Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Harnessing a peptide holds promise for increasing crop yields without more fertilizer

25.11.2015

UMass Amherst researchers identify a key molecule in nitrogen-fixing bacteria

Molecular biologists at the University of Massachusetts Amherst who study nitrogen-fixing bacteria in plants have discovered a "double agent" peptide in an alfalfa that may hold promise for improving crop yields without increasing fertilizer use.


UMass Amherst researchers identified a key molecule in nitrogen-fixing bacteria, here stained green, that take residence in host cells. Host nuceli are stained red.

Credit: UMass Amherst/Chris Waters

In the current early online edition of Proceedings of the National Academy of Sciences, lead author and postdoctoral researcher Minsoo Kim, former undergraduate student Chris Waters, and professor Dong Wang of UMass Amherst's biochemistry and molecular biology department, with colleagues at the Noble Foundation in Oklahoma, report that alfalfa appears to use an advanced process for putting nitrogen-fixing bacteria, rhizobia, to work more effectively after they are recruited from soil to fix nitrogen in special nodules on plant roots.

As Wang and Kim explain, legumes attract nitrogen-fixing bacteria to their roots from the surrounding soil. Once inside the host plant, rhizobia form nodules on its roots and the plant starts to transform the bacteria into their nitrogen-fixing state. In return for borrowing the rhizobia's essential enzymes that turn nitrogen into useful ammonia, the plant gives the bacteria fixed carbon, the product of photosynthesis.

In alfalfa, this transformation of bacteria is called differentiation, which Wang likens to domestication, because it makes the bacteria reliant on their plant host. "They are no longer wild and able to live outside the plant," he says. "I think of it as analogous to domestication of animals by humans." He adds, "Bacteria that can no longer proliferate as free-living individuals are a bit like slaves at that point, living to serve the plant."

At the molecular level, plant peptides found exclusively in the nodule, known as NCR peptides, act on the bacteria in the differentiation process. By studying this differentiation processes in an alfalfa-clover, Medicago truncatula, the researchers discovered that one of these peptides, DNF4, also known as NCR211, can act as a sort of double agent, Wang says. DNF4 supports nitrogen-fixing bacteria when inside the plant, but its actions can kill free-living bacteria outside.

"At first sight, it may appear perplexing that DNF4/NCR211 supports the survival of differentiating bacteria in plants while also blocking free-living bacteria from forming colonies in culture," Wang and Kim write.

However, the two activities may actually reflect similar action by NCR211 on bacteria in different physiological states. The dual effect of DNF4/NCR211 may reflect a mechanism to ensure that the rhizobia stay in a properly differentiated state, say the authors. Host control of bacteria differentiation has evolved in multiple lineages of legumes, indicating a possible fitness benefit to the host plant. Furthermore, nodules with differentiated bacteroids returned more benefit to the host. Curiously, the legume with the most economic value, soybean, doesn't seem to have evolved this strategy, opening possible avenues to improve their yield.

Wang says, "We haven't solved it all yet," but discovering NCR211 peptides that maintain bacterial survival inside host cells may turn out to be a key factor in future efforts to improve legume crops without using more fertilizer, which would be an important advance for farming in developing countries and organic farming in the developed world.

"Next we want to find out why this peptide helps the bacteria inside the plant, but it can kill free-living bacteria outside the plant. Why does one molecule function as a double agent?"

Wang says that in a companion study also appearing in PNAS, Price et al. at Brigham Young University recovered a bacterial peptidase capable of degrading host NCR peptides. "This collection of discoveries demonstrates the evolving nature in controlling bacterial differentiation in classical host-microbe mutualism," Wang and Kim conclude.

###

Funding for this work was from the University of Massachusetts Amherst.

Media Contact

Janet Lathrop
jlathrop@admin.umass.edu
413-545-0444

 @umassscience

http://www.umass.edu 

Janet Lathrop | EurekAlert!

Further reports about: Amherst bacteria crop crop yields fertilizer nitrogen nitrogen-fixing bacteria peptides rhizobia

More articles from Agricultural and Forestry Science:

nachricht New 3-D model predicts best planting practices for farmers
26.06.2017 | Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign

nachricht Fighting a destructive crop disease with mathematics
21.06.2017 | University of Cambridge

All articles from Agricultural and Forestry Science >>>

The most recent press releases about innovation >>>

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

Im Focus: Manipulating Electron Spins Without Loss of Information

Physicists have developed a new technique that uses electrical voltages to control the electron spin on a chip. The newly-developed method provides protection from spin decay, meaning that the contained information can be maintained and transmitted over comparatively large distances, as has been demonstrated by a team from the University of Basel’s Department of Physics and the Swiss Nanoscience Institute. The results have been published in Physical Review X.

For several years, researchers have been trying to use the spin of an electron to store and transmit information. The spin of each electron is always coupled...

Im Focus: The proton precisely weighted

What is the mass of a proton? Scientists from Germany and Japan successfully did an important step towards the most exact knowledge of this fundamental constant. By means of precision measurements on a single proton, they could improve the precision by a factor of three and also correct the existing value.

To determine the mass of a single proton still more accurate – a group of physicists led by Klaus Blaum and Sven Sturm of the Max Planck Institute for Nuclear...

Im Focus: On the way to a biological alternative

A bacterial enzyme enables reactions that open up alternatives to key industrial chemical processes

The research team of Prof. Dr. Oliver Einsle at the University of Freiburg's Institute of Biochemistry has long been exploring the functioning of nitrogenase....

Im Focus: The 1 trillion tonne iceberg

Larsen C Ice Shelf rift finally breaks through

A one trillion tonne iceberg - one of the biggest ever recorded -- has calved away from the Larsen C Ice Shelf in Antarctica, after a rift in the ice,...

Im Focus: Laser-cooled ions contribute to better understanding of friction

Physics supports biology: Researchers from PTB have developed a model system to investigate friction phenomena with atomic precision

Friction: what you want from car brakes, otherwise rather a nuisance. In any case, it is useful to know as precisely as possible how friction phenomena arise –...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

»We are bringing Additive Manufacturing to SMEs«

19.07.2017 | Event News

The technology with a feel for feelings

12.07.2017 | Event News

Leipzig HTP-Forum discusses "hydrothermal processes" as a key technology for a biobased economy

12.07.2017 | Event News

 
Latest News

Researchers create new technique for manipulating polarization of terahertz radiation

20.07.2017 | Information Technology

High-tech sensing illuminates concrete stress testing

20.07.2017 | Materials Sciences

First direct observation and measurement of ultra-fast moving vortices in superconductors

20.07.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>