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Researchers determine groundbreaking new way to identify pesticide resistance: ‘I’m really excited about this study’
Tina Deines
Sun, April 7, 2024 at 12:00 PM CDT·2 min read
Researchers are exploring an exciting new approach that uses genomics to help monitor and identify pesticide resistance in the insects that munch on our crops.
Pest management is important for farmers, but insects often become immune to pesticides, making them less effective. In the new research, published in the Proceedings of the National Academy of Science, a team of scientists from the University of Maryland (UMD) presents a new strategy that analyzes genomic changes in pests to monitor and identify emerging resistance to specific toxins early on.
They zoned in on one pest in particular: the corn earworm, a crop-destroying caterpillar that has developed widespread resistance to a number of natural toxins bred into corn. They were able to identify resistance to toxins among these caterpillars after just a single generation of exposure. They also identified how common strategies for avoiding resistance could actually be doing the opposite.
“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 senior author Megan Fritz, an associate professor of entomology at UMD, per Phys.org. “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.”
The new research is one of many that is helping farmers to produce more successful harvests.
For instance, a team of American and Chinese researchers found a way to genetically engineer plants that can survive heat waves. University of Minnesota scientists are on their way to developing a “Super Grape” that could stave off powdery mildew and reduce the need for fungicide.
These developments in agriculture come at a critically important time — as our planet continues to warm, there are frequent heat waves and droughts, which threaten our food security. Plus, climate change scientists predict that a warming world will drive a surge in certain insect pests that attack our crops, further threatening food security and causing economic losses for those in the agricultural sector.
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Bees and Biocontrol: A Leap Towards Sustainable Agriculture
In an innovative approach to agriculture, Agrobío SL is trialing a natural precision agriculture system that uses bees for biocontrol to combat the Botrytis cinerea pathogen. This method promises a leap towards sustainable farming by reducing chemical pesticides, increasing crop yield, and protecting the environment.
Bees and Biocontrol: A Leap Towards Sustainable Agriculture
In a groundbreaking approach to agriculture and pest control, Agrobío SL, a pioneering entity in the field of sustainable agriculture, has embarked on a trial that could mark a significant shift in how crops are protected and nurtured. This initiative, launched in December, leverages the innovative Natural Precision Agriculture System developed by Bee Vectoring Technologies International Inc. (BVT), aiming to tackle the pervasive threat of Botrytis cinerea, commonly known as gray mold. This pathogen, notorious for affecting over 1000 plant species, poses a substantial challenge to crop productivity and sustainability worldwide.
The Dawn of a New Era in Crop Protection
The collaboration is part of Agrobío’s contribution to the ADOPT-IPM project, an undertaking funded by the European Union, designed to refine and enhance Integrated Pest Management (IPM) strategies. By integrating BVT’s natural precision agriculture system into their greenhouse tomato crops in Spain, Agrobío is not just combating a prevalent plant disease but is also pioneering a shift towards more sustainable, efficient, and environmentally friendly farming practices. The eight to ten-month trial will critically assess the system’s effectiveness in managing Botrytis compared to traditional chemical-based spray programs, promising a potential paradigm shift in agricultural pest management.
A Symbiotic Solution Harnessing Nature’s Ingenuity
At the heart of BVT’s system is a remarkably innovative method of delivering biological pesticide alternatives directly to crops, utilizing commercially grown bees. This eco-friendly approach not only aims to reduce the reliance on chemical pesticides but also seeks to enhance crop yield and protect the ecosystem. By exploiting the natural behavior of bees, the system ensures precise and targeted delivery of natural pest control agents, minimizing waste and maximizing effectiveness. This method presents a win-win scenario, safeguarding both plant health and the surrounding environment, thereby supporting the broader goals of sustainability and ecological balance.
Implications for the Future of Agriculture
The trial by Agrobío not only signifies a critical step forward in the fight against plant pathogens like Botrytis cinerea but also embodies the broader movement towards natural precision agriculture. As the results of this trial are eagerly awaited, the implications for agricultural practices are profound. Success could herald a new age of farming where efficiency, sustainability, and environmental stewardship are not mutually exclusive but are instead seamlessly integrated into a holistic approach to crop management and protection. Moreover, the adoption of such innovative solutions underscores the potential for technology and nature to work in harmony, offering promising avenues for addressing some of the most pressing challenges in contemporary agriculture.
As Agrobío SL and Bee Vectoring Technologies International Inc. navigate through this trailblazing trial, the eyes of the world are on them, anticipating the outcomes that might not just revolutionize the way we protect our crops but also how we envisage the future of farming. With a focus on harmony with nature, efficiency, and sustainability, this venture into using bees for biocontrol represents not just a step but a leap towards a future where agriculture works hand in hand with nature, for a healthier planet and a more sustainable tomorrow.
