Steve Diggle, a professor in the School of Biological Sciences and director of Georgia Tech’s Center for Microbial Dynamics and Infection (CMDI), is one of 65 new 2023 Fellows of the American Academy of Microbiology (AAM).

The AAM is an honorific leadership group and think tank within the American Society of Microbiology (ASM). Fellows are elected annually through a highly selective, peer-review process, based on their records of scientific achievement and original contributions that have advanced microbiology. The Academy received 148 nominations this year. 

“On behalf of the School of Biological Sciences, I am thrilled to hear about Steve’s election to the American Academy of Microbiology,” said Todd Streelman, professor and chair of the School of Biological Sciences. “This is a tremendous feather in our cap and further illustrates the success of the Center for Microbial Dynamics and Infection, its faculty and students, on our campus.”

Arturo Casadevall, Chair of the Governors of the American Academy of Microbiology, notified Diggle of his election. The Academy “recognizes excellence, originality, service and leadership in the microbial sciences,” Casadevall wrote. “As a nominee, you were strongly supported by your nominators … Your election to the Academy this year is a mark of distinction.”

“I am delighted to be elected,” Diggle said. “It is an honor to be chosen by your peers to be part of this fellowship and to recognize the work my group has done over the years. The award would not have been possible without all the hard work and talents of many undergraduates, graduate students, postdocs and collaborators since I started my own group back in 2006. Thank you to all.”

More than 2,600 Academy Fellows represent all subspecialties of the microbial sciences. They are involved in basic and applied research, teaching, public health, industry, and government service.

Diggle’s research interests focus on cooperation and communication in microbes, and how these are related to virulence, biofilms, and antimicrobial resistance. He has a longstanding interest in understanding how the opportunistic pathogen Pseudomonas aeruginosa causes disease, and is especially interested in how this organism evolves during chronic infections such as those found in cystic fibrosis patients and chronic wounds.

Diggle currently serves as a senior editor on the editorial board of the journal Microbiology. He has previously served on the editorial boards of FEMS Microbiology Letters, BMC Microbiology, Microbiology Open, and Royal Society Open Science. He served as an elected member of the Microbiology Society Council from 2012-2016, and was also on their conference and policy committees.

In 2020, Diggle received the Cullen-Peck Scholar Award, which recognizes research accomplishments led by Georgia Tech College of Sciences faculty at the associate professor or advanced assistant professor level. Diggle was selected as an American Society for Microbiology Distinguished Lecturer in 2021.  

About Georgia Tech

The Georgia Institute of Technology, or Georgia Tech, is one of the top public research universities in the U.S., developing leaders who advance technology and improve the human condition.

The Institute offers business, computing, design, engineering, liberal arts, and sciences degrees. Its more than 46,000 students, representing 50 states and more than 150 countries, study at the main campus in Atlanta, at campuses in France and China, and through distance and online learning.

As a leading technological university, Georgia Tech is an engine of economic development for Georgia, the Southeast, and the nation, conducting more than $1 billion in research annually for government, industry, and society.

Steve Diggle, a professor in the School of Biological Sciences and director of Georgia Tech’s Center for Microbial Dynamics and Infection (CMDI), is one of 65 new 2023 Fellows of the American Academy of Microbiology (AAM).

The AAM is an honorific leadership group and think tank within the American Society of Microbiology (ASM). Fellows are elected annually through a highly selective, peer-review process, based on their records of scientific achievement and original contributions that have advanced microbiology. The Academy received 148 nominations this year. 

“On behalf of the School of Biological Sciences, I am thrilled to hear about Steve’s election to the American Academy of Microbiology,” said Todd Streelman, professor and chair of the School of Biological Sciences. “This is a tremendous feather in our cap and further illustrates the success of the Center for Microbial Dynamics and Infection, its faculty and students, on our campus.”

Arturo Casadevall, Chair of the Governors of the American Academy of Microbiology, notified Diggle of his election. The Academy “recognizes excellence, originality, service and leadership in the microbial sciences,” Casadevall wrote. “As a nominee, you were strongly supported by your nominators … Your election to the Academy this year is a mark of distinction.”

“I am delighted to be elected,” Diggle said. “It is an honor to be chosen by your peers to be part of this fellowship and to recognize the work my group has done over the years. The award would not have been possible without all the hard work and talents of many undergraduates, graduate students, postdocs and collaborators since I started my own group back in 2006. Thank you to all.”

More than 2,600 Academy Fellows represent all subspecialties of the microbial sciences. They are involved in basic and applied research, teaching, public health, industry, and government service.

