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 insight into why Pierce's disease is so deadly to grapevines
11.06.2018 | University of California - Davis

nachricht Where are Europe’s last primary forests?
29.05.2018 | Humboldt-Universität zu Berlin

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: Temperature-controlled fiber-optic light source with liquid core

In a recent publication in the renowned journal Optica, scientists of Leibniz-Institute of Photonic Technology (Leibniz IPHT) in Jena showed that they can accurately control the optical properties of liquid-core fiber lasers and therefore their spectral band width by temperature and pressure tuning.

Already last year, the researchers provided experimental proof of a new dynamic of hybrid solitons– temporally and spectrally stationary light waves resulting...

Im Focus: Overdosing on Calcium

Nano crystals impact stem cell fate during bone formation

Scientists from the University of Freiburg and the University of Basel identified a master regulator for bone regeneration. Prasad Shastri, Professor of...

Im Focus: AchemAsia 2019 will take place in Shanghai

Moving into its fourth decade, AchemAsia is setting out for new horizons: The International Expo and Innovation Forum for Sustainable Chemical Production will take place from 21-23 May 2019 in Shanghai, China. With an updated event profile, the eleventh edition focusses on topics that are especially relevant for the Chinese process industry, putting a strong emphasis on sustainability and innovation.

Founded in 1989 as a spin-off of ACHEMA to cater to the needs of China’s then developing industry, AchemAsia has since grown into a platform where the latest...

Im Focus: First real-time test of Li-Fi utilization for the industrial Internet of Things

The BMBF-funded OWICELLS project was successfully completed with a final presentation at the BMW plant in Munich. The presentation demonstrated a Li-Fi communication with a mobile robot, while the robot carried out usual production processes (welding, moving and testing parts) in a 5x5m² production cell. The robust, optical wireless transmission is based on spatial diversity; in other words, data is sent and received simultaneously by several LEDs and several photodiodes. The system can transmit data at more than 100 Mbit/s and five milliseconds latency.

Modern production technologies in the automobile industry must become more flexible in order to fulfil individual customer requirements.

Im Focus: Sharp images with flexible fibers

An international team of scientists has discovered a new way to transfer image information through multimodal fibers with almost no distortion - even if the fiber is bent. The results of the study, to which scientist from the Leibniz-Institute of Photonic Technology Jena (Leibniz IPHT) contributed, were published on 6thJune in the highly-cited journal Physical Review Letters.

Endoscopes allow doctors to see into a patient’s body like through a keyhole. Typically, the images are transmitted via a bundle of several hundreds of optical...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Munich conference on asteroid detection, tracking and defense

13.06.2018 | Event News

2nd International Baltic Earth Conference in Denmark: “The Baltic Sea region in Transition”

08.06.2018 | Event News

ISEKI_Food 2018: Conference with Holistic View of Food Production

05.06.2018 | Event News

 
Latest News

Graphene assembled film shows higher thermal conductivity than graphite film

22.06.2018 | Materials Sciences

Fast rising bedrock below West Antarctica reveals an extremely fluid Earth mantle

22.06.2018 | Earth Sciences

Zebrafish's near 360 degree UV-vision knocks stripes off Google Street View

22.06.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>