Ames, Iowa
May 22, 2009
Researchers at
Iowa State University have
discovered a previously unknown pathway in plant cells that
regulates plant growth.
Yanhai Yin, an assistant professor in genetics, development and
cell biology, examined signaling mechanisms of a plant hormone
called brassinosteroids. The hormone controls the growth of
cells.
The brassinosteroids (BRs) have a major impact on how large the
plant grows, says Yin.
"Previously, we knew that steroids promote growth," said Yin.
"In model plants like Arabidopsis (a relative of mustard) and
crops such as corn and rice, if you have more steroids, you have
more growth, and if you have less steroids, you have less growth
and the plant is smaller."
Now Yin knows that the HERK1 (named for Hercules -- the Greek
and Roman god who possessed superhuman strength) pathway,
induced by BRs, is controlling much of that growth.
Yin and his team's findings are in the May 5 edition of the
journal Proceedings of the National Academy of Sciences of the
United States of America.
There are many other internal and external factors such as
light, nutrition and hydration that effect plant growth, but the
HERK1, along with some unknown signals, have a great effect.
Yin and his team of Hongqing Guo, assistant scientist; Lei Li,
Huaxun Ye, and Xiaofei Yu, all graduate students; and Alexandria
Algreen, undergraduate student; have shown that by
over-expressing HERK1, they were able to increase a plant's size
by 10 to 15 percent.
By under-expressing HERK1, the plants were about 50 percent
smaller.
Now Yin and his group are trying to find what regulates HERK1
and how HERK1 controls growth.
Understanding what make plants get bigger could be a critical
component when producing grain and bio-mass for biofuels.
"With that knowledge, maybe we have one more tool to manipulate
corn and rice if we want more grain, or if we want more mass for
bio-energy crops," he said. |
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