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Cycad plant roots release signals into the soil that triggers the transformation of bacteria into its motile form, helping them move to the plant roots and establish a symbiotic partnership.

The cycad Cycas revoluta is a palm-like plant that grows on rocky coastal cliffs in the sub-tropics and tropics. It has a symbiotic relationship with the Nostoc species of bacteria that can convert nitrogen from the atmosphere into ammonia, which the host plant can then use for its growth. Scientists knew that cycad roots produce a compound that can induce Nostoc species within the soil to transform into their motile form, hormogonia, and attracting them to the roots. However, nobody has determined what exactly the compound is.

In the current study published in the journal Scientific Reports, agricultural chemist Yasuyuki Hashidoko and colleagues at Hokkaido University investigated an extract made from the “coralloid roots” of C. revoluta plants. These are specialized roots that branch out from the plant’s main root system.

They found that the extract was able to trigger the transformation of Nostoc bacteria into hormogonia. Further analyses revealed the main active elements present in the extract were a mixture of diacylglycerols; typical compounds contained in plants that are composed of two fatty acid chains linked together.

The team tested each of the diacylglycerols for their abilities to act as hormogonia-inducing factors (HIF), and found that 1-palmitoyl-2-linoleoyl-sn-glycerol showed pronounced HIF-like activity on the bacteria. The investigations also enabled the researchers to theorize which specific changes to fatty acid chain segments led to the compounds having more, less, or no HIF-like activity.

“These findings appear to indicate that some common diacylglycerols act as hormogonium-inducing signal for Nostoc cyanobacteria, enabling them to move and transfer to host plants,” the researchers conclude. “Since the bacteria can provide host plants nitrogen to help them grow, better understanding of the system could someday lead to more efficient, less fertilizer-dependent agricultural production.”

Read the paper: Scientific Reports

Article source: Hokkaido University

Image: Yasuyuki Hashidoko, Hokkaido University

Exploring how a hazardous fungal pathogen ‘tastes’ its surroundings within a wheat plant to coordinate virulence could be the key to developing new control strategies, scientists believe.

Researchers at the University of Bath and Rothamsted Research have been examining how “fungal G-protein coupled receptors”, which are similar to taste receptors on our tongues, are involved in promoting Fusarium Head Blight (FHB) – a damaging and hazardous disease of wheat which is the number one floral disease in cereals globally.

Fusarium Head Blight targets the ear and grain of the wheat plants and is therefore a major problem for farmers of one of the world’s most important crops. The disease is economically costly, damaging wheat crops towards the end of the growing cycle, and contaminating the wheat grain with fungal toxins (mycotoxins) which are dangerous for humans and animals to eat.

In the UK we have outbreaks of FHB every few years, experiencing wheat crop losses of around 10% in 2012. In other parts of the world such as the USA, Brazil and China, the disease causes severe crop losses and mycotoxin contamination problems for farmers every harvest.

Currently there are no truly effective ways to control FHB, which is spread by airborne spores.

The research team, led by fungal biologist Dr Neil Brown from the University of Bath’s Department of Biology & Biochemistry, thinks that G-protein coupled receptors are a promising targets to develop new approaches to control fungal diseases, including the FHB causing pathogen Fusarium graminearum.

These fungal receptors ‘taste’ their environment and signal changes to the fungi cell, kicking off an appropriate biological response, including mating, mycotoxin production and virulence.

In a series of experiments the scientific team demonstrated that F. graminearum’s receptors are important in wheat infection. The team made a collection of fungal mutants lacking individual receptors. They went on to show that the absence of one type of receptor, specific to fungi, allowed the wheat plant to mount a stronger defence, which causes a traffic jam of invading filamentous fungal structures called hyphae and reducing the progression of infection.

The team also showed that the removal of this receptor meant that the virulence on wheat was reduced, because various fungal processes required for infection were disrupted and dysregulated.

The research is published in PLOS Pathogens.

Dr Brown said: “Fusarium Head Blight is the number one floral disease of cereals worldwide.

“G-protein coupled receptors have been studied extensively in humans, where around 40% of our pharmaceuticals target these human receptors, as they’re exposed on the cell surface, making them accessible to drugs, and they control important biological functions. Fungi have their own G-protein coupled receptors, but we know very little about them.