‘Tiny titans of the farm’: Nanotechnology poised to revolutionize agriculture, but cautious steps needed
on February 18, 2024
In a landmark review, scientists highlight how nanotechnology is set to transform the global agricultural sector, addressing challenges posed by climate change and rapid population growth. A comprehensive review by a research team at the School of Biological Sciences, Central University of Kerala in India sheds light on how this cutting-edge technology is poised to revolutionize farming practices, ensuring food security for the rapidly growing global population.
According to the research team, the specter of food insecurity looms large, fueled by a potent cocktail of climate change, population growth, and unsustainable farming practices. Yet, amidst the challenges, a glimmer of hope emerges from the world of the infinitely small: nanotechnology. This powerful science, manipulating matter at the atomic and molecular level, holds the potential to transform agriculture, boosting yields, minimizing environmental impact, and ensuring food security for generations to come.
Imagine a future where farmers wield tools not unlike magic wands. Nano-fertilizers deliver nutrients directly to plant roots, eliminating waste and pollution. Miniscule biosensors embedded in soil whisper vital information about nutrients and moisture levels, guiding irrigation with laser precision. Even the genetic makeup of crops could be subtly tweaked, imbuing them with resilience against pests and diseases.
These aren’t mere futuristic fantasies; they are the tangible promises offered by nanotechnology. Researchers are already exploring a dazzling array of applications. Nano-capsules loaded with pesticides target specific pests, minimizing collateral damage to beneficial insects and the environment. Nano-coated seeds sprout faster and resist disease, while nanoscale materials woven into packaging extend the shelf life of fruits and vegetables.
The environmental benefits are equally compelling. By delivering nutrients with pinpoint accuracy, nanotechnology promises to drastically reduce agricultural runoff, a major source of water pollution. Additionally, the development of more precise pesticides and the potential for pest-resistant crops could translate to significant reductions in harmful chemicals used in conventional agriculture.
However, with great power comes great responsibility. While the potential of nanotechnology is undeniable, concerns linger. The long-term impact of nanoparticles on the environment and human health remains unclear. Questions hang over potential toxicity, unintended ecological consequences, and the possibility of nanoparticles entering the food chain.
Furthermore, ethical considerations cannot be ignored. The large-scale adoption of nanotechnology in agriculture raises questions about corporate control, access to technology for small farmers, and potential economic disruptions.
Acknowledging these concerns is crucial. Responsible development and rigorous research are paramount. We must ensure public engagement, transparent dialogues, and robust regulatory frameworks to guide the path of nanotechnology in agriculture.
Imagine a scenario where diverse groups of farmers, scientists, policymakers, and consumers collaborate to unlock the potential of nanotechnology while mitigating its risks. This collective effort could pave the way for a future where food security is not a dream but a reality, achieved through sustainable practices that nourish both people and the planet.
The journey towards this future will not be easy. It will require careful navigation, but the potential rewards are too significant to ignore. In the face of mounting food security challenges, nanotechnology offers a beacon of hope, but only if we approach it with wisdom, precaution, and a collective commitment to responsible development. The tiny titans of the farm stand ready, waiting for us to decide whether they will be wielded for abundance or allowed to remain untapped potential.
New evidence that insect wings may have evolved from gills
Phys.Org
by Biology Centre of the Czech Academy of Sciences How did insect wings originate? This is a question that represents an unsolved mystery of insect evolution. Despite many years of research, it is still not entirely clear from which body structure insect wings actually evolved and what their original function was when they were not yet efficient enough to perform active flight.
Scientists from the Biology Centre of the Czech Academy of Sciences (BC CAS) were also involved in looking for answers to these questions in newly discovered prehistoric fossils of an ancient group of insects.
There are various hypotheses regarding the origin of insect wings. To some extent, they depend on the fact whether the common ancestor of winged insects lived in an aquatic or terrestrial environment. While several studies connect the origin of wings with the gills of some representatives of aquatic insects, the support of the terrestrial origin of winged insects is currently more prevalent.
New evidence is provided by an international team of researchers with the participation of entomologists from the Biology Centre in a study just published in the journal Communications Biology.
Photosynthesis first evolved in living organisms at least 1.75 billion years ago, according to a new study into ancient organisms by a team of Belgian biologists.
