Columbia, Missouri
May 27, 2009
A plant's immune system protects
the plant from harmful pathogens. If the system overreacts to
pathogens, it can stunt plant growth and reduce seed production.
Now, University of Missouri
researchers have identified important suppressors that
negatively regulate the responses of the immune system in the
plant species Arabidopsis thaliana. Understanding the immune
system of plants would allow breeders to create better yielding
crop plants.
"The immune system provides plants with strong protection from
pathogens," said Walter Gassmann, associate professor of plant
sciences in the MU Christopher S. Bond Life Sciences Center and
the College of Agriculture, Food and Natural Resources.
"However, this response has the potential to be highly
deleterious to the plant and needs to be tightly controlled.
Certain suppressors protect the plant from responding to
harmless stimuli and from overreacting to pathogens. If there is
a mutation in these suppressors, the immune system can actually
do more damage than good."
One way that plants fight pathogens is through
effector-triggered immunity (ETI), which relies on the detection
of pathogen effector proteins (proteins that are deployed by
pathogens to interfere with the plant immune system). After the
detection of a pathogen, specific proteins in the plant, known
as resistance proteins, elicit an effective defense response.
The plants' resistance proteins are regulated by suppressors to
achieve minimal side effects to the plant while providing
optimal responses to pathogens. However, when the ETI is overly
activated, it can cause stunted growth and poor seed production.
In the study, MU researchers examined plants with genetic
mutations that resulted in heightened plant immunity. By
examining this mutation, researchers were able to identify
specific genetic components that may negatively regulate the
immune system and thus contribute to an appropriate immune
response.
"The general control of effector-triggered signaling is poorly
understood," Gassmann said. "Better insight into the immune
system response will allow us to develop plants with more
durable safeguards against pathogens."
Gassmann's research has been published recently in The Plant
Journal and Plant Signaling & Behavior. The papers were
co-authored by former post-doctoral researcher Soon Il Kwon,
current graduate student Sang Hee Kim, current post-doctoral
researcher Saikat Bhattacharjee, and former visiting scientist
Jae-Jong Noh. |
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