Study shows how plant roots access deeper soils in search of water
image:
Watered (left) vs water stressed (right) image – showing change in root angle to make the architecture steeper
view more
Credit: University of Nottingham
Scientists have discovered how plants adapt their root systems in drought conditions to grow steeper into the soil to access deeper water reserves.
Plant scientists from the University of Nottingham, in collaboration with Shanghai Jiao Tong University, have identified how abscisic acid (ABA), a plant hormone known for its role in drought response, influences root growth angles in cereal crops such as rice and maize. The results have been published in Current Biology.
The study highlights how ABA and auxin, another key hormone, work together to shape root growth angle, providing a potential strategy to develop drought-resistant crops with improved root system architecture.
Drought poses a major threat to global food security, and enhancing the ability of crops to withstand water shortages is crucial. Drought, a major abiotic stressor, has caused substantial crop production losses of approximately $30 billion over the past decade. With a projected population of 10 billion by 2050 and serious freshwater depletion, developing drought-resistant crops is of paramount importance
Plants rely on their root systems, the primary organs for interacting with soil, to actively seek water. In drought conditions, water often depletes in the topsoil and remains accessible only in the deeper subsoil layers. Abscisic acid (ABA) plays an important role in helping plants adapt to these challenging conditions. This new study gives new insights into how ABA changes root growth angles to enable plants to reach out deeper subsoils in search of water.
The researchers discovered a new mechanism where ABA promotes the production of auxin, which enhances root gravitropism to grow them at steeper angles in response to drought. Experiments showed that plants with genetic mutations that block ABA production had shallower root angles and weaker root bending response to gravity compared to normal plants. These defects were linked to lower auxin levels in their roots. By adding auxin externally, the researchers restored normal root growth in these mutants, showing that auxin is key to this process.
The findings were consistent across both rice and maize, suggesting that this mechanism could apply to other cereal crops as well.
Dr Rahul Bhosal, Assistant Professor from the School of Bioscience is one of the lead authors on the study, he said: “Finding ways to tackle food insecurity is vital and the more we understand the mechanisms that control plant growth, the closer we are to designing systems to help plants to do this and improve crop yields during droughts.”
Journal
Current Biology
Method of Research
Experimental study
Subject of Research
Not applicable
Article Title
ABA-auxin cascade regulates crop root angle in response to drought
Article Publication Date
10-Jan-2025
Repairing a domestication mutation in tomato leads to an earlier yield
University of Lausanne
image:
Picture of a tomato plant with an unfavorable natural mutation (on the left) and a tomato plant in with the mutation was repaired by genome editing (on the right). The repair of the mutation leads to earlier fruit yield. Scale: 7.5 cm.
view moreCredit: Anna Glaus, UNIL
Genome editing with CRISPR-Cas is often associated with the induction of mutations. However, a team of researchers from the Swiss University of Lausanne now shows that it can also be used to repair natural mutations.
All living organisms mutate, which is a major driver of biodiversity and evolution. Humans have been domesticating plants for thousands of years, by selecting mutations that lead to favorable characteristics such as larger or more numerous fruits. However, this process often caused the co-selection of other undesirable mutations that can have negative effects on plant growth and development. This phenomenon is called the “cost of domestication”.
The selection and combination of mutations is also essential for breeding new crop varieties. To increase the frequency at which mutations occur, plants are exposed to chemicals or radiation. But this mutagenesis approach is random and makes breeding of new varieties very time consuming. Genome editing with CRISPR-Cas is a new approach to introduce mutations into the genome of plants - in a precise and predictable manner. Even better, with genome editing it is not only possible to induce mutations, but also to repair existing ones: this was shown by researchers of the University of Lausanne in a paper published in Nature Genetics. And not in any plant! The biologists of the Department of Plant Molecular Biology (DBMV) at the Faculty of Biology and Medicine, published their work on the second most consumed vegetable crop (or fruit for insiders) worldwide after the potato: the tomato.
