New fungus is the oldest disease-causing species found to date


New fungus is the oldest disease-causing species found to date

by Natural History Museum

Artistic rendition of the Rhynie Chert in the Early Devonian period. Credit: Victor O. Leshyk

The earliest disease-causing fungus has been discovered within the Natural History Museum’s fossil collections. The new fungal plant pathogen, Potteromyces asteroxylicola, which is 407-million-years-old, has been named in honor of celebrated Tales of Peter Rabbit author, and fungi enthusiast, Beatrix Potter.

The paper, “A fungal plant pathogen discovered in the Devonian Rhynie Chert,” has been published in Nature Communications

Beatrix’s drawings and study of the growth of fungi, which were in some cases decades ahead of scientific research, have garnered her a reputation as a significant figure in mycology.

Potteromyces was discovered in fossil samples from the Rhynie Chert, a crucial geological site in Scotland. The site is known for a remarkably preserved Early Devonian community of plants and animals, including bacteria and fungi.

The new study, completed in collaboration with mycologists at the Royal Botanic Gardens, Kew, suggests that disease-causing fungi, such as ash die-back currently decimating the UK’s native ash trees, and fungi which can circulate nutrients that plants and other organisms depend on to survive, have a historical precedent in Potteromyces.

Dr. Christine Strullu-Derrien, Scientific Associate at the Natural History Museum and lead author of the study describing the new species, says, “Although other fungal parasites have been found in this area before, this is the first case of one causing disease in a plant. What’s more, Potteromyces can provide a valuable point from which to date the evolution of different fungus groups, such as Ascomycota, the largest fungal phylum.”

“Naming this important species after Beatrix Potter seems a fitting tribute to her remarkable work and commitment to piecing together the secrets of fungi.”

Christine found the first Potteromyces specimen in 2015. Its reproductive structures, known as conidiophores, had an unusual shape and formation unlike anything seen before.

Equally unusual was the fact this mysterious fungus was found attacking an ancient plant called Asteroxylon mackiei. The plant had responded by developing dome-shaped growths, showing that it must have been alive while the fungus making its attack.

In order for the team to determine that it was indeed a new species, another case of the fungus needed to be found. This is due to the nature of fungi differing greatly between individuals.

The confirmation was achieved when a second specimen was found in the collections of the National Museums of Scotland in another specimen slide from the Rhynie Chert.

“New technology available to us, such as confocal microscopy, has enabled us to unlock more secrets from fossils housed in museum collections, such as those within the Natural History Museum,” said Christine.

“When I first started work on the Rhynie Chert, it was only meant to take two or three years,” Christine says, “It’s now been 12, and I still think there is a lot to discover from this fabulous site.

More information: Christine Strullu-Derrien et al, A fungal plant pathogen discovered in the Devonian Rhynie Chert, Nature Communications (2023). DOI: 10.1038/s41467-023-43276-1

Journal information: Nature Communications 

Provided by Natural History Museum 

This story is republished courtesy of Natural History Museum. Read the original story here


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‘Toxic bait’ from Indian pitcher plants lures hungry insects to their doom


‘Toxic bait’ from Indian pitcher plants lures hungry insects to their doom

Nectar produced on and around the traps is laced with a neurotoxin that may drug ants in addition to drawing them in

Nepenthes khasiana produces a sweet nectar on its traps that attracts insects.MICHAEL DURHAM/MINDEN PICTURES

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Pitcher plants in the genus Nepenthes thrive in places where they shouldn’t. There’s very little nitrogen in the Southeast Asian and Australian soils where they grow—but they do just fine, thanks to a macabre source for this essential nutrient: the dissolved flesh of small animals, mostly insects, that slip into their bulbous traps.

A new study suggests why Nepenthes is so effective at catching its victims: It produces a sweet nectar containing a potent neurotoxin that could make them lose their balance at the pitcher’s edge. The work, published as a preprint on bioRxiv this month, is the first known example of nectar acting both as a lure and a poison.

The finding is intriguing, says University of Bristol researcher Ulrike Bauer, who has studied Nepenthes plants for nearly 2 decades but who wasn’t involved with the research. “The nectar has really been neglected for a long time,” she says, and the idea that it contains compounds that “drug” insects is plausible. Still, she and others would like clearer evidence that the toxin originates from the nectar—and that it really accounts for the unlucky ants’ falls.

Phytochemist Sabulal Baby has been studying carnivorous plants—“the most unique life forms on Earth,” he says—for more than a decade. He and his colleagues at the Jawaharlal Nehru Tropical Botanic Garden and Research Institute had previously discovered that the rims of the Indian pitcher plant Nepenthes khasiana are fluorescent and that newly opened traps emit carbon dioxide—features that attract insects. Because they knew the plants also produce nectar on and around their traps, which acts as a lure, they decided to examine it more closely.

