Archive for the ‘Climate change’ Category

Insects have a weak capacity to adjust their critical thermal limits. Sam England, Author provided (no reuse)

Insects will struggle to keep pace with global temperature rise – which could be bad news for humans

Published: October 3, 2022 11.01am EDT


  1. Hester WeavingPhD Candidate in Entomology, University of Bristol

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Animals can only endure temperatures within a given range. The upper and lower temperatures of this range are called its critical thermal limits. As these limits are exceeded, an animal must either adjust or migrate to a cooler climate.

However, temperatures are rising across the world at a rapid pace. The record-breaking heatwaves experienced across Europe this summer are indicative of this. Heatwaves such as these can cause temperatures to regularly surpass critical thermal limits, endangering many species.

In a new study, my colleagues and I assessed how well 102 species of insect can adjust their critical thermal limits to survive temperature extremes. We found that insects have a weak capacity to do so, making them particularly vulnerable to climate change.

The impact of climate change on insects could have profound consequences for human life. Many insect species serve important ecological functions while the movement of others can disrupt the balance of ecosystems.

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How do animals adjust to temperature extremes?

An animal can extend its critical thermal limits through either acclimation or adaptation.

Acclimation occurs within an animal’s lifetime (often within hours). It’s the process by which previous exposure helps give an animal or insect protection against later environmental stress. Humans acclimate to intense UV exposure through gradual tanning which later protects skin against harmful UV rays.

One way insects acclimate is by producing heat shock proteins in response to heat exposure. This prevents cells dying under temperature extremes.

A ladybird drinking a speck of water on a narrow leaf.
Insects in warmer environments develop fewer spots to reduce heat retention. mehmetkrc/Shutterstock

Some insects can also use colour to acclimate. Ladybirds that develop in warm environments emerge from the pupal stage with less spots than insects that develop in the cold. As darker spots absorb heat, having fewer spots keeps the insect cooler.

Adaptation occurs when useful genes are passed through generations via evolution. There are multiple examples of animals evolving in response to climate change.

Over the past 150 years, some Australian parrot species such as gang-gang cockatoos and red-rumped parrots have evolved larger beaks. As a greater quantity of blood can be diverted to a larger beak, more heat can be lost into the surrounding environment.

A colourful red-rumped parrot perched on a branch.
The red-rumped parrot has evolved a larger beak to cope with higher temperatures. Alamin-Khan/Shutterstock

But evolution occurs over a longer period than acclimation and may not allow critical thermal limits to adjust in line with the current pace of global temperature rise. Upper thermal limits are particularly slow to evolve, which may be due to the large genetic changes required for greater heat tolerance.

Research into how acclimation might help animals survive exceptional temperature rise has therefore become an area of growing scientific interest.

A weak ability to adjust to temperature extremes

When exposed to a 1℃ change in temperature, we found that insects could only modify their upper thermal limit by around 10% and their lower limit by around 15% on average. In comparison, a separate study found that fish and crustaceans could modify their limits by around 30%.

But we found that there are windows during development where an insect has a greater tolerance towards heat. As juvenile insects are less mobile than adults, they are less able to use their behaviour to modify their temperature. A caterpillar in its cocoon stage, for example, cannot move into the shade to escape the heat.

Exposed to greater temperature variations, this immobile life stage has faced strong evolutionary pressure to develop mechanisms to withstand temperature stress. Juvenile insects generally had a greater capacity for acclimating to rising temperatures than adult insects. Juveniles were able to modify their upper thermal limit by 11% on average, compared to 7% for adults.

But given that their capacity to acclimate is still relatively weak and may fall as an insect leaves this life stage, the impact is likely to be limited for adjusting to future climate change.

What does this mean for the future?

A weak ability to adjust to higher temperatures will mean many insects will need to migrate to cooler climates in order to survive. The movement of insects into new environments could upset the delicate balance of ecosystems.

Insect pests account for the loss of 40% of global crop production. As their geographical distribution changes, pests could further threaten food security. A UN report from 2021 concluded that fall armyworm populations, which feed on crops such as maize, have already expanded their range due to climate change.

A damaged corn crop following an attack by fall armyworms.
The fall armyworm is a damaging crop pest which is spreading due to climate change. Alchemist from India/Shutterstock

Insect migration may also carry profound impacts on human health. Many of the major diseases affecting humans, including malaria, are transmitted by insects. The movement of insects over time increases the possibility of introducing infectious diseases to higher latitudes.

There have been over 770 cases of West Nile virus recorded in Europe this year. Italy’s Veneto region, where the majority of the cases originate, has emerged as an ideal habitat for Culex mosquitoes, which can host and transmit the virus. Earlier this year, scientists found that the number of mosquitoes in the region had increased by 27%.