“Our results show that fungal receptors are important for Fusarium infection of wheat. By learning more about the structure and function of these fungal-specific receptors, and the compounds they detect, we may be able to develop new approaches to control FHB and other plant pathogens.”

Professor Kim Hammond-Kosack, from Rothamsted Research, said: “The options to control Fusarium floral infections in cereal crops are very limited at the moment. This is causing growers and processors in the food and feed industries a tremendous headache, and why Rothamsted has been looking to apply our considerable expertise in crop diseases to this problem. These results open up the possibility of devising novel ways to control FHB disease through either targeted drug development or by eliminating the signals these receptors perceive during a fungal attack.”

Read the paper: PLOS Pathogens

Article source: University of Bath

Image: Manfred Richter / Pixabay

Web-based gaming, such as simulation games, can promote innovative communication strategies that engage farmers with scientific research and help them adapt to climate change.

Methods employed to tackle climate change, such as, for example, improving drainage systems to cope with increased levels of precipitation, are known as adaptation strategies. “Maladaptation” is the implementation of poor decisions or methods that were initially considered beneficial, but which could actually increase people’s vulnerability in the future.

Researchers from Sweden and Finland have developed the interactive web-based Maladaptation Game, which can be used to better understand how Nordic farmers make decisions regarding environmental changes and how they negotiate the negative impacts of potentially damaging decisions.

Their research is presented in the article “Benefits and challenges of serious gaming – the case of “The Maladaptation Game” published in De Gruyter’s journal Open Agriculture, by author Therese Asplund and colleagues from Linköping University in Sweden and the University of Helsinki in Finland. Tested on stakeholders from the agricultural sector in Sweden and Finland, the Maladaptation Game presents the player with four agricultural challenges: precipitation, temperature increase/drought, longer growing seasons and increased risk of pests and weeds. For each challenge, the player must make a strategic decision based on the options given. At the end, the player receives a summary of the potential negative outcomes based on their decisions.

“While we observed that the conceptual thinking of the game sometimes clashes with the players’ everyday experiences and practice, we believe gaming may function as an eye-opener to new ways of thinking,” explains Asplund.

Based on recent literature on serious gaming and climate communication, the authors suggest that serious games should be designed to include elements of thinking and sharing, which will stimulate reflection and discussion among stakeholders.

“Serious games have great potential of how to address complex environmental issues. Used as a communication strategy, they illustrate, visualise and communicate research findings,” says Asplund.

Read the paper: Open Agriculture

Article source: De Gruyter

Image: Monoar Rahman Rony / Pixabay

The use of gene-editing technology to create virus-resistant cassava plants could have serious negative ramifications, according to new research by plant biologists at the University of Alberta, the University of Liege in Belgium, and the Swiss Federal Institute of Technology. Their results show that attempts to genetically engineer the plants to fight off viruses, in fact resulted in the propagation of mutated viruses in controlled laboratory conditions.

“We concluded that because this technology both creates a selection pressure on the viruses to evolve more quickly, and also provides the viruses a means to evolve, it resulted in a virus mutant that is resistant to our interventions,” explained Devang Mehta, postdoctoral fellow in the Department of Biological Sciences. CRISPR-Cas9 is found in nature, where bacteria use it to defend against viruses, however the researchers found that the technology results in very different outcomes in plants—and researchers are stressing the importance of screening against these sorts of unintended results in the future.

The cassava plant, the object of the study, is a starchy root vegetable that is consumed for food throughout the tropics. Cassava is a primary staple crop grown in South America, Africa, and Asia, from which 1 billion people get most of their calories each day. Each year, cassava crops are plagued by cassava mosaic disease, which causes 20 per cent crop loss. It is the mosaic disease that Mehta and his colleagues endeavoured to engineer against.

Unsuccessful results

The researchers used a new gene-editing technology called CRISPR-Cas9 to attempt to design cassava plants that could cut the DNA of the mosaic virus and make the plants resistant to its damaging effects. Unfortunately, their results were not successful. To understand what happened, the team sequenced hundreds of viral genomes found in each plant.

“We discovered that the pressure that CRISPR-Cas9 applied to the virus probably encouraged it to evolve in a way that increased resistance to intervention,” said Mehta. Mehta hastens to add that CRISPR-Cas9 has many other applications in food and agriculture that do not pose the same risks.