In other plants, such extrafloral nectar isn’t designed to harm insects. The liquid’s high sugar content appeals to ants, whose presence—and aggression—wards off potential herbivores. But when Baby and colleagues teased out the contents of the nectars of N. khasiana and several other pitcher plants growing in their institute’s botanic garden, they found something unexpected. The nectars contained (+)–isoshinanolone—a compound that interferes with the activity of an enzyme called acetylcholinesterase, which prevents the buildup of the neurotransmitter acetylcholine between neurons. Too much acetylcholine in lab animals leads to muscle cramps, weakness, blurry vision, and paralysis.

And indeed when Baby and his colleagues examined ants that had drowned in the pitcher fluid of N. khasiana, they found almost no acetylcholinesterase activity in their tissues. Ants collected on the plant’s exterior showed more of this activity. This indicates that the nectar inhibits the insects’ locomotion, Baby says, making them temporarily clumsy and more likely to tumble into a pitcher. The nectar is a “toxic bait,” he says. “Prey capture by these pitchers is a story of total deception.”

Bauer doesn’t agree that the relationship is that unbalanced. The nectar isn’t so potent that the plants catch every ant that imbibes; many of the insects are able to shrug off its effects and make it home to deliver the sweet treat. “Sugar is an important food resource for ants, because it’s very energy dense,” Bauer notes. Meanwhile, worker ants are relatively expendable. “It’s a good deal for the ant colony to sacrifice some workers, as long as the workers that survive bring in enough sugar to offset that loss.”

It wouldn’t be completely unheard of for nectar to manipulate insects to the plant’s benefit, says Martin Heil, an expert on ant-plant interactions and extrafloral nectar with the Mexican Center for Research and Advanced Studies of the National Polytechnic Institute.

That said, he finds the data provided—that drowned ants exhibited high levels of acetylcholinesterase inhibition—are circumstantial at best. He would like to see experiments examining live ants before and after consuming the nectar to be convinced that the fluid has a real impact on prey capture.

Bauer says that in her work, she hasn’t seen ants with impaired movement after drinking pitcher plant nectar, though others have, and she notes the effect need not be dramatic to benefit the plant. She also hasn’t worked with N. khasiana specifically, and nectar components vary between species—a fact she can personally confirm from tasting the nectars of several pitcher plants.

Bauer notes that the authors’ method for nectar sampling—which involved rinsing cut sections of plant to collect the fluid—could have introduced intracellular compounds. So future work should confirm that (+)–isoshinanolone is in the nectar that the ants consume, not just the plant’s tissues.

Still, she wouldn’t be too surprised if it is. Pitcher plants have “such an amazing diversity of tricks for how to trap insects” that toxic nectar would hardly be the strangest.


doi: 10.1126/science.zzb21md

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Christie Wilcox

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Christie Wilcox is the Newsletter Editor for Science.



Viruses Shown to Be Effective Biological Control Agents


Viruses Shown to Be Effective Biological Control Agents

Beyond Pesticides

Viruses Shown to Be Effective Biological Control

(Beyond Pesticides, November 30, 2023) Scientists at Minami Kyushu University in Japan have made a groundbreaking discovery of a new biological control for a target insect. They have identified a virus in tobacco cutworms that kills males, creating all-female generations. The discovery was described in a recent issue of the Proceedings of the National Academies of Sciences and The New York Times as evidence that multiple viruses have evolved to kill male insects.

This “male-killing” virus could be added to the growing attempts to control unwanted insects with biological, as distinguished from genetically engineered (GE) solutions. Efforts range from the introduction of natural predators, to radiation-based sterilization of insects, CRISPR-based genetic mutations, and other techniques. While the GE approach has run into controversy because of unanswered questions associated with their release into natural ecosystems, some approaches have also run into resistance problems. Nearly a decade ago, researchers found armyworm resistance to Bacillus thuringiensis (Bt)-incorporated genetically engineered (GE) maize in the southeastern region of the U.S., calling this evolution of insect resistance to a naturally occurring soil bacterium engineered into crops “a serious threat to the sustainability of this technology.”

The general population knows to avoid eating raw eggs because the bacteria salmonella, can live inside chicken eggs. Similarly, scientists have long known that microbes can live in insects’ eggs. One of the scientists, Daisuke Kageyama, PhD, explained that the Wolbachia bacteria, another male-killer, is propagated through females. Dr. Kageyama told the The New York Times, “Males are useless” because they cannot help propagate the microbe, so the bacteria prevents male eggs from hatching.

