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Archive for the ‘Pest diagnostics’ Category

NEWS RELEASE 29-JUN-2021

DNA barcodes decode the world of soil nematodes

To understand soil ecosystems and contribute to advanced agriculture

TOYOHASHI UNIVERSITY OF TECHNOLOGY (TUT)

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IMAGE: SOIL SAMPLING SITES (TOP). CLASSIFICATION OF SOIL NEMATODE COMMUNITIES BY FEEDING GROUP (RESULTS FOR BARCODE REGION 4) (BOTTOM). view more CREDIT: COPYRIGHT (C) TOYOHASHI UNIVERSITY OF TECHNOLOGY. ALL RIGHTS RESERVED.

Overview

The research team of Professor Toshihiko Eki of the Department of Applied Chemistry and Life Science (and Research Center for Agrotechnology and Biotechnology), Toyohashi University of Technology used a next-generation sequencer to develop a highly efficient method to analyze soil nematodes by using the 18S ribosomal RNA gene regions as DNA barcodes. They successfully used this method to reveal characteristics of nematode communities that inhabit fields, copses, and home gardens. In the future, the target will be expanded to cover all soil-dwelling organisms in agricultural soils, etc., to allow investigations into a soil’s environment and bio-diversity. This is expected to contribute to advanced agriculture.

Details

Similar to when the UN declared 2015 to be the International Year of Soils, there have recently been many efforts worldwide to raise awareness of the importance of the soil that covers our Earth and its conservation. Diverse groups of organisms such as bacteria, fungi, protists, and small soil animals inhabit the soil, and together they form the soil ecosystem. Nematodes are a representative soil animal; they are a few millimeters long and have a shape resembling a worm. They play an important role in the cycling of soil materials. Many soil nematodes are bacteria feeders, but they have a wide variety of feeding habits, such as feeding on fungi, plant parasitism, or being omnivorous. In particular, plant parasitic nematodes often cause devastating damage to crops. Therefore, the classification and identification of nematodes is also important from an agricultural standpoint. However, nematodes are diverse, and there are over 30,000 species. Additionally, because nematodes resemble one another, morphological identification of nematodes is difficult for anyone but experts.

The research team focused on “DNA barcoding” to identify the species based on their unique nucleotide sequences of a barcode gene, and they established a method using a next-generation sequencer that can decode huge numbers of nucleotide sequences. They used this to analyze nematode communities from different soil environments. Initially, four DNA barcode regions were set for the 18S ribosomal RNA genes shared by eukaryotes. The soil nematodes used for analysis were isolated from an uncultivated field, a copse, and a home garden growing zucchini. The PCR was used to amplify the four gene fragments from the DNA of the nematodes and determine the nucleotide sequences. Additionally, the nematode-derived sequence variants (SVs) representing independent nematode species were identified, and after taxonomical classification and analysis of the SVs, it was revealed that plant parasitizing nematodes were abundant in the copse soil and bacteria feeders were abundant in the soil from the home garden. It was also determined that predatory nematodes and omnivorous nematodes were abundant in the uncultivated field, in addition to bacteria feeders.

This DNA barcoding method using a next-generation sequencer is widely used for the analysis of intestinal microbiota, etc., but analyses of eukaryotes such as nematodes are still in the research stage. This research provides an example of its usefulness for the taxonomic profiling of soil nematodes.

Development Background

Research team leader Toshihiko Eki stated, “Through genetic research, I have been working with nematodes (mainly C. elegans) for around 20 years. As a member of our university’s Research Center for Agrotechnology and Biotechnology, I came up with this theme while considering research that we could perform that is related to agriculture. As a test, we isolated nematodes from the university’s soybean field and unmanaged flowerbed and analyzed the DNA barcode for each nematode. Bacteria feeders were abundant in the soybean field, and that was used for comparison with the flowerbed, where weed-parasitizing nematodes and their predator nematodes were abundant. This discovery was the start of our research (Morise et al., PLoS ONE, 2012). If that method using one-by-one DNA sequencing was the first generation, the current method using the next-generation sequencer is the second generation, and we were able to clarify characteristics of nematode communities representing the three ecologically different soil environments according to expectations.”