Diggle’s research interests focus on cooperation and communication in microbes, and how these are related to virulence, biofilms, and antimicrobial resistance. He has a longstanding interest in understanding how the opportunistic pathogen Pseudomonas aeruginosa causes disease, and is especially interested in how this organism evolves during chronic infections such as those found in cystic fibrosis patients and chronic wounds.

Diggle currently serves as a senior editor on the editorial board of the journal Microbiology. He has previously served on the editorial boards of FEMS Microbiology Letters, BMC Microbiology, Microbiology Open, and Royal Society Open Science. He served as an elected member of the Microbiology Society Council from 2012-2016, and was also on their conference and policy committees.

In 2020, Diggle received the Cullen-Peck Scholar Award, which recognizes research accomplishments led by Georgia Tech College of Sciences faculty at the associate professor or advanced assistant professor level. Diggle was selected as an American Society for Microbiology Distinguished Lecturer in 2021.  

About Georgia Tech

The Georgia Institute of Technology, or Georgia Tech, is one of the top public research universities in the U.S., developing leaders who advance technology and improve the human condition.

The Institute offers business, computing, design, engineering, liberal arts, and sciences degrees. Its more than 46,000 students, representing 50 states and more than 150 countries, study at the main campus in Atlanta, at campuses in France and China, and through distance and online learning.

As a leading technological university, Georgia Tech is an engine of economic development for Georgia, the Southeast, and the nation, conducting more than $1 billion in research annually for government, industry, and society.

This news release first appeared in the Chinese Academy of Sciences newsroom, and has been tailored for Georgia Tech readers.

Mycorrhizal symbiosis — a symbiotic relationship that can exist between fungi and plant roots — helps plants expand their root surface area, giving plants greater access to nutrients and water. Although the first and foremost role of mycorrhizal symbiosis is to facilitate plant nutrition, scientists have not been clear how mycorrhizal types mediate the nutrient acquisition and interactions of coexisting trees in forests.  

To investigate this crucial relationship, Lingli Liu, a professor at the Institute of Botany of the Chinese Academy of Sciences (IBCAS) led an international, collaborative team, which included School of Biological Sciencesprofessor Lin Jiang. The team studied nutrient acquisition strategies of arbuscular mycorrhizae (AM) and ectomycorrhizal (EcM) trees in the Biodiversity–Ecosystem Functioning (BEF) experiment in a subtropical forest in China, where trees of the two mycorrhizal types were initially evenly planted in mixtures of two, four, eight, or 16 tree species.   

The researchers found that as the diversity of species increased, the net primary production (NPP) of EcM trees rapidly decreased, but the NPP of AM trees progressively increased, leading to the sheer dominance (>90%) of AM trees in the highest diversity treatment. 

The team's analyses further revealed that differences in mycorrhizal nutrient-acquisition strategies, both nutrient acquisition from soil and nutrient resorption within the plant, contribute to the competitive edge of AM trees over EcM ones.  

In addition, analysis of soil microbial communities showed that EcM-tree monocultures have a high abundance of symbiotic fungi, whereas AM-tree monocultures were dominated by saprotrophic and pathogenic fungi.  

According to the researchers, as tree richness increased, shifts in microbial communities, particularly a decrease in the relative abundance of Agaricomycetes (mainly EcM fungi), corresponded with a decrease in the NPP of EcM subcommunities, but had a relatively small impact on the NPP of AM subcommunities.  

These findings suggest that more efficient nutrient-acquisition strategies, rather than microbial-mediated negative plant-soil feedback, drive the dominance of AM trees in high-diversity ecosystems.  

This study, based on the world’s largest forest BEF experiment, provides novel data and an alternative mechanism for explaining why and how AM trees usually dominate in high-diversity subtropical forests.

These findings also have practical implications for species selection in tropical and subtropical reforestation—suggesting it is preferable to plant mixed AM trees, as they have a more efficient nutrient-acquisition strategy than EcM trees.  

This study was published as an online cover article in Sciences Advances on Jan. 19 and was funded by the Strategic Priority Research Program of CAS and the National Natural Science Foundation of China.

This news release first appeared in the Chinese Academy of Sciences newsroom, and has been tailored for Georgia Tech readers.

Mycorrhizal symbiosis — a symbiotic relationship that can exist between fungi and plant roots — helps plants expand their root surface area, giving plants greater access to nutrients and water. Although the first and foremost role of mycorrhizal symbiosis is to facilitate plant nutrition, scientists have not been clear how mycorrhizal types mediate the nutrient acquisition and interactions of coexisting trees in forests.  

