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Effect of reduced arginine decarboxylase activity on salt tolerance and on polyamine formation during salt stress in Arabidopsis thaliana
Author(s) -
Kasinathan Vasuki,
Wingler Astrid
Publication year - 2004
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1111/j.0031-9317.2004.00309.x
Subject(s) - polyamine , arginine decarboxylase , biochemistry , chemistry , polyamine oxidase , mutant , wild type , arginine , arabidopsis thaliana , spermine , spermidine , enzyme , amino acid , gene
Polyamines have been suggested to play an important role in stress protection. However, attempts to determine the function of polyamines have been complicated by the fact that, dependent on the conditions, polyamine contents increase or decrease during stress. To determine the importance of polyamine formation during salt stress, we analysed polyamine contents and salt tolerance in two Arabidopsis thaliana mutants, spe1‐1 and spe2‐1 (Watson et al. Plant J 13: 231–239, 1998), with reduced activity of arginine decarboxylase (EC 4.1.1.19), an important enzyme in polyamine synthesis. Polyamines accumulated in wild‐type plants (Col‐0 and Ler‐0) that were pre‐treated with 100 m M NaCl before transfer to 125 m M NaCl, but not in plants that were directly transferred to 125 m M NaCl without prior treatment with 100 m M NaCl. This shows that polyamine accumulation depends on acclimation to salinity. The salt treatment that induced polyamine accumulation in wild‐type plants did not lead to polyamine accumulation in the spe1‐1 and spe2‐1 mutants. Decreased fresh weight, chlorophyll content and photosynthetic efficiency indicated that the spe1‐1 mutant was more severely affected by salt stress than its wild type, Col‐0. In the spe2‐1 mutant decreased salt tolerance compared to its wild type, Ler‐0, became apparent as bleaching under severe salt stress. The present results demonstrate that decreased polyamine formation due to lower arginine decarboxylase activity leads to reduced salt tolerance.