The scientists in Japan discovered the new male-killing virus in tobacco cutworms and called it SIMKV. The New York Times described the discovery of the virus as being very lucky that research technician Misato Terao stumbled upon the caterpillars while cleaning the greenhouse and placed them in Yoshinori Shintani’s lab. Even luckier was the temperature zone that enabled the virus to impact the resulting all-female generation of moths.

Anne Duplouy, PhD, an evolutionary biologist at the University of Helsinki specializing in the study of microbial symbionts in insects, suggests that there is a diminishing window of opportunity for humanity to glean insights from these microbes sensitive to temperature changes. Due to climate change, she said, “we are likely to be losing many of these interactions” before they can be documented.

The authors of the study believe the identification of this male-killing virus in insects has the potential to revolutionize methods for managing agricultural pests and disease-carrying insects. Conventional pest control approaches rely on the use of toxic pesticides, which can adversely affect the environment and human health.

Many scientists believe a “female-killer” virus could be a more ecologically friendly approach to pest control. However, these biological controls do not always consider the entirety of a systems-based organic approach that focuses on the root causes of pest problems. To see a more systematic approach to mosquito control, see the city of Boulder, Colorado’s mosquito management plan, which includes  Living with Mosquitoes and Ecological Mosquito Management.

As scientists delve deeper into the study of the relationships between mosquitos and the interactions of species in an ecosystem, there is the prospect of uncovering novel strategies for pest and disease control that are both more efficacious and less environmentally harmful.

The revelation of the male-killing virus in insects serves as a poignant reminder of the extraordinary biodiversity of life on Earth. As scientists persist in their exploration of biological control, they are bound to reveal many more captivating discoveries that will contribute to a better understanding of the natural world.

As The New York Times wrote in November 2018, “The Insect Apocalypse is Here.” Karen Lipps, PhD, and other scientists and researchers observed the consequences for ecosystems that experience the loss of one species and its cascading impact on other species. Dr. Lipps writes about the massive loss of frogs and other amphibians due to a fungus and its resulting increase in insect populations. This, in turn, decreased snake populations (which would have preyed on the frogs).

In industrial agriculture, the typical approach to addressing pest issues often involves prioritizing the destruction of a single “pest” using a pesticide as the primary solution. This practice results in a cascade of harmful effects throughout the food chain, impacting both prey and predator as they fall victim to the broad-spectrum pesticides. While it intuitively makes sense that pesticides can affect more than just their intended insect targets, the extent of this issue came to light through a study conducted by German researchers and published in PLOS One. Their findings, based on 27 years of trapping flying insects, reveals a staggering 75% decline in overall biomass during the study period.

To learn more about using biological control for your yard and outdoor pest problems, make sure the use of any pest management fits within a broader, structured, ecological approach to pest management. Use Beyond Pesticides ManageSafe webpage to assist your research on biological controls.

All unattributed positions and opinions in this piece are those of Beyond Pesticides.

Source: Male-Killing Virus Is Discovered in Insects

This entry was posted on Thursday, November 30th, 2023 at 12:01 am and is filed under AgricultureAlternatives/OrganicsBiological ControlClimate ChangeEcosystem ServicesMalariaMosquitoesPesticide EfficacyPestsUncategorized. You can follow any responses to this entry through the RSS 2.0 feed. You can skip to the end and leave a response. Pinging is currently not allowed.

Spider’s distribution differs by urban habitat


Spider’s distribution differs by urban habitat

Nebraska Today

POCKET SCIENCE: EXPLORING THE ‘WHAT,’ ‘SO WHAT’ AND ‘NOW WHAT’ OF HUSKER RESEARCH

by Scott Schrage | University Communication and Marketing

Shutterstock

A funnel-weaving spider, Agelenopsis pennsylvanica, rests on its web while waiting out the rain.

Welcome to Pocket Science: a glimpse at recent research from Husker scientists and engineers. For those who want to quickly learn the “What,” “So what” and “Now what” of Husker research.

Pocket Science icon

What?

The concept of urbanization rests on the population distribution of human beings, more than 50% of whom now live near large, often densely packed groups of other people. But the consequences of that urbanization — shifts in vegetation, localized fluctuations in temperature and wind, light and sound — can alter the distribution of other animals, too.

Given their limited lifespans, spiders and other arthropods must adapt more quickly than most, making them a valuable proxy for the ecological effects of urbanization. While hard data is hard to come by, arachnologists suspect that the global population of spiders — which eat up to 800 million metric tons of pests in a year — is now falling. Whether urbanization is contributing, and to what extent, remains a subject of some debate.

So what?

In search of factors that might sway the distribution and abundance of city-dwelling spiders, Nebraska’s Brandi Pessman and her colleagues turned to the wide-ranging species Agelenopsis pennsylvanica. The team sought out A. pennsylvanica in two areas of Lincoln: Nebraska U’s City Campus, considered an urban center, and Wilderness Park, an urban forest. As expected, the team found that those habitats differed in ways potentially relevant to the spiders. City Campus featured more artificial light, traffic and engineered surfaces — the latter contributing to higher temperatures — whereas Wilderness Park included more tree cover and plant diversity.