The research team is keen to share their results with other scientists who are using CRISPR-Cas9 technology to engineer virus-resistant plants, and encourage these groups to test their plants to detect similar viral mutations.

“We need to do more research on these types of applications of CRISPR-Cas9 technology before we proceed with field testing” said Mehta. Mehta, a postdoctoral fellow with Professor Glen Uhrig, began this research during his PhD studies at the Swiss Federal Institute of Technology(ETH) in Zurich.

Read the paper: Genome Biology

Article source: University of Alberta

Image: Hervé Vanderschuren

The composition of regrowing wet and dry tropical forests follow opposite pathways while these forests are growing older. This has large consequences for forest restoration initiatives. The findings of a new study published in Nature Ecology and Evolution provide insights to select the best tree species for a forest area, thus enhancing and accelerating tropical forest restoration success.

Tropical forests can regrow naturally after agricultural fields are abandoned. During this regrowing process, called succession, the vegetation gradually builds up, leading to changes in environmental conditions at the forest floor. And because species differ in their growing strategies this leads to shifts in species composition over time. Understanding how succession works is crucial to improve forest restoration initiatives and to select the best species for planting.
Soft woods have a rock-and-roll life style

A large team of ecologists from Latin America, United States, Australia and Europe followed recovery of tropical forests in fifty locations across ten Latin American countries. This 2ndFOR research team found that wet and dry forests show actually opposite successional pathways. Species with different characteristics thrive under different environmental conditions, says Prof. Lourens Poorter from Wageningen University & Research and lead author of the study. “A key characteristic of tree species is their stem wood density. Species that produce soft, and cheap, wood have the ability to grow very fast when light and water are abundant. However, this soft wood comes at the expense of a reduced survival, especially under suboptimal conditions like shade and drought. As a result, soft-wooded species have a ‘rock-and-roll’ life style; they peak early in life, live fast and die young.”

On the other hand, species that produce durable, and expensive, wood can persist for a very long time, especially under adverse conditions, the research team describes in their paper. This strategy comes at the expense of a reduced and slow growth. These results provide an important step to understand the shift in species composition during forest succession. The successional theory predicts that early in succession light and water resources are in abundant supply, which leads to the dominance of ‘fast’ pioneer species with soft wood. Later in the succession resource availability declines, leading to the dominance of ‘slow’ late-successional species with hard wood, like Maçaranduba (Manilkara bidentata) a Neotropical timber species that produces such heavy wood that it sinks in water.

“In wet forest we see a shift from soft- to hard-wooded species over time. However, in dry forest we see an opposite shift from hard- to soft-wooded species” Danaë Rozendaal.

Shift from soft to hard wood species in wet forests

To evaluate successional changes in wood density, the research team analysed forest recovery at an unprecedented spatial scale, using original data from fifty sites, 1400 plots and more than 16,000 trees from tropical forests across Latin America. Co-author Dr. Danaë Rozendaal says: “Our results show that in wet forest we indeed see a shift from soft- to hard-wooded species over time. However, in dry forest we see an opposite shift from hard- to soft-wooded species.”
Opposite trend in dry forests

This opposite trend happens because in wet forests, resources (e.g. light) decline during succession, whereas in dry forests initial conditions are very harsh, dry and hot. Only hard-wooded species can tolerate these extreme conditions. When they grow they create a milder micro environment, which paves the way for the establishment of soft-wooded species. “Intriguingly”, Danaë Rozendaal adds, “the results show that wet and dry forests start out very differently, but become more similar over time in terms of microclimate and species wood density.”

Tree species selection for forest recovery

The new ecological insights can be used to improve species selection for restoration, Wageningen Professor Frans Bongers assures. “Where possible, forest restoration should rely on natural regeneration, as it is cheaper, and leads to a more diverse and resilient vegetation. However, in degraded areas, where natural regeneration is difficult, active planting provides a good alternative. Our findings suggest that forest restoration in areas with an intense dry season, covering 16% of the Neotropical forests, should prioritize planting species with high wood density. These have higher chances of surviving the dry period. In addition, well-adapted, native tree species are preferred rather than exotic species, because they support biodiversity. This selection can also lower mortality rates among planted trees, which often exceeds more than one third of the planted trees. In wet forests, though, a mix of local soft and hard wooded species can be successfully planted at the onset. The fast soft-wooded species rapidly establish a protecting vegetation, and shelter the slower growing hard-wooded species that will form the basis of a long-term stable forest.”

