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The lack of alternative oxidase at low temperature leads to a disruption of the balance in carbon and nitrogen metabolism, and to an up‐regulation of antioxidant defence systems in Arabidopsis thaliana leaves
Author(s) -
WATANABE CHIHIRO K.,
HACHIYA TAKUSHI,
TERASHIMA ICHIRO,
NOGUCHI KO
Publication year - 2008
Publication title -
plant, cell and environment
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.646
H-Index - 200
eISSN - 1365-3040
pISSN - 0140-7791
DOI - 10.1111/j.1365-3040.2008.01834.x
Subject(s) - alternative oxidase , biochemistry , antioxidant , chemistry , arabidopsis thaliana , biology , mitochondrion , gene , mutant
Alternative oxidase (AOX) catalyses the ATP‐uncoupling cyanide (CN)‐resistant pathway. In this study, our aim was to clarify the physiological role of AOX at low temperature. We examined the effect of low‐temperature treatment on CN‐resistant respiration (CN‐resistant R) and on the transcription of respiratory components in wild‐type (WT) and aox1a knock‐out transgenic ( aox1a ) Arabidopsis thaliana plants. In WT leaves, the expression of AOX1a mRNA was strongly induced by the low‐temperature treatment, and thus CN‐resistant R increased during low‐temperature treatment. In aox1a , the CN‐sensitive respiration, and the expression of NDB2 and UCP1 were increased compared with WT. We compared several physiological parameters between WT and aox1a . Low‐temperature treatment did not result in a visible phenotype to distinguish aox1a from WT. In aox1a , several antioxidant defence genes were induced, and the malondialdehyde content was lower than in WT. Starch content and a ratio of carbon to nitrogen were higher in aox1a than in WT. Our results indicate that a lack of AOX was linked to a difference in the carbon and nitrogen balance, and an up‐regulation of the transcription of antioxidant defence system at low temperature. It is likely that AOX is a necessary component in antioxidant defence mechanisms and for the control of a balanced metabolism.