Inoculation against diseased fields
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THE FUNGI WERE MIXED INTO THE SOIL BEFORE SOWING CROPS ON 800 TRIAL PLOTS AT 54 MAIZE FARMS IN NORTHERN AND EASTERN SWITZERLAND.
view moreCREDIT: UNIVERSITY OF ZURICH
Intensive use of fertilizers and pesticides on fields reduces biodiversity and pollutes the environment. There is therefore great interest in finding sustainable ways to protect yields without the use of agricultural chemicals. One example of alternative biologicals is mycorrhizal fungi, which are beneficial organisms that help plants acquire nutrients.
Yields improved by up to 40 percent
A team of researchers from the universities of Zurich and Basel, Agroscope and the Research Institute of Organic Agriculture (FiBL) has now shown for the first time on a large scale that the application of mycorrhizal fungi in the field works. The fungi were mixed into the soil before sowing crops on 800 trial plots at 54 maize farms in northern and eastern Switzerland. “On a quarter of the plots, the mycorrhizal fungi enabled up to 40 percent better yields. That’s huge,” says the study’s co-lead Marcel van der Heijden, a soil ecologist at the University of Zurich and at Asgroscope. But there’s a catch: on a third of the plots, the yield did not increase and in some cases even decreased. The research team was initially unable to explain why this happened.
Pathogens in the soil
In their search for the cause, the researchers analyzed a variety of chemical, physical and biological soil properties, including the biodiversity of soil microbes. “We discovered that the inoculation functioned best when there were lots of fungal pathogens already in the soil,” says co-first author Stefanie Lutz from Agroscope, the federal center of competence for agricultural research. “The mycorrhizal fungi act as a kind of protective shield against pathogens in the soil that would weaken the plants.” As a result, the normal yield can be maintained in fields where without mycorrhizal fungi there would have been losses. In contrast, mycorrhizal fungi had only a minor effect on fields that are not contaminated with pathogens. “The plants there are strong anyway and grow excellently. The use of mycorrhizal fungi in such cases brings no additional benefits,” says the other first author Natacha Bodenhausen from the Research Institute of Organic Agriculture.
Vaccination success can be predicted
The aim of the study, funded by the Gebert Rüf Foundation, was to be able to predict the conditions under which mycorrhizal inoculation works. “With just a few soil indicators – mainly soil fungi – we were able to predict the success of inoculation in nine out of 10 fields, and thus could also predict the harvest yield even before the field season,” says the study’s co-lead Klaus Schläppi of the University of Basel. “This predictability makes it possible to target the use of the fungi in fields where they will work. That’s a crucial element for developing these technologies into a reliable agricultural method,” says Schläppi.
Further research is still required to find out the easiest way to spread the fungi over large areas. Nevertheless, “the results of this field trial represent a big step toward a more sustainable agriculture,” concludes Marcel van der Heijden.
JOURNAL
Nature Microbiology
METHOD OF RESEARCH
Experimental study
SUBJECT OF RESEARCH
Cells
ARTICLE TITLE
Soil microbiome indicators can predict crop growth response to large-scale inoculation with arbuscular mycorrhizal fungi
ARTICLE PUBLICATION DATE
29-Nov-2023
Riding the whims of the wind
Researchers at the University of Missouri and Michigan State University develop a model that analyzes the future survival of plants in a changing climate based on how far wind can carry a plant’s seeds
As Earth’s climate continues to change, a plant’s ability to adapt to its shifting environment is critical to its survival. Often, to stay alive a plant must move locations by releasing its seeds, but plants are rooted in the ground and cannot move themselves. Instead, they are dependent on animals or the wind to carry their seeds to a new location.
Playing an essential foundational role in an ecosystem, plants contribute to the well-being of human health by helping create resources like food and medicine. Therefore, to better understand how plants can maintain resiliency in the face of challenges like climate change, a team of researchers at the University of Missouri and Michigan State University recently collaborated to develop an innovative mathematical model that can provide fast and reliable predictions of how far wind can carry a plant’s seeds.
“Once seeds are released from a plant, we wanted to know how far they can go because as wind conditions fluctuate the seeds will be moved around differently as a result of various weights, sizes and shapes,” said Binbin Wang, an assistant professor in the Department of Civil and Environmental Engineering at the MU College of Engineering. “This model gives us a better idea of the probability of where a seed will land on the ground in different conditions depending on the seed type, the plant type and the wind speed.”
One advantage of the model is its ability to predict the probability of where seeds might eventually land on the ground when winds are turbulent, said Jeffrey Wood, an assistant professor in School of Natural Resources at the MU College of Agriculture, Food and Natural Resources.
“Like eddies created by currents in a river, there are also eddies swirling around in the atmosphere, particularly in the lowest part closest to the Earth’s surface,” Wood said. “These atmospheric eddies, called turbulence, are chaotic, swirling movements that can transport gases and heat around in the atmosphere. They also move seeds through the air.”
Changes in one part of the ecosystem can create a “snowball effect” on other parts. For instance, a loss in plant diversity can disrupt the fragile stability of the entire ecosystem, and impact both human and animal populations. That’s why understanding seed dispersal is important. Plants can only make this move once during their life — as a seed, said Lauren Sullivan, an assistant professor in the College of Natural Science at Michigan State University.