To investigate this crucial relationship, Lingli Liu, a professor at the Institute of Botany of the Chinese Academy of Sciences (IBCAS) led an international, collaborative team, which included School of Biological Sciencesprofessor Lin Jiang. The team studied nutrient acquisition strategies of arbuscular mycorrhizae (AM) and ectomycorrhizal (EcM) trees in the Biodiversity–Ecosystem Functioning (BEF) experiment in a subtropical forest in China, where trees of the two mycorrhizal types were initially evenly planted in mixtures of two, four, eight, or 16 tree species.   

The researchers found that as the diversity of species increased, the net primary production (NPP) of EcM trees rapidly decreased, but the NPP of AM trees progressively increased, leading to the sheer dominance (>90%) of AM trees in the highest diversity treatment. 

The team's analyses further revealed that differences in mycorrhizal nutrient-acquisition strategies, both nutrient acquisition from soil and nutrient resorption within the plant, contribute to the competitive edge of AM trees over EcM ones.  

In addition, analysis of soil microbial communities showed that EcM-tree monocultures have a high abundance of symbiotic fungi, whereas AM-tree monocultures were dominated by saprotrophic and pathogenic fungi.  

According to the researchers, as tree richness increased, shifts in microbial communities, particularly a decrease in the relative abundance of Agaricomycetes (mainly EcM fungi), corresponded with a decrease in the NPP of EcM subcommunities, but had a relatively small impact on the NPP of AM subcommunities.  

These findings suggest that more efficient nutrient-acquisition strategies, rather than microbial-mediated negative plant-soil feedback, drive the dominance of AM trees in high-diversity ecosystems.  

This study, based on the world’s largest forest BEF experiment, provides novel data and an alternative mechanism for explaining why and how AM trees usually dominate in high-diversity subtropical forests.

These findings also have practical implications for species selection in tropical and subtropical reforestation—suggesting it is preferable to plant mixed AM trees, as they have a more efficient nutrient-acquisition strategy than EcM trees.  

This study was published as an online cover article in Sciences Advances on Jan. 19 and was funded by the Strategic Priority Research Program of CAS and the National Natural Science Foundation of China.

Wearable robotics promise to help older people retain their mobility and paraplegic patients regain theirs. They could help make humans stronger and faster. But, so far, they’re not great at keeping people from falling.

Human balance is a complicated dance, and even the most advanced robots and wearables like robotic exoskeletons have trouble replicating how our brains and bodies work together to keep us upright. A new study from researchers at the Georgia Institute of Technology and Emory University is taking the first step toward addressing the balance problem.

In a paper published Feb. 15 in Science Robotics, the group showed an ankle exoskeleton must react faster than our bodies to improve balance. Participants didn’t recover any more quickly when the exoskeleton delayed applying power until the same time muscles in the leg and ankle activated to restore balance.

Read about the study on the College of Engineering website.

Wearable robotics promise to help older people retain their mobility and paraplegic patients regain theirs. They could help make humans stronger and faster. But, so far, they’re not great at keeping people from falling.

Human balance is a complicated dance, and even the most advanced robots and wearables like robotic exoskeletons have trouble replicating how our brains and bodies work together to keep us upright. A new study from researchers at the Georgia Institute of Technology and Emory University is taking the first step toward addressing the balance problem.

In a paper published Feb. 15 in Science Robotics, the group showed an ankle exoskeleton must react faster than our bodies to improve balance. Participants didn’t recover any more quickly when the exoskeleton delayed applying power until the same time muscles in the leg and ankle activated to restore balance.

Read about the study on the College of Engineering website.

Over 15 faculty from the College of Sciences have been recognized for their teaching excellence by Georgia Tech’s Center for Teaching and Learning (CTL) in the Fall 2022 Course Instructor Opinion Survey (CIOS).

Using optional feedback from students, the survey serves to celebrate instructors who exhibit exceptional respect and concern for students, ability to stimulate interest in the subject matter of the course, and enthusiasm for course content.

Four College of Sciences faculty have won the Student Recognition of Excellence in Teaching: CIOS Awards, while 14 faculty have been named to the Student Recognition of Excellence in Teaching: Class of 1934 CIOS Honor Roll for Fall 2022. 

“To be named as a Student Recognition of Excellence in Teaching awardee, or appearing on the honor roll, is a significant accomplishment for our faculty,” shared David Collard, professor in the School of Chemistry and Biochemistry and senior associate dean in the College of Sciences. “Those who are recognized in this way have made strong connections with their students, both in lecture courses and in our instructional laboratories. I imagine that these are the faculty that their students will fondly remember long after graduation.”

