Environmental stress sensitivity of an ascorbic acid-deficient Arabidopsis mutant.
AUTOR(ES)
Conklin, P L
RESUMO
L-ascorbic acid (vitamin C) is a powerful reducing agent found in millimolar concentrations in plants, and is proposed to play an important role in scavenging free radicals in plants and animals. However, surprisingly little is known about the role of this antioxidant in plant environmental stress adaptation or ascorbate biosynthesis. We report the isolation of soz1, a semi-dominant ozone-sensitive mutant that accumulates only 30% of the normal ascorbate concentration. The results of genetic approaches and feeding studies show that the ascorbate concentration affects foliar resistance to the oxidizing gas ozone. Consistent with the proposed role for ascorbate in reactive oxygen species detoxification, lipid peroxides are elevated in soz1, but not in wild type following ozone fumigation. We show that the soz1 mutant is hypersensitive to both sulfur dioxide and ultraviolet B irradiation, thus implicating ascorbate in defense against varied environmental stresses. In addition to defining the first ascorbate deficient mutant in plants, these results indicate that screening for ozone-sensitive mutants is a powerful method for identifying physiologically important antioxidant mechanisms and signal transduction pathways. Analysis of soz1 should lead to more information about the physiological roles and metabolism of ascorbate.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=38539Documentos Relacionados
- Deoxyribonucleic acid-deficient strains of Candida albicans.
- Potential of hydrogen (pH) differentially modulates cadmium stress response in abscisic acid-deficient sitiens tomato mutant
- Uncoupling the Effects of Abscisic Acid on Plant Growth and Water Relations. Analysis of sto1/nced3, an Abscisic Acid-Deficient but Salt Stress-Tolerant Mutant in Arabidopsis1
- Accumulation of Zeaxanthin in Abscisic Acid-Deficient Mutants of Arabidopsis Does Not Affect Chlorophyll Fluorescence Quenching or Sensitivity to Photoinhibition in Vivo.
- Characterization of a Bacillus subtilis Thermosensitive Teichoic Acid-Deficient Mutant: Gene mnaA (yvyH) Encodes the UDP-N-Acetylglucosamine 2-Epimerase