Future Outlook

Currently, the research team is developing the third-generation DNA barcoding method which involves purifying DNA directly from the soil and analyzing the organisms in the whole soil instead of isolating and analyzing any particular soil-dwelling organisms. They are currently analyzing the soil biota of cabbage fields, etc. They are aiming to precisely analyze how communities of soil-dwelling organisms including microbes change with crop growth, clarify the effects that cultivated plants have on these organisms, and investigate biota closely related to plant diseases. If this research moves forward, crops can be cultivated and managed logically based on biological data in agricultural soils, and it can contribute to advancing smart agriculture in Japan, such as in the prominent Higashi-Mikawa agriculture region and beyond.

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This research was performed with the support of the Takahashi Industrial and Economic Research Foundation.

Reference

Harutaro Kenmotsu, Masahiro Ishikawa, Tomokazu Nitta, Yuu Hirose and Toshihiko Eki (2021). Distinct community structures of soil nematodes from three ecologically different sites revealed by high-throughput amplicon sequencing of four 18S ribosomal RNA gene regions.
PLoS ONE, 16(4): e0249571.

Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.

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JUNE 25, 2021

Kiwi disease study finds closely related bacterial strains display different behaviors

by American Phytopathological Society

Kiwi disease study finds closely related bacterial strains display different behaviors
Elodie Vandelle, Annalisa Polverari, Davide Danzi, Vanessa Maurizio, Alice Regaiolo, Maria Rita Puttilli, Teresa Colombo, Tommaso Libardi. Credit: Elodie Vandelle

Over the last decade, severe outbreaks of bacterial canker have caused huge economic losses for kiwi growers, especially in Italy, New Zealand, and China, which are among the largest producers. Bacterial canker is caused by the bacterial pathogen Pseudomonas syringae pv. actinidiae (Psa) and more recent outbreaks have been particularly devastating due to the emergence of a new, extremely aggressive biovar called Psa3.

Due to its recent introduction, the molecular basis of Psa3’s virulence is unknown, making it difficult to develop mitigation strategies. In light of this dilemma, a group of scientists at the University of Verona and University of Rome collaborated on a study comparing the behavior of Psa3 with less-virulent biovars to determine the basis of pathogenicity.

They found that genes involved in bacterial signaling (the transmission of external stimuli within cells) were especially important, especially the genes required for the synthesis and degradation of a small chemical signal called c-di-GMP, that suppresses the expression of virulence factors. Compared to other biovars, Psa3 produces very low levels of c-di-GMP, contributing to an immediate and aggressive phenotype at the onset of infection before the plant can corral a defense response.

“It was exciting to discover this diversified arsenal of pathogenicity strategies among closely related bacterial strains that infect the same hosts but display different behaviors,” said Elodie Vandelle, one of the scientists involved with this study. “Although their ‘small’ genomes mainly contain the same information, our research shows that bacterial populations within a pathovar are more complex than expected and their pathogenicity may have evolved throughout different strategies to attack the same host.”

Their research highlights the importance of working on a multitude of real-life pathogenic bacterial strains to shed light on the diversity of virulence strategies. This approach can contribute to the creation of wider pathogenicity working models. In terms of kiwi production, Vandelle hopes their findings can help scientists develop new mitigation methods. In the long-term, their research could lead to the identification of key molecular switches responsible for the transition between high and low bacterial virulence phenotypes.

“This identification would allow, at industrial level, to develop new targeted strategies to control phytopathogenic bacteria, weakening their aggressiveness through switch control, instead of killing them,” Vandelle explained. “This would avoid the occurrence of new resistances among bacterial communities, thus guaranteeing a sustainable plant protection.”


Explore furtherUnpacking the two layers of bacterial gene regulation during plant infection


More information: Elodie Vandelle et al, Transcriptional Profiling of ThreePseudomonas syringaepv.actinidiaeBiovars Reveals Different Responses to Apoplast-Like Conditions Related to Strain Virulence on the Host, Molecular Plant-Microbe Interactions (2020). DOI: 10.1094/MPMI-09-20-0248-RJournal information:Molecular Plant-Microbe InteractionsProvided by American Phytopathological Society

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Identifying ToBRFV and ToMV using CRISPR/Cas

CRISPR/Cas12a-based detection is a novel approach for the efficient, sequence-specific identification of viruses. In new research,  CRISPR/Cas12a is used to identify the tomato brown rugose fruit virus (ToBRFV), a new and emerging tobamovirus that is causing substantial damage to the global tomato industry.