Using CRISPR to harvest earlier
Researchers in the laboratory of Sebastian Soyk, assistant professor at the DBMV used a genome editing technology, called base editing, to change one of the ~850 million DNA base pairs in the genome of the tomato to repair an unfavorable domestication mutation. Anna Glaus, doctoral student in the research group, first selected and then investigated the mutated and repaired plants. “To obtain these results, I characterized 72 plants and harvested during two consecutive days 4’500 fruits that I sorted by size, weight, and maturity (red or green) and measured their sugar content”, explains Anna Glaus.
By repairing the deleterious domestication mutation with genome editing, the Swiss researchers have obtained a tomato variety that is earlier yielding. Considering, the Swiss moratorium banning the growth of genetically modified organism (GMO), which expires in June 2025, this new study is thought-provoking. “We show here the varied application of genome editing and its benefit for agriculture”, says Anna Glaus. “It is important to take this scientific data into consideration when thinking about the legal frame of genome editing. With genome editing we have now the tools at hand to precisely re-write the genetic code and make crop breeding more predictable”, says Sebastian Soyk. “We should now combine this ability with other directions in breeding and agricultural research, such as agroecology, to make agriculture more resilient and sustainable”.
Journal
Nature Genetics
Method of Research
Experimental study
Subject of Research
Not applicable
Article Title
Repairing a deleterious domestication variant in a floral regulator gene of tomato by base editing
Article Publication Date
8-Jan-2025
Hydrogen peroxide and the mystery of fruit ripening: ‘Signal messengers’ in plants
Chinese Academy of Sciences Headquarters
image:
Micro-Tom tomato planted in a greenhouse
view moreCredit: Photo by ZHOU Leilei
A research team led by Prof. QIN Guozheng from the Institute of Botany of the Chinese Academy of Sciences has unveiled a previously unrecognized mechanism by which the RNA N6–methyladenosine (m6A) demethylase SlALKBH2 undergoes reduction-oxidation (redox) modification. This alteration affects its stability and its physiological role in regulating the normal ripening of tomato fruits.
In this study, published in Nature Plants, the researchers deepened their understanding of the role of hydrogen peroxide (H2O2), a mild oxidant that functions as a pivotal signaling molecule in controlling multiple biological processes. They found that H2O2-mediated oxidative modification regulates the function of SlALKBH2, which is essential for the proper ripening of fleshy fruits. This ripening stage represents the final phase of fruit development, directly influencing fruit quality and shelf life.
Specifically, the researchers showed how H2O2 signaling interacts with RNA methylation modification to regulate plant development in a coordinated way.
The most prevalent chemical modification in eukaryotic mRNAs is m6A methylation. It regulates various biological processes, including mRNA stability and translation efficiency, by modulating mRNA metabolism.
As members of the dioxygenase family, m6A demethylases, including SlALKBH2, are capable of oxidatively reversing m6A methylation. This capacity raises the question of whether SlALKBH2 itself is subject to oxidative modification, similar to other redox-sensitive proteins.
To test this hypothesis, the researchers transiently expressed the SlALKBH2 gene in Nicotiana benthamiana leaves treated with or without H2O2, then subsequently monitored the redox status of SlALKBH2.
The results indicated a marked sensitivity of SlALKBH2 to H2O2-induced oxidation, resulting in the formation of homodimers both in N. benthamiana leaves and in tomato fruits. Notably, exposure to H2O2 was shown to accelerate tomato fruit ripening, implicating SlALKBH2 oxidation in this process.
The formation of SlALKBH2 homodimers was attributed to the involvement of multiple cysteine (Cys) residues, with Cys39 identified as a crucial site; mutation at this location drastically reduced homodimer formation. While oxidative modification improved the stability of the SlALKBH2 protein, it did not affect its m6A demethylase activity.
