Expression of genes for ethylene biosynthetic enzymes and anethylene receptor in senescing flowers of miniature potted roses

Abstract

SummaryExpression of genes for the ethylene biosynthetic enzymes ACC oxidase and ACC synthase, and the gene for a putative ethylene receptor, termed RhETR, in miniature roses (Rosa hybrida) were examined during flower senescence of the long-lasting cv. Vanilla and cv. Bronze, which has a short flower life. The abundance of ACC oxidase transcript increased during the late stages of flower development in petals of both cultivars, being higher for `Bronze' than for `Vanilla'. The ACC synthase transcript increased during flower senescence in `Vanilla' but remained constant at a low level in `Bronze'. The expression of RhETR was distinctly higher in the cultivar with short flower life (`Bronze') than in the long-lasting cultivar (`Vanilla'), and modulation of receptor levels was also observed during flower development. Exposure to low ethylene concentrations resulted in an up-regulation of RhETR in flowers of both cultivars. Differences in the expression of the putative ethylene receptor of cultivars with short or long flower life suggest that variation in flower longevity may be due to differences in receptor levels during flower development.