Read the paper: Nature Ecology and Evolution

Article source: WUR

Image: Frans Bongers

Nanyang Technological University, Singapore (NTU Singapore) scientists have developed a sustainable way to demonstrate a new genetic modification that can increase the yield of natural oil in seeds by up to 15 per cent in laboratory conditions.

The new method can be applied to crops such as canola, soybean and sunflower, which are in a multi-billion dollar industry that continues to see increasing global demand.

The research team led by Assistant Professor Wei Ma from NTU’s School of Biological Sciences genetically modified a key protein in plants which regulates the amount of oil they produce. This results in larger oil reserves in the seed that primarily serves as an energy source for germination.

The team’s patent-pending method involves modifying the key protein known as “Wrinkled1” or “WRI1”, which regulates plants’ oil production. After modification, the seeds have a wrinkled appearance, which is the basis for its scientific codename.

In the lab, these modified seeds have successfully displayed seed oil increase that is able to produce up to 15 per cent more natural oils. The research findings were published in the scientific journal Plant Signaling & Behavior.

“Plant seed oil is an essential component in our daily diet and the agricultural industry is seeking ways to maximise plants’ yield while reducing environmental effects of crop cultivation, especially land use. Our research helps to increase the production of seed oil in a sustainable and cost-effective way, and it also opens up new doors in agriculture research,” said Asst Prof Ma.

The ability to increase oil yield in a sustainable manner is expected to result in higher economic gain. Past research has shown that a small 1.5 per cent increase in oil yield (by dry weight) in soybean seeds equates to a jump of US$ 1.26 billion in the United States market.

Discovery a boost for biofuel production

The increased yield in seed oil would also benefit the production of biofuel, which is a form of clean fuel produced from organic sources, such as vegetable oils.

Biofuel is being used in various applications, including powering machines in protected forests to reduce fossil fuel contamination and fuelling long-distant transportation by automobiles, ships, and airplanes.

“Global demand for vegetable oil is increasing very rapidly, and it is estimated to double by 2030. In addition, research is also ramping up in the use of biofuels in various applications, which can provide a cleaner and more sustainable source of fuel than petroleum. Increasing oil production of key crops such as soybean, sunflower, and canola is thus essential for a more sustainable and greener future,” said Asst Prof Ma.

He is currently exploring industrial collaboration to commercialise and further develop the technology.

The NTU team is also studying other ways to maximise plants’ oil reserves, for example, using other plant parts such as stems, for oil production.

Sustainable way to increase oil yield

Previous research efforts to improve seed oil yield involved increasing the number of the WRI1 protein – known as overexpression – but this did not succeed in increasing the oil yield stably and consistently.

Asst Prof Ma used the Arabidopsis plant – a small flowering plant related to cabbage and mustard. It contains all the characteristics of crops such as sunflower, canola and soybean, which serves as an ideal model plant for research.

He and the NTU research team developed a patent-pending method that stabilises the key WRI1 protein which also improves its ability to interact with other proteins. This enhances its effectiveness in producing natural oils and the method can be easily done on other crops. This also encourages a more sustainable way for industries to produce natural oils instead of simply increasing the amount of land used for agriculture.

Dr. Bo Shen, a Senior Manager at DuPont Pioneer, a US-based international producer of hybrid seeds for agriculture who is not involved in the NTU team’s research said, “Vegetable oil is an important renewable resource for biodiesel production and for dietary consumption by humans and livestock. The total production of vegetable oil worldwide reached about 185 million tons in 2017. Wrinkled1 (WRI1) is a ubiquitous regulator controlling oil biosynthesis in maize, soybean, canola, and palm. With increasing demand for vegetable oil, Asst Prof Wei Ma’s research on WRI1 can have global importance. A better understanding of how WRI1 regulates oil biosynthesis could inform how we breed plants that produce more oil.”

