Tuesday, March 19, 2024

UMD researchers develop genomic method of monitoring for pesticide resistance

Study identifies genomic changes responsible for Bt resistance in corn earworm, and finds VIP3 contamination in non-Bt corn could trigger resistance

Peer-Reviewed Publication

UNIVERSITY OF MARYLAND

Farmers rely on pesticides to control agricultural pests. But insects often develop resistance to the toxins in pesticides. University of Maryland researchers have developed and successfully tested a strategy for using genomics to monitor for and identify emerging resistance to specific toxins early, well before it becomes a widespread problem. The work will enable farmers to mitigate resistance and prolong the effectiveness of pest management tools.

The research was published on March 18, 2024, in the Proceedings of the National Academies of Science.

“Global food security and protection of public health rely on the availability of effective strategies to manage pests, but as it currently stands, the evolution of resistance across many pests of agricultural and public health importance is outpacing the rate at which we can discover new technologies to manage them,” said Megan Fritz, an associate professor of entomology at UMD and senior author of the study. “I'm really excited about this study, because we're developing the framework for use of genomic approaches to monitor and manage resistance in any system.”

For many years, farmers have been planting corn that has been bred to contain natural chemicals that are harmless to humans but toxic to many pests, including the voracious, crop-damaging caterpillar known as corn earworm. But corn earworm has developed widespread resistance to some of these toxins, and it is unclear how farmers can prolong effectiveness of the remaining toxins, largely because it is difficult to monitor and identify emerging resistance before it’s too late.

In a previous paper in 2021, Fritz and her team showed that genomic tools could be used to detect signs that resistance was evolving in corn earworms four years prior to the insect being able to cause widespread failure in managed crops. But the approaches the team used were more suited for research than widespread use in agriculture, because they required two separate experiments to distinguish the genomic changes linked to toxin resistance from those associated with other factors such as environmental changes.

For this study, the researchers modified their strategy and identified the specific genomic changes responsible for resistance to multiple types of toxins called Bt toxins. Corn earworm have largely developed resistance to two of the three Bt toxins, Cry1Ab and Cry1F. The third toxin, known as Vip3A, is the only Bt toxin that remains effective against corn earworm.

To test their new strategy, the researchers first sequenced the genomes of corn earworm collected from corn that expressed only individual Cry toxins and compared it to those collected from non-toxin-expressing corn.

They found that genomic signatures of resistance to toxins could be detected after only a single generation of exposure.The team also identified specific genes with mutations that could explain toxin resistance. These genes encode digestive enzymes that chop Cry toxins into smaller pieces, perhaps preventing them from killing the caterpillars.

Fritz and her team then used the same genome sequencing approach to identify changes in corn earworm collected from corn expressing the Vip3A toxin. Not only did they identify early warning signs of emerging resistance to Vip3A, but they also described how common strategies for preventing resistance could actually be facilitating Vip3A resistance.

Non-Bt expressing corn is often planted near Bt corn, so that corn earworm have a refuge from Bt toxins. It was believed that corn earworm feeding on non-Bt corn would not be exposed to Vip3A and thus maintain their susceptibility to it. That would allow susceptible corn earworm to persist and multiply in greater abundance than resistant corn earworm. The thinking is that this strategy prevents or slows the buildup of resistance in a corn earworm population.

However, Fritz’s team found that non-Bt corn planted within four rows of Bt corn expresses some level of Bt toxins, including Vip3A. This is likely due to wind pollination that causes Bt pollen to land on non-Bt corn. As they grow, some non-Bt kernels are “contaminated” and express Vip3A toxin. The team’s results suggest that inter-planting non-Bt corn with Bt corn to prevent resistance, sometimes called “seed-blended refuge” may in fact expose caterpillars to low levels of Vip3A and hasten the emergence of Vip3A resistance.

Fritz’s work indicates that true resistance prevention might require changing strategies, both for how Bt corn is planted, as well as how resistance is monitored. This study offers a genomic testing framework for monitoring the success of resistance prevention in the future.

This work was funded by USDA NIFA 542 Biotechnology Risk Assessment Grants 2018-33522-28741 and 2019-33522-29992.

This study was conducted with colleagues from University of North Carolina. Post Doctoral Associate Katherine Taylor, from UMD Department of Entomology is a co-author on this study.

