Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Researchers find gene that may be at root of potato blight

18.05.2005


Researchers have found a gene they suspect plays an important role in triggering the blight that wiped out Ireland’s potato crops a century-and-a-half ago.



And the pathogen that contains this gene still causes massive amounts of agricultural damage throughout the modern world– on the order of billions of dollars each year. The scientists describe the gene, called Avr3a, in a study that appears online in the early edition of the Proceedings of the National Academy of Sciences.

Researchers call Avr3a an avirulence gene. This gene is the first avirulence gene identified from the plant pathogen that causes late blight, a devastating disease that can destroy fields of potato and tomato plants. Plant pathogens contain a diverse set of such avirulence genes which, depending on the plant variety, can either facilitate disease or trigger resistance.


Avr3a scouts a potato plant on the cellular level to determine whether the plant is a likely victim. “This avirulence gene is kind of like a weapon that triggers a metal detector,” said Sophien Kamoun, a study co-author and an associate professor of plant pathology at Ohio State University ’s Ohio Agricultural Research and Development Center in Wooster . “If you take a gun through the metal detector at an airport, the alarms go off,” he said. “This gene (Avr3a) sends a signal alerting the plant that it is infected by the pathogen.”

Phytophthora infestans is the pathogen that causes late blight. For decades, controlling this disease has involved regular applications of agrochemicals, Kamoun said.

But some experts fear that the pathogen is making a comeback.

“Given the recent widespread occurrence of new fungicide-resistant strains of this pathogen, it could be considered a reemerging threat to global food security,” Kamoun said. “Disturbing reports predict that potato late blight could cause food shortages and hunger in several parts of the world.”

He added that the spread of P. infestans may hit developing nations particularly hard, as potatoes are a staple crop in many of these countries.

P. infestans belongs to a group of destructive pathogens called oomycetes. Oomycetes aren’t easy to categorize – although they physically look like fungi, on a molecular level they more closely resemble algae.

Over the last 75 years, potato breeders have introduced at least a dozen late blight-resistant genes into the cultivated potato. The researchers looked at one of these genes, R3a.

Kamoun and his colleagues thought that if a potato plant contained R3a, that it could detect P. infestans manifestation by recognizing Avr3a and then ward off an impending disease. The R3a gene was discovered earlier this year by scientists at Wageningen University, The Netherlands.

In laboratory experiments on leaves from potato plants, the scientists found that the leaves containing the R3a gene successfully resisted late blight infection when exposed to P. infestans races that carried the Avr3a gene. However, some races of P. infestans with mutations in their Avr3a gene escaped the resistance response triggered by R3a.

Further laboratory analysis showed that when R3a detected Avr3a in a leaf cell, that plant cell died.

“This programmed cell death is how the plant keeps the pathogen from spreading to other cells,” Kamoun said. “Only a few cells die. It’s one mechanism of defense some plants have.”

Until now, researchers knew little about P. infestans on the molecular level.

By studying Avr3a, R3a and similar genes, researchers may be able to determine what happens during the earliest stages of late blight infection.

“This study is a big step forward in late blight research,” Kamoun said. “Current strategies for managing late blight in potato and tomato crops are unsustainable and costly. In the United States and other developed countries, the chronic use of chemicals to manage late blight reduces the profit margins of farmers and is not always successful.

“In developing countries, late blight also affects subsistence potato production,” he continued. For example, a late blight breakout in 2003 brought potato production to a halt in Papua New Guinea , one of the few countries in the world that was previously free of the disease.

Agricultural problems caused by oomycetes don’t stop with P. infestans. Related Phytophthora species cause root rot in soybean plants as well as sudden oak death, which is devastating stands of oak trees along California ’s coast and is present in at least three other states.

Kamoun conducted the multidisciplinary study with lead author Miles Armstrong and other researchers from the Scottish Crop Research Institute in Dundee; Jorunn Bos, a graduate student in plant pathology at Ohio State; the University of Warwick; and the Wellcome Trust Sanger Institute, Cambridge, all in the United Kingdom; and Wageningen University in The Netherlands.

The researchers received financial support for this work from the National Science Foundation Plant Genome Research Program, the Scottish Executive Environment and Rural Affairs Department and the Biotechnology and Biological Sciences Research Council.

Sophien Kamoun | EurekAlert!
Further information:
http://www.osu.edu

More articles from Life Sciences:

nachricht Zebrafish's near 360 degree UV-vision knocks stripes off Google Street View
22.06.2018 | University of Sussex

nachricht New cellular pathway helps explain how inflammation leads to artery disease
22.06.2018 | Cedars-Sinai Medical Center

All articles from Life Sciences >>>

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 >>>