Specific CRISPR RNAs (crRNAs) were designed to detect either ToBRFV or the closely related tomato mosaic virus (ToMV). This technology enabled the differential detection of ToBRFV and ToMV.

Sensitivity assays revealed that viruses can be detected from 15–30 ng of RT-PCR product, and that specific detection could be achieved from a mix of ToMV and ToBRFV.

“In addition, we show that this method can enable the identification of ToBRFV in samples collected from commercial greenhouses. These results demonstrate a new method for species-specific detection of tobamoviruses,” the researchers explain. “A future combination of this approach with isothermal amplification could provide a platform for efficient and user-friendly ways to distinguish between closely related strains and resistance-breaking pathogens.” 

Read the complete research here.

Alon, Dan & Hak, Hagit & Bornstein, Menachem & Pines, Gur & Spiegelman, Ziv. (2021). Differential Detection of the Tobamoviruses Tomato Mosaic Virus (ToMV) and Tomato Brown Rugose Fruit Virus (ToBRFV) Using CRISPR-Cas12a. Plants. 10. 1256. 10.3390/plants10061256. 

Publication date: Fri 25 Jun 2021

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New technology enables rapid sequencing of entire genomes of plant pathogens

Date:May 15, 2021Source: American Phytopathological Society Summary: Next-generation sequencing technology has made it easier than ever for quick diagnosis of plant diseases.Share:FULL STORY


Next-generation sequencing technology has made it easier than ever for quick diagnosis of plant diseases. “It’s really exciting to see how sequencing technologies have evolved and how this new technology facilitates sequencing of entire genomes in such a short amount of time,” said Yazmín Rivera, a plant pathologist with the United States Department of Agriculture’s Plant Protection and Quarantine program, who recently published a research paper on the efficacy of Oxford Nanopore Technologies protocols.

“We wanted to provide an unbiased assessment of the technology and protocols available for long read sequencing,” Rivera explained. Along with other plant pathologists, Rivera used the company’s protocols to prepare RNA and DNA libraries from virus-infected plant material and from a plant pathogenic bacterium, respectively. After one hour of data sequencing, scientists had enough data to assemble small genomes.

“Diagnosticians will welcome an objective review of this technology,” Rivera said. Rivera and her colleagues published their findings in Plant Health Progress, presenting a side-by-side comparison of the protocols that will allow the reader to identify which library preparation kit is best suited for their needs.

The ability to quickly obtain the entire genome of an organism has great implications for the plant pathology field. “Having more information readily available facilitates identification of emerging pathogens and of pathogens that are difficult to identify,” explains Rivera. For more information, read “Comparison of Nanopore Sequencing Protocols and Real-Time Analysis for Phytopathogen Diagnostics” published in the March issue of Plant Health Progress.

Disclaimer: Mention of trade names or commercial products in this publication is solely to provide specific information and does not imply recommendation or endorsement by the U.S. Department of Agriculture.


Story Source:

Materials provided by American Phytopathological SocietyNote: Content may be edited for style and length.


Journal Reference:

  1. Tommy Phannareth, Schyler O. Nunziata, Michael J. Stulberg, Marco E. Galvez, Yazmín Rivera. Comparison of Nanopore Sequencing Protocols and Real-Time Analysis for Phytopathogen DiagnosticsPlant Health Progress, 2021; 22 (1): 31 DOI: 10.1094/PHP-02-20-0013-RS

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NEWS RELEASE 14-MAY-2021

EurekAlert

New technology enables rapid sequencing of entire genomes of plant pathogens

AMERICAN PHYTOPATHOLOGICAL SOCIETY

Research NewsSHARE PRINT E-MAIL

Next-generation sequencing technology has made it easier than ever for quick diagnosis of plant diseases. “It’s really exciting to see how sequencing technologies have evolved and how this new technology facilitates sequencing of entire genomes in such a short amount of time,” said Yazmín Rivera, a plant pathologist with the United States Department of Agriculture’s Plant Protection and Quarantine program, who recently published a research paper on the efficacy of Oxford Nanopore Technologies protocols.

