Unexpected potential bacterial symbiosis found in fungus that causes angular leaf spot

American Phytopathological Society

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Scientists have uncovered an unexpected microbial relationship that could help explain differences in the severity of a major disease affecting common beans. The discovery sheds light on how the pathogen evolves and may point to new strategies for breeding disease-resistant crops and reducing reliance on chemical pesticides.

Angular leaf spot, caused by the fungus Pseudocercospora griseola, is a destructive disease of common beans worldwide. The pathogen is known for its variability and ability to evolve alongside its host plant, making disease management particularly challenging.

In a new study, published in Phytopathology and led by Luz M. Serrato-Diaz of the United States Department of Agriculture–Agricultural Research Service (USDA-ARS) Tropical Agriculture Research Station in Mayagüez, Puerto Rico, researchers analyzed 48 isolates of P. griseola collected from Puerto Rico, Guatemala, Honduras, and Tanzania. Using a DNA sequencing method called 3RADseq, the team examined genetic differences among the fungal isolates to better understand how the pathogen evolves and spreads across regions.

“This research highlights the complex hidden relationships between microorganisms and shows how DNA technology can help promote global food security in the context of evolving plant diseases,” said Serrato-Diaz.

The genetic analyses confirmed previous findings that the pathogen population is divided into two major groups: Andean and Middle American. The Middle American group is further split into three previously unknown subpopulations corresponding to isolates from Guatemala and Honduras, Tanzania, and Puerto Rico. The findings highlight how geographic separation and local agricultural practices may influence the genetic diversity of plant pathogens.

The researchers also performed pathogenicity tests by infecting 12 different common bean varieties with fungal isolates from Puerto Rico. These tests identified 10 distinct fungal strains, reflecting the pathogen’s ability to vary in aggressiveness. However, the observed differences in disease severity were not linked to known virulence genes identified in the genetic analysis.

One of the study’s most surprising discoveries was the presence of DNA from an endophytic bacterium, Achromobacter xylosoxidans, within several fungal isolates. This bacterium was found in seven isolates that caused mild disease symptoms; highly virulent isolates did not contain the bacterium, suggesting that it may influence disease severity. These findings represent the first reported potential symbiotic relationship between P. griseola and this bacterial species. If confirmed, this interaction could open new possibilities for biological control using beneficial microbes to naturally suppress plant disease.

The study also identified transposable elements, sometimes called “jumping genes,” within the fungal genome. These genetic elements may help the pathogen adapt rapidly to new environments and host plants, contributing to the continuing challenge of controlling angular leaf spot.

Understanding the genetic diversity and evolutionary dynamics of P. griseola is essential for developing durable disease resistance in common beans, one of the world’s most important food crops. The researchers note that further work is needed to investigate how the bacterium, the fungus, and the host plant interact and how these relationships shape disease outcomes.

Read “Population Genomics of Pseudocercospora griseola Reveals New Groups in the Middle American Clade and the Presence of the Endophytic Bacterium Achromobacter xylosoxidans” to learn more.

For over 100 years Phytopathology®, published by The American Phytopathological Society, has been the premier international journal for publication of articles on fundamental research that advances understanding of the nature of plant diseases, the agents that cause them, their spread, the losses they cause, and measures used to control them. Articles are characterized by their novelty, innovativeness, and the hypothesis-driven nature of their research.

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Journal

Phytopathology

DOI

10.1094/PHYTO-09-24-0302-R 

 

Copper-loaded starch nanoparticles can target bacteria in microbial communities

Nanoparticles can target Staphylococcus aureus, a common cause of healthcare-associated infections

Michigan Medicine - University of Michigan

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Bacteria are a major cause of infections and death within hospital settings, in part due to the rising number of antibiotic resistance.

In the United States, antibiotic-resistant bacteria are involved in more than 2 million infections and cause 23,000 deaths annually.

There's a growing need for new options that can both treat infections and limit resistance.

In a recent study, University of Michigan researchers developed copper-loaded starch nanoparticles that can be broken down by specific bacteria to release antibacterial copper molecules.

They hope that these nanoparticles can be used to target microbial communities, called biofilms, which account for 50-70% of healthcare-associated infections.

Nanoparticles have been previously investigated to target bacteria. However, they fail to work in clinical settings because they are not soluble in water and are not stable enough to work properly.

Additionally, they need to be non-toxic while remaining in the body at high enough concentrations to be effective.

In the present study, the researchers used starch, which can act as a stabilizer and carrier for copper nanoparticles.

Starch has a positive charge that is attracted to the negative charge on the surface of bacteria.

