Senescence and Gene Expression of Transgenic Non-ethylene-producing Carnation Flowers.

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2,4-Pyridinedicarboxylic acid (PDCA) is a structural analog of 2-oxoglutarate and has been shown to inhibit 2-oxoglutarate-dependent dioxygenases by competing with 2-oxoglutarate, and ethylene production in detached carnation flowers by competing with ascorbate on 1-aminocyclopropane-1-carboxylate (ACC) oxidase action. In the present study, the inhibition of ACC oxidase action by PDCA was confirmed with a recombinant enzyme produced in Escherichia coli from carnation DcACO1 cDNA. PDCA had various effects on ethylene production in cut 'Light Pink Barbara (LPB)' carnation flowers; ethylene production was accelerated or delayed in some flowers, whereas it did not change in others as compared to untreated control flowers. This varied action of PDCA may be caused by its possible combined actions; that is, inhibition of ACC oxidase action as well as its action on unidentified biochemical processes which use 2-oxoglutarate as a co-substrate, such as the biosynthesis and inactivation of gibberellins. Meanwhile, PDCA treatment significantly prolonged the vase life of bunches of cut 'LPB' carnation flowers; the magnitude of the extension of vase life was 53, 111, and 135% at 0.3, 1, and 2 mM PDCA, respectively, as compared with the non-treated control. Also, PDCA lengthened the vase life of 'Mule' carnation flowers. The present findings suggest the potential of PDCA as a preservative for cut flowers of spray carnations.

Section: Determination Of the Vase Life By Observing The Number Of Opmentioning

confidence: 99%

2,4-Pyridinedicarboxylic Acid Prolongs the Vase Life of Cut Flowers of Spray Carnations

Satoh

Kosugi

Sugiyama

et al. 2014

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“…Previously, it was demonstrated that ethylene production in carnation flowers was suppressed by transformation with the sACO transgene, DC-ACO1 cDNA in sense orientation. Kosugi et al (2002) suggested that the sACO transgene inhibited ethylene production in the flowers by cosuppression of expression of endogenous DC-ACO1 gene in flower tissues. On the analogy of the action of sACO transgene, we speculate that sACS transgene inhibits the expression of endogenous DC-ACS1 gene in 16-0-66 flower tissues by cosuppression.…”

Section: Resultsmentioning

confidence: 99%

Repressed Expression of DC-ACS1 Gene in a Transgenic Carnation Supports the Role of its Expression in the Gynoecium for Ethylene Production in Senescing Flower

茂¹,

慶介²

2006

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DC-ACS1 is a gene for 1-aminocyclopropane-1-carboxylate (ACC) synthase which is expressed slightly in the gynoecium, but abundantly in petals of carnation (Dianthus caryophyllus L.) flowers. It is known that ethylene evolved from the gynoecium triggers the expression of DC-ACS1 and DC-ACO1 (the gene for carnation ACC oxidase), which results in an abundant ethylene production in petals. In a transgenic carnation (16-0-66 line) transformed with DC-ACS1 cDNA in sense orientation, the exogenous ethylene treatment caused the expression of DC-ACO1 in the gynoecium and petals, but not that of DC-ACS1. This suggests that the cosuppression of the expression of endogenous DC-ACS1 gene by the integrated transgene. DC-ACS1 transcript is absent in both gynoecium and petals of senescing 16-0-66 flowers, so that the flowers produce no ethylene; whereas DC-ACO1 transcript is present in the gynoecium but absent in the petals. These findings give further support on the role of the DC-ACS1 gene in the gynoecium for ethylene production by petals in senescing carnation flowers.

“…Savin et al (1995) reported that the vase life of carnation flowers was extended by the introduction of an antisense ACC oxidase gene; the transgenic plants had a vase life of 8 to 9 days at 21°C. Similarly, Kosugi et al (2002) reported that cut flowers of a transgenic carnation line (the sACO-1 line), which was transformed by using a carnation ACC oxidase cDNA in the sense orientation, had a longer vase life than had flowers of the non-transformed plants. Cut flowers of the sACO-1 line had a vase life of 9.5 days, versus 5.8 days for the non-transformed control line at 23°C.…”

Section: Discussionmentioning

confidence: 99%

Breeding of Carnations (Dianthus caryophyllus L.) for Long Vase Life and Rapid Decrease in Ethylene Sensitivity of Flowers after Anthesis

Onozaki¹,

Tanikawa²,

Yagi³

et al. 2006

Genetic improvement of flower vase life is an important breeding target. A breeding program aimed to improve the vase life of carnations (Dianthus caryophyllus L.) that carried out by repeatedly crossing and selecting promising progenies was effective. Thus, we developed many carnation lines with extremely long vase life by using the conventional cross-breeding technique. Selected lines from second-, third-and fourthgeneration have vase lives that are 2.7 to 4.1 times longer than the control cultivar, 'White Sim'. The mean vase life of line 108-44 was 23.6 days in 2003 and 19.1 days in 2004 (414% and 341% of 'White Sim' flower longevity, respectively). All selected lines showed low ethylene production in whole flowers during senescence. In addition, the petals and the gynoecia of three selected lines 908-46, 702-21, and 006-13, produced only trace amounts of ethylene during senescence, indicating that the ethylene biosynthesis pathway in these lines was almost completely blocked during senescence. Although ethylene sensitivity of the selected lines was generally high on day 0, immediately after harvesting, ethylene sensitivity after anthesis rapidly decreased with age in the three selected lines. These lines became completely ethylene-insensitive or showed low sensitivity at the end of senescence. Autocatalytic ethylene production by the gynoecia and petals of the three selected lines also decreased on days 3 and 6, respectively, after harvest.