Portrait of Brandi Pessman

Pessman

A sampling expedition identified 131 funnel webs constructed by A. pennsylvanica, 64 of which brought forth spiders when the team stimulated the webs with a toothpick affixed to an electric toothbrush. City Campus boasted substantially more of those webs, and more spiders, than did Wilderness Park. Less distance separated the webs of the urban center than in the urban forest. And webs built on campus generally resided closer to the ground. Those findings suggest that differences between the urban environments could be motivating the real estate chosen by A. pennsylvanica, whose varied diet may help it adapt to human-disturbed areas that are less hospitable to pickier predators.

Yet the team also found that, even within City Campus, A. pennsylvanica webs were fewer and farther apart in spaces adjacent to roads or highways. The vibrations that propagate when rubber meets road might be to blame: Like many spider species, A. pennsylvanica relies on vibratory signals both to hunt and woo mates.

Now what?

Pessman is already conducting follow-up research on A. pennsylvanica in rural versus urban areas, hoping to determine whether environmental vibrations in the latter can limit the spider’s ability to detect prey. She’s also looking into whether the spider could be using webs to dampen disruptive frequencies.

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Chloroplasts are a key player in plant immunity


Chloroplasts are a key player in plant immunity

by UC Davis

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.

More information: Nathan Meier et al, Calponin-homology domain containing kinesin, KIS1, regulates chloroplast stromule formation and immunity, Science Advances (2023). DOI: 10.1126/sciadv.adi7407www.science.org/doi/10.1126/sciadv.adi7407

Journal information: Science Advances 

Provided by UC Davis 


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New insight into plants’ self-defense


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MOROCCO: TOMATO BROWN RUGOSE FRUIT VIRUS – FIRST REPORT


MOROCCO: TOMATO BROWN RUGOSE FRUIT VIRUS – FIRST REPORT

Monday, 20 November 2023 12:05:05

Grahame Jackson posted a new submission ‘TOMATO BROWN RUGOSE FRUIT VIRUS – MOROCCO: FIRST REPORT’

Submission

TOMATO BROWN RUGOSE FRUIT VIRUS – MOROCCO: FIRST REPORT

ProMED
https://promedmail.org/

Source: European Plant Protection Organisation (EPPO) Reporting Service 10/2023/235 [summ. Mod.DHA, edited]
https://gd.eppo.int/reporting/article-7717
The NPPO [National Plant Protection Organisation] of Morocco recently informed EPPO of the occurrence of _Tomato brown rugose fruit virus_ (_Tobamovirus_, ToBRFV – EPPO A2 List) on its territory. During the production season 2022-2023, about 10 outbreaks have been confirmed on tomato (_Solanum lycopersicum_) grown in glasshouses for fruit production. The sources of the outbreaks are infected imported seed.

ToBRFV has been a priority quarantine pest in Morocco since 2018, and official measures are taken in case of findings. They include the destruction of infected plants, restriction on cultivation of host plants and hygiene measures. In 2023, yield losses were observed, as well as increased management costs.

Communicated by:
ProMED
[_Tomato brown rugose fruit virus_ (ToBRFV) was identified as a new member of the genus _Tobamovirus_ (type member _Tobacco mosaic virus_, TMV) in Jordan and soon after in Israel (see links below). Since then, it has also been reported from Europe and the Mediterranean region, where it continues to spread (see links below), as well as from China and North America, but so far not from South America. The virus was shown to affect also capsicum and has been detected in both plants and seeds of both crops. ToBRFV symptoms on tomato vary depending on host cultivar but may include chlorosis, mottling, mosaic, crinkling (rugosis) on leaves; necrotic spots on petioles and calyces; yellowish mottling, brown spots and rugosis on fruit to make them unmarketable. On capsicum, leaf symptoms are similar; fruits may be deformed with yellow mottling or green stripes. Almost 100% incidence was reported for some outbreaks in tomato, but not every fruit on an infected plant may show symptoms.

ToBRFV (like many tobamoviruses) is seed transmitted and can also be spread by mechanical means, contaminated equipment, as well as with plant or other materials. It is very stable and can remain infectious for months outside a host. Bumblebees, which are used widely as commercial pollinators in glasshouse tomato production, have been shown to be effective vectors of ToBRFV (see link below). Volunteer crop plants and solanaceous weed species are likely pathogen reservoirs. The Tm-22 resistance gene used in some tomato cultivars to protect from other tobamoviruses (such as _Tomato mosaic virus_) does not appear to be effective against ToBRFV. Disease management relies mainly on exclusion but may include phytosanitation (disinfecting tools, removing crop debris) and control of virus reservoirs. Use of certified clean seeds or crop transplants is crucial. Research on possible seed treatments to eliminate the virus is being carried out (see link below). Tomato seeds are traded widely and are known to pose a risk of spreading viruses and other pathogens internationally (e.g., ProMED post 20140122.2222560).