JOURNAL

Proceedings of the National Academy of Sciences

DOI

10.1073/pnas.2319838121

METHOD OF RESEARCH

Experimental study

SUBJECT OF RESEARCH

Not applicable

ARTICLE TITLE

Cross-pollination in seed blended refuge and selection for Vip3A resistance in a lepidopteran pest as detected by genomic monitoring

ARTICLE PUBLICATION DATE

18-Mar-2024

Virtual reality better than video for evoking fear, spurring climate action

Virtual reality may prove more effective at promoting environmental advocacy by evoking fear, according to new research

PENN STATE

VR More Effective at Advocacy when Evoking Fear — VIDEO:
DEPICTING WORST-CASE CLIMATE SCENARIOS, LIKE THE BLEACHED CORALS IN THE VIDEO ABOVE, MAY BETTER MOTIVATE PEOPLE TO SUPPORT ENVIRONMENTAL POLICIES WHEN DELIVERED VIA VIRTUAL REALITY, ACCORDING TO RESEARCHERS.
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CREDIT: COURTESY OF PEJMAN SAJJADI, MENG QI LIAO AND S. SHYAM SUNDAR, PENN STATE.

UNIVERSITY PARK, Pa. — Depicting worst-case climate scenarios like expanding deserts and dying coral reefs may better motivate people to support environmental policies when delivered via virtual reality, according to a research team led by Penn State that studied how VR and message framing affect the impact of environmental advocacy communications. The study findings, published in the journal Science Communication, may help advocacy groups decide how best to frame and deliver their messages.

The researchers examined individuals’ responses to climate change messaging when delivered through traditional video and desktop virtual reality — VR programs like Google Earth that can run on a mobile phone or computer. They found that loss-framed messages, or those that transitioned from a positive to negative climate scenario to emphasize what humanity has to lose, were more effective at convincing people to support environmental policies when delivered via VR. Gain-framed messages, which depict a more hope-inspiring change from a negative to a positive environmental outcome, had a greater impact when delivered through traditional video format.

“The findings of this study suggest that in terms of seeking support for climate change policy, it’s the combination of the medium and the message that can determine the most effective solution for promoting a particular advocacy message,” said S. Shyam Sundar, senior author and the James P. Jimirro Professor of Media Effects at Penn State. “For consumers, the media literacy message here is that you’re much more emotionally vulnerable or more likely to be swayed by a VR presentation of an advocacy message, especially if the presentation focuses on loss.”

The research team created two desktop virtual reality experiences, one gain-framed and one loss-framed, using the Unity3D game engine. In addition to the loss and gain framed messages, the VR programs also depicted healthy and unhealthy coral reef ecosystems, accompanied by lighter or darker ambient lighting and hopeful or sad audio, and allowed users to explore the aquatic environments. The researchers used the programs to record loss- and gain-framed videos based on the VR experiences.

They chose to depict coral reef ecosystems because corals are one of the species most endangered by the effects of climate change and far removed from many peoples’ lived experiences.

“It’s difficult to communicate environmental issues to non-scientists because the consequences are usually long-term and not easily foreseeable,” said Mengqi Liao, first author and doctoral candidate in mass communication at Penn State. “Not to mention that it’s usually very hard to bring people to an environment that has been damaged by climate change, such as coral reefs, which, based on decades of data collected in part from NASA’s airborne and satellite missions, have declined rapidly over the past 30 years. This is where VR comes in handy. You can bring the environment to people and show them what would happen if we fail to act.”

The researchers recruited 130 participants from Amazon Mechanical Turk and asked them to complete a pre-questionnaire to measure variables like attitudes toward climate change and political ideology. Then they randomly assigned participants to a video or desktop VR experience. Within each of these groups, half saw the gain-framed messaging while the other half saw the loss-framed messaging.

Participants in the loss-framed experiences saw healthy then unhealthy coral ecosystems, with a message explaining the negative consequences of failing to adopt climate change mitigation behaviors. Those in the gain-framed versions saw unhealthy then healthy coral ecosystems, with messages explaining the positive impacts of adopting climate policies. After completing the experiences, participants answered a questionnaire to measure how likely they would be to support environmental policies.

The researchers found that loss-framed messages were most effective at motivating people to support climate change mitigation policies when delivered through desktop VR. Gain-framed messages were most effective when delivered in video format.

Virtual reality is inherently interesting and attention-grabbing, and it has a low cognitive barrier to entry — even small children with limited reading ability can use it, according to Sundar.

