PLANT PHYSIOLOGY , Vol 115, Issue 1 229-240, Copyright © 1997 by American Society of Plant Biologists
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WHOLE PLANT, ENVIRONMENTAL, AND STRESS PHYSIOLOGY |
Recovery from Heat Shock in Heat-Tolerant and Nontolerant Variants of Creeping Bentgrass
S. Y. Park, K. C. Chang, R. Shivaji and D. S. Luthe
Department of Biochemistry and Molecular Biology, Box 9650, Mississippi State University, Mississippi State, MS 39762
Recovery from the heat-shock response was tested in heat-tolerant (selected
bentgrass [SB]) and nontolerant (nonselected bentgrass [NSB]) variants of
creeping bentgrass (Agrostis palustris Huds.) SB increased incorporation of
radioactive amino acids into protein 2 h earlier than NSB when leaf blades
were incubated at the recovery temperature following heat shock.
Electrophoresis indicated that heat-shock protein (HSP) synthesis decreased
and normal protein synthesis increased at 4 h in SB and at 6 to 8 h in NSB.
Increased synthesis of normal proteins was not due to increased abundance
of normal mRNAs, which were equivalent in SB and NSB at 4 h. But at 4 h,
more of the normal mRNA population was associated with polysomes in SB than
in NSB. Synthesis of HSP70 and HSP18 decreased earlier in SB than in NSB.
The decreased synthesis of these HSPs appeared to be correlated with
decreased mRNA abundance. But at 4 h, some of the HSP18 mRNA may have been
associated with heat-shock granules in SB. Synthesis of HSP25 continued
through the 8-h recovery in both variants. Although the abundance of HSP25
was equivalent in SB and NSB during heat shock and recovery, more HSP25
mRNA was associated with polysomes in SB than in NSB.
