Columbia, Missouri
March 31, 2008
Plants are not only smart, but
they also wage a good fight, according to a
University of Missouri
biochemist. Previous studies have shown that plants can sense
attacks by pathogens and activate their defenses. However, it
has not been known what happens between the pathogen attacks and
the defense activation, until now. A new MU study revealed a
very complex process that explains how plants counter attack
pathogens. This discovery could potentially lead to crops with
enhanced disease resistance.
“There is a chemical warfare between plants and pathogens,” said
Shuqun Zhang, associate professor of biochemistry in the College
of Agriculture, Food and Natural Resources and the College of
Medicine. “Normally, plants put effort into growth and
development. However, when plants sense pathogens, they have to
use some of their energy and resources to make secondary
metabolites to fight disease. Until now, very little has been
known about how this process is regulated.”
According to the study, plants first sense the attack of a
pathogen, and then activate defense responses by triggering a
complex signaling cascade in plants. One of the defense
responses is the induction and accumulation of anti-microbial
defense chemicals, known as phytoalexins.
In his study, Zhang found the specific signaling path, known as
a mitogen-activated protein kinase (MAPK) cascade, in the plants
that ends when the defense chemical camalexin is created.
Camalexin is essential for resistance to some plant diseases.
Zhang used Arabidopsis, a small flowering plant and the first to
have its entire genome sequenced, and Botrytis cinera, a fungal
pathogen that causes grey mold disease in a number of plants
including grapes and strawberries.
“By understanding at the molecular and cellular levels how
plants protect themselves under adverse environmental
conditions, such as pathogen attacks, we could eventually
improve the disease resistance of crops,” Zhang said.
The study will be published in the March 31 online early edition
publication of the Proceedings of
the National Academy of Sciences (PNAS). |
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