Expression of ethylene biosynthetic and receptor genes in rose floral tissues during ethylene-enhanced flower opening

Abstract

Ethylene production, as well as the expression of ethylene biosynthetic (Rh-ACS1–4 and Rh-ACO1) and receptor (Rh-ETR1–5) genes, was determined in five different floral tissues (sepals, petals, stamens, gynoecia, and receptacles) of cut rose (Rosa hybrida cv. Samantha upon treatment with ethylene or the ethylene inhibitor 1-methylcyclopropene (1-MCP). Ethylene-enhanced ethylene production occurred only in gynoecia, petals, and receptacles, with gynoecia showing the greatest enhancement in the early stage of ethylene treatment. However, 1-MCP did not suppress ethylene production in these three tissues. In sepals, ethylene production was highly decreased by ethylene treatment, and increased dramatically by 1-MCP. Ethylene production in stamens remained unchanged after ethylene or 1-MCP treatment. Induction of certain ethylene biosynthetic genes by ethylene in different floral tissues was positively correlated with the ethylene production, and this induction was also not suppressed by 1-MCP. The expression of Rh-ACS2 and Rh-ACS3 was quickly induced by ethylene in gynoecia, but neither Rh-ACS1 nor Rh-ACS4 was induced by ethylene in any of the five tissues. In addition, Rh-ACO1 was induced by ethylene in all floral tissues except sepals. The induced expression of ethylene receptor genes by ethylene was much faster in gynoecia than in petals, and the expression of Rh-ETR3 was strongly suppressed by 1-MCP in all floral tissues. These results indicate that ethylene biosynthesis in gynoecia is regulated developmentally, rather than autocatalytically. The response of rose flowers to ethylene occurs initially in gynoecia, and ethylene may regulate flower opening mainly through the Rh-ETR3 gene in gynoecia.

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

“…Flowers were separated into five distinct parts: sepals, petals, stamens, gynoecia, and receptacles. Total RNA of sepals, petals, stamens, and receptacles was extracted using the hot borate method described by Ma et al (2005), and total RNA from gynoecia was extracted using the hot phenol method described by Xue et al (2008). We purified mRNA from total RNA using an Oligotex mRNA Purification Kit (Qiagen).…”

“…Total RNAs were isolated from rose petals under the cyclic dehydration process as well as under control conditions following the procedures described by Xue et al (2008). cDNAs were synthesized from 1 mg of total RNA using Moloney murine leukemia virus reverse transcriptase (Promega).…”

“…are the most important ornamental plants worldwide, and cut roses account for about 21% and 31% of all cut flowers traded in China and at the European auctions, respectively (Heinrichs, 2008). Commercially, roses are usually harvested at the open bud stage and are extremely susceptible to WDS during postharvest handling; WDS causes abnormal flower opening, flower wilting, wilting of the pedicel (bent neck), and failure to open (Jin et al, 2006;Xue et al, 2008). The effect of dehydration on flower opening and senescence in cut roses, therefore, has been studied at the physiological and biochemical levels for several decades (Kumar et al, 2008).…”

Role of ethylene receptors during senescence and ripening in horticultural crops

“…This confirmed that ethylene regulates flower opening of roses through signaling pathway and not through biosynthetic pathway. It 128 showed that ethylene enhanced both ethylene production and the expression of Rh-ACS2 or Rh-ACS3 in gynoecia, petals, and receptacles, with gynoecia showing the earliest ethylene enhancement. However, 1-MCP did not suppress ethylene production and the expression of the ethylene biosynthetic genes in these three tissues.…”

Flower senescence: some molecular aspects

“…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). Similar observations have also been reported in carnation, where CARAS1 (also named as DCASC2) showed a quicker and stronger response to ethylene treatment in gynoecia than in petals (Have and woltering 1997).…”