Ethylene biosynthetic genes are differentially expressed during carnation (Dianthus caryophyllus L.) flower senescence.

TEN HAVE A AND WOLTERING EJ

PLANT MOLECULAR BIOLOGY

Año: 1997 vol. 34 p. 89 - 97

0167-4412

Ethylene production and expression patterns of an 1-aminocyclopropane-1-carboxylic acid (ACC) oxidase(CARAO1) and of two ACC synthase (EC 4.4.1.14) genes (CARACC3 and CARAS1) were studied in floralorgans of cut carnation flowers (Dianthus caryophyllus L.) cv. White Sim. During the vase life and after treatmentof fresh flowers with ethylene, production of ethylene and expression of ethylene biosynthetic genes first started inthe ovary followed by the styles and the petals. ACC oxidase was expressed in all the floral organs whereas, duringthe vase life, tissue-specific expression of the two ACC synthase genes was observed. After treatment with a highethylene concentration, tissue specificity of the two ACC synthase genes was lost and only a temporal difference inexpression remained. In styles, poor correlation between ethylene production and ACC synthase (CARAS1) geneexpression was observed suggesting that either activity is regulated at the translational level or that the CARAS1gene product requires an additional factor for activity.   Isolated petals showed no increase in ethylene production and expression of ethylene biosynthetic genes whenexcised from the flower before the increase in petal ethylene production (before day 7); showed rapid cessation ofethylene production and gene expression when excised during the early phase of petal ethylene production (day 7)and showed a pattern of ethylene production and gene expression similar to the pattern observed in the attachedpetals when isolated at day 8. The interorgan regulation of gene expression and ethylene as a signal molecule inflower senescence are discussed.