Insect species incapable of migrating may also become extinct. This is of concern because many insects perform important ecological functions. Three quarters of the crops produced globally are fertilised by pollinators. Their loss could cause a sharp reduction in global food production.

The vulnerability of insects to temperature extremes means that we face an uncertain and worrying future if we cannot curb the pace of climate change. A clear way of protecting these species is to slow the pace of climate change by reducing fossil fuel consumption. On a smaller scale, the creation of shady habitats, which contain cooler microclimates, could provide essential respite for insects facing rising temperatures.

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Scientists warn of ‘insect apocalypse’ amid climate change

insect egg
Credit: CC0 Public Domain

An emerging “insect apocalypse” will have radical effects on the environment and humankind, an Australian scientist has warned.

An international study on the future of insects under climate change scenarios has found the loss of insects will drastically reduce the ability of humankind to build a sustainable future.

Co-author William Laurance, of James Cook University in Australia, said the biosphere had already warmed by about 1.1 degrees Celsius since industrialization. It is projected to warm a further 2–5 degrees Celsius by 2100 unless greenhouse gas emissions are significantly reduced.

An insect’s small body size and inability to regulate their own body temperature made them particularly susceptible to changing temperature and moisture levels, Laurance said in a Tuesday statement.

“A growing body of evidence shows many populations of insects are declining rapidly in many places. These declines are of profound concern, with terms like an emerging ‘insect apocalypse’ being increasingly used by the media and even some scientists to describe this phenomenon,” Laurance said.

“The loss of insects works its way up the food chain, and may already be playing an important role in the widespread decline of their consumers, such as insect-eating birds in temperate environments.”

Insects are important parts of biodiversity and provide services to the wider environment—including pollination, pest control and nutrient recycling—all of which are beneficial to other creatures, including humans, Laurance said.

The study found climate change amplified the effects of other factors threatening insect populations, such as pollution, habitat loss and predation.

“It’s essential to manage and restore habitats that make them as ‘climate-proof’ as possible and enable insects to find refuges in which they can ride out extreme climatic events,” Laurance said.

“The evidence is clear and striking. We need to act now to minimize impacts on insect populations—we know how to do it, but the decision making and requisite funding keep getting pushed down the road,” Laurance added.

2022 dpa GmbH.

Distributed by Tribune Content Agency, LLC.

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Temperate insects as vulnerable to climate change as tropical species

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Heightened weed burden could mean growers need to replace inundated crops

24 Oct 2022


Frontdesk / Arable

As a result of the summer’s prolonged drought, some early-drilled winter wheats are facing a heightened weed burden after the dry conditions have prevented pre-emergence herbicides from working effectively. That’s according to Mike Thornton, head of crop production for agronomy firm ProCam, who urges growers to assess affected fields to determine if the current crop should be retained or sprayed off and re-drilled.

 “Despite being a distant memory, the summer’s dry and hot conditions are still having an effect on the new cycle of cereal crops,” Mr Thornton explains. “Some wheats which were drilled ahead of schedule or on lighter land have suffered from a lack of soil moisture, which has prevented soil-acting pre-emergence herbicides from working to the best of their ability. As a result, some winter cereals are currently facing heightened competition from out-of-control weeds which, in the most severe cases, could threaten the crop’s viability and profitability.”

 Mr Thornton therefore recommends that each field should be assessed on a case-by-case basis to decide if the current crop, or part of it, should be sprayed off and re-drilled, either with a replacement winter crop, or with a subsequent spring crop.

 “Where the weed burden is excessive or contains difficult-to-control competitors such as black-grass, ryegrass and brome, it could be quite an easy decision to make. For example, if grass weeds have made it to the two-leaf stage or beyond, they will be very difficult to control as most contact herbicides have been rendered ineffective by mounting resistance.

 “In the most severe cases, it will make sense to admit defeat sooner rather than later and to write-off the current crop so that weeds can be burned off ahead of a replacement crop being established.”

 For many growers, Mr Thornton says it’s still not too late to get a replacement winter crop into the ground. For others, deferring to a spring-sown cropping strategy might be the better option.

 “In both cases, growers should be aware of the restrictions imposed by certain active ingredients on replacement crops. The best approach is to seek definitive advice from your agronomist and, where necessary, to implement a ‘plan B’ sooner rather than later.”

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October 14, 2022 

Cambria Finegold 

World Food Day: How can data science and modelling help smallholders adapt to climate change?

By Cambria Finegold, Global Director Digital Development, CABI 

Data science and modelling are relatively new concepts when it comes to farming. For centuries, smallholders have carefully passed down agricultural skills from generation to generation. They depended on this knowledge. And stable seasons and weather meant this information remained relevant for years. 

