alexander Schlaich

Liquids containing ions or polar molecules are ubiquitous in many applications needed for green technologies such as energy storage, electrochemistry or catalysis. When such liquids are brought to an interface such as an electrode—or even confined in a porous material—they exhibit unexpected behavior that goes beyond the effects already known. Recent experiments have shown that the properties of the employed material, which can be insulating or metallic, strongly influence the thermodynamic and dynamic behavior of these fluids.

To shed more light on these effects, physicists at the University of Stuttgart, Université Grenoble Alpes and Sorbonne Université Paris have developed a novel computer simulation strategy using a virtual fluid that allows the within any material to be taken into account while being computationally sufficiently efficient to study the properties of at such interfaces. The new method has now made it possible for the first time to study the wetting transition at the nanoscale, which depends on whether the ionic liquid encounters a material that has insulating or metallic properties. This breakthrough approach provides a new theoretical framework for predicting the unusual behavior of charged liquids, especially in contact with nanoporous metallic structures, and has direct applications in the fields of energy storage and environment.

Despite their key role in physics, chemistry and biology, the behavior of ionic or dipolar near surfaces—such as a porous material—remains puzzling in many respects. One of the greatest challenges in the theoretical description of such systems is the complexity of the electrostatic interactions. For example, an ion in a perfect metal produces an inverse counter-charge, which corresponds to the negative mirror image. In contrast, no such image charges are induced in a perfect insulator because there are no freely moving electrons. However, any real, i.e., non-idealized material has properties that lie exactly between the two previously mentioned asymptotes. Accordingly, the metallic or insulating nature of the material is expected to have a significant influence on the properties of the adjacent fluid. However, established theoretical approaches reach their limits here, since they assume either perfectly metallic or perfectly insulating materials. To date, there is a gap in the description when it comes to explaining the observed surface properties of real materials in which the mirror charges are sufficiently smeared out.

In their recent paper published in Nature Materials, Dr. Alexander Schlaich from the University of Stuttgart and the research team present a new atomic-scale simulation method that allows them to describe the of a liquid to a surface while explicitly considering the electron distribution in the metallic material.

While common methods consider surfaces made of an insulating material or a perfect metal, they have developed a method that mimics the effects of electrostatic shielding caused by any material between these two extremes. The essential point of this approach is to describe the Coulombic interactions in the metallic material by a “virtual” fluid composed of light and fast charged particles. These create electrostatic shielding by reorganizing in the presence of the fluid. This strategy is particularly easy to implement in any standard atomistic simulation environment and can be easily transferred. In particular, this approach allows the calculation of the capacitive behavior of realistic systems as used in energy storage applications.

As part of the SimTech cluster of excellence at the University of Stuttgart, Alexander Schlaich is using such simulations of porous, conductive electrode materials to optimize the efficiency of the next generation of supercapacitors, which can store enormous power density. The wetting behavior of aqueous salt solutions in realistic porous materials is also the focus of his contribution to the Stuttgart Collaborative Research Center 1313 “Interface-driven multi-field processes in porous media—flow, transport and deformation,” which also investigates precipitation and evaporation processes related to soil salinization. The developed methodology is thus relevant for a wide range of systems, as well as for further research at the University of Stuttgart.

More information:
Alexander Schlaich et al, Electronic screening using a virtual Thomas–Fermi fluid for predicting wetting and phase transitions of ionic liquids at metal surfaces, Nature Materials (2021). DOI: 10.1038/s41563-021-01121-0

Using virtual fluid for the description of interfacial effects in metallic materials (2021, November 17)

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