Providing another independent view, Dr. Eric Moellering, a Senior Scientist from Synthetic Genomics, a California company focusing on synthetic biology, said, “Asst Prof Ma’s research on the plant transcriptional factor WRI1 has greatly advanced our understanding of how seed oil biosynthesis is regulated. While the WRI1 gene has been known for some time, Asst Prof Ma’s research has revealed key insight into the structural features of the WRI1 protein that are critical for its function, WRI1 interactions with other regulatory proteins, and the role of WRI1 in processes outside of seed oil regulation.

“These discoveries will undoubtedly contribute to the optimisation of seed oil yield in a variety of crops. As such, Asst Prof Ma’s research is helping to address some of the major 21st century challenges we face in feeding a growing global population and developing renewable transport energy.”

Read the paper: Plant Signaling & Behavior

Article source: Nanyang Technological University

Image: Manfred Richter / Pixabay

Scientists from 21 research institutes globally, have successfully completed sequencing of 429 chickpea lines from 45 countries to identify genes for tolerance to drought and heat.

The efforts equipped the team with key insights into the crop’s genetic diversity, domestication and agronomic traits. The study also mapped the origins of chickpea and its ascent in Asia and Africa.

The team led by the International Crops Research Institute for the Semi-Arid Tropics (ICRISAT) in close collaboration with the BGI-Shenzhen, China, involved 39 scientists from leading research institutes (listed below) world over. This is the largest-ever exercise of whole-genome resequencing of chickpea.

What this means to the agricultural community is potential development of newer varieties of chickpea with higher yields, which are disease-and-pest-resistant, and better able to withstand the vagaries of weather.

The results of the three-year-long efforts have been published in Nature Genetics online with the title, ‘Resequencing of 429 chickpea accessions from 45 countries provides insights into genome diversity, domestication and agronomic traits’.

More than 90% of chickpea cultivation area is in South Asia. Drought and increasing temperatures are said to cause more than 70% yield loss in chickpea globally. Chickpea being a cool season crop is likely to suffer further reduction in productivity due to rising temperatures.

“The genome-wide association studies identified several candidate genes for 13 agronomic traits. For example, we could identify genes (e.g. REN1, β-1, 3-glucanase, REF6) which can help the crop tolerate temperatures up to 38oC and provide higher productivity,” says Dr Rajeev Varshney, the project leader and Research Program Director, Genetic Gains, ICRISAT.

Dr Xu Xun, CEO and President, BGI Research, China, co-leader of the project said, “BGI is very excited to work with CGIAR institutes like ICRISAT in high-end science research which could enable development of drought and heat-tolerant chickpea varieties for India and Africa. BGI has been enjoying a collaboration with ICRISAT for the past decade and we look forward to work together on many exciting projects in the years to come”.

The study established a foundation for large-scale characterization of germplasm, population genetics and crop breeding. It also helped understand domestication and post-domestication divergence of chickpea.

“This new found knowledge will enable breeders to enhance the use of diverse germplasm and candidate genes in developing improved (Climate-change ready) varieties that will contribute significantly to the increased productivity and sustainability of agricultural development in developing countries,” said Dr Peter Carberry, Director General, ICRISAT.

Highlighting the importance of this study, Ms Marie Haga, Executive Director, Global Crop Diversity Trust based in Germany, said, “This is exciting work by ICRISAT and partners to unlock the genetic diversity of chickpea. This deeper understanding of the crop could enable scientists to breed new varieties that are both highly productive and resilient to climate change, benefitting farming communities in many developing countries”.

The study was done in close collaboration with partners from the National Agricultural Research Systems. India, for instance as the biggest consumer of pulses in the world, faces increasing production gap. This new research could take India closer towards attaining self-sufficiency in pulse production.

“This is a significant contribution to global agricultural research and these unique, scientific solutions will help mitigate issues the world is facing right now. Science is key to ongoing efforts within ICAR and ICRISAT and also the way forward for agriculture in the country,” said Dr Trilochan Mohapatra, Secretary, Department of Agricultural Research and Education & Director General, Indian Council of Agricultural Research (ICAR).

The study also confirms that chickpea came to India from Fertile Crescent/ Mediterranean via Afghanistan and may have been introduced back to the primary centers of origin after 200 years. The new study speculates about possible introduction of chickpea to the New World directly from Central Asia or East Africa rather than the Mediterranean.