However, climate change has brought with it erratic conditions. New scenarios are forcing family farmers to abandon the techniques they have shared. Unexpected droughts, floods and changes in temperature destroy their crops. But they lack the knowledge to address the unpredictability. 

For example, in a +2°C environment, aphids can reproduce an extra five generations each year. The pest problems that smallholders face are becoming overwhelming. How do they adapt to a rapidly changing and unstable environment? Digital technology is helping to answer this question. 

The benefits of data science and modelling 

Data science and modelling offer a solution. These dynamic new fields in agricultural technology are helping farmers to adapt. As climate change contributes to an increasingly uncertain future, they support decision-making. They show how environments are changing and how pests are spreading. But they also reveal how to address these problems. 

From managing invasive species to strengthening plant health systems, high-quality data helps farmers. It can advise them on pest management, crop and variety choices, and the timing of agricultural tasks. Data modelling supports decisions that farmers must make around all of these things. 

Furthermore, data science and modelling help smallholders make more sustainable farming choices, for example, decisions around natural, sustainable pest control. Farmers can use technology to address climate change and protect the environment simultaneously. 

At the heart of this technology are predictive models. These models help smallholders understand what might happen – tools to navigate uncertainty. What happens in a cooler or warmer year? What agricultural practices can they employ to protect crops from drought or flood? What must they do today to safeguard tomorrow? 

Data science and modelling can make a big difference to smallholders. Farmers face conditions that do not make sense to them anymore. Technology can help guide them through the uncertainty. 

PRISE and data science and modelling 

One concrete example of this is the Pest Risk Information SErvice (PRISE). It is an early-warning information system that provides farmers with alerts. These alerts notify the farmers of the best times to take action to protect their crops. The service builds resilience to climate shocks by supporting preventative measures.  Since 2017, the service has reached over 1.8 million farmers in Ghana, Kenya, Malawi and Zambia. 

PRISE is showing remarkable success. The service held a phone survey following the 2019-20 short rains season in Kenya. It focused on smallholders receiving alerts about the fall armyworm pest. And it showed that 60% of smallholders reported changing their farming practices based on the alerts’ recommendations.  

The PRISE consortium is examining how it can expand from its focus on plant pests. Could it grow to a risk warning system that delivers information about weather risks? Can it expand to include a strong climate change angle? 

Using a data science and modelling in hybrid advisory services 

While technology is important, we must also combine it with on-the-ground support. Once a farmer has received new information, they will often need help implementing it. Hybrid approaches that combine technology with face-to-face advice are often more effective than digital-only approaches. For this reason, we must invest in agricultural advisory services

How we deliver information is essential. Farmers might be dismissive of advice given over text messages. Or the service might provide the recommendations in the farmer’s second language and might, therefore, be unclear. Agricultural advisory services can discuss any question the farmer has. They can support the move from traditional information delivery to technology. They can help to manage the perceived risks that farmers might have. 

Data science and modelling have a vital role to play in modern farming. They can help smallholders to grow more crops and safeguard their livelihoods. And they can help them adapt to climate change. Technology can provide solutions when traditional systems no longer give the farmers the answers they need. It provides a little more certainty in an uncertain world. 

Data scienceFood securityPRISEWorld Food Daymodeling

Agriculture and International Development

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CABI is a member of:   The Association of International Research and Development Centers for Agriculture

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The Guardian

Plants damaged by extreme temperatures are most at risk of disease, Royal Horticultural Society says

Honey Fungus on an oak trunk.
Honey fungus (Armillaria mellea) is ‘the most destructive fungal disease in the UK’, the RHS says. Photograph: FLPA/Alamy

Summer’s prolonged droughts and extreme heat have made plants more susceptible to problems such as fungi and insects this coming autumn, the Royal Horticultural Society has warned.Plants stressed or damaged by the heat are most at risk of disease, but the charity’s experts say gardeners should also look out for specific plants that are typically more vulnerable such as tomatoes.

Tomato growers may be noticing more blight than other years and the RHS advises those worried to “pick off green tomatoes and leave them to ripen on a windowsill”.The changing seasons are also expected to lead to more mildew. “Mildew can look bad but it’s nothing to panic about for gardeners,” said the RHS. “Gardeners can pick off the worst affected leaves and ensure plants are watered but not saturated.”

