S. Korean scientists unravel aging, death mechanism in plants

By Lee Joon-seung
SEOUL, Feb. 20 (Yonhap) -- A team of South Korean scientists said Friday it has
unraveled the mechanism of aging and death in plants that may hold clues to human
longevity.

The group, led by Nam Hong-gil, a professor at Pohang University of Science and
Technology (POSTECH), showed conclusively that aging and death are genetically
programmed into living organisms, making the process irreversible.
The discovery, however, opens the possibility that through genetic manipulation,
it may be possible to slow down the inevitable and bring about considerable
benefits.
Nam, a professor of molecular life science, said the discovery is noteworthy
since very little is known about the underlying reason for aging, despite
longstanding interest in the topic that affects all living things.
He and fellow researchers Kim Jin-hee and Woo Hye-ryun made the breakthrough by
analyzing the leaves of Arabidopsis thaliana, commonly called mouse-ear cress
plants, which are frequently used in experiments since their entire genome is
fully sequenced.
The POSTECH team said that in the Arabidopsis, the ORESARI1 (ORE1), EIN2 and
miR164 ribonucleic acids (RNAs) interact with each other to cause aging.
"In young leaves, there are few ORE1 RNAs, and those that exist are broken up by
the miR164," the scientists said. He said that as the leaves get older, the EIN2s
inhibit and reduce the number of miR164, causing the amount of ORE1 to rise. This
naturally accelerates aging and causes death.
The team said that if the ORE1 is genetically removed from the Arabidopsis
leaves, aging is delayed by a factor of about 20 percent, although subjecting the
plant to environmental stress causes a sharp rise in aging.
"The research confirms that plants are programmed to submit to the natural
process of growing old, but it also provides a new paradigm and view about aging
and death," he said.
The research, supported by the Ministry of Education, Science and Technology and
the Korea Science and Engineering Foundation, was published in the latest
Internet issue of the U.S. journal "Science" on the same day.
The discovery makes Nam the only South Korean scientist to have his papers
published in the top three internationally recognized journals "Science,"
"Nature" and "Cell."
yonngong@yna.co.kr
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