“The nickname for VR is empathy machine. It can generate better empathy because you’re one with the environment,” he said. “Loss-framed messaging tends to be more effective, more about emotions like fear rather than hope. Sometimes fear can be better represented in visually resplendent media like VR.”

Gain-framed messaging, on the other hand, tends to involve more thinking about the consequences of action or inaction for the environment and what humans have to gain, Sundar explained. The movement and interactivity that come with VR may distract too much from the kind of thinking needed to process the potential gains highlighted in that type of messaging, which is better suited for traditional video or text.

“With politicized topics like climate change, people are guided by their motivated reasoning, whereby an individual readily accepts information consistent with their worldview and ignores or rejects information that is inconsistent with that view,” Liao said. “Our study suggests that showing stark portrayals of environmental loss can be persuasive in spurring people into action, to support climate change issues regardless of their pre-existing worldviews.”

Pejman Sajjadi, who completed the work as a postdoctoral scholar at Penn State and is now with Meta, also contributed to the research.

JOURNAL

Science Communication

DOI

10.1177/10755470241229453

ARTICLE TITLE

How Does VR Affect Emotional Appeal and Persuasiveness of Gain Versus Loss-Framed Messages?

Global wildlife study during COVID-19 shows rural animals are more sensitive to human activity

Plant-eating animals more active, carnivores more cautious around humans

Peer-Reviewed Publication

UNIVERSITY OF BRITISH COLUMBIA

Wolverine seen along a hiking trail — IMAGE:
A WOLVERINE SEEN ALONG A HIKING TRAIL DURING CLOSURE OF THE POPULAR JOFFRE LAKES PROVINCIAL PARK, BRITISH COLUMBIA, CANADA
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CREDIT: CREDIT: COLE BURTON, UBC WILDCO

One of the largest studies on wildlife activity—involving more than 220 researchers, 163 mammal species and 5,000 camera traps worldwide—reveals that wild animals react differently to humans depending on where the animals live and what they eat.

Bigger herbivores—plant-eating animals like deer or moose—tend to become more active when humans are around, while meat-eaters like wolves or wolverines tend to be less active, preferring to avoid risky encounters.

Urban animals like deer or raccoons may become more active around people, as they get used to human presence and find food like garbage or plants, which they can access at night. But animals living farther from cities and other developed areas are more wary of encountering people.

Wildlife during the pandemic ‘anthropause’

The new study, a collaboration across researchers from 161 institutions, used data from before and during the COVID-19 lockdowns to examine wildlife behaviour amid changing human activity levels.

“COVID-19 mobility restrictions gave researchers a truly unique opportunity to study how animals responded when the number of people sharing their landscape changed drastically over a relatively short period,” said lead author Dr. Cole Burton, an associate professor of forest resources management at UBC and Canada Research Chair in Terrestrial Mammal Conservation.

“And contrary to the popular narratives that emerged around that time, we did not see an overall pattern of ‘wildlife running free’ while humans sheltered in place. Rather, we saw great variation in activity patterns of people and wildlife, with the most striking trends being that animal responses depended on landscape conditions and their position in the food chain.”

In Canada, researchers monitoring areas such as Banff and Pacific Rim national parks, Cathedral, Golden Ears and South Chilcotin Mountains provincial parks, and the Sea-to-Sky corridor in B.C. found that carnivores like wolverines, wolves and cougars were generally less active when human activity was higher.

In several of these parks, and in cities such as Edmonton, large herbivores often increased their activity but became more nocturnal with the presence of more humans. Large carnivores were notably absent from the most human-dominated landscapes.

Preventing conflict through smart conservation measures

These findings highlight the importance of measures to minimize any detrimental effects of human disturbance on wildlife, including reducing overlaps that might lead to conflict.

“In remote areas with limited human infrastructure, the effects of our actual presence on wildlife may be particularly strong. To give wild animals the space they need, we may consider setting aside protected areas or movement corridors free of human activity, or consider seasonal restrictions, like temporary closures of campsites or hiking trails during migratory or breeding seasons,” said study co-author and UBC biologist Dr. Kaitlyn Gaynor.