Honey fungus (Armillaria mellea) is described by the RHS as the “most destructive fungal disease in the UK” and is expected to cause greater devastation than usual this autumn after summer’s exceptionally hot weather left plants more vulnerable. It can be deadly to plants, spreading underground to attack and kill the roots, before causing the dead wood to decay.With no chemical able to control the spread, the RHS advises gardeners to improve plant resilience by maintaining good plant health, making sure plants grow “in suitable conditions” and watering young plants less often but more thoroughly.The UK’s record-breaking summer temperatures have also given rise to the glasshouse thrip, a tiny insect that can thrive in greenhouses.Generally found in hot and dry conditions, this species of thrip has increasingly been able to survive in the south of the UK as the climate heats up.Although the insects often do not cause noticeable damage, a garden infestation can cause mottling or spread plant viruses. Symptoms to look out for include silvery discoloured leaves, marked with small brown-red spots caused by the insects’ excrement. Worried gardeners should note that thrips can be controlled by natural garden predators, including the bug Orius laevigatus.Sara Redstone, the biosecurity lead at RHS, said: “One of the best ways to maintain healthy plants year round is to let nature help in your garden. Gardens can play an important role in climate resilience and gardeners can maximise this by selecting and planting species which tolerate weather extremes in their local conditions.“These resilient plants will be less stressed by the increasingly frequent harsh conditions we expect to see under climate change, and therefore stand a better chance of surviving disease.”

There can be no more hiding, and no more denying. Global heating is supercharging extreme weather at an astonishing speed. Guardian analysis recently revealed how human-caused climate breakdown is accelerating the toll of extreme weather across the planet. People across the world are losing their lives and livelihoods due to more deadly and more frequent heatwaves, floods, wildfires and droughts triggered by the climate crisis.At the Guardian, we will not stop giving this life-altering issue the urgency and attention it demands. We have a huge global team of climate writers around the world and have recently appointed an extreme weather correspondent. Our editorial independence means we are free to write and publish journalism which prioritises the crisis. We can highlight the climate policy successes and failings of those who lead us in these challenging times. We have no shareholders and no billionaire owner, just the determination and passion to deliver high-impact global reporting, free from commercial or political influence.And we provide all this for free, for everyone to read. We do this because we believe in information equality. Greater numbers of people can keep track of the global events shaping our world, understand their impact on people and communities, and become inspired to take meaningful action. Millions can benefit from open access to quality, truthful news, regardless of their ability to pay for it. 

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 Grahame Jackson


 Sydney NSW, Australia

 For your information

 18 days ago

Insects struggle to adjust to extreme temperatures making them vulnerable to climate change

ScienceDailySource:University of BristolSummary:As more frequent and intense heat waves expose animals to temperatures outside of their normal limits, an international team has studied over 100 species of insect to better understand how these changes will likely affect them.Insects have weak ability to adjust their thermal limits to high temperatures and are thus more susceptible to global warming than previously thought.

As more frequent and intense heat waves expose animals to temperatures outside of their normal limits, an international team led by researchers at the University of Bristol studied over 100 species of insect to better understand how these changes will likely affect them.

Insects — which are as important as pollinators, crop pests and disease vectors — are particularly vulnerable to extreme temperatures. One way insects can deal with such extremes is through acclimation, where previous thermal exposure extends their critical thermal limits. Acclimation can trigger physiological changes such as the upregulation of heat shock proteins, and result in changes to phospholipid composition in the cell membrane.

Read on: https://www.sciencedaily.com/releases/2022/09/220913183113.htm


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Contribute to CABI’s new Plant Health Cases

Real-life examples of plant health in practice. 

About Plant Health Cases

Fresh green soy plants on the field in spring. Rows of young soybean plants . High quality photo

CABI, together with Editors in Chief Lone Buchwaldt, David B. Collinge, and Boyd A. Mori is embarking on a new type of online publication called Plant Health Cases.

Plant Health Cases will be a curated, peer-reviewed collection of real-life examples of plant health in practice. This will be an invaluable resource for students, lecturers, researchers, and research-led practitioners. We will be developing cases in all areas relevant to plant health, including:

  • plant diseases
  • plants pests
  • weeds
  • environmental factors
  • agronomic practices
  • diagnosis, prevention, monitoring and control
  • international trade and travel

What is a Case Study?

A Plant Health Case is a relatively short publication with a well-defined example of research in plant health, e.g. a study which results in reduced impact from a disease or pest problem. Cases should be between 3000 and 5000 words long, and can include photos, figures and tables. They should be written in an engaging style that is both science-based and accessible using a limited number of references. Importantly, each case should suggest points for discussion to broaden the reader’s horizon, inspire critical thinking and lead to interactions in the classroom or field.

Interested in Contributing to Plant Health Cases?

We are currently looking for contributions of case studies, and we welcome your ideas! You may have existing case study material ready prepared for use in teaching, or a good example of research in plant health which could be easily adapted to our template. For further information and guidance on how to submit your idea for a case study please see here: https://www.cabi.org/products-and-services/plant-health-cases/

Your submission will be peer-reviewed, and a DOI assigned at the time of publication similar to your other scientific publications. The corresponding author will receive £100 upon acceptance of the final case study. 

