plants – Lightsources.org

Power of Movement in Plants

2024/02/292024/03/01

Published in Nature, researchers from Aarhus University and the Technical University of Munich used Diamond’s eBIC facility to uncover new insights into what drives movement in plants.

Auxins are hormones playing a central role and controlling nearly all aspects of plant growth and development. Charles Darwin observed that plants could grow directionally in response to environmental stimuli such as light or gravity. In his book, The Power of Movement in Plants, published in 1880, Darwin showed that the part of the plant responding to such a stimulus differs from the part that perceives it. He proposed that some kind of ‘influence’ must travel from the perception site to the response area. However, Darwin was unable to identify the influence.

Darwin’s ‘growth accelerating substance’ was identified in 1926 as the hormone auxin. Later research identified that auxin is the growth factor that determines almost all plant responses to environmental changes. Directional transport of the auxin molecule between cells is required to ensure that the auxin response occurs in the correct part of the plant.

It wasn’t until the 1990s that scientists identified the proteins involved in the process. PIN-FORMED (PIN) proteins are auxin transporters, and they are essential for the development of auxin gradients within plant tissues that guide plant growth. They’re named from the distinct needle-like ‘pin’ form, without shoots or flowers, into which plants with dysfunctional PIN proteins grow. Even then, how PIN proteins fold, how they recognise substrates and inhibitors and the molecular mechanism behind transport have remained unknown.

Now researchers from Aarhus University and the Technical University of Munich have used single particle cryo-EM at eBIC to provide the first structural basis of auxin transport by PIN proteins.

Read more on Diamond website

Image: PIN8 is a 40 kDa membrane protein that transports the plant hormone Auxin. It forms a homodimer with each monomer containing two domains: transporter (green) and scaffold (blue). In the transporter domain a distinct crossover (red) is localized at the middle of the membrane plane that defines the auxin binding site. Below the structure are show 8 representative 2D classes from the data collected at eBIC that resulted in 3 distinct conformations solved. To the left are shown a schematic of the transport of Auxin (IAA) with two key conformations coloured that summarizes the transport mechanism as described by the data obtained at eBIC.

The key to why plants flower early in a warming world

2023/07/032023/07/12

Scientists have unveiled a new mechanism that plants use to sense temperature. This finding could lead to solutions to counteract some of the deleterious changes in plant growth, flowering and seed production due to climate change. The results are published today in PNAS.

The rise of temperatures worldwide due to climate change is having detrimental consequences for plants. They tend to flower earlier than before and rush through the reproductive process, which translates into less fruits and less seeds and reduced biomass.

Scientists are now working on the plants’ circadian clock, which determines their growth, metabolism and when they flower. The key thermosensor of the circadian clock is EARLY FLOWERING 3 (ELF3), a protein that plays a vital role in plant development. It integrates various environmental cues, such as light and temperature, with internal developmental signals, to regulate the expression of flowering genes and determine when plants grow and bloom.

A team from the ESRF, CEA and CNRS have determined the molecular mechanism of how ELF3 works in vitro and in the model plant Arabidopsis thaliana. As temperature rises, ELF3 undergoes a process called phase separation. This means that two liquid phases co-exist, in a similar way to oil and water. “We believe that when it goes through phase separation, it sequesters different protein partners like transcription factors, which translates into faster growth and early flowering as a function of elevated temperature”, explains Chloe Zubieta, CNRS Research Director from the Laboratoire de Physiologie Cellulaire et Vegetale at the CEA Grenoble (CNRS/Univ. Grenoble Alpes/CEA/INRAE UMR 5168) and co-corresponding author of the publication. “We are trying to understand the biophysics of the prion-like domain inside ELF3, which we think is the responsible for this phase separation.

ELF3 is a flexible protein, with no well-defined structure, so it cannot be studied using X-ray crystallography, as it needs to be in solution. Instead, the team used mainly Small Angle X-ray Scattering. All existing models showed that the structure would be highly disordered. Then the surprise came up: “I’ve seen many prion-like domains involved in phase separation, but this is the first time I saw something fundamentally different”, explains Mark Tully, ESRF scientist on BM29 and co-corresponding author of the publication.

Read more on the ESRF website

Helping to grow more food in Africa

2020/04/082020/04/14

University of Saskatchewan scientists help farmers in West Africa improve crops.

