[ASC-media] CSIRO: Building disease-beating wheat

Rebecca.Eveleigh at csiro.au Rebecca.Eveleigh at csiro.au
Tue Dec 11 23:58:37 CET 2007

12 December 2007 

Ref 07/247

Building disease-beating wheat

Disease resistance genes from three different grass species have been
combined in the world's first 'trigenomic' chromosome, which can now be
used to breed disease resistant wheat varieties.

Pioneered by CSIRO researchers, in collaboration with the International
Maize and Wheat Improvement Center (CIMMYT) and Sydney University, the
research illustrates the major genetic improvements possible without
genetic modification (GM) technology.

"Wheat breeders often use wild relatives of wheat as sources of novel
genes in breeding new disease-resistant wheats," research team leader Dr
Phil Larkin says.

"Unfortunately genes from wild relatives usually come in large blocks of
hundreds of genes, and often include undesirable genes. Furthermore,
these blocks of genes tend to stay together, even after many generations
of breeding.

"The problem can be so difficult to overcome that plant breeders
sometimes give up on very valuable genes because they cannot separate
them from the problematic genes."

A paper published this month in the respected international journal
Theoretical and Applied Genetics details how the team 'recombined' two
wild blocks of genes from two different Thinopyrum grass species - a
wild relative of wheat - bringing together resistance genes for leaf
rust and Barley Yellow Dwarf Virus (BYDV), two of the world's most
damaging wheat diseases. The recombined gene 'package' may also carry a
resistance gene against a new stem rust strain which is causing concern

"The exciting part of the new research is that we have been able to
retain the useful genes but leave behind the associated undesirable
genes - most notably in this case those for yellow flour colour, an
important quality characteristic in wheat," Dr Larkin says.

By developing new 'DNA markers' and by careful testing the team has
produced a number of the disease resistance 'packages' for wheat
breeders, making it faster and easier to include these important disease
resistance traits in future wheat varieties.

It is hoped other examples will follow and the genetic diversity
available in wild species can be recruited more extensively for wheat

Image available at:

Further Information:

Dr Phil Larkin, CSIRO Plant Industry
02 6246 5060, Philip.Larkin at csiro.au 

Background information available at:

Media Assistance:

Tony Steeper, CSIRO Plant Industry
02 6246 5323, 0407 032 131, tony.steeper at csiro.au 


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