Publication Plan

We’re aiming to launch Plant Health Cases in mid-2023. Our case studies will offer practical, real-life examples in one easily searchable platform. All users will be able to search, browse and read summaries of case studies. Full text access will be available via individual or institutional subscription, or by purchasing a single case study.

Further Information

Please get in touch with Rebecca Stubbs, Commissioning Editor, CABI


About CABI

CABI is a not-for-profit, scientific research, international development and publishing organisation. Unlike other publishers, we use our surpluses to support scientific and rural development projects that help improve the lives of the world’s poorest people, which means that by publishing with us, you are helping to improve the lives of some of the world’s poorest people. Please visit our website at www.cabi.org

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Biotech will mitigate food insecurity – OFAB

Published 4 days ago

on July 4, 2022


 Open Forum on Agricultural bio technology Nigeria OFAB an International Organisation has urged Nigerians to embrace bio technology to mitigate issues around climate change and ensure food security in the country Dr Rose Gidado Country Director OFAB Nigeria said this at the sideline of the science hangout organised by the Alliance for Science Nigeria ASN on Monday hellip

Open Forum on Agricultural bio-technology, Nigeria (OFAB), an International Organisation, has urged Nigerians to embrace bio-technology to mitigate issues around climate change and ensure food security in the country.

Dr Rose Gidado, Country Director, OFAB Nigeria, said this at the sideline of the science hangout, organised by the Alliance for Science Nigeria (ASN) on Monday in Abuja.

She said the meeting was to discuss “the status of genetically modified food” and how best to deploy bio-technology to ensure food security in Nigeria.

Gidado explained that conventional Agriculture might be failing due to a lot of reasons related to climate change, including incessant high rise in temperature, gully erosion and desert encroachment.

“Also, we have other environmental reasons why conventional agriculture is failing; the oil spillage, insecurities on our farms and a lot more.

“Bio-technology has been adopted in Nigeria, a seed launch was held last year in Kano and farmers are testifying to greater yields and one of the economic benefits is 20 per cent yields increase per hectare.

“With the use of this technology, we are saving Nigeria N16 billion, which is normally used to import cowpeas; these crops undergo rigorous testing, making them safer for consumption compared to organic crops,” she added.

According to her, what makes genetic modification unique is its flexibility to adopt desired genes from donor plants and input into a crop aimed at improving given best desired results and helping also with resistance in certain crops.

Also, Prof. Hamzat Lawal, , Follow The Money, said that although GM- crops were facing issues around conspiracy theories, there were data and evidences to show that the technologies were straightforward science.

“Six million people in Nigeria go to bed hungry on a daily basis; the issue of food insecurity is at a critical stage globally.

“That’s why the bio-technology innovation is here to stay; it is an intervention that will save us from food shortage in the country.

“Until now, there were debates around climate change too; people will naturally reject what they don’t know because there is no trust yet which is only expected.

“The best we can do is to educate the public and carry out more sensitisation on this technology that will change a lot of things and ensure we eat safer food,” he added.

NewsSourceCredit: NAN

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Safeguarding Plant Immunity against Climate Change

June 30, 2022


Credit: Andreas Rockstein licensed under CC BY-SA 2.0


Heat waves increase the vulnerability of plants to infectious diseases by compromising their immunity. Short periods of high temperatures suppress the production of a defense hormone in plants called salicylic acid, although the mechanism has remained unclear, until now.

In an article published on June 29, 2022, in the journal Nature, “Increasing the resilience of plant immunity to a warming climate” scientists led by Duke University biologist Sheng-Yang He, PhD, claim to have identified a gene in plant cells that explains why immunity falters with rising heat, and demonstrate optimizing the expression of this gene could restore the production of salicylic acid and bolster immunity in plants against heat waves. The investigators conducted their experiments on the model plant Arabidopsis thaliana. If their findings in this model hold in crops, it would go a long way to ensure food security in a warming world, said He.

Earlier studies from He’s team has shown even brief heat waves can have a dramatic effect on hormone defenses in Arabidopsis, leaving them more prone to infection by the bacterium Pseudomonas syringae. Under normal ambient temperatures, salicylic acid levels increase nearly seven-fold upon infection, but when temperatures rise above 86°F, the plant can no longer produce enough of the defense hormone, and the infection spreads.

“Plants get a lot more infections at warm temperatures because their level of basal immunity is down,” He said. “So we wanted to know, how do plants feel the heat? And can we fix it to make plants heat-resilient?”

Earlier studies from other labs had identified plant proteins called phytochromes that act as thermometers and trigger growth and flowering in spring. He and his colleagues wondered whether phytochromes played a role in suppressing plant immunity as temperatures rise.