The updated timescale is the result of their study into fossilised cyanobacteria (sometimes referred to as ‘blue-green algae’) sourced from the McArthur Basin, which stretches from the northern fringe of Australia along the Arafura Sea and Gulf of Carpentaria.
The group from the University of Liège believe they’ve found in microfossils of Navifusa majensis the “oldest direct evidence” of specialised biological structures – thylakoid membranes – which are essential to oxygenic (oxygen-producing) photosynthesis.
A photomicrograph of a modern-day cyanobacterium. Credit: N Nehring via Getty Images
Photosynthesis is the chemical process by which plants and some single-celled organisms create energy. In the cells of most photosynthesising organisms, carbon dioxide and water are converted using light energy into sugar and oxygen.
Typically, this occurs at sites in plant cells called chloroplasts. Within these structures are thylakoids, which house the green pigment chlorophyll that absorbs sunlight for use in photosynthesis.
They do have thylakoids, which is why evolutionary biologists think these single-celled organisms were incorporated into complex plant cells as chloroplasts.
But not all cyanobacteria produce their energy using thylakoids – the genus Gloeobacter instead photosynthesises via light-capturing protein structures in their plasma membrane.
Understanding cyanobacteria evolution could help scientists understand a major change in Earth’s history.
Oxygen-producing photosynthesis is the likely cause of a major historic spike of oxygen in Earth’s atmosphere about 2.4 billion years ago – vital for the development of life on our planet. Scientists working across several disciplines have struggled to pinpoint the precise cause of this so-called Great Oxidation Event, however the Liège study published today in the journal Nature at least pushes the dial backwards.
Led by PhD student Catherine Demoulin and Dr Emmanuelle Javaux, the research team studied N. majensis microfossils obtained from rock formations in the Northwest Territories in Canada, the Democratic Republic of Congo and the McDermott Formation in the Northern Territory, Australia. Of these, the McDermott samples were the oldest – dating back 1.75 billion years – providing a new minimum timepoint for the emergence of thylakoid-containing cyanobacteria.
Stromatolites formed by billion-year-old cyanobacteria at the Hamelin pools in Western Australia. Credit: Intst via istock/Getty Images Plus
In their study, they note the specimens were highly preserved, allowing the arrangement of thylakoid membranes to be microscopically observed.
“Thylakoids represent direct ultrastructural evidence for oxygenic [oxygen-producing] photosynthesis,” they write.
“The discovery of preserved thylakoids within N. majensis reported here provides direct evidence for a minimum age of about 1.75 Ga for the divergence between thylakoid-bearing and thylakoid-less cyanobacteria.
“By probing the older fossil record, it may also allow testing of the hypothesis that the emergence of thylakoid membranes may have contributed to the rise in oxygen around the GOE, and to the permanent oxygenation of the early Earth.”
The Insect Eavesdropper, a system that uses a contact microphone and minicomputer to analyze the vibrational signals of insects feeding on plants, took 1st Place in the 2023 ESA Antlion Pit, an innovation competition for entomology-related products and services. View the 2023 Antlion Pit presentation session here. (The video is cued to start with the Insect Eavesdropper presentation; skip back or ahead to see other segments.)
Last November at Entomology 2023 saw the return of the Antlion Pit, an innovation competition for entomology-related products and services. Six teams were selected to compete out of nine applications, with the “Insect Eavesdropper” team earning 1st Place and a $5,000 prize to invest in advancing their product, a system using a contact microphone and a minicomputer to detect and identify the vibrational signals of insects feeding on plants.
A system that uses a contact microphone and minicomputer to analyze the vibrational signals of insects feeding on plants took 1st Place in the 2023 ESA Antlion Pit, an innovation competition for entomology-related products and services. The creators of the Insect Eavesdropper are Emily Bick, Ph.D., BCE-Intern (left), assistant professor in the Department of Entomology at the University of Wisconsin-Madison, and Dev Mehrotra (right), master’s student in computer science working in Bick’s lab at UW.
The creators of the Insect Eavesdropper are Emily Bick, Ph.D., BCE-Intern, assistant professor in the Department of Entomology at the University of Wisconsin-Madison, and Dev Mehrotra, master’s student in computer science working in Bick’s lab at UW.
Entomology Today connected with Bick and Mehrotra for a Q&A to learn more about Insect Eavesdropper and its development.
Entomology Today: How did you both get started on developing the Insect Eavesdropper? What inspired this pursuit?
Bick and Mehrotra: When Emily visited a sugarcane farm in Indonesia, she was challenged to develop a sensor to directly measure insects boring within plants, rather than monitoring adult immigration and using degree days to predict when boring larvae were active. After looking into existing technologies such as laser vibrometers, electric stethoscopes, and other potential methods, Dev built the very first Insect Eavesdropper.