Moreover, the researchers identified NADPH-thioredoxin reductase C (SlNTRC) as the interacting protein of SlALKBH2. They demonstrated that SlNTRC regulates the redox state of SlALKBH2, thus affecting its m6A demethylation function in tomatoes.
Stable SlNTRC knockout mutants were then generated in tomatoes using CRISPR–Cas9-mediated gene editing. The homozygous mutant line experienced substantial delays in vegetative growth and an inability to bear fruit.
This study established a connection between H2O2 signaling and m6A methylation, highlighting the significance of redox regulation of m6A modifiers in the control of fruit ripening.
Given the crucial role of RNA m6A methylation in various biological processes, researchers speculate that this regulatory mechanism may also play a role in other developmental processes.
In summary, this study not only enhances our understanding of the molecular mechanisms underlying fruit ripening, but also offers new insights and strategies for improving crop varieties.
Journal
Nature Plants
Article Title
Redox modification of m6A demethylase SlALKBH2 in tomato regulates fruit ripening
Article Publication Date
10-Jan-2025
Shade plants in the spotlight
image:
Experimental plant (Bittersweet) under experimental light conditions with extra red and far-red light
view moreCredit: Utrecht University
Plants in the shade of other plants receive more light than scientists had previously believed. A team of researchers from Utrecht University and Wageningen University & Research (WUR) describe how, in a recent article in the scientific journal Plant Cell & Environment. Their conclusions not only advance research into the functioning of photosynthesis in shady conditions, but may also benefit greenhouse horticulture. “When you have a better understanding of how different colours of light affect photosynthesis and plant growth, you can help growers develop smart ways to supplement natural sunlight with coloured light.”
“The effect occurs in plants shaded by other plants”, explains Utrecht University environmental scientist Hugo de Boer, who initiated the study. This is because plants only capture some of the sunlight for photosynthesis; the process plants use to convert sunlight and CO2 into glucose. Some of the light also passes through their leaves, mostly in the form of green light. You can see that yourself when you look up into a woodland canopy: the leaves look a bit like green filters above you. The same effect occurs with light beyond the visible part of the red colour spectrum, in the frequency range of 700 to 750 nm. We call that colour ‘far-red’. “Plants that grow in the shadow of other plants therefore receive a larger proportion of green and far-red light than plants that grow in full sunlight. Our research shows that plants have a special way of using the far-red part of the colour spectrum for photosynthesis.”
Photosynthesis in the shade
“Until now, researchers have seldom considered the possibility that plants utilise far-red light for photosynthesis”, says WUR PhD candidate Tinko Jans. That is because previous experiments with monochromatic light have shown that plants mainly use light from the visible wavelengths (400 to 700 nm) for photosynthesis, and that light with shorter or longer wavelengths contributes little to the process. “But when you combine far-red light with a small amount of visible light, it does in fact contribute considerably to photosynthesis. So we’ve developed a new method for measuring and modelling how additional far-red light contributes to photosynthesis.”
Shade avoidance response
Scientists and horticulturalists have known for some time that plants can use the far-red part of the colour spectrum to identify nearby plants from the shadows they cast. Jans: “Many plants react to a relative increase in far-red light by growing straight up, to win the competition for light. This shade avoidance response also helps horticulturalists, because it allows them to grow more plants closer together. Recent developments in LED technology have given a major stimulus to research into plants’ shadow reaction and the use of far-red light in horticulture.”
From measurement to mathematical model
“In earlier experiments we also studied the shade avoidance response”, De Boer adds. “In addition to showing morphological changes, our shade plants started growing much quicker when we tried to fool them by installing LED lamps to supplement far-red light. To our astonishment, our plants were perfectly capable of using the additional far-red light for photosynthesis.”
