St. Louis, Missouri
Jan. 6, 2009
Building on plant virus research
started more than 20 years ago, researchers at the
Donald Danforth Plant
Science Center have discovered a technology that reduces
infection by the virus that causes Rice Tungro Disease, once
referred to as a limiting factor of rice production in Asia.
Danforth Center President Dr. Roger N. Beachy and Research
Scientist Dr. Shunhong Dai demonstrated that transgenic rice
plants that overexpress either of two rice proteins are tolerant
to infection caused by the rice tungro bacilliform virus (RTVB)
which is largely responsible for the symptoms associated with
Rice Tungro disease. The two proteins, RF2a and RF2b were
discovered in Beachy’s lab several years ago and are
transcription factors known to be important for plant
development; the new data suggest that they may be involved in
regulating defense mechanisms that protect against virus
infection. The discovery, published in the December 22, 2008
issue of the Proceedings of the
National Academy of Sciences, may open new avenues in the
search for disease resistance genes and pathways in plants and
other organisms.
Plant viral diseases cause serious economic losses in
agriculture, second only to those caused by fungal diseases.
Rice Tungro disease is prevalent primarily in South and
Southeast Asia and accounts for nearly $1.5 billion annual loss
in rice production worldwide. Preventing the occurrence and
spread of this virus could result in increased yields ranging
from five and 10 per cent annually in affected areas.
“Rice Tungro disease is complex and requires interactions
between two different viruses, an insect vector and the host. It
has taken a great deal of research effort through the years to
gain sufficient information and knowledge about the virus and
the host to come to the point of developing a type of resistance
to the disease. Hopefully, the results of these studies will
lead to improved yields of rice in areas of the world most
affected by the disease,” said Roger N. Beachy, president,
Donald Danforth Plant Science Center.
Beachy and Dai’s research laboratory and greenhouse findings
conducted in St. Louis were confirmed in a greenhouse trial
conducted in partnership with the
Philippine Rice Research
Institute. This breakthrough provides a clearer
understanding of how these two specific transcription factors
‘turn on’ specific genes in rice plants as well as which
proteins help the virus complete the cycle of infection.
Understanding the development of disease symptoms is critical
for engineering plants that can resist the biological effects of
viral pathogen infection.
Virus infections alter gene expression and physiological status
in the host, resulting in disease symptoms. Although viruses are
relatively simple genetically speaking, little is known about
the mechanisms that underlie the development of disease symptoms
caused by viral pathogens.
A major challenge for the treatment or prevention of viral
infections is the identification of specific factors in host
organisms that contribute to disease susceptibility and
symptoms. Some of these factors include genetic and biochemical
pathways and gene expression that influence multiple aspects of
host biology.
In this case of Rice Tungro disease, viral infection is commonly
transmitted by the green leaf hopper. Combining genes that
overexpress RF2a and RF2b with genes that provide resistance to
the insect vector could generate new rice varieties with
significantly improved resistance to Rice Tungro disease in
vulnerable regions in the world.
About the Philippine Rice Research Institute
PhilRice is the national lead agency for the planning,
coordination, implementation, and monitoring of all rice
research and development (R&D) activities in the Philippines.
For more information please visit
www.philrice.gov.ph
About The Donald Danforth Plant Science Center
Founded in 1998, the Donald Danforth Plant Science Center is a
not-for-profit research institute with a global vision to
improve the human condition. Research at the Danforth Center
will enhance the nutritional content of plants to improve human
health, increase agricultural production to create a sustainable
food supply, and build scientific capacity to generate economic
growth in the St. Louis region and throughout Missouri. For more
information please visit
www.danforthcenter.org.
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