Navigation Links
Nutrient and toxin all at once: How plants absorb the perfect quantity of minerals

In order to survive, plants should take up neither too many nor too few minerals from the soil. New insights into how they operate this critical balance have now been published by biologists at the Ruhr-Universitt in a series of three papers in the journal The Plant Cell. The researchers discovered novel functions of the metal-binding molecule nicotianamine. "The results are important for sustainable agriculture and also for people to prevent health problems caused by deficiencies of vital nutrients in our diet" says Prof. Dr. Ute Krmer of the RUB Department of Plant Physiology.

Plants: at the start of the food chain

All organisms need iron, zinc, and copper as nutrients. They contribute to the essential catalytic functions within the cell. Because plants are at the beginning of the food chain, sufficient content of these minerals in them is essential for the human diet. These metals are chemically very similar, making it difficult for organisms to distinguish between them.

How the cell tells the competitors zinc and iron apart

The metal-binding molecule nicotianamine is important for iron transport in plants. In her time at the universities of Heidelberg and Bochum, Krmer has demonstrated that it also makes a major contribution to the zinc balance. "Too much zinc can poison iron-dependent processes and vice versa" the biologist explains. How much zinc is available in the cytosol depends on where the nicotianamine is stored in the cell. The membrane transport protein Zinc-Induced Facilitator1 (ZIF1) can move the metal-binding molecule from the cytosol to the vacuole a separate area of the cell which stores substances, among other roles. Given high zinc concentrations in the cytosol, ZIF1 transports nicotianamine into the vacuole. As a consequence, zinc ions are also transported into the vacuole and thus removed from the cytosol and the internal transport routes of the plant. The zinc is now less competition for the iron, so that iron is more readily available in the cell.

From the roots to the leaves: nicotianamine is crucial for zinc transport

For genetic reasons, plants contain very different amounts of minerals depending on their living environment. Arabidopsis halleri, for example, which is native to Germany, gathers a hundred times more zinc in its leaves than many other plants. In cooperation with colleagues from the University of Bayreuth, Krmer's team has contributed to showing how this functions: Arabidopsis halleri produces large amounts of nicotianamine. When the researchers deactivated the synthesis of this molecule by means of genetic manipulation, the plants also transported less zinc from the roots to the leaves. Nicotianamine is therefore crucial for the high zinc concentration in leaves. "In developing countries, zinc deficiency is one of the biggest dietary risk factors for health problems" Krmer explains. "Our data may provide important clues on how to breed crops with increased zinc content".

How copper gets into the plant cell

The Bochum biologists also researched how plant cells absorb copper together with American colleagues. For this, they employed what is known as next-generation sequencing. The method they employed simultaneously decodes all messenger RNAs within a cell. This gives a complete picture of what proteins the cell should produce in what quantities. From these data, Krmer's team identified new molecules with a critical role in the absorption of copper. The scientists demonstrated that the copper ions are first converted from the double positively charged cupric to the single positively charged cuprous form, which is essential for the following absorption in the plant. Two specific enzymes, called copper reductases, are responsible for this. "Independently of this, we have also discovered that copper deficiency in plants triggers a secondary iron deficiency contrary to previous expectations, and very similar to human metal metabolism".

Contact: Prof. Dr. Ute Krmer
Ruhr-University Bochum

Related biology news :

1. EPA and USDA should create new initiative to better monitor nutrients
2. Nutrient pollution chokes marine and freshwater ecosystems
3. Powerful nutrient cocktail can put kids with Crohns into remission
4. Essential nutrient found in eggs may help lower risk of neural tube defects
5. New research to unravel how nutrients drive toxic brown tides on East Coast
6. Mystery solved: Marine microbe is source of rare nutrient
7. Common herbicides and fibrates block nutrient-sensing receptor found in gut and pancreas
8. Brown and beige dominate the plate: Daily dose of color needed to fill Americas phytonutrient gap
9. ADA releases updated position paper on nutrient supplementation
10. Brooding fishes take up nutrients from their own children
11. Supermarket lighting enhances nutrient level of fresh spinach
Post Your Comments:
(Date:11/17/2015)... , Nov. 17, 2015  Vigilant Solutions announces ... joined its Board of Directors. --> ... after recently retiring from the partnership at TPG Capital, ... companies with over $140 Billion in revenue.  He founded ... across all the TPG companies, from 1997 to 2013.  ...
(Date:11/12/2015)... Nov. 12, 2015  A golden retriever that stayed ... dystrophy (DMD) has provided a new lead for treating ... the Broad Institute of MIT and Harvard and the ... . Cell, pinpoints a protective ... the disease,s effects. The Boston Children,s lab of ...
(Date:11/11/2015)... --  MedNet Solutions , an innovative SaaS-based eClinical technology company ... to announce that it will be a Sponsor of the ... be held November 17-19 in Hamburg , ... iMedNet , MedNet,s easy-to-use, proven and affordable ... been able to deliver time and cost savings of up ...
Breaking Biology News(10 mins):
(Date:12/1/2015)... ... , ... Matthew “Tex” VerMilyea, PhD, HCLD, has joined Texas Fertility Center as ... lab procedures as well as continue his research efforts into the emerging technologies of ... New Zealand to bring home a High Complexity Clinical Laboratory Director named Tex,” says ...
(Date:11/30/2015)... ... 30, 2015 , ... Global Stem Cells Group ... the Santiago Marriott. The Global Stem Cells Group GMP facility is equipped with ... qualified medical researchers and practitioners, experienced in administering stem cell protocols using highly ...
(Date:11/30/2015)... 2015 Partnership includes an MPP ... for the u niversity , s ... treatment s cale - up through ... Africa , where licensees based anywhere in the world will have ... --> Africa , where licensees based anywhere in the world ...
(Date:11/30/2015)... Spherix Incorporated (Nasdaq: SPEX ) an ... and monetization of intellectual property, today provided an ... to create shareholder value. Anthony ... on published reports, the total addressable market of ... Spherix will seek to secure fair and reasonable ...
Breaking Biology Technology: