Tag Archives: #ethylene

Hard to Crack Research Reveals How Crop Roots Penetrate Hard Soils (Botany)

Scientists have discovered a signal that causes roots to stop growing in hard soils which can be ‘switched off’ to allow them to punch through compacted soil – a discovery that could help plants to grow in even the most damaged soils.

Root Compaction © University of Nottingham

An international research team, led by scientists from the University of Nottingham’s Future Food Beacon and Shanghai Jiao Tong University has discovered how the plant signal ‘ethylene’ causes roots to stop growing in hard soils, but after this signal is disabled, roots are able to push through compacted soil. The research has been published in Science.

Hard (compacted) soils represent a major challenge facing modern agriculture that can reduce crop yields over 50% by reducing root growth, causing significant losses annually. Europe has over 33-million-hectares of soil prone to compaction which represents the highest in the world. Soil compaction triggers a reduction in root penetration and uptake of water and nutrients. Despite its clear importance for agriculture and global food security, the mechanism underpinning root compaction responses has been unclear until now.

Malcolm Bennett © University of Nottingham

Understanding how roots penetrate hard soils has huge implications for agriculture, as this knowledge will be crucial for breeding crops more resilient to soil compaction. Our team’s identification that the plant signal ethylene controls root responses to hard soil opens up new opportunities to select novel compaction resistant crops.Professor Malcolm Bennett, University of Nottingham, School of Biosciences

The research utilised X-ray Computed Tomography scanners available at the Hounsfield Facility at the University of Nottingham to visualise in situ how plant roots responded to compacted soil. Professor Sacha Mooney from the University of Nottingham and Director of the Hounsfield Facility explained: “Prior to this research we assumed that the hardness of the soil prevented roots growing deeper. By using our imaging approach, we were able to see that roots continued growing in very hard soils when the ethylene signal was switched off. The potential for new crops that can now go deeper in soils and capture previously unavailable resources is really exciting!”

The international team involved in this new Science paper includes researchers drawn from nine universities based in Europe, China and USA, integrating expertise spanning plant and soil sciences, bioimaging and mathematics. The team involves several early career researchers including Dr. Bipin Pandey and Dr. Rahul Bhosale who are funded by Royal Society Challenge Grant, BBSRC Discovery Fellowship and University of Nottingham Future Food Beacon awards.

Reference: Bipin K. Pandey, Guoqiang Huang, Rahul Bhosale, Sjon Hartman, Craig J. Sturrock, Lottie Jose, Olivier C. Martin, Michal Karady, Laurentius A. C. J. Voesenek, Karin Ljung, Jonathan P. Lynch, Kathleen M. Brown, William R. Whalley, Sacha J. Mooney, Dabing Zhang, Malcolm J. Bennett, “Plant roots sense soil compaction through restricted ethylene diffusion”, Science  15 Jan 2021: Vol. 371, Issue 6526, pp. 276-280
DOI: 10.1126/science.abf3013 https://science.sciencemag.org/content/371/6526/276/tab-article-info

Provided by University of Nottingham

Carbon Dioxide Converted to Ethylene — The ‘Rice of the Industry’ (Chemistry)

Understanding intermediates of the electrochemical CO2 reduction to ethylene. Encouraging catalyst design-a key component of CO2 utilization using renewable energy.

In recent times, “electrochemical conversion (e-chemical)” technology-which converts carbon dioxide to high-value-added compounds using renewable electricity-has gained research attention as a carbon capture utilization (CCU) technology. This green carbon resource technology employs electrochemical reactions using carbon dioxide and water as the only feedstock chemical to synthesize various compounds, instead of conventional fossil fuels. Electrochemical CO2 conversion can produce value-added important molecules in a petrochemical industry such as carbon monoxide and ethylene. Ethylene, referred to as the “rice of the industry”, is widely used to produce various chemical products and polymers, but it is more challenging to produce from electrochemical CO2 reduction. The lack of understanding of the reaction pathway by which carbon dioxide is converted to ethylene has limited to develop high-performance catalyst systems and to advance its application to produce more valuable chemicals.

