Expression and Regulation of Senescence-related Genes in Carnation Flowers with Low Ethylene Production during Senescence

Abstract

We investigated ethylene production, ethylene biosynthesis genes, and senescence-related genes in flowers of a carnation (Dianthus caryophyllus L.) cultivar 'Miracle Symphony' (MS) and lines 006-13 and 62-2, which have a longer vase life than flowers of 'White Sim' (WS). WS flowers showed typical symptoms of senescence, but flowers of MS, 006-13, and 62-2 did not show symptoms of senescence, although they showed differences in vase life and ethylene production by day 15. The flowers of 006-13 and 62-2 produced small amounts of ethylene as a result of the low expression of two ethylene biosynthesis genes, DcACS1 and DcACO1; those of MS produced extremely low levels of ethylene. By day 15, the flowers of 006-13 and 62-2 showed increased expression of some senescence-related genes (DcCP1, DcbGal, DcGST1, and DcLip) that were upregulated by exogenous ethylene, indicating that a low level of ethylene production could induce the senescence of petals. In contrast to the upregulation of these senescence-related genes, the expression of DcCPIn, which was downregulated by exogenous ethylene decreased in petals of MS, 006-13, and 62-2 during flower senescence and was the same in all three lines at day 15. The results suggest that extended vase life depends on reduced levels of ethylene production, ethylene biosynthesis gene expression, and senescence-related gene expression.

Expression levels of ethylene biosynthetic genes and senescence-related genes in carnation (Dianthus caryophyllus L.) with ultra-long-life flowers

“…This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/3.0/). (Onozaki et al, 2006;Tanase et al, 2008Tanase et al, , 2013, which have a life of 10-20 days. The expression of DcACS1, but not DcACO1, is low throughout the flower life in 'White Candle' (Nukui et al, 2004).…”

Regulation of Ethylene- and Senescence-related Genes in Pot Carnation Flowers during Flower Senescence

“…For example, the expression of ethylene biosynthesis genes DcACS1 and DcACO1 was reduced in the flowers of the long-flower-life cultivars 'Miracle Rouge' and 'Miracle Symphony', whereas expression of DcACS1 (but not DcACO1) was reduced in the flowers of 'White Candle' (Nukui et al, 2004;Tanase et al, 2008). Expression of DcACS1 and DcACO1 is also low in other long-life breeding cultivars and lines, including line 532-6, which is the progeny of full-sib lines of 'Miracle Rouge' (Tanase et al, 2013. In the present study, we compared flower longevity, and examined both ethylene production and expression of DcACS1 and DcACO1 in flowers of several pot carnation cultivars.…”

“…The DcCP1, DcGST1, and DcbGal which lead to cell death during senescence of petals, were previously thought to be related to the induction of inrolling (Hong et al, 2000;Jones et al, 1995;Kosugi et al, 2000). However, recent research has shown that they are upregulated during senescence regardless of whether inrolling is observed (Otsu et al, 2007;Tanase et al, 2013). Exogenous ethylene treatment for 12 h upregulated these genes in the cultivars with low ethylene sensitivity (Fig.…”

“…We used quantitative real-time PCR (qPCR) analysis to determine the expression of ethylene biosynthesis genes (DcACS1, DcACO1), SR genes (DcCP1, DcbGal, DcGST1), a DcCP1 inhibitor gene (DcCPIn), ER genes (DcETR1, DcERS1, DcERS2), and EIL genes (DcEIL1/2, DcEIL3, DcEIL4) in carnation flowers as described previously (Tanase et al, 2008(Tanase et al, , 2011(Tanase et al, , 2013. Gynoecium and petals were sampled on days 0, 3, and 5 in 'Ariel' and 'Orange Duo', on days 0, 3, and 6 in 'Lemon Soft', and on days 0, 3, 6, and 11 in 'Polaris'.…”

“…This downregulation of ethylene biosynthesis delayed upregulation of the senescence-related (SR) genes DcCP1, DcbGal, and DcGST1, which promote senescence, in the petals of long-life carnations (Tanase et al, 2013).…”