Coinfection of ToBRFV with _Pepino mosaic virus_ (genus _Potexvirus_) and _Tomato spotted wilt virus_ (TSWV; genus _Orthotospovirus_) has been found in tomato (ProMED posts 20191029.6751082, 20200507.7307615), as well as with TSWV in capsicum (see link below). It is thought that the respective symptoms may have been due to either virus or synergism. Further research is needed to clarify a potential role of ToBRFV in coinfections and to determine whether its presence in coinfections may have led to earlier cases of misdiagnosis and delayed identification of this new virus.
Pictures
ToBRFV on tomato:
https://gd.eppo.int/media/data/taxon/T/TOBRFV/pics/1024×0/4137.jpg and
https://gd.eppo.int/media/data/taxon/T/TOBRFV/pics/1024×0/4138.jpg
ToBRFV symptoms on capsicum:
https://agriculture.vic.gov.au/__data/assets/image/0009/555759/TOBRFV_figure-5.jpg

Links
Information and characterisation of ToBRFV:
https://gd.eppo.int/taxon/TOBRFV (with distribution and host list),
https://doi.org/10.1007/s00705-015-2677-7 (Jordan),
https://doi.org/10.1371/journal.pone.0170429 (Israel),
https://doi.org/10.1007/s42161-023-01436-8 (TSWV co-infection, capsicum) and via
https://www.semanticscholar.org/topic/Tomato-brown-rugose-fruit-virus/3579397
ToBRFV spread:
https://doi.org/10.1371/journal.pone.0282441 (new reservoir hosts) and
https://doi.org/10.1371/journal.pone.0210871 (by pollinators)
Tomato resistance breeding:
https://www.hortidaily.com/article/9544570/intermediate-resistance-ir-to-tobrfv-in-tomato-varieties-confirmed/,
https://www.hortidaily.com/article/9265808/we-can-eradicate-tobrfv-from-the-tomato-industry-with-our-newly-found-resistance/ and
https://www.hortidaily.com/article/9272889/commercial-tomato-variety-with-tobrfv-resistance-to-be-offered-in-early-2021/
ToBRFV seed treatment:
https://doi.org/10.1007/s10658-020-02151-1
Recent ToBRFV updates. Europe:
https://www.hortidaily.com/article/9574147/greece-tobrfv-found-in-laconia,
https://www.hortidaily.com/article/9571654/italy-tobrfv-virus-officially-confirmed- in-sardinia,
https://www.freshplaza.com/europe/article/9544392/new-measures-to-prevent-the-spread-of-the-tobrfv-virus-in-the-eu-will-apply-from-september/,
https://gd.eppo.int/reporting/article-7531 (1st report Slovakia, ex Austria) and
https://www.hortidaily.com/article/9507097/thirteen-new-tobrfv-infections-in-the-netherlands/ (first at seed production and breeding site)
International spread of tobamoviruses by seeds (review):
https://doi.org/10.5772/intechopen.70244
Virus taxonomy via:
https://ictv.global/taxonomy
EPPO A2 quarantine list:
https://www.eppo.int/ACTIVITIES/plant_quarantine/A2_list
– Mod.DHA

The power of underground fungi to shape forests.


The power of underground fungi to shape forests.

NOVEMBER 10, 2023

 Editors’ notes

by Chris Woolston, Washington University in St. Louis

A tree-lined path at Washington University’s environmental field station, Tyson Research Center, located near Eureka, Mo. Credit: Tyson Research Center

A large study involving 43 research plots in the Forest Global Earth Observatory (ForestGEO) Network—including a swath of trees at Tyson Research Center, the environmental field station of Washington University in St. Louis—has helped clarify the power of underground fungi to shape forests.

From the tropics to the far north, fungi in the soil seem to directly determine the number and types of trees that can thrive in a given area, said Jonathan Myers, an associate professor of biology whose work at Tyson contributed to the global findings. The study was published in Communications Biology.

Many trees depend on a special partnership with mycorrhizal fungi that grow around their roots. The fungi provide the tree with nitrogen, phosphorus and other nutrients, and the tree gives the fungi carbon in the form of sugar and lipids for energy. “It’s a mutually beneficial arrangement,” Myers said.

The results from this study suggest that fungi are more than casual acquaintances with their tree companions: the fungi drive diversity—or lack thereof.