“We wanted to provide an unbiased assessment of the technology and protocols available for long read sequencing,” Rivera explained. Along with other plant pathologists, Rivera used the company’s protocols to prepare RNA and DNA libraries from virus-infected plant material and from a plant pathogenic bacterium, respectively. After one hour of data sequencing, scientists had enough data to assemble small genomes.

“Diagnosticians will welcome an objective review of this technology,” Rivera said. Rivera and her colleagues published their findings in Plant Health Progress, presenting a side-by-side comparison of the protocols that will allow the reader to identify which library preparation kit is best suited for their needs.

The ability to quickly obtain the entire genome of an organism has great implications for the plant pathology field. “Having more information readily available facilitates identification of emerging pathogens and of pathogens that are difficult to identify,” explains Rivera. For more information, read “Comparison of Nanopore Sequencing Protocols and Real-Time Analysis for Phytopathogen Diagnostics“? published in the March issue of Plant Health Progress.

###

Disclaimer: Mention of trade names or commercial products in this publication is solely to provide specific information and does not imply recommendation or endorsement by the U.S. Department of Agriculture.

Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.SHARE PRINT

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GarciaArocajpg.jpg

Teddy Garcia-Aroca, an LSU Ph.D. student, holds a sample of a fungus he found and named that causes the disease soybean taproot decline.Discovery just “tip of the iceberg” as scientists strive to learn more about this devastating soybean disease.

Bruce Shultz, Louisiana State University | Apr 13, 2021

An LSU graduate student has identified and named a new species of fungus that causes a devastating soybean disease. 

LSU doctoral student Teddy Garcia-Aroca identified and named the fungus Xylaria necrophora, the pathogen that causes soybean taproot decline. He chose the species name necrophora after the Latin form of the Greek word “nekros,” meaning “dead tissue,” and “-phorum,” a Greek suffix referring to a plant’s stalk. https://f51f4f44a38d9cb02edf74f97f4f06e6.safeframe.googlesyndication.com/safeframe/1-0-38/html/container.html

“It’s certainly a great opportunity for a graduate student to work on describing a new species,” said Vinson Doyle, LSU AgCenter plant pathologist and co-advisor on the research project. “It opens up a ton of questions for us. This is just the tip of the iceberg.” 

Taproot decline

The fungus infects soybean roots, causing them to become blackened while causing leaves to turn yellow or orange with chlorosis. The disease has the potential to kill the plant. 

“It’s a big problem in the northeast part of the state,” said Trey Price, LSU AgCenter plant pathologist who is Garcia-Aroca’s major professor and co-advisor with Doyle. 

“I’ve seen fields that suffered a 25% yield loss, and that’s a conservative estimate,” Price said. Heather Kellytaproot decline in soybeans

Yellowing leaves are early symptoms of taproot decline in soybeans.

Louisiana soybean losses from the disease total more than one million bushels per year. 

Price said the disease has been a problem for many years as pathologists struggled to identify it. Some incorrectly attributed it to related soybean diseases such as black-root rot. 

“People called it the mystery disease because we didn’t know what caused it.” 

Price said while Garcia-Aroca was working on the cause of taproot decline, so were labs at the University of Arkansas and Mississippi State University. 

Price said the project is significant. “It’s exciting to work on something that is new. Not many have the opportunity to work on something unique.” 

Research 

Garcia-Aroca compared samples of the fungus that he collected from infected soybeans in Louisiana, Arkansas, Tennessee, Mississippi and Alabama with samples from the LSU Herbarium and 28 samples from the U.S. National Fungus Collections that were collected as far back as the 1920s. 

Some of these historical samples were collected in Louisiana sugarcane fields, but were not documented as pathogenic to sugarcane. In addition, non-pathogenic samples from Martinique and Hawaii were also used in the comparison, along with the genetic sequence of a sample from China. 

Garcia-Aroca said these historical specimens were selected because scientists who made the earlier collections had classified many of the samples as the fungus Xylaria arbuscula that causes diseases on macadamia and apple trees, along with sugarcane in Indonesia. But could genetic testing of samples almost 100 years old be conducted? “It turns out it was quite possible,” he said. 

