Expression of etr1-1 gene in transgenic Rosa hybrida L. increased postharvest longevity through reduced ethylene biosynthesis and perception

The present research aimed to scrutinize the role of Arabidopsis etr1-1 gene in ethylene sensitivity of two cut roses, namely the etr1-1 mutated transgenic (TR) and wild type lines of Rosa hybrida L. cv. Vendetta. The cut roses were treated either by exogenous 1.2 mu g L-1 ethylene or 80 mg L-1 gibberellic acid (GA(3)) at commercial bud stage. The postharvest longevity, contents of peroxide and phenolics, ethylene production, and expression of ethylene signal transduction genes (RhETR1,2,3,4,5 and RhCTR1,2) were measured in both treated and control samples of the wild type and TR lines at both bud and half-open stages. The TR rose lines were not fully insensitive to ethylene and only showed less ethylene induced oxidative stress and flower senescence. The GA(3)-treated TR lines showed the highest vase life (22 d) mainly because of increasing the contents of total phenols and decreasing the ethylene synthesis. The cut roses showed a significant expression of RhETR2,4,5 genes upon GA(3) treatment and the expression of RhETR1,3 and RhCTR1,2 genes upon ethylene exposure. The ert1-1 mutation of the rose decreased both endogenous ethylene biosynthesis and perception.