Can you summarize what the Insect Eavesdropper does and how it works?
The Insect Eavesdropper is a contact microphone strategically clipped to or stuck on a plant. A minicomputer starts, stops, and saves a recording of insects chomping on the leaves, sucking on the plant, boring through its tissue, or chewing on the roots. The recording is pre-processed and the feeding “event” is extracted and then run through a machine learning algorithm for species identification. Thus far, the Insect Eavesdropper can detect, identify to species, and count insects that are directly feeding on plants.
What are the likely potential applications for the Insect Eavesdropper? Who might be the primary customers for it as a commercial product?
The Insect Eavesdropper addresses the unmet need for cost-effective and accurate digital monitoring of insects as they directly feed on crops. The technology’s potential use cases are twofold:
Subscription to data, analysis, and alerts from a network of Insect Eavesdroppers continuously monitoring sentinel crops. This method mimics trapping networks or predictions from degree days in an accurate, efficient, and cost-effective way.
The mobile version of the Insect Eavesdropper, termed “Rambling Eavesdropper,” which crop consultants, growers, extension folk, and researchers can use to sample crops for pests via non-destructive, efficient methods.
We highlight the Eavesdropper ecosystem below, with each type of user on the left, the sensor flow within the gray boxes, and leaving the decision making up to the better-informed stakeholder, on the left.
The Insect Eavesdropper, a system that uses a contact microphone and minicomputer to analyze the vibrational signals of insects feeding on plants, took 1st Place in the 2023 ESA Antlion Pit, an innovation competition for entomology-related products and services. The creators of the Insect Eavesdropper envision it being used as both a sensor network for continuous monitoring or a mobile, handheld sensor for spot-checking crops for pests. (Figure courtesy of Emily Bick, Ph.D., BCE-Intern, and Dev Mehrotra)
What stage are you in now in developing and testing the Insect Eavesdropper? What challenges do you currently face?
On the hardware, Dev has led the efforts in Emily’s lab to successfully develop two prototypes for the Insect Eavesdropper and Rambling Eavesdropper. The former is a stationary version, continuously monitoring insects similar to Malaise traps or sticky cards; the latter is version that can be carried around a field, mimicking a sampling tool like a sweep net.
We received an accelerator grant from the Wisconsin Alumni Research Foundation to “unwire” the Insect Eavesdropper, using a module such as LoRa, Bluetooth, or Wi-Fi for data transmission. On the software, we are building a toolkit to make the sensor more accessible to anyone, regardless of programing capability. This will allow a broad variety of potential users to independently work with the Insect Eavesdropper.
Functionally, we are formalizing the machine learning algorithms that identify species, adding to our species library, and working through density estimates based on feeding events. Additionally, we are handing the Insect Eavesdropper to researchers working across the world, trying to find the limits of the Insect Eavesdropper as well as externally validate the sensor.
How did competing in and taking 1st Place in ESA’s Antlion Pit competition advance your work on the Insect Eavesdropper?
The Antlion Pit competition helped spread the word about the Insect Eavesdropper and its potential. It was exciting to expose our idea to scrutiny across the entomology community. The Antlion Pit competition provided us with valuable feedback that will shape the Insect Eavesdropper for years to come.
For those interested in the Insect Eavesdropper, where can they learn more, and what should we be on the lookout for next from you?
To learn more, please visit www.bicklab.com/eavesdropper. If academics are interested in applying the Insect Eavesdropper to a difficult entomological problem, they should reach out to Emily at ebick@wisc.edu. If industry folks are interested in potentially licensing the method, they should reach out to Emily Bauer at the Wisconsin Alumni Research Foundation at emily@warf.org. Everyone else should keep your eyes peeled for our upcoming publications.
The Insect Eavesdropper, a system that uses a contact microphone and minicomputer to analyze the vibrational signals of insects feeding on plants, took 1st Place in the 2023 ESA Antlion Pit, an innovation competition for entomology-related products and services. It also received an accelerator grant from the Wisconsin Alumni Research Foundation to incorporate a module for wireless data transmission.
Experimental seedlings in the laboratory. UC Davis plant biologists have discovered how chloroplasts, responsible for photosynthesis in green plants, also play a key role in plant immunity to infections. Credit: Sasha Bakhter, UC Davis College of Biological Sciences
Scientists have long known that chloroplasts help plants turn the sun’s energy into food, but a new study, led by plant biologists at the University of California, Davis, shows that they are also essential for plant immunity to viral and bacterial pathogens.