DNA sequencing showed a match for Xylaria necrophora for five of these historical, non-pathogenic samples — two from Louisiana, two from Florida, and one from the island of Martinique in the Caribbean — as well as DNA sequences from the non-pathogenic specimen from China. All of these were consistently placed within the same group as the specimens causing taproot decline on soybeans. 

Why now? 

Garcia-Aroca said a hypothesis that could explain the appearance of the pathogen in the region is that the fungus could have been in the soil before soybeans were grown, feeding on decaying wild plant material, and it eventually made the jump to live soybeans. 

Arcoa’s study poses the question of why the fungus, after living off dead woody plant tissue, started infecting live soybeans in recent years. “Events underlying the emergence of X. necrophora as a soybean pathogen remain a mystery,” the study concludes. 

But he suggests that changes in the environment, new soybean genetics and changes in the fungal population may have resulted in the shift. 

The lifespan of the fungus is not known, Garcia-Aroca said, but it thrives in warmer weather of at least 80 degrees. Freezing weather may kill off some of the population, he said, but the fungus survives during the winter by living on buried soybean plant debris left over from harvest. It is likely that soybean seeds become infected with the fungus after coming in contact with infected soybean debris from previous crops. These hypotheses remain to be tested. 

Many of the fungal samples were collected long before soybeans were a major U.S. crop, Doyle said. “The people who collected them probably thought they weren’t of much importance.” 

Garcia-Aroca said this illustrates the importance of conducting scientific exploration and research as well as collecting samples from the wild. “You never know what effect these wild species have on the environment later on.” 

What’s next? 

Now that the pathogen has been identified, Price said, management strategies need to be refined. Crop rotation and tillage can be used to reduce incidence as well as tolerant varieties. 

“We’ve installed an annual field screening location at the Macon Ridge Research Station where we provide taproot decline rating information for soybean varieties,” Price said. “In-furrow and fungicide seed treatments may be a management option, and we have some promising data on some materials. However, some of the fungicides aren’t labeled, and we need more field data before we can recommend any.” 

He said LSU, Mississippi State and University of Arkansas researchers are collaborating on this front. 

Doyle said Garcia-Aroca proved his work ethic on this project. “It’s tedious work and just takes time. Teddy has turned out to be very meticulous and detailed.” 

The final chapter in Garcia-Aroca’s study, Doyle said, will be further research into the origins of this fungus and how it got to Louisiana. Source: Louisiana State University, which is solely responsible for the information provided and is wholly owned by the source. Informa Business Media and all its subsidiaries are not responsible for any of the content contained in this information asset.  

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SunMedia

New app to detect plants at risk from myrtle rust

Capsules (also known as gumnuts) of Eucalyptus pilularis. Features like this can enable users of the NZ Myrtaceae Key to identify species of interest. Supplied photo.

People keen to support the fight against the fungal disease myrtle rust, which threatens many of Aotearoa-New Zealand’s native trees, shrubs and climbers, now have a new tool to help identify vulnerable plants in the myrtle family.

Manaaki Whenua – Landcare Research and Biosecurity New Zealand have partnered in the development of the NZ Myrtaceae Key – a free app that makes it easy for citizen biosecurity volunteers to identify susceptible plants and keep an eye out for the fungal disease myrtle rust.

Myrtle rust has already spread across the top half of the North Island and cases have been recorded as far south as Greymouth.

“We know how much damage plant pests and diseases are causing overseas, and science partnerships, like this, will help us stay ahead,” says Veronica Herrera, MPI’s diagnostics and surveillance services director.

The NZ Myrtaceae Key is a Lucid identification tool envisaged and funded by Biosecurity New Zealand and developed by botanists from Manaaki Whenua, the National Forestry Herbarium, Unitec, and other experts.

The app is easy-to-use, interactive and comprehensively illustrated with more than 1,600 fully captioned images built in and it is downloadable for both iPhone and Android smartphones.

“The key includes more than 100 of the most commonly found Myrtaceae species, subspecies, hybrids and cultivars in New Zealand. Of these, 27 species, such as the iconic pōhutukawa, mānuka and kānuka, are indigenous to New Zealand: others, such as feijoa and eucalyptus, are exotics of economic importance,” says Dr Herrera.