“Our study indicates Ethiopia as secondary center of diversity and also maps a migration route from Mediterranean/ Fertile Crescent to Central Asia, and in parallel from Central Asia to East Africa (Ethiopia) and South Asia (India),” Dr Varshney added.

Read the paper: Nature Genetics

Article source: International Crops Research Institute for the Semi-Arid Tropics -ICRISAT

Image: Patricia Maine / Pixabay

Plants have developed a robust system that stops their cell cycle in hostile environments such as abnormally hot temperatures. In response, they direct their energy to survival rather than growth. A new study led by scientists at the Nara Institute of Science and Technology (NAIST) reports in eLife that two transcription factors, ANAC044 and ANAC085, are critical for this response in the flowering plant Arabidopsis. The findings give clues on ways to modulate the growth of crops and other agriculture products.

Upon DNA damage, plants and animals halt cell division and execute DNA repair. This response prevents the damaged cells from proliferating. NAIST Professor Masaaki Umeda has made a career studying the molecular biology behind this protective measure.

“We reported that SOG1 is activated by DNA damage and regulates almost all genes induced by the damage,” he says. Another study from the lab showed “Rep-MYBs are stabilized in DNA damage conditions to suppress cell division,” he adds.

In the laboratory’s newest study, Umeda’s research team shows that ANAC044 and ANAC085 act as a bridge between SOG1 and Rep-MYB.

The scientists disrupted DNA in Arabidopsis cells by treating the cells with bleomycin, a compound commonly used to halt the growth of human cancer cells. The Arabidopsis cells failed to proliferate as expected unless they possessed a mutation in ANAC044 or ANAC085. In the mutant cases, the cells proliferated as though they were never exposed to bleomycin.

“We found that ANAC044 and ANAC085 are essential for root growth retardation and stem cell death, but not for DNA repair,” says Umeda.

Specifically, ANAC044 and ANAC085 were responsible for preventing the cell cycle from proceeding from G2 phase to mitosis in response to the DNA damage.

Rep-MYBs cause the same arrest in the cell cycle. Consistently, in normal cells, bleomycin caused a rise in the accumulation of Rep-MYBs, but not in cells with ANAC044 and ANAC085 mutations. These findings suggest ANAC044 and ANAC085 act as a bridge between SOG1 and Rep-MYBs in the halting of the cell cycle upon DNA damage.

DNA damage is just one form of stress that can cause the cell cycle to pause. To investigate whether ANAC044 and ANAC085 act in response to other forms of external stress, the researchers exposed the cells to different temperatures and osmotic pressure which cause the retardation in G2 and G1 progression, respectively.

Growth arrest was observed in both mutant and normal cells at a high osmotic pressure, but higher temperatures only caused pauses in the cell cycle in normal cells, indicating that ANAC044 and ANAC085 act as gatekeepers in the progression from the G2 phase in the cell cycle under abiotic stress conditions.

The fact that ANAC044 and ANAC085 operate in response to different types of abiotic stress suggests to Umeda that they may be at the core of new technologies designed to modulate plant growth.

“The research illuminates a new mechanism that optimizes organ growth under stressful conditions. When trying to increase plant productivity, scientists should consider ANAC044 and ANAC085,” he says.

Read the paper: eLife

Article source: Nara Institute of Science and Technology (NAIST)

Image: Masaaki Umeda

Compounds produced by sorghum plants to defend against insect feeding could be isolated, synthesized and used as a targeted, nontoxic insect deterrent, according to researchers who studied plant-insect interactions that included field, greenhouse and laboratory components.

The researchers examined the role of sorghum chemicals called flavonoids –specifically 3-deoxyflavonoid and 3-deoxyanthocyanidins — in providing resistance against the corn leaf aphid, a tiny blue-green insect that sucks sap from plants. To defend against pests like the aphids, sorghum has evolved defenses that includes biosynthesis of secondary metabolites, including flavonoids to poison the pests.

A previous Penn State study showed that in sorghum, accumulation of these flavonoids is regulated by a gene called yellow seed1 that controls responses to stresses such as fungal pathogens, noted Surinder Chopra, professor of maize genetics, Penn State. His research group in the College of Agricultural Sciences led both studies.

