examining how the hormone jasmonate works to protect plants and promote their
growth have revealed how a transcriptional repressor of the jasmonate signaling
pathway makes its way into the nucleus of the plant cell.
hope the recently published discovery will eventually help farmers experience
better crop yields with less use of potentially harmful chemicals.
is a small piece of a bigger picture, but it is a very important piece,” said
Maeli Melotto, a University of Texas at Arlington assistant professor of biology.
recently co-authored a paper that advances current understanding of plant
defense mechanisms with her collaborator Sheng Yang He and his team at Michigan
State University’s Department of Energy Plant Research Laboratory (DOE-PRL). He is a Howard Hughes Medical
Institute-Gordon and Betty Moore Foundation investigator. A paper on the
collaboration was published online Nov. 19 in the Proceedings of the National Academy of
Sciences under the title, “Transcription factor-dependent nuclear import of
transcriptional repressor in jasmonate hormone signaling.”
signaling has been a target of intense research because of its important role
in maintaining the balance between plant growth and defense. In healthy plants,
jasmonates play a role in reproductive development and growth responses. But,
when stressors such as herbivorous insects, pathogen attack, or drought,
jasmonate signaling shifts to defense-related cellular processes.
team from UT Arlington and Michigan State focused on the role of jasmonate
signaling repressors referred to as JAZ. Specifically, they looked at how JAZ
interacts with a major transcription factor called MYC2 and a protein called
COI1, which is a receptor necessary for jasmonate signaling.
researchers discovered that a physical interaction between the repressors and
the MYC2 persisted inside the plant cell nucleus, preventing
jasmonate-associated gene transcription.
tight repression of transcription factors may be important because activation
of jasmonate signaling, although important for plant defense against pathogens
and insects, is energy-consuming and could lead to growth inhibition – a widely
known phenomenon called growth-defense tradeoff,” said He, the Michigan State
plant biologist. “In other words, plants have developed a mechanism to tightly
repress presumably energy-consuming, jasmonate-mediated defense responses until
it becomes necessary, such as upon pathogen and insect attacks.”
National Institutes of Health, the U.S. Department of Energy, Howard
Hughes Medical Institute and
and Betty Moore Foundation
funded the work featured in the recent paper.
said understanding jasmonate signaling at the molecular level is also vital
because some plant pathogens, such as Pseudomonas syringae, have developed ways
to mimic the hormone’s action in the cell. This gives them the ability to
aggressively colonize plants without activating natural defense mechanisms, she
who is currently receiving National Institutes of Health funding to examine
plant defenses, said the next step in her jasmonate research is to determine
which domain of the JAZ protein is responsible for plant innate immunity.
is one way to have sustainable agriculture,” Melotto said of the research. “By
increasing genetic resistance we could reduce the use of pesticides, decrease
crop production costs and promote environmentally friendly farming practices.”
work with Michigan State University is an example of the collaborative research
going on at UT Arlington, a comprehensive research institution
of more than 33,200 students and more than 2,200 faculty members in the heart
of North Texas. Visit www.uta.edu to