Specifically, the underground back-and-forth helps explain why tropical forests can support multiple species of trees in a small area, why forests in the far north and south are often dominated by just a few species, and why the oak and hickory forests at Tyson fall near the middle of the diversity spectrum. “The study really zeroed in on one of the basic patterns in ecology, which is that forests become more diverse the closer you get to the equator,” Myers said.

Researchers used mathematical models and tree surveys to track the impact of different types of mycorrhizal fungi on diversity. As Myers explained, these come in two main types: arbuscular mycorrhizae (AM) and ectomycorrhizae (EM). AM fungi—”living fossils” that are essentially identical to the fungi that partnered with the earliest plants known to science—are especially abundant in the tropics. EM fungi, a newer arrival to the scene, become increasingly common farther from the equator.

The study suggests that a shift from one type of fungi to another has had major consequences for tree diversity. AM fungi are equal-opportunity partners that will support just about any AM tree species that happen to live nearby. Because the fungi are not too picky, any AM seedling or sapling trying to grow in a given spot can expect a boost from the local mycorrhizae.

EM fungi, in contrast, are much more discerning and will only help certain tree species—spurning all others. As a result, a sapling that depends on EM fungi is more likely to thrive if it can share space—and fungi—with a member of its own species. In that way, choosy fungi encourage communities of trees of the same species to cluster together.

EM fungi also help protect their favored species of trees from diseases. As Myers explained, this helpful action actually makes forests less diverse. If a forest suffers a disease outbreak that targets a specific type of tree, it could be risky to grow too close to a neighbor of the same species. But EM fungi reduce that risk, making it safer for trees to grow close to their own kind. AM fungi don’t offer as much disease protection, so trees in tropical forests find safety in diversity.

A better understanding of fungi helps put the trees of Tyson into perspective, Myers said. Roughly halfway between the tropics and the boreal forests of northern Canada, Tyson is home to both of the kinds of fungi examined in the study. It also boasts a moderate mix of trees—mostly varieties of hickories and oaks— that is neither wildly diverse nor unrelentingly monotonous. Tyson’s position between the extremes made it a valuable source of data for the global study, Myers said.

“We have just over 40 different species of trees on the plot that we studied, which is the size of about 45 football fields,” Myers said. “In most tropical forests, there would be hundreds of different species in a plot that size. In the boreal forests of northern Canada, there might be fewer than 10.”

To further understand the forces driving forest diversity, researchers should study exactly how fungi interact with tree roots at a physical and chemical level, Myers said. “We have a lot more work to do underground,” he said.

More information: Camille S. Delavaux et al, Mycorrhizal feedbacks influence global forest structure and diversity, Communications Biology (2023). DOI: 10.1038/s42003-023-05410-z

Journal information: Communications Biology 

Provided by Washington University in St. Louis 


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Forests found to benefit from tree species variety and genetic diversity

Research Protects U.S. Woodlands From Insect Pests


<img aria-describedby=”caption-attachment-21079″ data-attachment-id=”21079″ data-permalink=”https://entomologytoday.org/2023/11/28/usda-forest-service-research-protects-woodlands-insect-pests/monongahela-national-forest/” data-orig-file=”https://i0.wp.com/entomologytoday.org/wp-content/uploads/2023/11/monongahela-national-forest.jpg?fit=3000%2C2004&ssl=1″ data-orig-size=”3000,2004″ data-comments-opened=”1″ data-image-meta=”{“aperture”:”6.3″,”credit”:””,”camera”:”ILCE-7SM2″,”caption”:”Fall Colors looking over Mower Tract, Monongahela National Forest, West Virginia.rThe Mower Basin Trails are in an area known as the Mower Tract in Randolph county, on formerly mined lands that have been the focus of a partnership-led restoration effort for the past ten years. The trails meander through open meadows, high-elevation red spruce, and northern hardwood forests. (USDA Forest Service photo by Tanya E Flores)”,”created_timestamp”:”1696511544″,”copyright”:””,”focal_length”:”24″,”iso”:”100″,”shutter_speed”:”0.004″,”title”:””,”orientation”:”1″}” data-image-title=”Monongahela National Forest” data-image-description=”<p>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 <em>Journal of Integrated Pest Management</em> reviews USFS pest-management research from 2011 to 2020, which helped manage over 2.2 million hectares of forest. (Photo by <a href=”https://www.flickr.com/photos/usforestservice/53288379400/in/album-72177720312228746/”>USDA Forest Service via Flickr</a>, public domain)</p>
” data-image-caption=”<p>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 <em>Journal of Integrated Pest Management</em> reviews USFS pest-management research from 2011 to 2020, which helped manage over 2.2 million hectares of forest. (Photo by <a href=”https://www.flickr.com/photos/usforestservice/53288379400/in/album-72177720312228746/”>USDA Forest Service via Flickr</a>, public domain)

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. (Photo by USDA Forest Service via Flickr, public domain)

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 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 an article published in October in the Journal 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 the Who’s Who of 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.