For example, if the winds are low, calm and not turbulent when a plant is producing its seeds, the seeds might fall straight down and not spread anywhere, she said.
“Understanding how plants move as seeds year-round is critical for us to analyze how they’ll be able to handle climate change,” Sullivan said. “This movement is also important for how we can increase diversity in the ecosystem. As a biologist, instead of making assumptions about how plants move, we’re now able to partner with researchers who can factor in aspects like aerodynamics and micro-meteorology. This innovative approach can help us develop accurate models that are simple enough to make good predictions in just a short amount of time.”
The model, which makes predictions based on seed and plant type, plant height and wind speed, can develop an entire year’s worth of predictive data in just one or two days. It’s similar to other models that Wang has created for predicting the spread of fish eggs in rivers, or the spread of virus-laden respiratory droplets in air.
As part of their future work, the team will develop educational programming for K-12 and college students. For example, they will provide opportunities for college students to explore how different disciplines, such as agriculture, biological sciences and engineering, can work together to solve different real-world problems.
“Modeling wind-driven seed dispersal using a coupled Lagrangian particle tracking and 1-D k-ɛ turbulence model,” was published in Ecological Modelling. This work was funded in part by the United States Department of Agriculture (58-5070-9-016 and 58-5070-2-018).
JOURNAL
Ecological Modelling
ARTICLE TITLE
Modeling wind-driven seed dispersal using a coupled Lagrangian particle tracking and 1-D k-ɛ turbulence model
Scarborough researchers discover the waxy surface protecting plants might hold the key to developing stronger crops
Discovery about protective wax around plants might help develop more resilient crops
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RESEARCHERS LOOKED AT THE ROLE WAXES PLAY IN POPLAR TREES FOR THE STUDY.
view moreCREDIT: DON CAMPBELL
A team of U of T Scarborough researchers have discovered that the waxy protective barrier around plants might play a role in sending chemical signals to other plants and insects.
The research, published in the journal Proceedings of the National Academy of Science, might eventually be harnessed to develop stronger plants that can deal with challenging environmental conditions.
For the study researchers looked at cuticular waxes, a thin layer that plants deposit on their surface to help protect them from losing water. “These waxes act as a physical defense,” says Eliana Gonzales-Vigil, an assistant professor in the department of biology who led the study.
“If plants didn’t have this wax, they would dry out very quickly. It’s the reason you see water drops beading on the surface of leaves. Plants evolved this trait over time when they moved from growing in water to growing on land.”
The waxes play a role in defending plants against ultraviolet radiation, fungus, bacteria, high and low temperatures as well as insects. It was thought these waxes were stable, unreactive barriers, but the researchers found that some waxes break down after being exposed to air and light, releasing other compounds in the process.
Using a method of analyzing waxes in a species of poplar tree (cottonwood), the researchers found that unsaturated waxes, known as alkenes, degrade to produce a well-known aldehyde signaling compound and insect pheromone known as nonanal.
It’s a complex bit of biochemistry, but Gonzales-Vigil says the key takeaway is that interesting smaller compounds can be released from larger waxes found in the plants. “This process could one day be used to engineer desirable traits in plants that can improve their resilience from drought or insects,” she says.
Role in plant communication
Aldehydes perform an essential role in both plants and animals, including humans. In animals, they work as signaling molecules, influencing various aspects of growth, development and reproduction. They’re also the reason why mosquitos are attracted to some people (and animals) more than others.
In plants they’re present in pheromones that attract insects and are also responsible for plant-to-plant communication. If a plant is stressed due to drought, for example, it will release the compound to let neighbouring plants know so they can prepare.
Jeff Chen, who recently completed a master’s in cell and systems biology at U of T Scarborough, discovered that waxes can break down to produce aldehydes by accident. He wanted to see what happened to waxes in poplar plants over time as they age. He tracked the plant’s leaves from the time they were young all the way until they were dying, finding the waxes decreased in abundance as they got older.
“This was surprising because you would expect something that is stable to be there for the lifetime of the plant,” says Chen who is now a PhD student at the University of Illinois.
“At the same time, we saw an increase of volatile compounds, these aldehydes. That led us to believe that as these waxes break down, there is a corresponding increase in volatile compounds.”
Potential for improving crop resilience
Alkenes, which is the precursor for creating aldehydes, is a specialized wax that is only present in some plants. The fact these waxes might play a role in signaling opens a bunch of possibilities for helping grow plants, including food crops, says Gonzales-Vigil. For example, they found that the hairs on an ear of corn, known as corn silk, also accumulate large quantities of alkenes that break down into aldehydes.
For this study, the researchers also looked at waxes in wheat and found that another major wax component in the crop also breaks down into smaller compounds.
“It opens up a lot of exciting opportunities. This process could be used to make pheromones that are released slowly from the wax to attract or repel insects,” says Gonzales-Vigil.
“Currently this is done synthetically, which is expensive, so it could also lead to cheaper more natural alternatives.”
Researchers looked at the role waxes play in poplar trees for the study.
Researchers looked at waxes on wheat.
JOURNAL
Proceedings of the National Academy of Sciences
ARTICLE TITLE
Dynamic changes to the plant cuticle include the production of volatile cuticular wax–derived compounds
ARTICLE PUBLICATION DATE
30-Nov-2023
