Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Analysis of RNA role in spreading disease advances study of damaging plant infections

23.04.2008
Recent research that links specific pieces of RNA to an infectious organism’s duplication and spread could lead the way to the prevention of viroids, pathogens that can kill or damage food crops and other plants.

The findings and the research approach used by Ohio State University scientists also could have applications in the study of how certain viruses spread in humans because the pathogens have some similar characteristics.

The researchers have developed an experimental system to identify specific structural parts of a viroid that are responsible for its multiplication and spread of the disease.

Because no chemical treatments exist that can specifically inhibit viroid infection, an effective way to prevent viroid multiplication and spread is through genetic alterations of susceptible plants. The best approach to such bioengineering is learning exactly how the pathogens function in the first place, said Biao Ding, senior author of the study and professor of plant cellular and molecular biology at Ohio State.

... more about:
»Ding »Infection »Pathogen »RNA »loop »type »viroid

“We’re trying to understand how the infection occurs, and how the RNA propagates itself in the cell. But more importantly, even for human diseases, is discovering how a disease spreads. That’s where the problem comes in the plant,” Ding said.

Viroids resemble viruses, but consist of only small RNA molecules that don’t have the protein coat found on viruses and that don’t encode any proteins. Viroids so far have been shown to infect only plants.

Ding and colleagues introduced mutations to specific points within the viroid RNA to see how such disruption affected the role of each piece of the structure. They don’t have all of the answers yet to explain the entire viroid RNA function, but their approach shows promise for expanding knowledge about how RNA works in the development of an organism and in the spread of multiple diseases, Ding said.

The research is published in a recent issue of the journal The Plant Cell.

About 30 species of viroids exist, affecting such plants as tomatoes, potatoes, palm trees and chrysanthemums. One type of viroid has been known to kill millions of palm trees, but more typical effects of the infection are low plant quality and reduced crop yield. The current way to treat viroids is to harvest and destroy infected crops and start over with new plants.

The effects of viroid infection were first noticed in the 1920s but the cause remained unknown until 1971.

“The scientist who discovered the first viroid spent many years trying to find the pathogen,” Ding said. “It’s not bacteria. It’s not a virus. It is really its own kind of pathogen. It doesn’t make any proteins or have any protein coat. It’s just a piece of RNA.”

Unlike the better-known DNA structure – a double helix with base pairs of nucleotides connecting the strands – many RNAs are formed by a single strand that folds back in on itself. As a result, the RNA structure has a series of loops that scientists have long assumed were empty holes with unclear roles in the RNA function.

Research from several labs has recently shown that many of those loops are not holes, but are actually the most important structural parts of the RNA.

“Those loops interact with proteins, other RNAs and small molecules. That helped us decide to look at all of the loops of a viroid RNA and see how each one functions,” Ding said.

The viroid model used for this research is called the Potato spindle tuber viroid, and its infection was studied in a tobacco-like plant called Nicotiana benthamiana for the experiment. Lead study author Xuehua Zhong, at the time a graduate student and now a postdoctoral researcher at Ohio State, led the work to introduce mutations to each of the 27 loops in this viroid to disrupt its structure and see how that disruption affected either viroid replication or the viroid’s ability to spread, or both actions in the case of some loops.

“It looks like all 27 loops are important, but we need to know which ones are important for the RNA’s ability to reproduce itself in the cell, and which ones are important for spreading from one part of the plant to another,” Zhong said. “And we know we can find similar structures in different RNAs, so that means that what we learned can be applied to other types of RNA.”

So far, the researchers have discovered that a change to almost any loop will slow or eliminate replication, except for one loop. In that case, when disrupted, it instead causes an increase in RNA duplication. A few loops also were identified that are required for movement of the viroid from one part of the plant to another, which spreads the infection.

“We still don’t know exactly where a particular mutant fails to spread because there are so many cell layers in the plant. We still need to take a look at each mutant to see where the infection starts in the plant and what kind of cell types are affected,” Ding said.