<img aria-describedby=”caption-attachment-21081″ data-attachment-id=”21081″ data-permalink=”https://entomologytoday.org/2023/11/28/usda-forest-service-research-protects-woodlands-insect-pests/forest-service-pest-management-charts/” data-orig-file=”https://i0.wp.com/entomologytoday.org/wp-content/uploads/2023/11/forest-service-pest-management-charts.jpeg?fit=3000%2C2315&ssl=1″ data-orig-size=”3000,2315″ data-comments-opened=”1″ data-image-meta=”{“aperture”:”0″,”credit”:””,”camera”:””,”caption”:””,”created_timestamp”:”0″,”copyright”:””,”focal_length”:”0″,”iso”:”0″,”shutter_speed”:”0″,”title”:””,”orientation”:”1″}” data-image-title=”Forest Service pest management charts” data-image-description=”<p>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 <em>Journal of Integrated Pest Management</em> reviews 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, <em>Journal of Integrated Pest Management</em>)</p>
” data-image-caption=”<p>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 <em>Journal of Integrated Pest Management</em> reviews 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, <em>Journal of Integrated Pest Management</em>)

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. (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 hold so much information 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.



Silk lines help pirate spiders trick, capture eight-legged prey


‘IT’S WORKING AS A SPIDER WEB FOR CATCHING SPIDERS’

ex Nebraska Today

by Scott Schrage | University Communication and Marketing

Gilbert Barrantes / Laura Segura Hernández / Diego Solano Brenes

Gelanor siquirres, a species of pirate spider, descends from its dragline while pursuing prey in a Costa Rican rainforest.

Headlamps alone illuminated the trail bisecting the Costa Rican rainforest. Having waded the black of the Tirimbina reserve so often before, Gilbert Barrantes, Laura Segura Hernández and Diego Solano Brenes knew the routine.

It was time, dusk informed the surrounding spiders, to let loose the wind-aided, floating lines of silk that might latch onto leaf, branch or ground, fortifying the first beams of the food-snaring webs to come. But even on a night so familiar, the team would encounter a hunting scene unfamiliar not just to these arachnologists, in this forest, but all of them, anywhere.

“It was completely serendipitous,” said Segura Hernández, who earned her doctorate from the University of Nebraska–Lincoln in August.

What the trio stumbled on was a trap: lines floated not for framing but for fishing, part of a gambit that gives other forest-dwelling spiders just enough silk to hang themselves. And at the center of the scheme, not to mention the lines? A venomous pirate.

Four lines of that silk, the researchers realized, were running horizontally and diagonally from the underside of the same leaf. From elsewhere, the end of another thread had drifted in and caught on one of those leaf-dangling lines. That thread was the product of a spiderling now skittering along it to inspect the joint and, with its silken pillar secured, commence the construction of a full-fledged web.

“And then,” Segura Hernández said, “we just saw this other spider shoot in out of nowhere.”

The interloper was Gelanor siquirres, a species from the family known as pirate spiders — named for their willingness to invade already-built spider webs, strategically pluck threads to draw out their eight-legged inhabitants, and dine on them. This was something different. This G. siquirres emerged from its hiding spot beneath the leaf, scuttled across its own floating line, paralyzed its harried, hapless prey with a bite, then retreated to the leaf with the spiderling clutched in its ultra-long jaws.

A close look at that leaf would reveal the swashbuckler’s identity. A close look at the research literature would reveal that no one had ever reported the devious hunting technique, which the team has since witnessed multiple times. With a recent paper in the journal Animal Behaviour, the Tirimbina-trekking team would become the first.

“It’s working as a spider web for catching spiders,” Segura Hernández said of the lines floated by G. siquirres, which, like its pirate brethren, does not build circular webs. “That’s one of the cool things about it.”

Not the only thing, though. Pirate spiders are known as slow, deliberate killers: While venturing onto another spider’s web, Segura Hernández said, some pirates might advance no more than a few centimeters in an hour, lest they risk triggering any unwanted vibrations. The stealth makes sense when considering that the prey are also accomplished predators with venom of their own, and that G. siquirres, at no more than a half-inch long, is more David than Goliath.

Yet when another spider approaches one of its floating lines, G. siquirres darts forward with an alacrity that initially stunned Segura Hernández and her colleagues — the equivalent of a sloth turning cheetah.

“So it’s not just a modification of web-building behavior,” she said. “It’s a modification of the spider’s locomotion, as well.”

Footage of a pirate spider capturing a smaller arachnid before retreating to a leaf.

