Michigan State University plant scientists have discovered another piece of
the genetic puzzle that controls how plants respond to high temperatures.

That may allow plant breeders to create new varieties of crops that flourish
in warmer, drier climates.

The MSU researchers found that the gene bZIP28 helps regulate heat stress
response in Arabidopsis thaliana, a member of the mustard family used as a
model plant for genetic studies. This is the first time bZIP28 has been
shown to play a role heat tolerance. The research is published in the Oct. 6
issue of the Proceedings of the National Academy of Sciences.

"We also found that bZIP28 was responding to signals from the endoplasmic
reticulum, which is the first time the ER has been shown to be involved with
the response to heat," said Robert Larkin, MSU assistant professor of
biochemistry and molecular biology and corresponding author of the paper.
"We're finding that heat tolerance is a more complex process than was first
thought."

Previous research has shown that the nucleus, the "brain" of the cell, and
cytosol, the fluid inside cells, play a role in how plants respond to heat.
The endoplasmic reticulum, a membrane in the cell that consists of small
tubes and sac-like structures, is mainly responsible for packaging and
storing proteins in the cell.

According to Christoph Benning, MSU professor of biochemistry and molecular
biology and a member of the research team, the scientists were looking for
genes that turn other genes on and off and are tied to cell membranes. These
membrane-tethered gene switches are seen in animals but hadn't been studied
in great detail in plants.

"The bZIP28 protein is anchored in the endoplasmic reticulum, away from its
place of action," Benning explained. "But when the plant is stressed by
heat, one end of bZIP28 is cut off and moves into the nucleus of the cell
where it can turn on other genes to control the heat response. Understanding
how the whole mechanism works will be the subject of more research."

Plants with an inactive bZIP28 gene die as soon as temperatures reach a
certain level.

Other scientists on the research team are Federica Brandizzi, MSU associate
professor of plant biology and member of the Plant Research Lab, and Hangbo
Gao, former MSU post-doctoral research associate.

The work was sponsored by the MSU-DOE Plant Research Lab. Benning's research
also is supported by the Michigan Agricultural Experiment Station.

About the Michigan State University
Michigan State University has been advancing knowledge and transforming
lives through innovative teaching, research and outreach for more than 150
years. MSU is known internationally as a major public university with global
reach and extraordinary impact. Its 17 degree-granting colleges attract
scholars worldwide who are interested in combining education with practical
problem solving.

For MSU news on the Web, go to news.msu.edu. For more information on the
MSU-DOE Plant Research Lab, go to www.prl.msu.edu & www.checkbiotech.org