The promoters of Arabidopsis thaliana genes AtCOX17-1 and -2, encoding a copper chaperone involved in cytochrome c oxidase biogenesis, are preferentially active in roots and anthers and induced by biotic and abiotic stress

CAROLINA V. ATTALLAH, ELINA WELCHEN AND DANIEL H. GONZALEZ

PHYSIOLOGIA PLANTARUM

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Lund; Año: 2007 vol. 129 p. 123 - 134

0031-9317

AtCOX17 genes encode Arabidopsis thaliana homologs of the yeast metallochaperone Cox17p, involved in the delivery of copper for cytochrome coxidase (COX) assembly. Two different AtCOX17 genes, located in chromosomes1 and 3, are present in the Arabidopsis genome. Sequences availablein data banks indicate that the presence of two genes is a common featurein monocots, but not in dicots, suggesting that Arabidopsis genes may be theresult of a recent duplication. Sequences upstream from the translation startsites of AtCOX17 genes, which include an intron located in the 5´ leaderregion, were introduced into plants in front of the gus gene. For both genes,expression was localized preferentially in young roots and anthers, but almost10-fold higher b-glucuronidase activity levels were observed in plantstransformed with AtCOX17-1 upstream regions. Both promoters were inducedto different extents by wounding, treatment of leaves with the bacterialpathogen Pseudomonas syringae and incubation with agents that produceoxidative stress and metals. AtCOX17-2 showed similar responses to thesefactors, while AtCOX17-1 was more strongly induced by relatively low(10–100 µM) copper. The results indicate that both AtCOX17 genes havesimilar, though not identical, expression characteristics and suggest theexistence in their promoters of elements involved in tissue-specific expressionand in responses to factors that may produce mitochondrial or cell damage.It can be speculated that Arabidopsis COX17 accumulates under stressconditions to actively replace damaged or inactive cytochrome c oxidase tosustain cyanide-sensitive respiration in plant cells.