Chloroplasts are generally spherical, but a small percentage of them change their shape and send out tube-like projections called “stromules.” First observed over a century ago, the biological function of stromules has remained enigmatic.
Previous studies have shown that chloroplasts produce more stromules when a plant detects an infection. Stromules aid in clustering chloroplasts around the nucleus and function as conduits to transport pro-defense signals from chloroplasts to the nucleus. Despite these findings, researchers have not been able to determine the role of stromules in immunity, as no genes involved with the formation of stromules have been identified.
In the new study, Savithramma Dinesh-Kumar, professor and chair in the Department of Plant Biology, graduate student Nathan Meier and colleagues have identified a key protein involved in stromule biogenesis during immunity. Their findings were published Oct. 25 in Science Advances.
A hidden player in immune defense
In order to test the stromules’ role in immunity, researchers need to switch them off and then observe how stromule-less plant cells fare when faced with a pathogen. However, without knowing which genes are involved with the creation of stromules, researchers have had no way to know which genes to switch off.
To overcome this roadblock, Dinesh-Kumar and his colleagues turned to kinesins, proteins that function as tiny motors that allow molecules and organelles to move around a cell. This intracellular movement usually involves the cell’s cytoskeleton, which is made up of two different types of fiber: large microtubules and smaller actin filaments.
The researchers wanted to investigate a type of kinesin that is unique to plants and capable of binding both microtubules and actin filaments. The researchers found that overexpression of one of these kinesins, KIS1, induced stromule formation in the absence of pathogen infection.
When the researchers manipulated tobacco and Arabidopsis plants so that they could not produce the KIS1 kinesin, they found that neither plant was able to form stromules, and their chloroplasts did not migrate toward the nucleus. This left the plants unable to defend themselves from introduced pathogens.
Secrets of chloroplast movement
To disentangle the roles of microtubules and actin, the researchers engineered one set of KIS1 variants that could only bind to microtubules, and another that could only bind to actin. Expression of these variants in tobacco showed that KIS1 needs to bind to microtubules in order for chloroplasts to form stromules, but in order for chloroplasts to move toward the nucleus, it must also bind to actin.
The team also wanted to know how stromules fit into the bigger picture of plant immunity. By using genetic manipulation to switch different immune signals off, they found that stromule formation is triggered by molecular signaling and that an intact immune signaling system is needed in order for stromules to form.
“If we remove any of the known immune signaling genes, the chloroplasts lose the ability to make stromules, which suggests that these structures are an integral part of the immune signaling pathways that activate defense,” said Dinesh-Kumar.
New light on plant immunity
This study is the first evidence of a plant kinesin directly involved in plant immunity. It’s also the first time that scientists have identified a gene—KIS1—involved in chloroplast stromule biogenesis, which opens the door to understanding the role of chloroplast stromules and why chloroplasts cluster around the nucleus during plant immune defense.
“If we can better understand at the cellular level how organelles like chloroplasts help cells to defend themselves, we could help to engineer resistance to the pathogen,” Dinesh-Kumar said.
Entomology Today posted: ” By David Coyle, Ph.D. Folks outside the forest entomology realm have likely heard of the USDA Forest Service but may have little knowledge of what this group actually does. Truth be told, they do a lot—from trail and road maintenance to fire su” Entomology TodayHow Forest Service Research Protects U.S. Woodlands From Insect PestsEntomology Today Nov 28 The USDA Forest Service funds hundreds of projects every year to protect our nation’s woodlands. Included in these research projects are several different types of pest management strategies spanning a wide range of pests, forest types, and ecosystems. A new article in the Journal of Integrated Pest Management reviews USFS pest-management research from 2011 to 2020, which helped manage over 2.2 million hectares of forest. Read more of this postCommentManage your email settings or unsubscribe. Trouble clicking? Copy and paste this URL into your browser: https://entomologytoday.org/2023/11/28/usda-forest-service-research-protects-woodlands-insect-pests/
The USDA Forest Service funds hundreds of projects every year to protect our nation’s woodlands. Included in these research projects are several different types of pest management strategies spanning a wide range of pests, forest types, and ecosystems. A new article in theJournal of Integrated Pest Managementreviews USFS pest-management research from 2011 to 2020, which helped manage over 2.2 million hectares of forest. (Photo byUSDA Forest Service via Flickr, public domain)
Folks outside the forest entomology realm have likely heard of the USDA Forest Service but may have little knowledge of what this group actually does. Truth be told, they do a lot—from trail and road maintenance to fire suppression and prevention to management, this group is responsible for managing millions of acres of our nation’s forestland. But, in addition to the management aspect, the Forest Service (USFS) also conducts and funds research—lots of research. In anarticle published in October in theJournal of Integrated Pest Management, several USFS scientists summarize the past decade’s USFS-funded forest health management, and, frankly, the impacts on U.S. forests are impressive.
