The isolation and analysis of OSAG243, an Oncidium senescence-associated gene
Date Issued
2006
Date
2006
Author(s)
King, Yu-Chi
DOI
zh-TW
Abstract
The cutting-flower of Onicidium Gower Ramsey is the most important export flowers in Taiwan. However, the vase life of the onicidium cutting-flower is not long enough for better economical value. Therefore, how to delay the senescence of onicidium cutting-flower is the prior way to study. Our laboratory used several methods, including suppression subtractive hybridization, differential display, and protein 2D-PAGE, to isolate the senescence-associated genes (SAGs). OSAG243 is one of them, and results from real-time PCR revealed that OSAG243 is a senescence-associated gene. The full length cDNA of OSAG243 was isolated using Rapid Amplification of cDNA Ends (RACE). After OSAG243 was compared to database in NCBI, it showed that OSAG243 is a C3HC4-type RING finger protein. In order to understand the functions of OSAG243 in plant, Arabidopsis expressing OSAG243 driven by 35S promoter or AGL5 promoter was constructed. In terms of phenotype and dark-induced senescence, no significant difference between wild-type and transgenic Arabidopsis was observed. Surprisingly, the flowering time of At243RNAi and Arabidopsis with T-DNA insertion in At243 gene is seven days earlier than that of wild-type Arabidopsis. Semi-quantitative RT-PCR indicated that depression of FLC caused the early flowering phenotype. The chlorophyll content of 40-day-old At243 T-DNA insertion line was lower than that of wild-type Arabidopsis. It indicated that At243 T-DNA insertion line might be senescent earliler than wild-type Arabidopsis. Westren blot results indicated that knocking out At243 in Arabidopsis caused lower level of methylation in histone H3, and it would down-regulate the expression of FLC. Conclusively, overexpression of OSAG243, a RING finger protein, may not affect the physiological functions of Arabidopsis. However, knocking out the At243 in Arabidopsis may decrease methylation level of histone H3 and down-regulate the expression of FLC, and finally influence the timing of flowering.
Subjects
老化
Oncidium
senescence
Type
other
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