Manaaki Whenua – Landcare Research researcher, Murray Dawson says the arrival of the windborne myrtle rust in 2017 gave a new importance to being able to identify Myrtaceae as heavily infected plants inevitably die.

“The disease is a threat to the important and substantial mānuka and kānuka honey industry. Using the new app to accurately identify species of Myrtaceae in New Zealand will make it easier to monitor and report cases of myrtle rust.

“By using the key, anyone, from farmers and trampers to gardeners and park users, will be able to identify plants to check for and report the tell-tale yellow spores, and diseased leaves,” says Mr Dawson.

To use the app, the characteristics of the plant being identified are entered, the app then sorts plants possessing these features, and it rejects those that don’t match. By progressively choosing additional features, the key will eventually narrow the results to just one or a few matching species.

Once you’ve correctly identified a plant in the myrtle family and if you think you see signs of the disease on it, don’t touch it.

If you have a camera or mobile phone you can take a photo and submit it to the iNaturalist website. Experts can check to confirm whether it is myrtle rust.

Capturing this information makes it available to agencies and scientists to analyse the rate of spread and observed impacts.

The NZ Myrtaceae Key is available from the Google Play (Android) store and the iPhone app store as a mobile (smartphone) app suitable for undertaking identifications in the field, or through a web-based browser hosted by Manaaki Whenua.

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science daily

Nanosensor can alert a smartphone when plants are stressed

Carbon nanotubes embedded in leaves detect chemical signals that are produced when a plant is damaged

Date:
April 15, 2020
Source:
Massachusetts Institute of Technology
Summary:
Engineers can closely track how plants respond to stresses such as injury, infection, and light damage using sensors made of carbon nanotubes. These sensors can be embedded in plant leaves, where they report on hydrogen peroxide levels.
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MIT engineers have developed a way to closely track how plants respond to stresses such as injury, infection, and light damage, using sensors made of carbon nanotubes. These sensors can be embedded in plant leaves, where they report on hydrogen peroxide signaling waves.

Plants use hydrogen peroxide to communicate within their leaves, sending out a distress signal that stimulates leaf cells to produce compounds that will help them repair damage or fend off predators such as insects. The new sensors can use these hydrogen peroxide signals to distinguish between different types of stress, as well as between different species of plants.

“Plants have a very sophisticated form of internal communication, which we can now observe for the first time. That means that in real-time, we can see a living plant’s response, communicating the specific type of stress that it’s experiencing,” says Michael Strano, the Carbon P. Dubbs Professor of Chemical Engineering at MIT.

This kind of sensor could be used to study how plants respond to different types of stress, potentially helping agricultural scientists develop new strategies to improve crop yields. The researchers demonstrated their approach in eight different plant species, including spinach, strawberry plants, and arugula, and they believe it could work in many more.

Strano is the senior author of the study, which appears today in Nature Plants. MIT graduate student Tedrick Thomas Salim Lew is the lead author of the paper.

Embedded sensors

Over the past several years, Strano’s lab has been exploring the potential for engineering “nanobionic plants” — plants that incorporate nanomaterials that give the plants new functions, such as emitting light or detecting water shortages. In the new study, he set out to incorporate sensors that would report back on the plants’ health status.

Strano had previously developed carbon nanotube sensors that can detect various molecules, including hydrogen peroxide. About three years ago, Lew began working on trying to incorporate these sensors into plant leaves. Studies in Arabidopsis thaliana, often used for molecular studies of plants, had suggested that plants might use hydrogen peroxide as a signaling molecule, but its exact role was unclear.

Lew used a method called lipid exchange envelope penetration (LEEP) to incorporate the sensors into plant leaves. LEEP, which Strano’s lab developed several years ago, allows for the design of nanoparticles that can penetrate plant cell membranes. As Lew was working on embedding the carbon nanotube sensors, he made a serendipitous discovery.

“I was training myself to get familiarized with the technique, and in the process of the training I accidentally inflicted a wound on the plant. Then I saw this evolution of the hydrogen peroxide signal,” he says.

He saw that after a leaf was injured, hydrogen peroxide was released from the wound site and generated a wave that spread along the leaf, similar to the way that neurons transmit electrical impulses in our brains. As a plant cell releases hydrogen peroxide, it triggers calcium release within adjacent cells, which stimulates those cells to release more hydrogen peroxide.