To answer this question, He’s team infected mutant plants with continuously active phytochromes and normal plants with P. syringae bacteria and grew them at 73 and 82°F. They found phytochrome mutants, like normal plants, still couldn’t make enough salicylic acid when temperatures rose.

The team spent several years testing other thermoregulatory genes but could not identify any that made plants resilient to infections in hot weather. This led the authors to conclude that suppression of salicylic acid production in Arabidopsis at high temperatures is independent of genes that regulate heat-responsive plant growth and development, such as phytochromeB and early flowering 3.

They then adopted next-generation sequencing to compare gene expression in infected Arabidopsis plants at normal and elevated temperatures and found many genes that were suppressed at high temperatures were regulated by a gene called CBP60g. CBP60g is a master switch that controls many other genes, including genes that produce salicylic acid.

In-depth analysis revealed heat impairs the molecular machinery that decodes CBP60g. The investigators demonstrated, Arabidopsis with continuously active CBP60g maintained adequate levels of salicylic acid and were resilient against bacterial infections even when exposed to heat.

However, constant activation of CBP60g can stunt plant growth. Therefore, the researchers optimized the regulation of the genetic master switch such that it turned on only under attack. He said, “These results could be good news for food supplies made insecure by climate change.”

In addition to Arabidopsis, He’s team found that increased temperatures also decreased salicylic acid defenses in tomato, rapeseed and rice. The team is currently restoring CBP60g gene activity in rapeseed and has seen promising results.

In addition to regulating the production of salicylic acid, CPB60g activity also protects other immunity-related genes against heat. “We were able to make the whole plant immune system more robust at warm temperatures,” He said. “If this is true for crop plants as well, that’s a really big deal because then we have a very powerful weapon.”

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Science News

from research organizations

Climate change is making plants more vulnerable to disease. New research could help them fight back

To keep food on the table in a warming world, researchers are bolstering plant immunity against the heat.

Date:June 29, 2022Source:Duke UniversitySummary:When heat waves hit, they don’t just take a toll on people — plants suffer too. That’s because when temperatures rise, certain plant defenses don’t work as well, leaving them more susceptible to attacks from pathogens and pests. Scientists say they have identified a specific protein in plant cells that explains why immunity falters as the mercury rises. They’ve also figured out a way to bolster plant defenses against the heat.Share:


When heat waves hit, they don’t just take a toll on people — the plants we depend on for food suffer too. That’s because when temperatures get too high, certain plant defenses don’t work as well, leaving them more susceptible to attacks from pathogens and insect pests.

Now, scientists say they have identified a specific protein in plant cells that explains why immunity falters as the mercury rises. They’ve also figured out a way to reverse the loss and bolster plant defenses against the heat.

The findings, appearing June 29 in the journal Nature, were found in a spindly plant with white flowers called Arabidopsis thaliana that is the “lab rat” of plant research. If the same results hold up in crops too, it would be welcome news for food security in a warming world, said Duke University biologist and corresponding author Sheng-Yang He.

Scientists have known for decades that above-normal temperatures suppress a plant’s ability to make a defense hormone called salicylic acid, which fires up the plant’s immune system and stops invaders before they cause too much damage. But the molecular basis of this immunity meltdown wasn’t well understood.

In the mid 2010s, He and his then-graduate student Bethany Huot found that even brief heat waves can have a dramatic effect on hormone defenses in Arabidopsis plants, leaving them more prone to infection by a bacterium called Pseudomonas syringae.

Normally when this pathogen attacks, the levels of salicylic acid in a plant’s leaves go up 7-fold to keep bacteria from spreading. But when temperatures rise above 86 degrees for just two days — not even triple digits — plants can no longer make enough defense hormone to keep infection from taking hold.

“Plants get a lot more infections at warm temperatures because their level of basal immunity is down,” He said. “So we wanted to know, how do plants feel the heat? And can we actually fix it to make plants heat-resilient?”

Around the same time, a different team had found that molecules in plant cells called phytochromes function as internal thermometers, helping plants sense warmer temperatures in the spring and activate growth and flowering.

So He and his colleagues wondered: could these same heat-sensing molecules be what’s knocking down the immune system when things warm up, and be the key to bringing it back?

To find out, the researchers took normal plants and mutant plants whose phytochromes were always active regardless of temperature, infected them with P. syringae bacteria, and grew them at 73 and 82 degrees to see how they did. But the phytochrome mutants fared exactly like normal plants: they still couldn’t make enough salicylic acid when temperatures rose to fend off infections.

Co-first authors Danve Castroverde and Jonghum Kim spent several years doing similar experiments with other gene suspects, and those mutant plants got sick during warm spells too. So they tried a different strategy. Using next-generation sequencing, they compared gene readouts in infected Arabidopsis plants at normal and elevated temperatures. It turned out that many of the genes that were suppressed at elevated temperatures were regulated by the same molecule, a gene called CBP60g.