Colour effect
The researchers conducted a large number of photosynthesis measurements using different colours and intensities of light. De Boer: “But it turned out to be much more difficult to quantify the colour effect on photosynthesis, because the available mathematical models and measurement methods were based on the assumption that plants only use light from the visible spectrum. So we adapted a commonly used photosynthesis model to quantify the colour effect using combined measurements of photosynthesis and the full light spectrum that reaches the leaf.”
Researcher Dr. Hugo de Boer places an experimental plant (Bittersweet) under experimental light conditions with reduced red and far-red light
Credit
Utrecht University
Journal
Plant Cell & Environment
Method of Research
Experimental study
Subject of Research
Not applicable
Article Title
PCE Coupling Modelling and Experiments to Analyse Leaf Photosynthesis under Far-Red Light
A fungus to save plants?
For the first time, researchers from Jena have been able to understand how the soil fungus 𝘔𝘰𝘳𝘵𝘪𝘦𝘳𝘦𝘭𝘭𝘢 𝘢𝘭𝘱𝘪𝘯𝘢 eliminates nematodes with the help of natural products and could thus also help agriculture
image:
Part of the intestine of Caenorhabditis elegans under the microscope, enriched with malpinins. To take the picture, Constanze Schultz of Leibniz-IPHT used Fluorescence-Lifetime Imaging Microscopy (FLIM) to optimally observe the tiny nematodes.
view moreCredit: Constanze Schultz/Leibniz Institute of Photonic Technology
The story begins under our feet: soils are not only a complex habitat, but also a battlefield where tiny nematodes fight against fungi and plant roots. Agriculture in particular suffers as a result. Out of concern about crop losses, the worms are conventionally controlled with chemical pesticides. However, these are increasingly being criticized for potentially damaging the soil and water. With a view to the future, alternatives must be found for sustainable agriculture.
Unlike us humans, the soil fungus Mortierella alpina has long known a natural trick against nematodes: it produces special molecules that make life difficult for its predators. These surface-active natural products are called malpinins and act as natural detergents. “Earlier studies had already shown that the fungus can fight nematodes, but the molecular mechanism of action behind this was still unknown. We wanted to elucidate this,” says first author Dr. Hannah Büttner from the Leibniz Institute for Natural Product Research and Infection Biology – Hans Knöll Institute (Leibniz-HKI).
Mortierella alpina, which is mainly found in the soil of temperate and cool regions, could be a key to sustainable agriculture. “If we find out exactly how Mortierella works against nematodes, we could perhaps use this fungus specifically as a biological control agent against plant pathogens,” says Büttner, who has just successfully completed her doctoral thesis.
Malpinins disrupt the digestion of worms
For the study, the scientists investigated the effect of malpinins on model nematodes. In order to track the natural products live in the nematodes, they used imaging techniques such as fluorescence microscopy and Raman spectroscopy in cooperation with Constanze Schultz from the neighboring Leibniz Institute of Photonic Technology. “We were able to observe how the malpinins accumulate specifically in the worms’ digestive tract,” explains Büttner. “However, the nematodes did not die immediately, but stopped feeding. This ultimately led to a slow but effective control of the worms.”
The chemical structure of malpinins is particularly remarkable and makes their worm-killing effect possible in the first place. A special building block is crucial here: the unusual amino acid dehydrobutyrin.
“Dehydrobutyrin has a reactive double bond and could therefore react with molecules that are essential for the function of the nematode intestine,” explains co-author Johannes Raßbach from the Institute of Pharmacy at Friedrich Schiller University Jena. These reactions could, for example, disrupt important enzymatic processes in the digestive tract of the pests or impair the membrane structure. Experiments showed that variants of malpinins in which the amino acid was replaced by a less reactive structure completely lost their effect. “This indicates that precisely this structure is essential for biological activity. Without it, the compound is ineffective,” says Raßbach.
The researchers suspect that their unique structure enables the malpinins to both penetrate the nematodes’ bodies and have a targeted effect there.
An ecological alternative to chemical pesticides?