Real-time analysis of catalytic surface in the process of electrochemical carbon dioxide conversion ethylene generation. ©Korea Institue of Science and Technology(KIST)

To overcome this limitation, a domestic research team in South Korea has made a breakthrough in unveiling a key path-triggering intermediate in the ethylene production reaction. Dr. Yun-Jeong Hwang and her team at the Clean Energy Research Center of the Korea Institute of Science and Technology (KIST) has announced that they have successfully observed the key intermediates adsorbed on the surface of a copper-based catalyst during electrochemical CO2 reduction to ethylene production and analyzed its behavior in real time. This was research was conducted in collaboration with Professor Woo-Yul Kim and his team at the Department of Chemical and Biological Engineering, Sookmyung Women’s University (President: Yoon-Geum Jang), with the support of the climate change response technology development project (Next Generation Carbon Upcycling Project Group, led by Ki-Won Jun).

It has been reported that copper-based catalysts can promote carbon dioxide conversion to synthesize not only relatively simple carbon monoxide or formic acid but also multi-carbon compounds such as ethylene and ethanol. Nevertheless, the development of control technology for selectively synthesizing high-value-added compounds has been limited because of the absence of information on major intermediates and pathways of the carbon-carbon bond forming reaction.

Through infrared spectroscopy, the research team observed the intermediate responsible for the formation of the ethylene intermediate (OCCO) as well as the one responsible for the production of methane (CHO). The intermediate is a dimer of carbon monoxide formed during the carbon dioxide conversion reaction on the surface of the copper nanoparticle catalyst. As a result, carbon monoxide and the ethylene intermediate (OCCO) were produced at the same time, whereas the methanol intermediate (CHO) was produced relatively slower than the two other intermediates, suggesting the possibility of further improving the selectivity of compound formation on the catalyst surface by controlling the reaction pathway.

In addition, copper hydroxide (Cu(OH)2) nanowire was proposed as a promising catalyst that exhibits excellent performance toward ethylene production by accelerating carbon-carbon bond formation. The research team found that there were multiple catalytic sites on which carbon monoxide can be adsorbed on the surface of the catalyst derived from copper hydroxide and that carbon monoxide adsorbed on a specific site quickly forms an intermediate through carbon-carbon bond formation. Further research on this intermediate is expected to contribute significantly to the identification of the active sites for the carbon-carbon bond forming reaction, which has been a subject of debate.

“The success of this study is significant in that it has presented a key direction for basic research related to artificial photosynthesis that has been unexplored in Korea through a joint investigation by the research institute as well as the university,” said Dr. Yun-Jeong Hwang of KIST. “Based on this, we will be able to contribute significantly to the growth of next-generation carbon resource conversion technology based on sustainable energy in response to climate change.”

This study was conducted with a grant from the Ministry of Science and ICT (MSIT), as part of the Institutional R&D Program of KIST and the Climate Change Technology Development Program (Next-Generation Carbon-as-a-Resource Project Group, Director Gi-won Jeon). The findings were reported in the latest edition of the international journal, Energy & Environmental Science (IF: 30.289, Top 0.189% in the field of JCR).

References: Younghye Kim, Sojung Park, Seung-Jae Shin, Woong Choi, Byoung Koun Min, Hyungjun Kim, Wooyul Kim and Yun Jeong Hwang, “Time-resolved observation of C–C coupling intermediates on Cu electrodes for selective electrochemical CO2 reduction”, Energy and Environmental Science, 2020. https://pubs.rsc.org/en/content/articlelanding/2020/EE/D0EE01690J#!divAbstract

Provided by National Research Council of Science and Technology

When Plants Attack: Parasitic Plants Use Ethylene As A Host Invasion Signal (Botany)

Researchers from Nara Institute of Science and Technology find that the plant hormone ethylene mediates the invasion of hosts by parasitic plants.

Mutants that reveal the secrets of how plants attack? No, it’s not a scene from a science fiction movie, but you could be forgiven for thinking that. Instead, it’s a scene from real life:

Photo of the model parasitic plant, Phtheirospermum japonicum (left), and its haustorium (right). P: parasitic plant, H: host plant. The right lower photo shows xylem connection between a host and a parasite. Bar = 200 μm. ©Satoko Yoshida.

Researchers at Nara Institute of Science and Technology in Japan report in a new study in Science Advances that parasitic plants use the plant hormone ethylene as a signal to invade the roots of host plants.

To develop a successful parasitic relationship, parasitic plants form a specialized structure, the haustorium which attaches to and invades the host plant. The formation of haustoria is regulated by signal molecules derived from the host plant and allows the parasitic plant to absorb water, nutrients, and small materials from the host plant.