“Like dominos successively falling, this makes a wave that can propagate much further than a hydrogen peroxide puff alone would,” Strano says. “The wave itself is powered by the cells that receive and propagate it.”

This flood of hydrogen peroxide stimulates plant cells to produce molecules called secondary metabolites, such as flavonoids or carotenoids, which help them to repair the damage. Some plants also produce other secondary metabolites that can be secreted to fend off predators. These metabolites are often the source of the food flavors that we desire in our edible plants, and they are only produced under stress.

A key advantage of the new sensing technique is that it can be used in many different plant species. Traditionally, plant biologists have done much of their molecular biology research in certain plants that are amenable to genetic manipulation, including Arabidopsis thaliana and tobacco plants. However, the new MIT approach is applicable to potentially any plant.

“In this study, we were able to quickly compare eight plant species, and you would not be able to do that with the old tools,” Strano says.

The researchers tested strawberry plants, spinach, arugula, lettuce, watercress, and sorrel, and found that different species appear to produce different waveforms — the distinctive shape produced by mapping the concentration of hydrogen peroxide over time. They hypothesize that each plant’s response is related to its ability to counteract the damage. Each species also appears to respond differently to different types of stress, including mechanical injury, infection, and heat or light damage.

“This waveform holds a lot of information for each species, and even more exciting is that the type of stress on a given plant is encoded in this waveform,” Strano says. “You can look at the real time response that a plant experiences in almost any new environment.”

Stress response

The near-infrared fluorescence produced by the sensors can be imaged using a small infrared camera connected to a Raspberry Pi, a $35 credit-card-sized computer similar to the computer inside a smartphone. “Very inexpensive instrumentation can be used to capture the signal,” Strano says.

Applications for this technology include screening different species of plants for their ability to resist mechanical damage, light, heat, and other forms of stress, Strano says. It could also be used to study how different species respond to pathogens, such as the bacteria that cause citrus greening and the fungus that causes coffee rust.

“One of the things I’m interested in doing is understanding why some types of plants exhibit certain immunity to these pathogens and others don’t,” he says.

Strano and his colleagues in the Disruptive and Sustainable Technology for Agricultural Precision interdisciplinary research group at the MIT-Singapore Alliance for Research and Technology (SMART), MIT’s research enterprise in Singapore, are also interested in studying is how plants respond to different growing conditions in urban farms.

One problem they hope to address is shade avoidance, which is seen in many species of plants when they are grown at high density. Such plants turn on a stress response that diverts their resources into growing taller, instead of putting energy into producing crops. This lowers the overall crop yield, so agricultural researchers are interested in engineering plants so that don’t turn on that response.

“Our sensor allows us to intercept that stress signal and to understand exactly the conditions and the mechanism that are happening upstream and downstream in the plant that gives rise to the shade avoidance,” Strano says.

The research was funded by the National Research Foundation of Singapore, the Singapore Agency for Science, Technology, and Research (A*STAR), and the U.S. Department of Energy Computational Science Graduate Fellowship Program.


Story Source:

Materials provided by Massachusetts Institute of Technology. Original written by Anne Trafton. Note: Content may be edited for style and length.


Journal Reference:

  1. Tedrick Thomas Salim Lew, Volodymyr B. Koman, Kevin S. Silmore, Jun Sung Seo, Pavlo Gordiichuk, Seon-Yeong Kwak, Minkyung Park, Mervin Chun-Yi Ang, Duc Thinh Khong, Michael A. Lee, Mary B. Chan-Park, Nam-Hai Chua, Michael S. Strano. Real-time detection of wound-induced H2O2 signalling waves in plants with optical nanosensors. Nature Plants, 2020; 6 (4): 404 DOI: 10.1038/s41477-020-0632-4

Cite This Page:

Massachusetts Institute of Technology. “Nanosensor can alert a smartphone when plants are stressed: Carbon nanotubes embedded in leaves detect chemical signals that are produced when a plant is damaged.” ScienceDaily. ScienceDaily, 15 April 2020. <www.sciencedaily.com/releases/2020/04/200415133512.htm>.

