Cu/ZnSOD involved in tolerance to d

Cu/ZnSOD involved in tolerance to dehydration in cut rose
(Rosa hybrida)
Dehydration results in abnormal
flower opening and quality loss during the marketing of cut rose
flowers.
Our previous studies have revealed that changes in superoxide dismutase (SOD) activity are related to the
dehydration tolerance of cut roses. Here, we demonstrate that cut roses were adversely influenced by
dehydration conditions, which affected the normal
flower opening process, suppressing the increase in
flower diameter and shortening vase life. Pretreatment with sodium diethyldithiocarbamate (DDTC), an
inhibitor of Cu/ZnSOD activity, accelerated the adverse effects of dehydration on
flower opening quality.
Compared to
flowers placed in water continuously, in dehydrated
flowers superoxide anion (SOA)
production and SOD activities were enhanced during dehydration and decreased during subsequent
rehydration. DDTC pretreatment diminished SOA production and inhibited Cu/ZnSOD activities during
both dehydration and subsequent rehydration. Five SOD genes, RhMnSOD1,RhCu/ZnSOD1, RhCu/ZnSOD2,
RhCu/ZnSOD3 and RhFeSOD1, were isolated and their expression was analyzed in petals. Dehydration
reduced the expression of RhMnSOD1 and RhCu/ZnSOD1/2/3 genes; during rehydration, expression levels
recovered. DDTC pretreatment delayed the reduction and recovery of gene expression during
dehydration and rehydration, respectively. In conclusion, our results suggest that SOD enzymes,
especially Cu/ZnSODs, are involved in the dehydration tolerance of cut rose
flowers and that the
inhibition of Cu/ZnSOD activities may increase the expression of RhCu/ZnSOD genes in cut rose
flower
petals via a negative feedback mechanism.