Copper-loaded starch nanoparticles act like Trojan horses. Some bacteria break down the starch, releasing antibacterial copper molecules,"

-J. Scott VanEpps, Associate Professor of Emergency Medicine and Biomedical Engineering and Associate Director of Weil Institute

The researchers found that the copper-loaded starch nanoparticles they developed were effective against Staphylococcus aureus, a common cause of healthcare-associated infections, and Bacillus subtilis.

Since the charge on the nanoparticles helps them target bacteria directly, they were more effective than what was seen in previous studies.

The team also found that the nanoparticles worked better when bacterial growth conditions favored starch degradation.

“Copper-loaded starch nanoparticles act like Trojan horses,” said J. Scott VanEpps, Associate Professor of Emergency Medicine and Biomedical Engineering and Associate Director of Weil Institute.

“Some bacteria break down the starch, releasing antibacterial copper molecules.”

Although S. aureus cannot break down starch, B. subtilis can by using the enzyme amylase.

These results suggest that copper-loaded starch nanoparticles can also be used to target microbial communities, often found in wound infections, especially if multiple bacterial species can make amylase.

The researchers are interested in building a database of nanomaterials that have been tested on bacteria.

They aim to use machine learning to guide the development of new nanoparticles.

“Currently, developing nanoparticles has involved guesswork, which is expensive and inefficient,” VanEpps said. “By going through everything that worked, or didn’t, we can pursue intelligent nanoparticle design.”

Additional authors: Nathan A. Jones, Usha Kadiyala, Benjamin Serratos and Joerg Lahann

Funding/disclosures: VanEpps was supported by the National Institutes of Health, National Institute for Allergy and Infectious Diseases, grant number K08AI128006. Lahann received support from the National Science Foundation and grant number 2243104, Center for Complex Particle Systems.

Paper cited: “Targeting of Bacteria Using Amylase-Degradable, Copper-Loaded Starch Nanoparticlea,” Antibiotics. DOI: 10.3390/antibiotics15010056

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Journal

Antibiotics

DOI

10.3390/antibiotics15010056 

Method of Research

Experimental study

Subject of Research

Cells

Article Title

Targeting of Bacteria Using Amylase-Degradable, Copper-Loaded Starch Nanoparticles

 

Understanding cell structures – Researchers develop tool for analyzing the plant actin cytoskeleton

University of Potsdam

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A research team led by Potsdam-based bioinformatician Prof. Dr Zoran Nikoloski has developed a computational approach and an accompanying tool that enables the detailed analysis and reconstruction of actin filamentous structures in plant cells. The tool, called the ‘Graph of Filaments over Time’ (GraFT), could revolutionise the study of filamentous structures in plant cells, as it enables the automated and highly precise tracking and tracing of filamentous structures. The results of the GraFT trials have now been published in the journal ‘Science Advances’.

The actin cytoskeleton, a complex network of protein filaments within the cell, is crucial for the shaping, stability and movement of cells. Despite advances in cell biology, the precise analysis of these filaments, particularly their dynamics and spatial arrangement, remains a challenge. The “Graph of Filaments over Time” (GraFT) tool overcomes this hurdle through a comprehensive network-based approach utilising two-dimensional time-resolved image data.
In experimental tests, including studies on the model plant Arabidopsis thaliana, the researchers were able to accurately map and analyse complex filament networks using GraFT. The tool proved its worth not only in the investigation of cell structures under various physiological conditions, but also in modelling dynamic changes within the cytoskeleton.
Furthermore, GraFT provides valuable insights into plant cell biology. With the tool’s assistance, the researchers were able to observe how certain virulence factors, which enable infections and cause tissue damage, alter the properties of the actin cytoskeleton – findings that are crucial for understanding plant pathogen defence.
“GraFT enables fully automated analysis of spatio-temporal arrangements of actin filamentous structures and paves the way for understanding the effect of actin dynamics on diverse plant traits,” said Prof. Dr Zoran Nikoloski.
In addition to its impressive analytical capabilities, GraFT is also user-friendly; a freely available Python implementation and an online version ensure that researchers worldwide have access to this groundbreaking technology.

Link to the publication: Isabella Østerlund, Arne Neumann, Zhiming Ma, Yansong Miao, Staffan Persson, Zoran Nikoloski, GraFT: A robust network-based spatiotemporal analysis of filamentous structures, 2026, Science Advances, https://doi.org/10.1126/sciadv.adz4132 

Photo: Prof. Dr. Zoran Nikoloski. Photo: Thomas Roese

Contact:
Prof. Dr. Zoran Nikoloski, Institute of Biochemistry und Biology
Tel.: 0331 977 6305
Email: zoran.nikoloski@uni-potsdam.de

Media information 03-30-2026 / Nr. 030

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Journal

Science Advances

DOI

10.1126/sciadv.adz4132 

Method of Research

Computational simulation/modeling

Subject of Research

Not applicable

Article Title

GraFT: A robust network-based spatiotemporal analysis of filamentous structures

Article Publication Date

27-Mar-2026

 

University of Tennessee faculty are trailblazing new evolutionary research

University of Tennessee at Knoxville

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image: 

Benjamin Auerbach, professor in the Department of Ecology and Evolutionary biology at the University of Tennessee, Knoxville.