College of Sciences recipients of the Fall 2022 “Student Recognition of Excellence in Teaching: CIOS Awards” include:

Small Classes:

Kirill Lobachev, associate professor, School of Biological Sciences
Deborah Santos, academic professional, School of Chemistry and Biochemistry
Samantha Wilson, academic professional, School of Earth and Atmospheric Sciences

Large Classes:

Emily Weigel, senior academic professional, School of Biological Sciences

College of Sciences recipients of the Fall 2022 “Student Recognition of Excellence in Teaching: Class of 1934 CIOS Honor Roll” include:

Small Classes: 

School of Mathematics — Austin Christian, postdoctoral researcher
School of Biological Sciences — Brian Hammer, associate professor; Colin Harrison, senior academic professional
Neuroscience — Alberto Stolfi, assistant professor, School of Biological Sciences

Large Classes:

School of Biological Sciences — Young-Hui Chang, professor and associate chair for Faculty Development; Adam Decker, senior academic professional and director of Anatomical Sciences
School of Mathematics — Miriam Kuzbary, postdoctoral researcher
Neuroscience — Qiliang He, postdoctoral researcher, School of Biological Sciences; Christina Ragan, lecturer, School of Biological Sciences
School of Psychology — Meghan Babcock, academic professional; Dobromir Rahnev, associate professor; Keaton Fletcher, assistant professor

Learn more about the Center for Teaching and Learning

Over 15 faculty from the College of Sciences have been recognized for their teaching excellence by Georgia Tech’s Center for Teaching and Learning (CTL) in the Fall 2022 Course Instructor Opinion Survey (CIOS).

Using optional feedback from students, the survey serves to celebrate instructors who exhibit exceptional respect and concern for students, ability to stimulate interest in the subject matter of the course, and enthusiasm for course content.

Four College of Sciences faculty have won the Student Recognition of Excellence in Teaching: CIOS Awards, while 14 faculty have been named to the Student Recognition of Excellence in Teaching: Class of 1934 CIOS Honor Roll for Fall 2022. 

“To be named as a Student Recognition of Excellence in Teaching awardee, or appearing on the honor roll, is a significant accomplishment for our faculty,” shared David Collard, professor in the School of Chemistry and Biochemistry and senior associate dean in the College of Sciences. “Those who are recognized in this way have made strong connections with their students, both in lecture courses and in our instructional laboratories. I imagine that these are the faculty that their students will fondly remember long after graduation.”

College of Sciences recipients of the Fall 2022 “Student Recognition of Excellence in Teaching: CIOS Awards” include:

Small Classes:

Kirill Lobachev, associate professor, School of Biological Sciences
Deborah Santos, academic professional, School of Chemistry and Biochemistry
Samantha Wilson, academic professional, School of Earth and Atmospheric Sciences

Large Classes:

Emily Weigel, senior academic professional, School of Biological Sciences

College of Sciences recipients of the Fall 2022 “Student Recognition of Excellence in Teaching: Class of 1934 CIOS Honor Roll” include:

Small Classes: 

School of Mathematics — Austin Christian, postdoctoral researcher
School of Biological Sciences — Brian Hammer, associate professor; Colin Harrison, senior academic professional
Neuroscience — Alberto Stolfi, assistant professor, School of Biological Sciences

Large Classes:

School of Biological Sciences — Young-Hui Chang, professor and associate chair for Faculty Development; Adam Decker, senior academic professional and director of Anatomical Sciences
School of Mathematics — Miriam Kuzbary, postdoctoral researcher
Neuroscience — Qiliang He, postdoctoral researcher, School of Biological Sciences; Christina Ragan, lecturer, School of Biological Sciences
School of Psychology — Meghan Babcock, academic professional; Dobromir Rahnev, associate professor; Keaton Fletcher, assistant professor

Learn more about the Center for Teaching and Learning

Plants, like animals and people, seek refuge from climate change. And when they move, they take entire ecosystems with them. To understand why and how plants have trekked across landscapes throughout time, researchers at the forefront of conservation are calling for a new framework. The key to protecting biodiversity in the future may be through understanding the past.

Jenny McGuire, assistant professor in the Schools of Biological Sciences and Earth and Atmospheric Sciences at Georgia Tech, spearheaded a special feature on the topic of biodiversity in The Proceedings of the National Academy of Sciences along with colleagues in Texas, Norway, and Argentina. In the special feature, “The Past as a Lens for Biodiversity Conservation on a Dynamically Changing Planet,” McGuire and her collaborators highlight the outstanding questions that must be addressed for successful future conservation efforts. The feature brings together conservation research that illuminates the complex and constantly evolving dynamics brought on by climate change and the ever-shifting ways humans use land. These factors, McGuire said, interact over time to create dynamic changes and illustrate the need to incorporate temporal perspectives into conservation strategies by looking deep into the past.