The CBP60g gene acts like a master switch that controls other genes, so anything that downregulates or “turns off” CBP60g means lots of other genes are turned off, too — they don’t make the proteins that enable a plant cell to build up salicylic acid.

Further experiments revealed that the cellular machinery needed to start reading out the genetic instructions in the CBP60g gene doesn’t assemble properly when it gets too hot, and that’s why the plant’s immune system can’t do its job anymore.

The team was able to show that mutant Arabidopsis plants that had their CBP60g gene constantly “switched on” were able to keep their defense hormone levels up and bacteria at bay, even under heat stress.

Next the researchers found a way to engineer heat-resilient plants that turned on the CBP60g master switch only when under attack, and without stunting their growth — which is critical if the findings are going to help protect plant defenses without negatively impacting crop yields.

The findings could be good news for food supplies made insecure by climate change, He said.

Global warming is making heat waves worse, weakening plants’ natural defenses. But already, up to 40% of food crops worldwide are lost to pests and diseases each year, costing the global economy some $300 billion.

At the same time, population growth is driving up the world’s demand for food. To feed the estimated 10 billion people expected on Earth by 2050, forecasts suggest that food production will need to increase by 60%.

When it comes to future food security, He says the real test will be whether their strategy to protect immunity in Arabidopsis plants works in crops as well.

The team found that elevated temperatures didn’t just impair salicylic acid defenses in Arabidopsis plants — it had a similar effect on crop plants such as tomato, rapeseed and rice.

Follow-up experiments to restore CBP60g gene activity in rapeseed thus far are showing the same promising results. In fact, genes with similar DNA sequences are found across plants, He says.

In Arabidopsis, keeping the CPB60g master switch from feeling the heat not only restored genes involved in making salicylic acid, but also protected other defense-related genes against warmer temperatures too.

“We were able to make the whole plant immune system more robust at warm temperatures,” He said. “If this is true for crop plants as well, that’s a really big deal because then we have a very powerful weapon.”

This work was a joint effort between He’s team and colleagues at Yale University, the University of California, Berkeley, and Tao Chen Huazhong Agricultural University in China. A patent application has been filed based on this work.

This research was supported by the Natural Sciences and Engineering Research Council of Canada, Korean Research Foundation Postdoctoral Fellowship, National Institutes of Health T32 Predoctoral Fellowship, Howard Hughes Medical Institute Exceptional Research Opportunities Fellowship, National Natural Science Foundation of China, and MSU Plant Resilience Institute and Duke Science and Technology Initiative.

Story Source:

Materials provided by Duke University. Original written by Robin A. Smith. Note: Content may be edited for style and length.

Journal Reference:

  1. Jong Hum Kim, Christian Danve M. Castroverde, Shuai Huang, Chao Li, Richard Hilleary, Adam Seroka, Reza Sohrabi, Diana Medina-Yerena, Bethany Huot, Jie Wang, Kinya Nomura, Sharon K. Marr, Mary C. Wildermuth, Tao Chen, John D. MacMicking, Sheng Yang He. Increasing the resilience of plant immunity to a warming climateNature, 2022; DOI: 10.1038/s41586-022-04902-y

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Effective plant health management is critical for improving the productivity, profitability, sustainability and resilience of agrifood systems. Yet, farming communities, especially in low- and middle-income countries, continue to struggle against plant pests and diseases. Each year, these threats cause 10–40% losses to major food crops, costing the global economy US$220 billion. Recent analyses show that the highest losses due to pests and diseases are associated with food-deficit regions with fast-growing populations.

Increasing trade and travel, coupled with weak phytosanitary systems, are accelerating the global spread of devastating pests and diseases. The situation is exacerbated by climate change, driving the emergence of new threats. These burdens fall disproportionately on women and poorly resourced communities.

Diagnostic capacity, global-scale surveillance data, risk forecasting and rapid response and management systems for major pests and diseases are still lacking. Inadequate knowledge and access to climate-smart control options often leave smallholders and marginalized communities poorly equipped to respond to biotic threats. Environmental effects of toxic pesticides, mycotoxin exposure and acute unintentional pesticide poisoning are major concerns globally.


This Initiative aims to protect agriculture-based economies of low- and middle-income countries in Africa, Asia and Latin America from devastating pest incursions and disease outbreaks, by leveraging and building viable networks across an array of national, regional and global institutions.


