Australia
February 24, 2009
CSIRO Plant Industry scientists
and international collaborators have discovered the key to
overcoming three major cereal diseases, which in epidemic years
cost wheat growers worldwide in excess of AUS$7.8 billion.
In a paper published today in the prestigious journal Science,
scientists from CSIRO Plant
Industry, the University of
Zurich and the International
Maize and Wheat Improvement Center have identified a wheat
gene sequence which provides protection against leaf rust,
stripe rust and powdery mildew.
"Genetic disease resistance is highly desirable in plants as it
is more environmentally friendly and profitable than strategies
like spraying pesticides," says a senior principal research
scientist at CSIRO Plant Industry, Dr Evans Lagudah. "The newly
identified resistance gene product – known as Lr34 transporter
protein – is the first of its kind to be found in a commercial
crop that is capable of delivering broad-spectrum control of
multiple pathogens."
Lr34 has two extremely valuable characteristics. Whereas one
gene usually only protects against a single disease for a
limited time under commercial production, Lr34 provides long
lasting disease resistance and acts against multiple diseases.
"The fungi that cause rust diseases are very adaptable and can
rapidly evolve to overcome resistant cereal varieties," Dr
Lagudah says. "Scientists and farmers can commonly only respond
to a rust outbreak after it has passed, but tests conducted
after identifying the Lr34 gene sequence show it has provided
partial but constant protection against leaf rust for over 80
years."
Understanding the molecular nature of this type of resistance
has important implications for long-term control of rust
diseases.
CSIRO Plant Industry's Dr Wolfgang Spielmeyer says an immediate
application is the use of the gene sequence to directly select
and breed wheat plants that carry the resistance against
multiple pathogens.
"The Lr34 gene can now be combined with other disease resistance
genes into single cultivars faster and with greater confidence
providing even more durable resistance," he says.
This work was supported in Australia by the
Grains Research and Development
Corporation. |
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