In the current research carried out at the University’s Russell E. Larson Agricultural Research Center, researchers grew two nearly identical lines of sorghum — one with a functional _y1_ gene that produced flavonoids, and the other a mutant called null y1, which did not possess the functional yellow seed1 gene responsible for producing the flavonoids.

When they compared the two lines of plants, researchers found that a significantly higher number of adult corn-leaf aphids colonized null y1 plants compared to the plants with functional _y1_ gene that produced flavonoids. The aphids actively fed on the null y1 plants to where some of them showed signs of stress with yellowed leaves. The functional sorghum plants that produced the flavonoids had much lower aphid numbers and showed no ill effects from aphid feeding.

Greenhouse experiments with similar potted sorghum plants demonstrated that the aphids clearly preferred to feed and reproduce on null y1 plants, and the adults produced many more nymphs.

In a companion laboratory experiment, researchers fed two groups of adult aphids diets of sorghum leaf tissues — but to one they added an extract containing the flavonoids. After a few days, most of the aphids that fed on the flavonoid-enriched leaf tissue died and reproduction was curtailed — none of those aphids had nymphs before they succumbed.

Perhaps surprisingly, Chopra explained, the flavonoids are not present in the phloem — vascular tissue in plants that conducts the sugars aphids seek — but are in the epidermal cells that form the outermost layer of defense. When aphids repeatedly probe and puncture the epidermal cells with their stylets, or beaks, they take up the flavonoids that lead to their demise.

The findings, published online in the Journal of Chemical Ecology, indicate flavonoids can potentially be deployed as potent insect deterrents to protect crops, Chopra suggested.

“Sorghum plants have evolved to precisely emit compounds offering defenses against harmful predatory insects that threaten them, and yet these chemicals in their defenses don’t hurt beneficial insects,” said Chopra. “If we could develop nontoxic insecticides, it would be a game changer — given that the toxicity of synthetic pesticides is of great concern, and they are considered to be dangerous to human health.”

Chopra, supported by Penn State, has applied for a patent on using flavonoids as insect deterrents. He pointed out that while much more research needs to be done, the most important consideration is that flavonoids are natural plant products that do not cause any pollution and are not harmful to human or animal health.

This research may be an early step toward developing new phytochemicals for crop defenses, Chopra believes. “How well the flavonoids work against other herbivores is being researched, but we know with corn leaf aphids they are very, very potent,” he said.

Read the paper: Journal of Chemical Ecology

Article source: Penn State

Image: USDA

Hedges, flowering strips and other seminatural habitats provide food and nesting places for insects and birds in agricultural landscapes. This also has advantages for agriculture: bees, flies, beetles and other animal groups pollinate crops and control pest insects in adjacent fields.

But how much of these habitats is necessary and how should they be arranged to make use of these nature-based ecosystem services?

This question has been addressed by a new study from the Chair of Animal Ecology and Tropical Biology at the Biocenter of Julius-Maximilians-Universität Würzburg (JMU) in Bavaria, Germany. The results are published in the journal “Ecology Letters”.

Small-scale land use is advantageous

According to the study, biodiversity, pollination, and pest control can be improved in landscapes even with a relatively small amount of non-crop habitat. To reach this effect, these habitats must be arranged to create a small-scale agricultural landscape.

For this study, Dr. Emily A. Martin‘s team took a closer look at data from ten European countries and 1,515 different agricultural landscapes. This clearly showed that small-scale land use is advantageous: it leads to a greater density of beneficial insects and spiders. And it increases the services provided by ecosystems for agriculture – pollination and natural pest control.

Creating a web of seminatural habitats

“In order to reduce pests and promote biodiversity, increasing the density of seminatural habitat elements can be an ideal solution for farms. You don’t have to remove much land from cultivation to reach a significant effect,” says Dr. Martin.

“The implementation of these findings would be an important step forward in the effort to achieve a sustainable and biodiversity-friendly agriculture”, Professor Ingolf Steffan-Dewenter, head of the Chair of Animal Ecology and Tropical Biology and co-author of the study, emphasises.

The JMU research team is now focusing on intensified cooperation with agricultural and environmental stakeholders. The scientists want to help implement a landscape management system that benefits everyone – nature and mankind.

Read the paper: Ecology Letters

Article source: University of Würzburg

Image: Matthias Tschumi