title: Azetidine-induced accumulation of class I small heat shock proteins in the soluble fraction provides thermotolerance in soybean seedlings.
abstract: 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.
authors.affiliation: Institute of Plant Biology, National Taiwan University, Taipei 106, Taiwan, R.O.C.
authors.forename: Tsung-Luo
authors.initials: TL
authors.lastname: Jinn
authors.forename: Chi-Chou
authors.initials: CC
authors.lastname: Chiu
authors.forename: Wei-Wen
authors.initials: WW
authors.lastname: Song
authors.forename: Yih-Ming
authors.initials: YM
authors.lastname: Chen
authors.forename: Chu-Yung
authors.initials: CY
authors.lastname: Lin
mesh_terms: 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*
chemical_list: D001384:Azetidines; D006360:Heat-Shock Proteins; D018832:Molecular Chaperones; C082735:azetidine; D011392:Proline