Forest Health Protection is a unit of the USFS State, Private, and Tribal Forestry Deputy Area, and this group regularly works with personnel from academia, government, industry, and nonprofit organizations to monitor pests and improve management of forests. New and existing grants are funded annually, and, while many of these projects result in peer-reviewed publications, this is the first time their impact has been summarized in one place.
In total, over 2,400 forest pest-management projects were supported between 2011 and 2020, directly impacting 2,284,624 hectares (5,645,429 acres or 8,821 square miles). The list of pests impacted by this work reads as theWho’s Whoof forest health issues and includes native species such as the mountain and southern pine beetle, Douglas-fir beetle, western spruce budworm, and Ips bark beetles. Invasive pests include the spongy moth, emerald ash borer, and hemlock woolly adelgid. Projects evaluated traditional and novel management methods, and the paper contains a plethora of interesting numbers and facts related to this program—way more than can be adequately summarized here.
The USDA Forest Service funds hundreds of projects every year to protect our nation’s woodlands. Included in these research projects are several different types of pest management strategies spanning a wide range of pests, forest types, and ecosystems. A new article in theJournal of Integrated Pest Managementreviews USFS pest-management research from 2011 to 2020, which helped manage over 2.2 million hectares of forest. (Image originally published in Coleman et al 2023,Journal of Integrated Pest Management)
But, as someone who works in the forest health realm and who works with the USFS very frequently, a few points are worth highlighting. First, the tables and figures alone in this paper holdso muchinformation on where federal funding goes and what it impacts. This is a common criticism from those who might not appreciate what our federal government does or where tax dollars go, and this paper goes a long way to help answer some of these questions as they pertain to USFS work. From the data, it seems clear that a lot is being done because of this program. Second, the question of where in the country our federal dollars go is also largely answered, as the authors clearly break down where the projects took place, acres impacted in each region, and several other location-specific bits of information. Finally, the comprehensive nature of this program is well-documented in this paper. It’s not just bark beetles, or defoliators, or native or invasive species—it’s all of them at the same time. It’s broad-scale forest health work, which is an excellent goal and objective for an entity such as the USDA Forest Service.
Whether you work in forests or not, this paper does an excellent job of summarizing a decade of government-supported integrated pest management work.
David Coyle, Ph.D., is an assistant professor in the Department of Forestry and Environmental Conservation at Clemson University. Find him on all the socials as@drdavecoyle. Email:dcoyle@clemson.edu.
Experimental studies showed that Wolbachia pipientis, which is native to fruit flies, can restore and enhance fertility of their hosts. Image courtesy of Shelbi Russell.Assistant Professor of Biomolecular Engineering Shelbi Russell studies Wolbachia to better understand the relationship between this bacteria and its insect hosts, with implications for the control of human diseases. Image by Christie Brown.
Mosquitoes and other insects can carry human diseases such as dengue and Zika virus, but when those insects are infected with certain strains of the bacteria Wolbachia, this bacteria reduces levels of disease in their hosts. Humans currently take advantage of this to control harmful virus populations across the world.
New research led at UC Santa Cruz reveals how the bacteria strain Wolbachia pipientis also enhances the fertility of the insects it infects, an insight that could help scientists increase the populations of mosquitoes that do not carry human disease.
“With insect population replacement approaches, they keep all the mosquitos and just add Wolbachia so that fewer viruses are carried in those mosquitoes and transmitted to humans when they bite them — and it’s working really, really well,” said Shelbi Russell, an assistant professor of biomolecular engineering at UCSC who led this research. “If there is some fertility benefit of Wolbachia that could evolve over time, then we could use that to select for higher rates of mosquitos that suppress our viral transmission.”
These results were detailed in a new paper led by Russell, published today in the journal PLOS Biology. UCSC Professor of Molecular, Cell, and Developmental Biology William Sullivan is the paper’s senior author.
Humans and Wolbachia
Different strains of Wolbachia bacteria naturally infect a number of different animals worldwide, such as mosquitos, butterflies, and fruit flies. Once they infect an insect, the bacteria are able to manipulate the reproduction and development of their host to increase their own population. Humans take advantage of this to control the population size of insects that carry diseases that threaten us.