Derek Peak and Abimfoluwa Olaleye are using Canadian Light Source at the University of Saskatchewan (Usask) to help farmers in Nigeria and the Republic of Benin to grow vegetables less expensively and more sustainably. The USask researchers and their team recently published a paper in Soil Systems that explores the effects of an innovative farming practice, fertilizer microdosing, on two vegetable systems in both countries.

“The overall idea was to scale up good, innovative ideas to solve food security problems in the regions,” says Peak. “We combine agricultural studies out in the field with socio-economic studies and development work.” Olaleye’s interest in the project is both scientific and personal. “Anything agriculture always gets my interest, it’s something I’m passionate about. And helping people is a big bonus. My dad was a farmer back in Nigeria, so I picked up on that,” he says.

Image: Abimfoluwa Olaleye (right) and Taylor Procyshen, a graduate student who helped with the project, working in the laboratory together.

Plastic from Wood

2020/02/272020/02/27

X-ray analysis points the way to lignin-based components made to measure

The biopolymer lignin is a by-product of papermaking and a promising raw material for manufacturing sustainable plastic materials. However, the quality of this naturally occurring product is not as uniform as that of petroleum-based plastics. An X-ray analysis carried out at DESY reveals for the first time how the internal molecular structure of different lignin products is related to the macroscopic properties of the respective materials. The study, which has been published in the journal Applied Polymer Materials, provides an approach for a systematic understanding of lignin as a raw material to allow for production of lignin-based bioplastics with different properties, depending on the specific application.

Image: Lignin is a promising raw material (left) for thermoplast (right) production.
Credit: KTH Stockholm, Marcus Jawerth

Stopping yellow spot fungus that attacks wheat crops

2020/01/142020/01/23

Scientists from the Centre for Crop and Disease Management (CCDM) and Curtin University in Western Australia have used an advanced imaging technique at the Australian Synchrotron for an in-depth look at how a fungus found in wheat crops is damaging its leaves.

Prof Mark Gibberd, director of the Centre, said the investigation was thought to be one of the first that utilised high-resolution X-ray imaging to examine biotic stress related to fungal infection in wheat.
Using X-ray fluorescence microscopy (XFM) on leaf samples collected from wheat plants, the team, which included project leader Dr Fatima Naim and ARC Future Fellow Dr Mark Hackett, mapped specific elements in the leaves in and around points of infection.

“Our research project looks at the physiological impact of plant diseases, such as yellow spot, on the function of leaves” said Gibberd.
Yellow spot is a ubiquitous fungal disease caused by Pyrenophora tritici-repentis (Ptr). It can reduce grain yields by up to 20 per cent – a significant amount which could be the difference between a profitable and non-profitable crop for a farmer.
In Australia, it is one of the most costly diseases to the wheat industry, with wheat yield losses due to yellow spot estimated at over $210 million per year.

>R ead more on the Autralisan Synchrotron at ANSTO website

Image: FM image reveals elements present in yellow spot fungs and the wheat leaves.
Credit: Curtin University

Educational science project: what trees tell about your community

2020/01/072020/01/09

Grade 6 to 12 classrooms from across Canada can participate for free.

The Canadian Light Source (CLS) at the University of Saskatchewan has launched a unique initiative that creates opportunities for school students across the country to be directly involved in a national research project: children across Canada can participate in a free, nation-wide science project to learn the secrets trees can tell about their communities.

The Trans-Canadian Research and Environmental Education (TREE) program involves the Canadian Light Source (CLS) and the Mistik Askiwin Dendrochronology Laboratory (MAD Lab), both located at the University of Saskatchewan (USask), in a study of how the environment affects trembling aspen trees. By combining CLS techniques for chemical analysis and MAD Lab expertise in the science of tree rings, TREE aims to paint a detailed picture of how trembling aspen are doing in communities throughout Canada.

Image: Tracy Walker (right) helps students to use the IDEAS beamline at the CLS.

Developing more nutritious crops to feed a growing world

2019/10/162019/10/17

Using synchrotron light to analyze new varieties of peas could be faster, more environmentally friendly, and help to nourish underfed populations around the world.