“To understand the genetic programs for haustorium development, we identified mutants that displayed haustorial defects on host invasion,” says lead author of the study Songkui Cui. “Genome sequencing showed that these mutants have defective ethylene signaling, and it turned out that ethylene signaling genes are crucial for the parasitic plant to infect its host plant.”

Ethylene is a gaseous plant hormone that is involved in fruit ripening, aging of leaves, and the formation of root nodules. Ethylene is also widely involved in plant interactions with viruses and numerous organisms, such as insects and bacteria, lending either resistance or susceptibility to plants depending on the types of pathogens.

“Our results indicate that ethylene mediates host recognition in parasitic plants for host invasion,” explains project leader Satoko Yoshida. “This is the first time that the mediation of host invasion by parasitic plant genes has been identified via forward genetics. Our findings offer a new understanding of how a parasitic plant uses the ethylene molecule to tweak haustorium development and host invasion.”

Forward genetics is used to identify genes, or sets of genes, that produce a particular characteristic in an organism. The model species used in this study is from a family of parasitic plants that includes destructive weeds. But the molecular basis for their parasitism has been largely unexplored until now.

“Our results suggest that parasitic plants have taken over ethylene signaling for parasitism at multiple stages of their life cycle, such as germination, haustorium growth termination, and host invasion. This knowledge could provide new ways to use ethylene and ethylene inhibitors to control a broader range of parasitic weeds, including those that don’t rely entirely on hosts to complete their life cycle, by manipulating haustorial function,” says Cui.

References: Songkui Cui, Tomoya Kubota, Tomoaki Nishiyama, Juliane K. Ishida, Shuji Shigenobu, Tomoko F. Shibata, Atsushi Toyoda, Mitsuyasu Hasebe, Ken Shirasu & Satoko Yoshida, “Ethylene signaling mediates host invasion by parasitic plants”, Science Advances, Vol. 6, no. 44, 2020. eabc2385 http://dx.doi.org/10.1126/sciadv.abc2385 DOI: 10.1126/sciadv.abc2385

Provided by Nara Institute Of Science and Technology

Scientists Find Efficient Way to Convert Carbon Dioxide into Ethylene (Chemistry)

Electrochemical CO2 reduction to value-added chemical feedstocks is of considerable interest for renewable energy storage and renewable source generation while mitigating CO2 emissions from human activity. Copper represents an effective catalyst in reducing CO2 to hydrocarbons or oxygenates, but it is often plagued by a low product selectivity and limited long-term stability. Now Choi and colleagues reported that copper nanowires with rich surface steps to catalyze a chemical reaction that reduces carbon dioxide (CO2) emissions while generating ethylene (C2H4), an important chemical used to produce plastics, solvents, cosmetics and other important products globally.

Copper represents an effective catalyst in reducing carbon dioxide to hydrocarbons or oxygenates, but it is often plagued by a low product selectivity and limited long-term stability. Choi et al report that copper nanowires with rich surface steps exhibit a remarkably high Faradaic efficiency for ethylene that can be maintained for over 200 hours. Image credit: Choi et al, doi: 10.1038/s41929-020-00504-x.

Using copper to kick start the carbon dioxide reduction into ethylene reaction has suffered two strikes against it.

First, the initial chemical reaction also produced hydrogen and methane — both undesirable in industrial production.

Second, previous attempts that resulted in ethylene production did not last long, with conversion efficiency tailing off as the system continued to run.

To overcome these two hurdles, Professor Goddard III and colleagues focused on the design of the copper nanowires with highly active steps — similar to a set of stairs arranged at atomic scale.

One intriguing finding of this collaborative study is that this step pattern across the nanowires’ surfaces remained stable under the reaction conditions, contrary to general belief that these high energy features would smooth out.

This is the key to both the system’s durability and selectivity in producing ethylene, instead of other end products.

The scientists demonstrated a carbon dioxide-to-ethylene conversion rate of greater than 70%, much more efficient than previous designs, which yielded at least 10% less under the same conditions.

The new system ran for 200 hours, with little change in conversion efficiency, a major advance for copper-based catalysts.

In addition, the comprehensive understanding of the structure-function relation illustrated a new perspective to design highly active and durable carbon dioxide reduction catalyst in action.

References: Choi, C., Kwon, S., Cheng, T. et al. Highly active and stable stepped Cu surface for enhanced electrochemical CO2 reduction to C2H4. Nat Catal (2020). https://doi.org/10.1038/s41929-020-00504-x link: https://www.nature.com/articles/s41929-020-00504-x