Wolbachia have developed a mechanism to poison the sperm of infected males so that if the male mates with an uninfected female, most of the potential offspring die at the very first cell division, and the rest are lost soon after. Humans have taken advantage of this to kill off insect populations.
However, research shows that later down the line once they have killed off as many uninfected hosts as possible, Wolbachia switch their evolutionary strategy to increase population levels of infected hosts. Understanding how this happens is important for avoiding unexpected consequences of human efforts to control insect populations.
“We need to understand all of these factors and their evolutionary potential if we’re going to be releasing bacteria into new ecosystems,” Russell said. “They’re evolving in real time, so we need to understand where these trajectories are going.”
Beyond disease prevention, controlling insect populations and range via bacteria could be an effective mechanism for crop security in the face of the changing climate.
Understanding increased fertility
The new results show that Wolbachia pipientis, which is native to fruit flies, has evolved to increase the fertility, and therefore the population size, of its fruit fly host. Previous research has found that the Wolbachia pipientis achieves this by manipulating a protein in fruit flies called Meiotic-P26 that affects fertility, but how exactly this happens was unclear.
To investigate, Russell and her colleagues bred fruit flies with various defects affecting Mei-P26, which caused them to have reduced fertility. These defects occasionally occur naturally in the wild, but are hard to track in that setting. The researchers then examined what happened when they infected the flies with Wolbachia pipientis.
They found that Wolbachia infection restored the fruit fly’s fertility, enabling them to produce even more offspring than uninfected flies. The researchers found that Wolbachia can essentially undo gene defects in their host that would otherwise cause the population to go extinct. The Wolbachia rescue their host population through several strategies, including restoring fruit fly stem cells and ensuring that egg cells properly develop.
In further experiments, the researchers also found that, beyond rescuing fruit flies with defects, the Wolbachia pipientis infection also enhances the health and fertility of fruit flies without defects, resulting in higher egg lay and hatch rates for those insects.
Wolbachia in the lab
Russell focuses on Wolbachia because it and its fruit fly hosts are relatively easy to keep alive and reproduce in the lab. Oftentimes when scientists study bacteria, their efforts are hindered because either the host, the bacteria, or both are difficult to keep alive in the lab setting — even research into common bacteria important to humans such as Chlamydia are slowed by this problem. Wolbachia and their fruit fly hosts offer a rare opportunity to understand how bacteria can change the DNA and biological processes of their host.
“Through studying this system, I can learn a lot about how these weird bacteria work and how they integrate with host biology,” Russell said. “Bacteria are able to hop into these eukaryotes and leverage some of those mechanisms that their ancestors didn’t even contain the genes for. It’s a really fascinating thing in general, and it’s cool that we can leverage this for biological control applications.”
Russell and her lab will continue to hone in on the specific changes that occur in the genomes and gene expression of host species, and look at the fertility benefits that Wolbachia may bring to their hosts in other insect populations.
Functional analyses of ΔN, ΔC, and Δ(N + C) compared to intact PDLP5 by viral movement assays. C) Cartoon illustrating the experimental setup. D) Representative plant photographs showing the extent of systemic TMV-GFP movement (left, low magnification; right, close-up views of the shoot tips). E) Quantitative analysis of the percentages of plants showing TMV-GFP systemic infectivity over 5 to 7 days after Agrobacterium-mediated infiltration of the virus. Experiments were performed 3 times using at least 5 plants per treatment. Credit: The Plant Cell (2023). DOI: 10.1093/plcell/koad152
Traffic lights signal to cars and buses when to stop, slow and go. Much like traffic lights, plant cells send signals to each other to perform photosynthesis to grow or fight off destructive viruses and pathogens.
Plant cells produce plasmodesmata, tiny tiny tubes that act as communication channels, allowing those signals to move from cell to cell. The plasmodesmata will open and close in response to various signals that activate protein regulators such as PDLP5.
“We knew that this protein is critical for plant defense,” said Jung-Youn Lee, a University of Delaware professor of plant molecular and cellular biology and the interim director of the Delaware Biotechnology Institute. “But how does this protein get to the plasmodesmata?”
The question—how these protein regulators find their destination to fulfill their purpose and help a cell function—had been plaguing scientists. Until the University of Delaware got involved.
In new research that made the cover of the journal The Plant Cell, UD researchers found that the protein—PDLP5—that helps guard plants from the invasion of viruses and bacteria has not one, but two special targeting signals, or “zip codes” as Lee calls them, unexpectedly stationed outside of cells.
“It is almost like you have a zip code hidden on an unusual side of the envelope,” Lee said. “We did more than just locate the zip code; we cracked the code. Now we understand where the zip code is and what it looks like.”