This objective will be achieved by:

  • Bridging knowledge gaps and networks for plant health threat identification and characterization, focusing on strengthening the diagnostic and surveillance capacity of national plant protection organizations and national agricultural research and extension systems, and facilitating knowledge exchange on pests and diseases.
  • Risk assessment, data management and guiding preparedness for rapid response, focusing on controlling the introduction and spread of pests and diseases by developing and enhancing tools and standards.
  • Integrated pest and disease management, focusing on designing and deploying approaches against prioritized plant health threats in targeted crops and cropping systems.
  • Tools and processes for protecting food chains from mycotoxin contamination: designing and deploying two innovations for reducing mycotoxin contamination to protect health, increase food/feed safety, enhance trade, diversify end-use and boost income.
  • Equitable and inclusive scaling of plant health innovations to achieve impacts, through multistakeholder partnerships, inter-disciplinary research and effective communications.


This Initiative will work in the following countries: Bangladesh, Benin, Bolivia, Burkina Faso, Burundi, Cambodia, Cameroon, Colombia, Democratic Republic of the Congo, Ecuador, Egypt, Ethiopia, Ghana, India, Ivory Coast, Kenya, Lebanon, Mali, Malawi, Mexico, Morocco, Mozambique, Nepal, Niger, Nigeria, Peru, the Philippines, Rwanda, Senegal, Sudan, Tunisia, United Republic of Tanzania, Uganda, Vietnam, Zambia and Zimbabwe.


Proposed 3-year outcomes include:

  1. National plant protection organizations in at least 10 target countries participate in a global plant diagnostic and surveillance network, exchanging data and knowledge.
  2. At least 25 national partners in 10 target countries use the novel diagnostic and surveillance tools to effectively counter existing or emerging plant health threats.
  3. At least 10 target national plant protection organizations increase their capacity to use epidemiological modeling data and decision support tools for pest risk assessment and preparedness to counter prioritized pests and diseases.
  4. A global plant health consortium comprising 60–70 institutions is operational, codeveloping and deploying integrated pest and disease management innovation packages and educational curriculum for effective plant health management.
  5. Adoption of eco-friendly and climate-smart integrated pest and disease management innovations by at least 4 million smallholders in 15 countries results in reduction in crop losses of at least 5% and use of toxic pesticides of at least 10%.
  6. At least 10 private sector partners in four focal countries in Africa commercialize Aflasafe to 200,000 farmers (400,000 ha of maize), resulting in enhanced availability of safe and nutritious food and feed.
  7. At least 300,000 smallholder households across five countries use affordable and easy-to-use pre- and post-harvest integrated mycotoxin management innovations for mitigating contamination of the food chain.
  8. Plant health research communities in at least 12 targeted countries use needs assessment evidence and data to develop demand-driven, equitable and scalable innovations.
  9. National and regional partners use validated scaling approaches for detection, surveillance and management of pests, diseases and mycotoxin.
  10. Based on science-based plant health policy briefs, investors and decision makers in targeted regions create an enabling environment for research for development and scaling of plant health innovations.


Projected impacts and benefits include:

POVERTY REDUCTION, LIVELIHOODS & JOBSLivelihoods of more than 27 million people (more than 6 million households) across 13 target countries are improved due to increased yield stability and containment of pest- and disease-induced crop and food losses at the field- and landscape-levels through development and delivery of eco-friendly innovations to detect and control pests and diseases.
NUTRITION, HEALTH & FOOD SECURITYMore than 110 million people (more than 16 million households) benefit from better resilience of crops and cropping systems, better preparedness to counter biotic threats exacerbated by climate variability and changing farming practices, further increasing food security and farm profitability, and reducing food prices.Losses in yield and quality of major food crops due to pests and diseases are reduced through integrated pest and disease management innovations. Food and feed are made safer for consumption by reducing pesticide and mycotoxin contamination in targeted crops, improving human and animal health.
GENDER EQUALITY, YOUTH & SOCIAL INCLUSIONAround 8 million women have increased access to and benefit from plant health innovations through prioritization and implementation of approaches for gender-equitable and socially inclusive design and scaling of plant health innovations. These are supported by multi-stakeholder partnerships and new opportunities for women and youth.
CLIMATE ADAPTATION & MITIGATIONMore than 8 million people (more than 1.27 million households) benefit from reduced impact of climate-induced changes in pests and diseases on crops, food security, and livelihoods through better preparedness and adaptation of plant health innovations based on improved forecasting of threats and modeling of impacts.
ENVIRONMENTAL HEALTH & BIODIVERSITYReduction in use of toxic pesticides and associated safety hazards, including pesticide residues in the environment, due to integrated disease and pest management and prioritization of nature-based solutions are applied on more than 9 million hectares of maize crops, benefiting more than 24 million people (more than 5 million households). Natural biodiversity and ecologies are protected from devastating invasive pests and pathogens and toxic pesticides.
For more details, view the Initiative proposal

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