Azetidine-induced accumulation of class I small heat shock proteins in the soluble fraction provides thermotolerance in soybean seedlings.
Accumulation of class I small heat shock proteins (sHSPs) is induced by the proline analog, azetidine-2-carboxylic acid (Aze) in soybean seedlings to a level similar to that induced by exposure to 40 degrees C. However, only the treatment with 10 mM Aze for 6 h and subsequently with 10 mM proline for 24 h protected the seedlings from damage during subsequent exposure to 45 degrees C as assessed by 2,3,5-triphenyltetrazolium chloride (TTC) staining. A chaperone activity assay showed that the purified class I sHSPs induced by Aze were functional in vitro and protected proteins from thermal denaturation. Amino acid composition analysis indicated that Aze was not incorporated into de novo synthesized class I sHSPs. Accumulation of class I sHSPs in the soluble post-ribosomal supernatant fraction was found to be important for acquisition of thermotolerance. We suggest that both the accumulation of class I sHSPs and their presence in the soluble fraction are important for establishment of thermotolerance.
Jinn
Tsung-Luo
TL
Institute of Plant Biology, National Taiwan University, Taipei 106, Taiwan, R.O.C.
Chiu
Chi-Chou
CC
Song
Wei-Wen
WW
Chen
Yih-Ming
YM
Lin
Chu-Yung
CY
D000595:Amino Acid Sequence / Q000502:physiology; D001384:Azetidines / Q000378:metabolism / Q000494:pharmacology*; D006360:Heat-Shock Proteins / Q000187:drug effects / Q000378:metabolism*; D018869:Heat-Shock Response / Q000187:drug effects / Q000502:physiology*; D007150:Immunohistochemistry; D046529:Microscopy, Electron, Transmission; D018832:Molecular Chaperones / Q000187:drug effects / Q000378:metabolism; D018517:Plant Roots / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure; D011392:Proline / Q000378:metabolism / Q000494:pharmacology; D011489:Protein Denaturation / Q000187:drug effects / Q000502:physiology; D036226:Seedlings / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism*; D013025:Glycine max / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism*
D001384:Azetidines; D006360:Heat-Shock Proteins; D018832:Molecular Chaperones; C082735:azetidine; D011392:Proline