Cloning of an Expansin Gene from Chimonanthus praecox Flowers and Its Expression in Flowers Treated with Ethephon or 1-Methylcyclopropene

Abstract

<jats:p>Expansins are extracellular proteins that are involved in cell wall modifications such as cell wall disassembly, cell separation, and cell expansion. Little is known about expansin gene expression during flower development of wintersweet (<jats:italic>Chimonanthus praecox</jats:italic>). In the present study, an expansin gene, <jats:italic>CpEXP1</jats:italic>, was isolated from the wintersweet flower cDNA library through random sequencing; this gene encodes a putative protein of 257 amino acids with the essential features conserved, like in other alpha expansins. The <jats:italic>CpEXP1</jats:italic> gene exhibited different transcription levels in different tissues and had a significantly higher expression in flowers than other tissues. It is strongly correlated with the development of the flower. The expression of <jats:italic>CpEXP1</jats:italic> increased in the flower buds or whole flowers from Stage 1 to 4 and decreased from Stage 5 to 6 during natural opening. Ethephon (an ethylene releaser) treatment promoted cut flower senescence, whereas 1-methylcyclopropene (1-MCP) (an ethylene perception inhibitor) delayed the process of flower wilting. This result is associated with the concomitant lower transcript levels of <jats:italic>CpEXP1</jats:italic> in the ethephon-treated samples as well as the steady expression in the 1-MCP-treated samples compared with that in control flowers. The studies show the interesting observation that the expression of an expansin gene <jats:italic>CpEXP1</jats:italic> is correlated with the development of <jats:italic>Chimonanthus praecox</jats:italic> flowers, the upregulation during flower opening vs. the downregulation during senescence.</jats:p>

Effects of Hormone Treatments on Cut Flower Opening and Senescence in Wintersweet (Chimonanthus praecox)

“…In wintersweet, however, previous research detected no obvious production of ethylene from the flowers during flower development (Sheng et al, 1999). On the other hand, it has been reported that ethephon treatment of wintersweet cut flowers can accelerate the process of flower opening (Ma et al, 2012). We previously measured ethylene production of wintersweet flowers at different stages.…”

“…In wintersweet, the role of exogenous ethylene in cut flower senescence is still unclear since conflicting results have been reported in the past (Ma et al, 2012;Sheng et al, 1999). The cytokinin 6-BA has been reported to be involved in the postharvest management of cut wintersweet flowers (Guo and He, 2004).…”

Transcriptomic analysis of flower opening response to relatively low temperatures in Osmanthus fragrans

“…Therefore, we screened the DEGs which may be involved in the cell wall metabolism under different temperatures. EXP and XTH are involved in cell expansion, loosening and rearranging the cell wall bers in growing tissues [8], which are up-regulated during oral open process in sandersonia [28], Mirabilis jalapa [29], petunia [9], carnation [30], and wintersweet [10]. In cucumber, EXPs consist of four sub families: α-EXP, β-EXP, EXP-like A and EXP-like B and were rst discovered to loosen cell walls in pH dependent manner [31].…”

“…Among them, EXP and XTH particularly participate in disrupting the non-covalent bonds between the cellulose micro brils and the cross-linking glycans of the cell wall to increase the cell-wall creep rate, while pectinase and endo-1,4β-D-glucanase can degrade the cell wall [9]. In wintersweet (Chimonanthus praecox), the expressions of EXP genes increase during ower opening [10]. The developing petals of carnation show high activities of cellulase and pectin esterase [11].…”

Isolation and Characterization of plant TAF9, an Orthologous Gene for TATA Binding Protein Associated Factor 9, from Wintersweet (Chimonanthus praecox)

“…A PrimeScript RT Reagent Kit with gDNA Eraser (TaKaRa Bio) was used to reverse transcribe equal amounts of DNA-free RNA (5 mg) from different tissues into cDNA. Real-time polymerase chain reaction (RT-PCR) was carried out according to Ma et al (2012). The relative transcript abundance was calculated with the genes for tubulin and actin (Sui et al 2012).…”