Simultaneous Inhibition of Ethylene Biosynthesis and Binding Using AVG and 1-MCP in Two Rose Cultivars with Different Sensitivities to Ethylene

Abstract

The primary factors that determine the longevity of cut roses are variable and depend on a cultivar’s sensitivity to ethylene. The vase life of ethylene-sensitive cultivars (SENS) is shortened by ethylene synthesis, while for ethylene-insensitive cultivars (INSENS) it is strongly related to water stress. In this study, we determined the effect of ethylene binding on the change in ethylene sensitivity in two rose cultivars with different sensitivities to the hormone. In addition, we determined the effects of ethylene binding and synthesis inhibition on flower senescence and gene expression using 1-methylcyclopropene (1-MCP) and aminoethoxyvinylglycine (AVG). The relationship between the mRNA levels of ethylene biosynthesis, receptor, and signaling genes and the degree of ethylene sensitivity was determined during flower development and senescence. The results showed that simultaneous treatment with AVG and 1-MCP effectively improved water balance, maintained leaf chlorophyll fluorescence ratios, and consequently extended the vase life of cut flowers for both SENS and INSENS cultivars. The results also revealed that the expression of the ethylene biosynthesis (RhACS2 and RhACO1) genes in cut roses was effectively suppressed by simultaneous treatments with both AVG and 1-MCP. The ethylene-induced induction of RhETR1-5 transcript levels and the degradation of RhCTR1-2 were both repressed by AVG and 1-MCP treatments; consequently, RhEIN3s transcripts were greatly inhibited in both SENS and INSENS cultivars. The findings from the current study revealed that a simultaneous inhibition of ethylene binding and synthesis suppressed plant responses to ethylene and consequently extended the vase life for cut rose flowers in both ethylene-sensitive and ethylene-insensitive cultivars.