Listening to the BBC this morning on WUNC, I
heard an interview of Dr Ralph Dean, professor of plant pathology
and director of North Carolina State University's Center for
Integrated Fungal Research. He's the lead author of "The Genome
Sequence of the Rice Blast Fungus Magnaporthe grisea", published in
Nature yesterday, April 21, which announces the DNA genome
mapping of the rice blast fungus.
Rice blast disease is caused by the fungus
Magnaporthe
grisea, and it's the plant's most destructive enemy. Sequencing
is determining the nucleotides of a DNA or RNA strand (source:
Sequencing).
The genome of an organism is a complete DNA sequence of one set of
chromosomes (source:
Genome).
It is estimated that rice blast, the leading cause of
rice loss, is responsible each year for killing enough rice to feed
60 million people worldwide.
Researchers
Uncover Genome Sequence of Major Rice Pathogen, the press
release from North Carolina State University announcing the genome
sequencing of
M. grisea and the
Nature article.
The fungus gets its name from the way it blasts its way
into the leaves of rice plants by growing a small 'bubble' that
sticks to the plant. Pressure inside the bubble builds up until it
bursts, allowing the fungus to push through the leaf's protective
surface and into the plant.
The fungus can then invade the plant tissue, reproduce and infect
other plants. When the fungus infects young rice seedlings it often
kills the whole plant. Older plants infected yield little
grain.
(Source, the excellent
SciDev.net article
Genetic secrets of rice's worst fungal pest unveiled, which
provides information on Dr Dean's team's work on the fungus enzymes
that break down the waxy coating that protects rice leaves, the
unusually high number of rice blast fungus genes that help it to
respond to changes in the environment: some of these genes are
'switched on' when the fungus attacks plant leaves, allowing the
rice blast fungus to respond to its environment better than other
fungi, and that viruses that effectively live inside rice blast
fungus make it more difficult for the plants to recognise the
fungus, meaning that both fungus and virus have a better chance of
reproducing.)
Scientists sequenced rice's genome in 2002, so 'we now have crucial
data for both the host (rice) and the pathogen (rice blast fungus).
This will lead to a new way of tackling the fungus,' according to
team member Lee Yong-hwan, of Seoul National University (source:
Genome on Rice Killer Unveiled at
The Korea Times)
M. grisea is highly adaptable, making it difficult to use
fungicides and chemicals to control the disease.
Our team created about 20,000 genetically-engineered
mutants of the rice blast fungus to get an insight into which gene
should be killed to prevent its infection of rice.
said Prof Lee.
Both Dr Dean on the BBC and Prof Lee in
The Korea Times said
that perhaps in five years, 'a genetic solution of keeping the rice
blast fungus at bay' could be developed.