Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

The gene of autumn colours

27.10.2016

Researchers have found Mendel’s Stay-Green gene encodes an enzyme that extracts magnesium from chlorophyll, adding clarity to understanding how the pigment degrades.

In plants, the pigment chlorophyll plays a central role in photosynthesis: the process of converting sunlight to energy. This process involves creating a flow of electrons by removing one from a molecule and transferring it to another. The first step happens when an electron is transferred from chlorophyll to a compound called pheophytin a.


SGR induces colour changes in leaves. SGR was experimentally induced (bottom) in Arabidopsis and compared with the normal leaves (top). Excised leaves were observed for up to 30 hours. (Shimoda Y et al., Plant Cell, September 7, 2016)

Autumn leaf colours occur when chlorophyll degrades as a normal part of leaf aging or “senescence”, playing an important role in nitrogen recycling. The process of chlorophyll degradation is triggered when an enzyme extracts magnesium (Mg) from chlorophyll. Researchers have named the enzyme Mg-dechelatase, but have never been able to detect its actual presence in experiments.

Yousuke Shimoda, Hisashi Ito, and Ayumi Tanaka at Hokkaido University have demonstrated that a gene with known involvement in chlorophyll degradation, called Stay-Green (SGR), codes for Mg-dechelatase.

Stay-Green mutants allow leaves to retain greenness during senescence. This gene was among several that led Gregor Mendel to establish the basic laws of genetics in the 19th century while studying the characteristics of peas over several generations. However, it has long been unknown what the gene actually encodes.

The team transiently induced SGR in fully green leaves of a small flowering plant called thale cress. They found this resulted in a reduction of chlorophyll levels. They also incubated chlorophyll in a test tube with SGR, which resulted in its conversion to pheophytin a. Chlorophyll can only be converted to pheophytin a by extracting Mg from it. The experiments strongly suggest that Mg-dechelatase is involved in chlorophyll degradation via SGR.

The team’s results also suggest that SGR can also extract Mg from chlorophyll embedded in the light-harvesting complex, therefore leading to degradation of it. “It remains unclear whether SGR plays a role via Mg-dechelatase activity in supplying pheophytin a for the process of photosynthesis” says Hisashi Ito. “Little is known about the mechanism by which an enzyme extracts a metal ion from an organic compound. Our study may lead to the discovery of novel reaction mechanisms.”

Contacts:
Assistant Professor Hisashi Ito
Institute of Low Temperature Science
Hokkaido University
Email: ito98[at]lowtem.hokudai.ac.jp
URL: http://www.lowtem.hokudai.ac.jp/plantadapt/eng/

Naoki Namba (Media Officer)
Global Relations Office
Institute for International Collaboration
Hokkaido University
Email: pr[at]oia.hokudai.ac.jp
Tel: +81-11-706-8034

Associated links

Journal information

Yousuke Shimoda, Hisashi Ito, Ayumi Tanaka, Arabidopsis STAY-GREEN, Mendel’s green cotyledon gene, encodes magnesium-dechelatase. Plant Cell, September 7, 2016.
DOI: 10.1105/tpc.16.00428

Hokkaido University | Research SEA
Further information:
http://www.researchsea.com

More articles from Life Sciences:

nachricht One step closer to reality
20.04.2018 | Max-Planck-Institut für Entwicklungsbiologie

nachricht The dark side of cichlid fish: from cannibal to caregiver
20.04.2018 | Veterinärmedizinische Universität Wien

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Spider silk key to new bone-fixing composite

University of Connecticut researchers have created a biodegradable composite made of silk fibers that can be used to repair broken load-bearing bones without the complications sometimes presented by other materials.

Repairing major load-bearing bones such as those in the leg can be a long and uncomfortable process.

Im Focus: Writing and deleting magnets with lasers

Study published in the journal ACS Applied Materials & Interfaces is the outcome of an international effort that included teams from Dresden and Berlin in Germany, and the US.

Scientists at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) together with colleagues from the Helmholtz-Zentrum Berlin (HZB) and the University of Virginia...

Im Focus: Gamma-ray flashes from plasma filaments

Novel highly efficient and brilliant gamma-ray source: Based on model calculations, physicists of the Max PIanck Institute for Nuclear Physics in Heidelberg propose a novel method for an efficient high-brilliance gamma-ray source. A giant collimated gamma-ray pulse is generated from the interaction of a dense ultra-relativistic electron beam with a thin solid conductor. Energetic gamma-rays are copiously produced as the electron beam splits into filaments while propagating across the conductor. The resulting gamma-ray energy and flux enable novel experiments in nuclear and fundamental physics.

The typical wavelength of light interacting with an object of the microcosm scales with the size of this object. For atoms, this ranges from visible light to...

Im Focus: Basel researchers succeed in cultivating cartilage from stem cells

Stable joint cartilage can be produced from adult stem cells originating from bone marrow. This is made possible by inducing specific molecular processes occurring during embryonic cartilage formation, as researchers from the University and University Hospital of Basel report in the scientific journal PNAS.

Certain mesenchymal stem/stromal cells from the bone marrow of adults are considered extremely promising for skeletal tissue regeneration. These adult stem...

Im Focus: Like a wedge in a hinge

Researchers lay groundwork to tailor drugs for new targets in cancer therapy

In the fight against cancer, scientists are developing new drugs to hit tumor cells at so far unused weak points. Such a “sore spot” is the protein complex...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Invitation to the upcoming "Current Topics in Bioinformatics: Big Data in Genomics and Medicine"

13.04.2018 | Event News

Unique scope of UV LED technologies and applications presented in Berlin: ICULTA-2018

12.04.2018 | Event News

IWOLIA: A conference bringing together German Industrie 4.0 and French Industrie du Futur

09.04.2018 | Event News

 
Latest News

Magnetic nano-imaging on a table top

20.04.2018 | Physics and Astronomy

Start of work for the world's largest electric truck

20.04.2018 | Interdisciplinary Research

Atoms may hum a tune from grand cosmic symphony

20.04.2018 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>