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A “superb” southwestern Missouri cicada, Neotibicen superbus

Back in the summer of 2015, I made an early August trip to the White River Hills region of extreme southwestern Missouri. I was actually looking for one of Missouri’s more uncommon cerambycid beetles – Prionus pocularis, associated with shortleaf pine in the mixed hardwood/pine forests across the southern part of the state. I did not encounter the beetle in either my prionic acid-baited pitfall traps or at the ultraviolet lights I had set up the evening before, but while I was in the area I thought I would visit one of my favorite places in the region – Drury-Mincy Conservation Area in Taney Co. Sitting right on the border with Arkansas, the rolling hills of this area feature high-quality dolomite glades and post oak savannas. I’ve had some excellent collecting here in the past and hoped I would find something of interest this time as well. I didn’t arrive until after midnight, and since there are no hotels in the area I just slept in the car.

Neotibicen superbus

The next morning temperatures began to rise quickly, and with it so did the cacophony of cicadas getting into high gear with their droning buzz calls. As I passed underneath one particular tree I noticed the song was coming from a branch very near my head. I like cicadas, but had it been the song of a “normal” cicada like Neotibicen lyricen (lyric cicada) or N. pruinosus (scissor grinder cicada) I would have paid it no mind. It was, instead, unfamiliar and distinctive, and when I searched the branches above me I recognized the beautiful insect responsible for the call as Neotibicen superbus (superb cicada), a southwest Missouri specialty—sumptuous lime-green above and bright white pruinose beneath. I had not seen this spectacular species since the mid 1980s (most of my visits to the area have been in the spring or the fall rather than high summer), and I managed to catch it and take a quick iPhone photograph for documentation. A species this beautiful, however, deserves ‘real’ photos, so I spent the next couple of hours attempting to photograph an individual in situ with the big camera. Of course, this is much, much easier said than done, especially with this species—their bulging eyes give them exceptional vision, and they are very skittish and quick to take flight. Most of the individuals that I located were too high up in the canopy to allow a shot, and each individual that was low enough for me to approach ended up fluttering off with a screech before I could even compose a shot, much less press the shutter. Persistence paid, however, and I eventually managed to approach and photograph an unusually calm female resting – quite conveniently – at chest height on the trunk of a persimmon tree.

Sanborn-Phillips_2013_Fig-16

According to Sanborn & Phillips (2013, Figure 16 – reproduced above), Neotibicen superbus, is found in trees within grassland environments primarily in eastern Texas and Oklahoma, although records of it exist from each of the surrounding states – especially southern Missouri and northern Arkansas (Figure 16 below, Sanborn & Phillips 2013). Later the same day I would see the species abundantly again in another of the region’s dolomite glades – this one in Roaring River State Park further west in Barry Co., suggesting that dolomite glades are the preferred habitat in this part of its range. Interestingly, I think the Missouri records at least must be relatively recent, as Froeschner (1952) did not include the species in his synopsis of Missouri cicadas. This was all the information I had back in the 1980s when I first encountered the species in southwestern Missouri, its apparent unrecorded status in the state making it an even more exciting find at the time.

Neotibicen superbus

REFERENCES:

Froeschner, R. C.  1952. A synopsis of the Cicadidae of Missouri. Journal of the New York Entomological Society 60:1–14 [pdf].

Sanborn, A. F. & P. K. Phillips. 2013. Biogeography of the cicadas (Hemiptera: Cicadidae) of North America, north of Mexico. Diversity 5(2):166–239 [abstractpdf].

© Ted C. MacRae 2018

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Thursday, June 28, 2018 Notification

New planthopper species, Sogatella unidentata (Hemiptera: Delphacidae), described from Argentina
Source: Revista Brasileira de Entomologia
Event:  New Description/Identification

A recent publication describes a new planthopper species, Sogatella unidentata (Hemiptera: Delphacidae), from Argentina. Sogatella unidentata was collected from cultivated Oryza sativa (rice) and Zea mays (corn) plants. The genus Sogatella is listed as reportable in the PEST ID database (queried 6/27/18).

References:

  1. Mariani, R. and A. M. Marino de Remes Lenicov. 2018. A new species of Sogatella (Hemiptera: Delphacidae) from temperate Argentina. Revista Brasileira de Entomologia 62(1):77-81. Last accessed June 28, 2018, from https://www.sciencedirect.com/science/article/pii/S0085562617301620.

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