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Credit: University of Tennessee

New research is significantly revising a widely cited evolutionary model, the Inhibitory Cascade Mode (ICM). Benjamin Auerbach, professor in the Department of Ecology and Evolutionary biology at the University of Tennessee, Knoxville, and Charles Roseman, associate professor in the Department of Ecology, Evolution, and Biology at the University of Illinois – Urbana-Champaign, published their findings in Evolution. 

The ICM, first published in 2007 in Nature, is a theory about how features that grow in a series (or row), such as molar teeth, develop. It claims there is an activating process and an inhibiting process, and the balance of the two determines the size of the feature. The model was postulated using molar teeth, which form in sequence from front to back. The size of traits like molars is predicted in the model using a statistical process of scaling the second and third molars, for example, to the first element of the series, the first molar. 

In their paper, Auerbach and Roseman explored the mathematical and developmental arguments made in support of the model by other researchers. They found that the mathematical predictions made using the model are the result of a flaw arising from standardization, and that there is little evidence to support the presence of factors in development that inhibit the growth of structures the way suggested under the model. 

After analyzing the ICM by evaluating the standardizing measurements of biological data, non-biological data, and stimulated data, they found there is no evidence that the model accurately reflects processes governing development. One of the indicators that the model is flawed is that it was applied to serial traits that do not form in sequence. For example, in the upper limb, the upper arm and hand form before the forearm, but the ICM still predicted the size of these segments even though the developmental processes claimed to underlie the model do not occur in the sequence. Thus, the researchers conclude that the model’s predictive accuracy is due to a mathematical artifact, which explains why it was successfully applied to parts of organisms that appear in a sequence but do not form in sequence. 

This research opens new opportunities for researchers to investigate how development and evolution unfold to structure the patterns of size in segmented parts of organisms. The advancements made in evolutionary developmental biology and perspectives on molar tooth evolution during the past two decades with the ICM will serve as a foundation for further discoveries.

The future of evolutionary and developmental research is now open to new horizons, with Auerbach and Roseman continuing to study how development and evolution inform each other in the generation of variation in organisms. 

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Journal

Evolution

DOI

10.1093/evolut/qpag020 

Article Title

The inhibitory cascade model and evolution in segmentally organized tissues

 

Drone imaging provides new insights into how grazing shapes grassland ecosystems

Journal of Remote Sensing

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Grasslands play a key role in supporting livestock, storing carbon, and maintaining biodiversity. However, early signs of degradation are often difficult to detect using traditional field surveys alone. A new study shows that drone-based hyperspectral imaging can help capture not only how much vegetation is present, but also how plant communities are changing under different grazing pressures. This approach may provide complementary information for assessing grassland condition.

Livestock grazing is one of the most widespread human pressures on grasslands worldwide. Its effects can vary: while moderate grazing may support biodiversity in some systems, heavier grazing is often associated with declines in productivity and shifts in species composition. Monitoring these changes is challenging because they involve not only vegetation cover, but also plant functional traits and the way species interact within communities.

In a study published on February 3, 2026, in Journal of Remote Sensing (DOI: 10.34133/remotesensing.0732), researchers from Peking University, Beijing Forestry University, Inner Mongolia University, the University of Twente, and Sun Yat-sen University investigated whether drone-based hyperspectral data could be used to monitor these ecological changes in the Xilin Gol Grassland Nature Reserve in Inner Mongolia, China.

The researchers found that drone observations could be used to estimate aboveground biomass and several plant functional traits with useful accuracy. Across the grazing gradient, biomass generally declined as grazing intensity increased, particularly under heavy grazing. At the same time, several nutrient-related traits tended to decrease, while traits such as leaf thickness and leaf carbon content tended to increase, consistent with a shift toward more stress-tolerant plant strategies.

The study also showed that, under heavier grazing, relationships between plant traits and biomass became stronger. In addition, functional diversity was more positively associated with biomass at higher grazing intensity. Patterns in trait networks were also linked to biomass, with less connected trait relationships associated with lower biomass under stronger grazing pressure. Together, these results suggest that changes in plant traits and community organization may provide additional insights into grassland responses to grazing.

“This study shows that monitoring grasslands may benefit from looking beyond how much vegetation is present, to also understanding how plant traits and community structure change under grazing pressure.” said Dr. Yiwei Zhang from Peking University, the study’s first author.

The work was based on a long-term grazing experiment established in 2013, including grazing exclusion, light grazing, moderate grazing, and heavy grazing treatments. By combining drone observations with field measurements, the researchers were able to relate patterns observed from the air to ecological changes on the ground.