G. siquirres seems to have adapted its schedule, too, getting an early start to ensure that its floating lines are in place by the time its potential prey is releasing its own.

“It’s not like spiders make webs all night,” Segura Hernández said. “There’s clearly a peak period of activity, right after dark, where you see all of these floating lines on the trail. So it’s not like (G. siquirres) can do this in the morning. They are targeting this specific time period.”

There remains a lot to learn about G. siquirres, which was officially described and named in 2016 but had not, until now, been the subject of any peer-reviewed research. The fact that the first G. siquirres behavior ever documented happens to double as a behavior never seen in any spider speaks to how much remains unknown about the eight-legged wonders as a whole, Segura Hernández said, especially those residing in prey-rich rainforests.

G. siquirres feeding on its prey, an immature spider (white arrow) that touched the silk line its predator had earlier floated as a trap.

For her, it also underscores the value of not overlooking observation itself, of remembering to seek ideas, questions and answers not just in pages but the wild. She hasn’t forgotten the words of Bill Eberhard, who mentored her as an undergrad at the University of Costa Rica and was commemorated in the same journal issue that features the G. siquirres study.

“One of my favorite things about this paper is that it highlights how important it is — what Bill Eberhard taught us — to observe and just pay attention to detail,” she said. “Sometimes people are so focused on hypotheses and questions that they kind of forget about the organisms. But I think both things are equally important.

“Can we even envision how many more incredible hunting strategies there are just waiting to be observed?”

It was that spirit, in part, that encouraged her to spend so much time wandering in Tirimbina. At this point, she can’t recall any specific reason that she and the others were out that fateful night. Not that she needed one. The rainforest itself — the trill of insects and pattering of lizards, the aromas of wildflowers floating, like the spider silk, on a breeze — offered its own draw.

“Everything is alive. And at night, it has a mystery. You realize how much you rely on vision, because you’re restricted to what your headlamp can show.

“But that one time, we were just walking down the trail, talking about something,” she said, “and then we noticed the silk.”

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Bacteria make lunar soil more fertile


Bacteria make lunar soil more fertile

by Bob Yirka , Phys.org

The photography of partial plants in two control groups and four treatments. We selected 11 images for each group of plants, including plants at the median leaf diameter of each treatment in the middle of the row, as well as five slightly larger and five slightly smaller plants on the left and the right. Each row of images shares one ruler, which is given in the image on the far right. The identifier of each image is given at the bottom of each image. Credit: Communications Biology (2023). DOI: 10.1038/s42003-023-05391-z

A team of agronomists and biotechnicians at China Agricultural University has found that adding bacteria to simulated lunar regolith increased the amount of phosphate in the soil for use by plants. In their study, published in the journal Communications Biology, the group added three types of bacteria to samples of volcanic material and then tested them for acidity and their ability to grow plants.

https://7dec37ccb6d1a85685906406b7021d19.safeframe.googlesyndication.com/safeframe/1-0-40/html/container.html

As several countries make plans to send humans back to the moon, they must address several issues—one of the most basic is figuring out a way to feed people working there for an extended period of time. The obvious solution is for workers to grow their own food. But that presents problems, as well, such as how to transport soil for growing edible plants from Earth to the moon.

Some have suggested that moon soil, known as lunar regolith, might be treated to make it amenable to plant growth. Last year, a team in the U.S. showed that it is possible to grow plants in lunar regolith by growing a small number of weeds called thale cress in real lunar soil samples. That test showed that lunar soil can work, but not well enough for plants to mature and produce food. In this new study, the research team found that adding microbes to lunar soil can improve its ability to host plant life.

To test the possibility of using microbes such as bacteria to make lunar regolith more hospitable to plant life, the research team obtained samples of volcanic material from a mountain in China—testing showed it to be a reasonable stand-in for regolith. The researchers then added one of three types of bacteria to three test pots filled with the volcanic material: Pseudomonas fluorescens, Bacillus megaterium and Bacillus mucilaginosus.

After cultivating the bacteria in the soil samples, the researchers tested the samples to see the effects. They found that the addition of all three types of bacteria had made the soil samples more acidic, which resulted in reducing the pH level of the soil. That dissolved the insoluble phosphate-containing minerals in the soil, which released phosphorus, making it available for plants.

The research team then directly tested the treated soil by planting Nicotiana benthamiana (benth). They found that the enhanced soil produce plants with more robust roots, longer stems and bigger leaves compared to untreated samples.

More information: Yitong Xia et al, Phosphorus-solubilizing bacteria improve the growth of Nicotiana benthamiana on lunar regolith simulant by dissociating insoluble inorganic phosphorus, Communications Biology (2023). DOI: 10.1038/s42003-023-05391-z

Journal information: Communications Biology 

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