With thousands of seed samples produced every growing season, Dr. Tom Warkentin needs fast, accurate and cost-effective techniques to assess the nutritional value of the pea varieties he has developed. Now, thanks to two recent studies, techniques available at the Canadian Light Source (CLS) synchrotron at the University of Saskatchewan show promise for Warkentin and many other plant breeders.

“These studies arose from the question, ‘Can we use the synchrotron to measure the nutrient traits in pea seeds?,’” explained Warkentin, professor of plant science and pulse breeder in the Crop Development Centre at the University of Saskatchewan’s College of Agriculture and Bioresources. “Improving the nutritional value of peas is a higher and higher priority for us in plant breeding so we wanted to look at the standard approaches we’ve been using to measure nutritional traits versus the techniques available at the CLS.”

Image: Scientists Tom Warkentin, Chithra Karunakaran, Jarvis Stobbs, and David Muir with pea samples at our IDEAS beamline.

Analyzing poppies to make better drugs

2019/09/112019/09/13

A team of researchers from the University of Calgary has uncovered new information about a class of plant enzymes that could have implications for the pharmaceutical industry. In a paper published in the Journal of Biological Chemistry, the scientists explain how they revealed molecular details of an enzyme class that is central to the synthesis of many widely used pharmaceuticals, including the painkillers codeine and morphine.

The team used the Canadian Light Source at the University of Saskatchewan and the SLAC National Accelerator Laboratory to better understand how the enzyme behaves, which is crucial for unleashing its potential to make novel medicines. “Until this study, we didn’t know the key structural details of the enzyme. We learned from the structure of the enzyme bound to the product how the methylation reaction locks the product into a certain stereochemistry. It was completely unknown how the enzyme did that before we determined this structure,” corresponding author Dr. Kenneth Ng explained.

Stereochemistry is an important concept when it comes to safety and efficacy in drug design. A molecule can have a few different arrangements—similar to how your left hand is a mirror image of your right hand. These arrangements can lead to very different effects.

Image: group photo of some of the researchers involved with this project. From left to right: Ken Ng (Professor and corresponding author), Jeremy Morris (PhD graduate and second author), Dean Lang (PhD student and first author), and Peter Facchini (Professor, CSO of Willow Biosciences and senior author).

Analyzing the world’s oldest woddy plant fossil

2019/08/282019/08/28

Scientists investigate the early evolution of tissue systems in plants.

Mapping the evolution of life on Earth requires a detailed understanding of the fossil record, and scientists are using synchrotron-based technologies to look back—way, way back—at the cell structure and chemistry of the earliest known woody plant. Dr. Christine Strullu-Derrien and colleagues used the Canadian Light Source’s SM[1] beamline at the University of Saskatchewan to study Armoricaphyton chateaupannense, an extinct woody plant that is about 400 million years old. Their research focused on lignin, an organic compound in the plant tracheids, elongated cells that help transport water and mineral salts. Lignin makes the cells walls rigid and less water permeable, thereby improving the conductivity of their vascular system.
Strullu-Derrien, a scientific associate at the Natural History Museum in London, England and the Natural History Museum in Paris, France, had described A. chateaupannense some years ago and returned to it for this project.
“Studies have been done previously on Devonian plants but they were not woody,” she said. “A. chateaupannense is the earliest known woody plant and it’s preserved in both 2D form as flat carbonaceous films and 3D organo-mineral structures. This allows for comparison to be done between the two types of preservation,” she said.
Although the fossils used in the study were collected in the Armorican Massif, a geologically significant region of hills and flatlands in western France, Strullu-Derrien said early Devonian woody plants have also been found in New Brunswick and the Gaspé area in Quebec “although these are 10 million years younger than the French one.”

Image: A, photograph of Armoricaphyton chateaupannense preserved in 2D as carbonaceous thin films. B, SEM image of a transverse section of an axis of a specimen of A. chateaupannense preserved in 3D showing the radially aligned tracheids.

Unraveling plants resistance to drought

2019/03/292019/04/09

Research investigates the chemical nanostructure of water conducting vessels.