The findings from the study could contribute to sustainable agriculture. Chemical pesticides always pose certain environmental and health risks. Natural alternatives such as malpinins, on the other hand, could be environmentally friendly solutions, especially as Mortierella fungi are often associated with healthy soil. “Mortierella has long been used in biotechnology, e.g. for the production of baby food. However, in order to be able to use it safely and effectively in agriculture, we first need to research the fungus further,” emphasizes Raßbach.
The study was carried out as part of the “ChemBioSys” Collaborative Research Center and the “Balance of the Microverse” Cluster of Excellence at Friedrich Schiller University Jena. The Cluster of Excellence investigates how microbial communities in different habitats interact with each other and with their environment. The interdisciplinary research project aims to understand fundamental principles of microbial balance in order to apply them in medicine, agriculture, environmental science and biotechnology and to develop sustainable solutions to global challenges such as climate change, food shortages and health problems. The work was funded by the German Research Foundation, the state of Thuringia and the EU, among others.
Fluorescent dyes can be used to visualize the distribution of malpinins in the digestive tract of nematodes of the species Caenorhabditis elegans.
Credit
Constanze Schultz/Leibniz Institute of Photonic Technology
The soil fungus Mortierella alpina in a petri dish. M. alpina produces special molecules with a worm-killing effect, the malpinins, which it uses to protect itself from predators.
Credit
Johannes Rassbach/Leibniz-HKI and FSU Jena
Journal
Journal of the American Chemical Society
Article Title
Beneficial Soil Fungus Kills Predatory Nematodes with Dehydropeptides Translocating into the Animal Gut
New findings may help researchers develop a grapefruit devoid of compounds that affect medication levels
Wiley
Grapefruit and pummelo contain compounds called furanocoumarins that may affect the blood levels of more than 100 prescription drugs, so that people taking these medications are advised to remove these fruits from their diets. Research published in New Phytologist reveals genetic information about the synthesis of furanocoumarins in different citrus plant tissues and species and provides new insights that could be used to develop grapefruit and pummelo that lack furanocoumarins.
The research indicates that the production of furanocoumarins in citrus fruit is dependent on the integrity of a single gene within a multi-gene cluster that encodes enzymes of the 2-oxoglutarate-dependent dioxygenase family.
“This research helps us to understand why fruit of certain citrus species produce furanocoumarins and demonstrates how breeders and researchers could develop furanocoumarin-free citrus varieties,” said co–corresponding author Yoram Eyal, PhD, of the Volcani Center, in Israel.
URL upon publication: https://onlinelibrary.wiley.com/doi/10.1111/nph.20322
Additional Information
NOTE: The information contained in this release is protected by copyright. Please include journal attribution in all coverage. For more information or to obtain a PDF of any study, please contact: Sara Henning-Stout, newsroom@wiley.com.
About the Journal
New Phytologist is an international journal publishing outstanding original research in plant science and its applications. Research falls into five sections: Physiology & Development, Environment, Interaction, Evolution, and Transformative Plant Biotechnology. Topics covered range from intracellular processes through to global environmental change. New Phytologist is owned by the New Phytologist Foundation, a non-profit organization dedicated to the promotion of plant science.
About Wiley
Wiley is one of the world’s largest publishers and a trusted leader in research and learning. Our industry-leading content, services, platforms, and knowledge networks are tailored to meet the evolving needs of our customers and partners, including researchers, students, instructors, professionals, institutions, and corporations. We empower knowledge-seekers to transform today’s biggest obstacles into tomorrow’s brightest opportunities. For more than two centuries, Wiley has been delivering on its timeless mission to unlock human potential. Visit us at Wiley.com. Follow us on Facebook, X, LinkedIn and Instagram.
Journal
New Phytologist
Article Title
A 2OGD multi-gene cluster encompasses functional and tissue specificity that direct furanocoumarin and pyranocoumarin biosynthesis in citrus
Article Publication Date
8-Jan-2025
