Senescence-specific alteration of hydrogen peroxide levels in Arabidopsis thaliana and oilseed rape spring variety Brassica napus L. cv. Mozart.
In order to analyze the signaling function of hydrogen peroxide (H(2)O(2)) production in senescence in more detail, we manipulated intracellular H(2)O(2) levels in Arabidopsis thaliala (L.) Heynh by using the hydrogen-peroxide-sensitive part of the Escherichia coli transcription regulator OxyR, which was directed to the cytoplasm as well as into the peroxisomes. H(2)O(2) levels were lowered and senescence was delayed in both transgenic lines, but OxyR was found to be more effective in the cytoplasm. To transfer this knowledge to crop plants, we analyzed oilseed rape plants Brassica napus L. cv. Mozart for H(2)O(2) and its scavenging enzymes catalase (CAT) and ascorbate peroxidase (APX) during leaf and plant development. H(2)O(2) levels were found to increase during bolting and flowering time, but no increase could be observed in the very late stages of senescence. With increasing H(2)O(2) levels, CAT and APX activities declined, so it is likely that similar mechanisms are used in oilseed rape and Arabidopsis to control H(2)O(2) levels. Under elevated CO(2) conditions, oilseed rape senescence was accelerated and coincided with an earlier increase in H(2)O(2) levels, indicating that H(2)O(2) may be one of the signals to inducing senescence in a broader range of Brassicaceae.
ZMBP (Center for Plant Molecular Biology), University of Tübingen, Auf der Morgenstelle 28, 72076 Tübingen, Germany.
Stefan
S
Bieker
Lena
L
Riester
Mark
M
Stahl
Jürgen
J
Franzaring
Ulrike
U
Zentgraf
D017360:Arabidopsis / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000235:genetics; D060387:Ascorbate Peroxidases / Q000378:metabolism; D029688:Brassica napus / Q000502:physiology*; D002374:Catalase / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000235:genetics; D017343:Genes, Plant; D006861:Hydrogen Peroxide / Q000378:metabolism*; D012097:Repressor Proteins / Q000235:genetics; D014157:Transcription Factors / Q000235:genetics
D029681:Arabidopsis Proteins; D029968:Escherichia coli Proteins; C552546:GBF1 protein, Arabidopsis; D012097:Repressor Proteins; D014157:Transcription Factors; C499299:oxyR protein, E coli; D006861:Hydrogen Peroxide; D060387:Ascorbate Peroxidases; D002374:Catalase