Exogenous Eethylene influences flower opening of cut roses (Rosa hybrida) by regulating the genes encoding ethylene biosynthesis enzymes

Abstract

The purpose of this paper is to investigate the differential responses of flower opening to ethylene in two cut rose cultivars, 'Samantha', whose opening process is promoted, and 'Kardinal', whose opening process is inhibited by ethylene. Ethylene production and 1-aminocyclopropane-1-carboxylate (ACC) synthase and oxidase activities were determined first. After ethylene treatment, ethylene production, ACC synthase (ACS) and ACC oxidase (ACO) activities in petals increased and peaked at the earlier stage (stage 3) in 'Samantha', and they were much more dramatically enhanced and peaked at the later stage (stage 4) in 'Kardinal' than control during vasing. cDNA fragments of three Rh-ACSs and one Rh-ACO genes were cloned and designated as Rh-ACS1, Rh-ACS2, Rh-ACS3 and Rh-ACO1 respectively. Northern blotting analysis revealed that, among three genes of ACS, ethylene-in- duced expression patterns of Rh-ACS3 gene corresponded to ACS activity and ethylene production in both cultivars. A more dramatic accumulation of Rh-ACS3 mRNA was induced by ethylene in 'Kardinal' than that of 'Samantha'. As an ethylene action inhibitor, STS at concentration of 0.2 mmol/L generally inhibited the expression of Rh-ACSs and Rh-ACO in both cultivars, although it induced the expression of Rh-ACS3 transiently in 'Kardinal'. Our results suggests that 'Kardinal' is more sensitive to ethylene than 'Samantha'; and the changes of Rh-ACS3 expression caused by ethylene might be related to the acceleration of flower opening in 'Samantha' and the inhibition in 'Kardinal'. Additional results indicated that three Rh-ACSs genes were differentially associated with flower opening and senescence as well as wounding

An Ethylene-Induced Regulatory Module Delays Flower Senescence by Regulating Cytokinin Content

“…The opening process of cut rose flowers can be divided into six stages (Ma et al, 2005). The expression patterns of RhPR10.1 in all the floral organs, including sepal, stamen, pistil, petal, and receptacle, showed similar trends, with transcript levels increasing progressively from the partially opened flower bud (stage 1) to the onset of petal wilting (stage 6; Fig.…”

“…It is well known that ethylene promotes rose flower senescence (Ma et al, 2005), while CTKs delay the process (Mayak and Halevy, 1970;Lukaszewska et al, 1994). Here, we report that an ethyleneinduced rose PR-10 family gene, RhPR10.1, inhibits Figure 1.…”

“…Stems were then recut under water to 25 cm length and placed in vases with distilled water. The cut flower opening stages were defined as described previously (Ma et al, 2005). Floral organ samples were collected at different opening stages, and petal samples were collected from the same middle whorl of the flowers.…”

RhNAC2 and RhEXPA4 Are Involved in the Regulation of Dehydration Tolerance during the Expansion of Rose Petals

“…Flower-opening stages were defined as described by Ma et al (2005). The flowers were delivered to the laboratory within 1 h of harvest.…”

Flower senescence: some molecular aspects

“…Henskens et al (1994) has suggested that the gene might encode a non-functional enzyme; however, the positive correlation between CARAS1 abundance and stylar ethylene production during aging is indicative of the fact that CARAS1 does encode a functional enzyme (Have and woltering, 1997). Ma et al (2005) while studying the differential induction features of three ACS genes in roses found that Rh-ACS2 is strongly induced by senescence. The tissue specificity of Rh-ACS2 has been found to be quickly induced by ethylene in gynoecia (Xue et al 2008).…”