He also said that although the viroids themselves don’t contain or make proteins, there must be proteins in the plant that are responsible for recognizing the viroid and allowing it to move around.

The viroid mutants that fail to replicate or move around will be valuable materials to help identify these proteins. For example, a protein that recognizes a viroid structure that is required for movement between cell layers would not be expected to bind to the viroid if the structure is mutated to abolish the movement. This also means that mutating the RNA might not be the only bioengineering target. Instead, proteins could be key to designing plants that will not succumb to viroid infection.

“Once you pinpoint a protein, you might be able to change the protein function so it cannot recognize the viroid and allow it to spread,” said Ding, whose lab is developing methods to look for all of the proteins that bind to viroids to promote infection.

“This is really just the beginning,” Ding said. “This is a new focus, not just for us, but for other researchers studying RNAs that can be analyzed in similar ways because their structure is the same or similar. This is really a new way of investigating.”

This work was supported by grants from the National Science Foundation.

Additional co-authors are Anthony Archual and Amy Amin, both undergraduates in Ohio State’s College of Biological Sciences.

Biao Ding | EurekAlert!
Further information:
http://www.osu.edu

Further reports about: Ding Infection Pathogen RNA loop type viroid

More articles from Life Sciences:

nachricht Single-stranded DNA and RNA origami go live
15.12.2017 | Wyss Institute for Biologically Inspired Engineering at Harvard

nachricht New antbird species discovered in Peru by LSU ornithologists
15.12.2017 | Louisiana State University

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: First-of-its-kind chemical oscillator offers new level of molecular control

DNA molecules that follow specific instructions could offer more precise molecular control of synthetic chemical systems, a discovery that opens the door for engineers to create molecular machines with new and complex behaviors.

Researchers have created chemical amplifiers and a chemical oscillator using a systematic method that has the potential to embed sophisticated circuit...

Im Focus: Long-lived storage of a photonic qubit for worldwide teleportation

MPQ scientists achieve long storage times for photonic quantum bits which break the lower bound for direct teleportation in a global quantum network.

Concerning the development of quantum memories for the realization of global quantum networks, scientists of the Quantum Dynamics Division led by Professor...

Im Focus: Electromagnetic water cloak eliminates drag and wake

Detailed calculations show water cloaks are feasible with today's technology

Researchers have developed a water cloaking concept based on electromagnetic forces that could eliminate an object's wake, greatly reducing its drag while...

Im Focus: Scientists channel graphene to understand filtration and ion transport into cells

Tiny pores at a cell's entryway act as miniature bouncers, letting in some electrically charged atoms--ions--but blocking others. Operating as exquisitely sensitive filters, these "ion channels" play a critical role in biological functions such as muscle contraction and the firing of brain cells.

To rapidly transport the right ions through the cell membrane, the tiny channels rely on a complex interplay between the ions and surrounding molecules,...

Im Focus: Towards data storage at the single molecule level

The miniaturization of the current technology of storage media is hindered by fundamental limits of quantum mechanics. A new approach consists in using so-called spin-crossover molecules as the smallest possible storage unit. Similar to normal hard drives, these special molecules can save information via their magnetic state. A research team from Kiel University has now managed to successfully place a new class of spin-crossover molecules onto a surface and to improve the molecule’s storage capacity. The storage density of conventional hard drives could therefore theoretically be increased by more than one hundred fold. The study has been published in the scientific journal Nano Letters.

Over the past few years, the building blocks of storage media have gotten ever smaller. But further miniaturization of the current technology is hindered by...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

See, understand and experience the work of the future

11.12.2017 | Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

AKL’18: The opportunities and challenges of digitalization in the laser industry

07.12.2017 | Event News

 
Latest News

Engineers program tiny robots to move, think like insects

15.12.2017 | Power and Electrical Engineering

One in 5 materials chemistry papers may be wrong, study suggests

15.12.2017 | Materials Sciences

New antbird species discovered in Peru by LSU ornithologists

15.12.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>