Effect of calcium and calmodulin antagonists on ethylene biosynthesis in tomato fruits

✍ Scribed by Njoroge, Charles K; Kerbel, Eduardo L; Briskin, Donald P

• Publisher: John Wiley and Sons
• Year: 1998
• Tongue: English
• Weight: 213 KB
• Volume: 76
• Category: Article
• ISSN: 0022-5142
• DOI: 10.1002/(sici)1097-0010(199802)76:2<209::aid-jsfa936>3.0.co;2-j

✦ Synopsis

The aim of this work was to elucidate the mode of action of calcium in calcium-inhibited ethylene biosynthesis. In one experiment, mature green tomatoes were treated with 1É5% (w/v) N-6(aminohexyl)-1-naphthalene-CaCl 2 ] 60 lM sulphonamide (W5). 1É5% (w/v) N-6(aminohexyl)-5-chloro-1-CaCl 2 ] 60 lM naphthalenesulphonamide (W7), 1É5% (w/v) alone or distilled water CaCl 2 (control). The control and the W7 treatment had much higher ethylene production than either the treatment alone or the treatment. In CaCl 2 CaCl 2 ] W5 another experiment, similar tomatoes were treated with 1É5% (w/v) CaCl 2 ] 15 lM triÑuoperazine (TFP). 1É5% (w/v) only, or distilled water (control). CaCl 2 The treatment with 1É5% TFP gave higher ethylene production CaCl 2 ] 15 lM than 1É5% (w/v)

without TFP, and nearly the same level as the control CaCl 2 towards the end of the experimental period. For enzyme and intermediate metabolite assays, mature green tomatoes were treated with 1É5% (w/v) CaCl 2 plus either W5 or W7. W5 treatment had a lower ethylene forming enzyme (EFE) activity, higher 1-aminocyclopropane-1-carboxylic acid (ACC) concentration, similar levels of ACC synthase activity and 1-(malonylamino)-cyclopropane-1carboxylic acid concentration, compared to the control and W7 treatment. As W7 is a more potent calmodulin antagonist than W5, these results suggest a calcium-calmodulin inactivation of EFE activity.

1998 SCI.