Ramularia and the 4 Rs: Resistance gene causes susceptibility to second disease

Jan 15, 2014

The gene that has provided spring barley with resistance to powdery mildew for over 30 years increases susceptibility to newly-important disease Ramularia leaf spot.

Scientists confirm the trade-off in a paper published in the Journal of Experimental Botany. Since 1980, the mlo gene has transformed mildew from the most important disease of barley to an occasional nuisance in wetter areas of the UK.

"Having suspected that one of the most successful and widely-used resistances to an important crop disease has the detrimental effect of increasing to another, we took a closer look," says Professor James Brown from the John Innes Centre.

Its effect on increasing the severity of Ramularia is most keenly felt in spring barley and it was found to be sensitive to environmental conditions.

However, the research also paves the way for lines to be bred that are resistant to both diseases by selecting for multiple genes.

"It has struck us that plant breeding relying on the successful use of a single major can increase susceptibility to another ," said R&D breeder Peter Werner from KWS UK.

"We have been observing more Ramularia than in the past and now that we know what is happening on a genetic level we can do something about it."

Symptoms of Ramularia can appear over as little as one weekend, but are notoriously hard to diagnose because of their similarity to other syndromes. In collaboration with Neil Havis of Scotland's Rural College, Professor Brown came up with a simple new method of scoring Ramularia in field trials:

The "Four 'R's":

  • The spots are Rectangular
  • They are Reddish brown
  • They are surrounded by a Ring of chlorosis
  • They go Right through to the other side of the leaf

The guide enabled the scientists to test 100s of lines in several locations while being sure of consistent results. The study also broke new ground for the speed of the genetic analysis carried out at the James Hutton Institute. Using maps of genetic markers, the scientists were able to quickly find the precise location for important traits within days rather than years.

Barley is the fourth most important cereal in terms of global production across temperate regions.

Explore further: Using genes to counter rust

add to favorites email to friend print save as pdf

Related Stories

Using genes to counter rust

Aug 05, 2013

An international study led by a Queensland scientist has found a way to better safeguard an important food crop—and the world's beer supply.

Fertility or powdery mildew resistance?

Nov 12, 2010

Powdery mildew is a fungus that infects both crop and ornamental plants. Each year, powdery mildew and other plant pathogens cause immense crop loss. Despite decades of intense research, little is known of the plant molecules ...

Sexual reproduction only second choice for powdery mildew

Jul 14, 2013

Powdery mildew is one of the most dreaded plant diseases: The parasitic fungus afflicts crops such as wheat and barley and is responsible for large harvest shortfalls every year. Beat Keller and Thomas Wicker, ...

DNA discovery key to drought resistant crops

May 31, 2012

(Phys.org) -- Scientists have pinpointed the ‘stay green' DNA in barley in new research that may help farmers to grow better crops in areas of drought, heat and salinity.

Recommended for you

Deadly human pathogen Cryptococcus fully sequenced

Apr 17, 2014

Within each strand of DNA lies the blueprint for building an organism, along with the keys to its evolution and survival. These genetic instructions can give valuable insight into why pathogens like Cryptococcus ne ...

User comments : 0

More news stories

Researchers successfully clone adult human stem cells

(Phys.org) —An international team of researchers, led by Robert Lanza, of Advanced Cell Technology, has announced that they have performed the first successful cloning of adult human skin cells into stem ...

Male monkey filmed caring for dying mate (w/ Video)

(Phys.org) —The incident was captured by Dr Bruna Bezerra and colleagues in the Atlantic Forest in the Northeast of Brazil.  Dr Bezerra is a Research Associate at the University of Bristol and a Professor ...

Researchers develop new model of cellular movement

(Phys.org) —Cell movement plays an important role in a host of biological functions from embryonic development to repairing wounded tissue. It also enables cancer cells to break free from their sites of ...

Impact glass stores biodata for millions of years

(Phys.org) —Bits of plant life encapsulated in molten glass by asteroid and comet impacts millions of years ago give geologists information about climate and life forms on the ancient Earth. Scientists ...