One example of this work highlighted in the journal is McGuire’s research about plants in North America, which investigates how and why they’ve moved across geography over time, where they’re heading, and why it’s important.

“Plants are shifting their geographic ranges, and this is happening whether we realize it or not,” McGuire said. “As seeds fall or are transported to distant places, the likelihood that the plant’s seed is going to be able to survive and grow is changing as climates are changing. Studying plants’ niche dynamics over thousands of years can help us understand how species adapt to climate change and can teach us how to protect and maintain biodiversity in the face of rapid climate change to come.”

Climate Fidelity: A New Metric for Understanding Vulnerability

The first step is to understand which type of plants exhibit what McGuire terms “climate fidelity,” and which do not. If a plant has climate fidelity, it means that the plant stays loyal to its preferred climatic niche, often migrating across geographies over thousands of years to keep up with its ideal habitat. Plants that don’t exhibit climate fidelity tend to adapt locally in the face of climate change. Being loyal to one’s climate, it turns out, doesn’t necessarily mean being loyal to a particular place.

To investigate the case of trees, McGuire and former Georgia Tech postdoctoral scholar Yue Wang (associate professor in the School of Ecology at Sun Yat-sen University in China) studied pollen data from the Neotoma Paleoecology Database, which contains pollen fossil data from sediment cores across North America. Each sediment core is sampled, layer by layer, producing a series of pollen data from different times throughout history. The data also contains breakdowns of the relative abundance of different types of plants represented by the pollen types – pine versus oak versus grass, for example – painting a picture of what types of plants were present in that location and when.

McGuire and Wang looked at data from 13,240 fossil pollen samples taken from 337 locations across the entirety of North America. For each of the 16 major plant taxa in North America, they divided the pollen data into six distinct chunks or “bins” of time of 4,000 years, starting from 18,000 years ago up to the present day. Wang used the data to identify all climate sites containing fossil pollen for any individual type of tree – such as oak, for example – for each period. Then, Wang looked at how each tree’s climate changed from one period to the next. Wang did this by comparing the locations of pollen types between adjacent time periods, which enabled the team to identify how and why each type of tree’s climate changed over time.

“This process allowed us to see the climate fidelity of these different plant taxa, showing that certain plants maintain very consistent climatic niches, even when climate is changing rapidly,” Wang said.

For example, their findings showed that when North American glaciers were retreating 18,000 years ago, spruce and alder trees moved northward to maintain the cool temperatures of their habitats.

Crucially, McGuire and Wang found that most plant species in North America have exhibited long-term climate fidelity over the past 18,000 years. They also found that plants that migrated farther did a better job of tracking climate during periods of change.

But some plants fared better than others. For example, the small seeds of willow trees can fly over long distances – enabling them to track their preferred climates very effectively. But the large seeds of ash trees, for example, can only be dispersed short distances from parent trees, hindering their ability to track climate. Habitat disruptions from humans could make it even more difficult for ash trees to be able to take hold in new regions. If there are no adjacent habitats for ash trees, their seeds are under pressure to move even farther – a particular challenge for ash, which slows their migration movements even more.

Protecting the Fabric of Life

On the bright side, by identifying which plants have historically been most sensitive to changing climates, McGuire and Wang’s research can help conservation organizations like The Nature Conservancy prioritize land where biodiversity is most vulnerable to climate change.

As a final step, McGuire and Wang identified “climate fidelity hotspots,” regions that have historically exhibited strong climate fidelity whose plants will most urgently need to move as their climates change. They compared these hotspots to climate-resilient regions identified by The Nature Conservancy that could serve as refuge areas for those plants. While plants in these resilient regions can initially adapt to impending climate change by shifting their distributions locally, the plants will likely face major challenges when a region’s climate change capacity is exceeded due to lack of connectivity and habitat disruptions from humans. Refining these priorities helps stakeholders identify efficient strategies for allowing the fabric of life to thrive.

“I think that understanding climate fidelity, while a new and different idea, will be very important going forward, especially when thinking about how to prioritize protecting different plants in the face of climate change,” McGuire said. “It is important to be able to see that some plants and animals are more vulnerable to climate change, and this information can help build stronger strategies for protecting the biodiversity on the planet.”

Citation: Yue Wang, Silvia Pineda-Munoz, and Jenny L. McGuire, "Plants maintain climate fidelity in the face of dynamic climate change." PNAS (2023).

DOI: doi.org/10.1073/pnas.2201946119