An interdisciplinary research team of biologists and computational scientists developed machine-learning algorithms and introduced mutations into the protein sequence of PDLP5 and reintroduced into plant species Arabidopsis thaliana and Nicotiana benthamiana to examine whether PDLP5 would go to plasmodesmata in these plants or not and to find where the second zip code is. The team discovered even if they got rid of one zip code, PDLP5 would still go to the plasmodesmata just fine.
“It gave us a lot of headaches,” Lee said. “We never really thought initially there are two zip codes right next to each other.”
Two ‘zip codes’
Historically, plants under a viral attack were considered “helpless losers,” Lee said. But in 2011, Lee and her team of researchers discovered plants send signals through plasmodesmata for cells to “close their borders” to defend themselves from pathogens. This new insight was made possible through their study of the then newly identified protein, PDLP5.
They have wanted to know how plants lead those PDLP5 proteins to help plasmodesmata close off their channels.
Several years ago, Lee’s former student and 2017 UD graduate Xu Wang had been working on his doctoral thesis studying plant cell-to-cell communication and the function of proteins that would go to plasmodesmata.
“I was trying to figure out which part of the protein that localized to plasmodesmata is important,” Wang said, “and whether this part contains a more universal or common feature that can help us to understand the localization mechanisms for other proteins, not only for the proteins we’re studying.”
When Wang introduced various mutations into PDLP5 to try to chop it up, he was stunned by what happened next.
“Nothing changed,” Wang said. “The mutated, or a shorthand form, always went to the plasmodesmata.”
Wang felt his study and the last piece of his thesis was stuck.
Following Wang’s graduation, Lee brought in computer scientists to develop machine-learning algorithms to help solve the mystery.
Li Liao, an associate professor of computer and information sciences, who worked with Lee and her then newly recruited postdoc Gabriel Robles Luna (currently a university faculty member in Argentina) on the research, said a computer model trained the machine-learning algorithms to make two types of predictions.
The model would predict whether a protein sequence was a PDLP5-targeting protein that would go to plasmodesmata or not and would predict where the targeting signals are in the protein sequence.
“One challenge was this problem that we had very limited training data, only eight such protein sequences,” Liao said. “Now, machine learning is powerful because it can train on large amounts of data. It won’t be easy if you have a small amount of data to train a model.”
To overcome that, Liao and his then new doctoral student Jiefu Li, a 2021 UD graduate, had to train the model in a new way.
“We have developed some novel mechanisms, including revision of the standard training algorithm to handle the partial signals,” Liao said. “If we know some tentative patterns, we can incorporate that into the training algorithm. This will allow us more importantly to do active learning.”
Understanding the protein regulation within plant cells can ultimately help scientists genetically engineer new crops capable of quickly fighting off viruses and other microbial pathogens, Lee said. It’s one more way to improve how plants and crops function.
“This becomes a cool new toolbox for scientists,” Lee said. “We have mechanisms and molecules we can manipulate.”
Wang agreed, adding that genetically engineering plants with plasmodesmata-located proteins that can open and close channels will help “manipulate the overall plant fitness or the plant’s defense to potentially have some agricultural benefits.”
The research doesn’t stop here. Researchers have submitted another grant proposal to the National Science Foundation to continue their research. Now, the team wants to use machine-learning algorithms to know how the protein signals are being used. Like how a UPS driver might use a zip code to deliver a package. Lee said the team wants to know the ins and outs of the whole “delivery system,” including which proteins are involved and any unknown players.
“If we just manipulate the zip code, it may work 50% of the time,” Lee said. “But if we know who the delivery man is and improve or change the delivery man so a virus can’t be transferred to plasmodesmata anymore, if we can change the system, plants will recognize the invaders better and know not to deliver them to plasmodesmata.”
More information: Gabriel Robles Luna et al, Targeting of plasmodesmal proteins requires unconventional signals, The Plant Cell (2023). DOI: 10.1093/plcell/koad152
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Entomology Today posted: ” By David Coyle, Ph.D. Folks outside the forest entomology realm have likely heard of the USDA Forest Service but may have little knowledge of what this group actually does. Truth be told, they do a lot—from trail and road maintenance to fire su” 
Entomology Today Nov 28 
The USDA Forest Service funds hundreds of projects every year to protect our nation’s woodlands. Included in these research projects are several different types of pest management strategies spanning a wide range of pests, forest types, and ecosystems. A new article in the Journal of Integrated Pest Management reviews USFS pest-management research from 2011 to 2020, which helped manage over 2.2 million hectares of forest. 
Global Plant Protection News 