PLANT PHYSIOLOGY , Vol 110, Issue 1 241-248, Copyright © 1996 by American Society of Plant Biologists
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GENE REGULATION AND MOLECULAR GENETICS |
Induction and Regulation of Heat-Shock Gene Expression by an Amino Acid Analog in Soybean Seedlings
YRJ. Lee, R. T. Nagao, C. Y. Lin and J. L. Key
Department of Botany, University of Georgia, Athens, Georgia 30602 (Y.-R.J.L, R.T.N. J.L.K.)
The effect of the proline analog azetidine-2-carboxylic acid (Aze) on the
induction and the regulation of heat-shock (HS) mRNA accumulation and
heat-shock protein (HSP) synthesis in soybean (Glycine max) seedlings was
studied. Treatment with Aze elicited an HS-like response at the normal
growth temperature, 28[deg]C, with seven of nine HS cDNA clones tested. Two
cDNA clones, Gm-Hsp22.5 and pFS2033, share 78% identity; however,
transcripts hybridizing to GmHsp22.5 but not pFS2033 accumulated with Aze
treatment at 28[deg]C. Substantial incorporation of radioactive amino acid
into high molecular weight HSPs but not low molecular weight HSPs was
observed in vivo during Aze treatment at 28[deg]C. Low molecular weight
HSPs were detected using antibodies raised against an abundant member of
low molecular weight class I HSPs, indicating that low molecular weight
HSPs were synthesized at normal growth temperatures during Aze treatment
despite a lack of substantial in vivo radioactive amino acid incorporation.
In summary, Aze treatment induced accumulation of most but not all HS mRNAs
and HSPs in soybean seedlings; the observations presented here suggest
differential regulation among various HS genes at the transcriptional and
posttranscriptional levels.