Plant cells are encased in a structure called the cell wall, composed mainly of cellulose and lignin. Among other functions, this wall gives structural stability to the cells and controls the entry of water, minerals and other substances. When they die, the cells leave behind their cell wall, forming different structures that support the plant giving rigidity to the stems and that facilitate the transport of substances from the roots to the leaves and vice versa. One such structure is the xylem: a continuous network of conduits about 100 micrometers in diameter that carries the water absorbed by the roots to the leaves.

When they lose water by transpiration, the leaves generate tension in the water column within the xylem. The pressure difference between the interior and exterior of the conduit causes the molecules to behave as links in a current: when a molecule of water evaporates, the rest of the “current” is pulled up.

Image: Schematic figure of the technique of infrared nanospectroscopy.

Analysing the structure of biopolymers for the food industry

2018/10/302018/10/31

A research group from the Institute of Agrochemistry and Food Technology (IATA-CSIC) in Valencia is using scattering techniques at the ALBA Synchrotron to develop new packaging systems made of biopolymers, an environmentally friendly solution for the food industry.

Plastic is the packaging material of most of the food we consume nowadays. This results in a severe problem as common plastics are made of petroleum – a limited resource with highly variable price – and supposes a huge environmental impact – most plastic wastes need more than 400 years to decompose.

Researchers from the Food Safety and Preservation department of the Institute of Agrochemistry and Food Technology (IATA-CSIC), located in Paterna (Valencia), are looking for more sustainable ways of producing food packaging with appropriate mechanical and chemical properties. They are investigating biopolymers that can be made from biomass such as algae.
“We need to look for alternative sources which do not compete with food. This is why marine resources such as algae and microalgae are very interesting. They proliferate very quickly, grow in a wide variety of environments and do not interfere with food production”, according to Ámparo López-Rubio, researcher at the IATA-CSIC.

>Read more on the ALBA website

Image: At the left, Juan Carlos Martínez, scientist from the ALBA Synchrotron with users Amparo López Rubio and Marta Martínez Sanz from IATA-CSIC at the NCD-SWEET experimental hutch.

Infrared beams show cell types in a different light

2018/08/232018/08/30

Berkeley Lab scientists developing new system to identify cell differences.

By shining highly focused infrared light on living cells, scientists at the U.S. Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) hope to unmask individual cell identities, and to diagnose whether the cells are diseased or healthy.
They will use their technique to produce detailed, color-based maps of individual cells and collections of cells – in microscopic and eventually nanoscale detail – that will be analyzed using machine-learning techniques to automatically sort out cell characteristics.

Using microscopic color maps to unlock cell identity

Their focus is on developing a rapid way to easily identify cell types, and features within cells, to aid in biological and medical research by providing a way to probe living cells in their native environment without harming the cells or requiring obtrusive cell-labeling techniques.
“This is totally noninvasive,” said Cynthia McMurray, a biochemist and senior scientist in Berkeley Lab’s Molecular Biophysics and Integrated Bioimaging (MBIB) Division who is leading this new imaging effort with Michael Martin, a physicist and senior staff scientist at Berkeley Lab’s Advanced Light Source (ALS).
The ALS has dozens of beamlines that produce beams of intensely focused light, from infrared to X-rays, for a broad range of experiments.

Image: From left to right: Aris Polyzos, Edward Barnard, and Lila Lovergne, pictured here at Berkeley Lab’s Advanced Light Source, are part of a research team that is developing a cell-identification technique based on infrared imaging and machine learning.
Credit: Marilyn Chung/Berkeley Lab

Plant roots police toxic pollutants

2018/08/062018/08/09

X-ray studies reveal details of how P. juliflora shrub roots scavenge and immobilize arsenic from toxic mine tailings.

Working in collaboration with scientists at the U.S. Department of Energy’s Brookhaven National Laboratory and SLAC National Accelerator Laboratory, researchers at the University of Arizona have identified details of how certain plants scavenge and accumulate pollutants in contaminated soil. Their work revealed that plant roots effectively “lock up” toxic arsenic found loose in mine tailings—piles of crushed rock, fluid, and soil left behind after the extraction of minerals and metals. The research shows that this strategy of using plants to stabilize pollutants, called phytostabilization, could even be used in arid areas where plants require more watering, because the plant root activity alters the pollutants to forms that are unlikely to leach into groundwater.