The broader implication of this study is that monitoring grasslands may benefit from moving beyond simple measures of vegetation quantity. By capturing changes in plant traits and community organization, remote sensing approaches such as this may provide complementary information on how ecosystems respond to grazing pressure. This could support more comprehensive and timely assessment of grassland condition, particularly in regions where large-scale field monitoring is difficult.

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References

DOI

10.34133/remotesensing.0732

Original Source URL

https://spj.science.org/doi/10.34133/remotesensing.0732

About Journal of Remote Sensing

The Journal of Remote Sensing is an online-only Open Access Science Partner Journal published in affiliation with Aerospace Information Research Institute, Chinese Academy of Sciences (AIR-CAS) and distributed by the American Association for the Advancement of Science (AAAS). Like all partners participating in the Science Partner Journal program, Journal of Remote Sensing is editorially independent from the Science family of journals and AIR-CAS is responsible for all content published in the journal. To learn more about the Science Partner Journal program, visit the SPJ program homepage.

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Journal

Journal of Remote Sensing

DOI

10.34133/remotesensing.0732 

Subject of Research

Not applicable

Article Title

Unraveling Ecosystem Function Responses to Grazing Intensity through UAV-Based Hyperspectral Analysis

 

With history standards prone to politicization, 'minimalism' approach would benefit teachers, scholar argues

Political involvement in history standards feeds culture wars, does not improve education; Kansas, Maine provide example

University of Kansas

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LAWRENCE — The practice of states revising standards for how their schools teach history is developing a storied and often contentious history of its own. A University of Kansas scholar has published new research arguing that history standards are prone to overt politicization and the best examples for how to handle history education are in states that practice “standards minimalism.”

Since the 1980s, an accountability movement in American education has seen standards drafted state by state for how schools should teach certain topics and which topics they should address. While those efforts may have begun and been argued for in good faith, the subject of history has proven difficult to standardize and worse, been prone to politicization.

“There is not much evidence that since the ‘80s these standards have improved history education. And there is a lot of evidence that they have made culture wars worse. They’ve also made things harder for teachers and schools,” said Stephen Jackson, assistant professor of educational leadership & policy studies at KU.

In his article “The Best History Standards Govern Least: The Case for Standards Minimalism,” published in The Journal of American History, Jackson traces how standards have evolved over the last several decades and how today states like Kansas and Maine provide the best examples for what history standards should be.

While arguments have been made that standards are unenforceable, research has shown that teachers rely on them for guidance on what topics to cover and how, especially those early in their careers or required to teach subjects they may not be experts in, demonstrating their influence in the classroom. However, politicians and special interest groups have increasingly developed standards that sideline expert opinion and offer polarizing and contentious versions of history in schools, according to Jackson.

“History is all about interpretation and showing multiple perspectives. That tends to get lost and flattened in these standards. Most people say we should have an open, honest conversation about history in school, but all too often what happens is that those in power want to insist their version becomes the accepted standard,” he said.

The result of such politically drafted standards and mandates is a long list of topics that must be covered, leaving little time to fully understand the significance of historical events, people and results in prescriptive memorization, Jackson wrote. In an era when less time is given in the school day to history and social studies, that takes away from time spent analyzing history, its lessons and what it says about how people and societies have evolved.

To avoid the dual problems of “the tyranny of coverage,” or racing to cover a long list of topics and politicization of standards, Jackson argues states should use “standards minimalism.” The author points to Kansas and Maine as two states who have standards employing such an approach.

Maine’s standards include helping each student become “a self-directed and lifelong learner” and “a responsible and involved citizen.” They also direct educators to include chronological eras and themes including “freedom and justice” and “conflict and compromise.” 

Kansas’ standards contain only five simplistic standards, including “choices have consequences” and “individuals have rights and responsibilities.” The lack of specific content guidance is intentional, Jackson points out.

“In other words,” Jackson said, “Kansas and Maine focus on high-level and abstract concepts or guiding principles rather than specific historical content recommendations.”

By reducing state involvement in history education standards, minimalism appeals to the principle of local control of education, a pillar of American educational practice, Jackson wrote. Ideally, giving more agency to local school districts and trusting in the professionalism of teachers can lower the temperature of the culture wars.

“I think the great strength of what Kansas and Maine are doing is avoiding a long list of prescriptive mandates and giving support teachers need to do their jobs,” Jackson said. “That is a welcome counter to national trends that continue moving towards more controversial and overly detailed standards.”

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Journal

Journal of American History

DOI

10.1093/jahist/jaag010 

Method of Research

Meta-analysis

Subject of Research

Not applicable

Article Title

The Best History Standards Govern Least: The Case for Standards Minimalism

Article Publication Date

13-Mar-2026