She added that strategies must also fit specific species and locations. In more remote areas, keeping human activity low will be necessary to protect sensitive species. In areas where people and animals overlap more, such as cities, nighttime is an important refuge for wildlife, and keeping it that way can help species survive. Efforts may focus on reducing human-wildlife conflict after dark, such as more secure storage of trash bins to reduce the number of animals getting into human food sources, or use of road mitigation measures to reduce vehicle collisions.

The findings are particularly useful amid the surge in global travel and outdoor recreation post-pandemic, Dr. Burton added.

“Understanding how wildlife respond to human activity in various contexts helps us develop effective conservation plans that have local and global impact. For that reason, we are working to improve wildlife monitoring systems using tools like the camera traps that made it possible to observe animal behaviours during the pandemic.”

The study was published today in Nature Ecology and Evolution

Bison camera trapped in Montana, USA

Media assets:

Camera trap images, infographic, video: Dropbox

JOURNAL

Nature Ecology & Evolution

DOI

10.1038/s41559-024-02363-2

METHOD OF RESEARCH

Observational study

SUBJECT OF RESEARCH

Animals

ARTICLE TITLE

Mammal responses to global changes in human activity vary by trophic group and landscape

ARTICLE PUBLICATION DATE

18-Mar-2024

Harnessing hydrogen at life’s origin

How hydrogen gas, the energy of the future, provided energy 4 billion years ago

HEINRICH-HEINE UNIVERSITY DUESSELDORF

Sulis formation in the Lost City hydrothermal field — IMAGE:
IMAGE FROM THE SULIS FORMATION IN THE LOST CITY HYDROTHERMAL FIELD, AN ALKALINE HYDROTHERMAL VENT THAT PRODUCES HYDROGEN.
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CREDIT: COURTESY OF SUSAN LANG, U. OF SOUTH CAROLINA /NSF/ROV JASON 2018 © WOODS HOLE OCEANOGRAPHIC INSTITUTION

A new report uncovers how hydrogen gas, the energy of the future, provided energy in the past, at the origin of life 4 billion years ago. Hydrogen gas is clean fuel. It burns with oxygen in the air to provide energy with no CO2. Hydrogen is a key to sustainable energy for the future. Though humans are just now coming to realize the benefits of hydrogen gas (H2 in chemical shorthand), microbes have known that H2 is good fuel for as long as there has been life on Earth. Hydrogen is ancient energy. The very first cells on Earth lived from H2 produced in hydrothermal vents, using the reaction of H2 with CO2 to make the molecules of life. Microbes that thrive from the reaction of H2 and CO2 can live in total darkness, inhabiting spooky, primordial habitats like deep-sea hydrothermal vents or hot rock formations deep within the Earth’s crust, environments where many scientists think that life itself arose. Surprising new insights about how the first cells on Earth came to harness H2 as an energy source are now reported in PNAS. The new study comes from the team of William F. Martin at the University of Düsseldorf and Martina Preiner at the Max Planck Institute (MPI) for Terrestrial Microbiology in Marburg with support from collaborators in Germany and Asia.

In order to harvest energy, cells first have to push the electrons from H2 energetically uphill. “That is like asking a river to flow uphill instead of downhill, so cells need engineered solutions,” explains one of the three first authors of the study, Max Brabender. How cells solve that problem was discovered only 15 years ago by Wolfgang Buckel together with his colleague Rolf Thauer in Marburg. They found that cells send the two electrons in hydrogen down different paths. One electron goes far downhill, so far downhill that it sets something like a pulley (or a siphon) in motion that can pull the other electron energetically uphill. This process is called electron bifurcation. In cells, it requires several enzymes that send the electrons uphill to an ancient and essential biological electron carrier called ferredoxin. The new study shows that at pH 8.5, typical of naturally alkaline vents, “no proteins are required,” explains Buckel, co-author on the study, “the H–H bond of H2 splits on the iron surface, generating protons that are consumed by the alkaline water and electrons that are then easily transferred directly to ferredoxin.”

How an energetically uphill reaction could have worked in early evolution, before there were enzymes or cells, has been a very tough puzzle. “Several different theories have proposed how the environment might have pushed electrons energetically uphill to ferredoxin before the origin of electron bifurcation,“ says Martin, “we have identified a process that could not be simpler and that works in the natural conditions of hydrothermal vents”.