The Arizona based researchers were particularly concerned with exploring phytostabilization strategies for mining regions in the southwestern U.S., where tailings can contain high levels of arsenic, a contaminant that has toxic effects on humans and animals. In the arid environment with low levels of vegetation, wind and water erosion can carry arsenic and other metal pollutants to neighboring communities.

Image: Scientists from the University of Arizona collect plant samples from the mine tailings at the Iron King Mine and Humboldt Smelter Superfund site in central Arizona. X-ray studies at Brookhaven Lab helped reveal how these plants’ roots lock up toxic forms of arsenic in the soil.
Credit: Jon Chorover

Fuel cells from plants

2018/07/182018/07/19

Using elements in plants to increase fuel cell efficiency while reducing costs

Researchers from the Institut National de la Recherche Scientifique, Québec are looking into reeds, tall wetlands plants, in order to make cheaper catalysts for high-performance fuel cells.

Due to rising global energy demands and the threat caused by environmental pollution, the search for new, clean sources of energy is on.

Unlike a battery, which stores electricity for later use, a fuel cell generates electricity from stored materials, or fuels.

Hydrogen-based fuel is a very clean fuel source that only produces water as a by-product, and could effectively replace fossil fuels. In order to make hydrogen fuel viable for everyday use, high-performance fuel cells are needed to convert the energy from the hydrogen into electricity.

Hydrogen fuel cells use platinum catalysts to drive energy conversion, but the platinum is expensive, accounting for almost half of a fuel cell’s total cost according to Qiliang Wei, a PhD student in Shuhui Sun’s group from the Institut National de la Recherche Scientifique – Énergie, Matériaux et Télécommunications who studies lower-cost alternatives to platinum catalysts.

Scientists explore how slow release fertilizer behaves in soil

2018/04/252018/04/26

Testing soil samples at the Canadian Light Source has helped a University of Saskatchewan soil scientist understand how tripolyphosphate (TPP), a slow release form of phosphorus fertilizer, works in the soil as a plant nutrient for much longer periods than previously thought.

Jordan Hamilton says the research also has implications for ongoing efforts by U of S soil scientists to use phosphorous-rich materials to clean up contaminated petroleum sites.

Hamilton, now a post-doctoral fellow working within U of S professor Derek Peak’s Environmental Soil Chemistry group, had a chapter of his PhD thesis, “Chemical speciation and fate of tripolyphosphate after application to a calcareous soil,” published earlier this year in the online journal Geochemical Transactions.

TPP needs to break down into a simpler form of phosphate in order to be used as a nutrient by plants. In most types of soil, the belief was that TPP would break down right away, says Hamilton.

“I would definitely say the biggest surprise is how quickly the TPP adsorbed (attached itself) to mineral sources, especially in these calcium-rich soils,” he said. “For the longer term, it was surprising to see it persist.”

Combining X-ray techniques for powerful insights into hyperaccumulator plants

2018/04/042018/04/12

The complementary power of combining multiple X-ray techniques to understand the unusual properties of hyperaccumulator plants has been highlighted in a new cover article just published in New Phytologist.

X-ray fluorescence microscopy (XFM) at the Australian Synchrotron has been used by a consortium of international researchers led by Dr Antony van der Ent of the Centre for Mined Land Rehabilitation at The University of Queensland, in association with A/Prof Peter Kopittke of the School of Agriculture and Food Science also at The University of Queensland.

The XFM technique generates elemental maps showing where elements of interest are found within plant tissue, seedlings or individual cells.
Visually striking images (obtained at the XFM beamline) show various hyperaccumulator plants, on the cover of the April issue of New Phytologist. In the images each element is depicted in a different colour, making up a red-green-blue (RGB) image.

“Hyperaccumulator plants have the unusual ability to accumulate extreme concentrations of metals and metalloids in their living tissues,” said van der Ent.
“Hyperaccumulators are of scientific interest because whilst metals are normally toxic to plants even at low concentrations, these plants are able to accumulate large concentrations without any toxic effects,” he added

Image: X‐ray Fluorescence (XRF) elemental maps of hyperaccumulator plants. The tricolour composite images show (left to right) root cross‐section of Senecio coronatus (red, iron; green, nickel; blue, potassium); and seedlings of Alyssum murale (red, calcium; green, nickel; blue, Compton scatter).
Credit: A. van der Ent.