Since the discovery of electron bifurcation, scientists have found that the process is both ancient and absolutely essential in microbes that live from H2. The vexing problem for evolutionarily-minded chemists like Martina Preiner, whose team in Marburg focusses on the impact of the environment on reactions that microbes use today and possibly used at life’s origin, is: How was H2 harnessed for CO2 fixing pathways before there were complicated proteins? “Metals provide answers,”, she says, “at the onset of life, metals under ancient environmental conditions can send the electrons from H2 uphill, and we can see relicts of that primordial chemistry preserved in the biology of modern cells.” But metals alone are not enough. “H2 needs to be produced by the environment as well” adds co-first author Delfina Pereira from Preiner’s lab. Such environments are found in hydrothermal vents, where water interacts with iron-containing rocks to make H2 and where microbes still live today from that hydrogen as their source of energy.

Hydrothermal vents, both modern and ancient, generate H2 in such large amounts that the gas can turn iron-containing minerals into shiny metallic iron. “That hydrogen can make metallic iron out of minerals is no secret” says Harun Tüysüz, expert for high-tech materials at the Max-Planck-Institut für Kohlenforschung Mülheim and coauthor on the study. “Many processes in chemical industry use H2 to make metals out of minerals during the reaction.” The surprise is that nature does this too, especially at hydrothermal vents, and that this naturally deposited iron could have played a crucial role at the origin of life.

Iron was the only metal identified in the new study that was able to send the electrons in H2 uphill to ferredoxin. But the reaction only works under alkaline conditions like those in a certain type of hydrothermal vents. Natalia Mrnjavac from the Düsseldorf group and co-first author on the study points out: “This fits well with the theory that life arose in such environments. The most exciting thing is that such simple chemical reactions can close an important gap in understanding the complex process of origins, and that we can see those reactions working under the conditions of ancient hydrothermal vents in the laboratory today.”

JOURNAL

Proceedings of the National Academy of Sciences

DOI

10.1073/pnas.2318969121

METHOD OF RESEARCH

Experimental study

SUBJECT OF RESEARCH

Not applicable

ARTICLE TITLE

Ferredoxin reduction by hydrogen with iron functions as an evolutionary precursor of flavin-based electron bifurcation

ARTICLE PUBLICATION DATE

18-Mar-2024

Alternative tidal wetlands in plain sight overlooked Blue Carbon superstars

AMERICAN INSTITUTE OF BIOLOGICAL SCIENCES

Blue Carbon projects are expanding globally; however, demand for credits outweighs the available credits for purchase.

Currently, only three types of wetlands are considered Blue Carbon ecosystems: mangroves, saltmarsh and seagrass.

However, other tidal wetlands also comply with the characteristics of what is considered Blue Carbon, such as tidal freshwater wetlands, transitional forests and brackish marshes.

In a new study, scientists from Australia, Indonesia, Singapore, South Africa, Vietnam, the US and Mexico have highlighted the increasing opportunities for Blue Carbon projects for the conservation, restoration and improved management of highly threatened wetlands.

Led by Griffith University’s Dr Fernanda Adame, from the Australian Rivers Institute, the team compiled information on the biophysical characteristics of various tidal wetlands and their managing potential, and concluded that all wetlands below the highest astronomical tide, directly or indirectly influenced by tides, should be classified as blue carbon ecosystems.

“By recognising and prioritising their protection and restoration, we can unlock myriad benefits, including biodiversity conservation,” she said.

"Our research provides compelling evidence that tidal wetlands, beyond mangroves, saltmarshes, and seagrass, exhibit characteristics aligned with Blue Carbon.

"These ecosystems store significant amounts of carbon dioxide in their soils and aboveground biomass, while emitting low levels of greenhouse gases."

Blue carbon projects, centred around the management of mangroves, saltmarshes, and seagrass, have garnered attention for their ability to enhance carbon sequestration and reduce greenhouse gas emissions.

Coastal wetlands in particular have emerged as critical players in the fight against climate change, offering promising opportunities to mitigate atmospheric greenhouse gases.

“By managing these ecosystems strategically, not only can we reduce curb emissions, but we can also make significant strides towards achieving the United Nations Sustainable Development Goals,” Dr Adame said.

By incorporating all tidal wetlands into blue carbon initiatives, we can maximize their potential as carbon sinks and fortify our efforts in combating climate change.

“This inclusive approach not only safeguards our environment but also offers opportunities for sustainable development and conservation.”

The paper ‘All tidal wetlands are blue carbon ecosystems’ has been published in BioScience.