Institute of Horticulture, Jiangsu Academy of Agricultural Sciences, Nanjing, China.
PLoS One. 2013 Jul 9;8(7):e65800. doi: 10.1371/journal.pone.0065800. Print 2013.
Flowers of ethylene-sensitive ornamental plants transformed with ethylene-insensitive 1-1(etr1-1), a mutant ethylene receptor first isolated from Arabidopsis, are known to have longer shelf lives. We have generated petunia plants in which the etr1-1 gene was over-expressed under the control of a chemically-inducible promoter, which would allow expression of etr1-1 to be initiated at the desired time and stage of development. Here, we showed that transgenic plants grew and developed normally without a chemical inducer. Semi-quantitative RT-PCR demonstrated that the abundance of transcripts of Arabidopsis etr1-1 gene was substantially induced in flowers with 30 μM dexamethasone (DEX). Consequently, t he life of the flowers was almost doubled and the peak of ethylene production was delayed. We compared gene expression changes of petals with DEX to those without DEX at 24 h and 48 h by microarray. Our results indicated that transcripts of many putative genes encoding transcription factors were down-regulated by etr1-1 induced expression at the early stage. In addition, putative genes involved in gibberellin biosynthesis, response to jasmonic acid/gibberellins stimulus, cell wall modification, ethylene biosynthesis, and cell death were down-regulated associating with etr1-1 induced expression. We investigated time-course gene expression profiles and found two profiles which displayed totally opposite expression patterns under these two treatments. In these profiles, 'the regulation of transcription' was predominant in GO categories. Taking all results together, we concluded those transcription factors down-regulated at early stage might exert a major role in regulating the senescence process which were consequently characterized by cell wall modification and cell death.
用乙烯不敏感的 1-1（etr1-1）转化的乙烯敏感观赏植物的花朵，etr1-1 是从拟南芥中首先分离出来的一种突变乙烯受体，其货架期已知较长。我们已经生成了在化学诱导启动子控制下过表达 etr1-1 基因的矮牵牛植物，这将允许在所需的时间和发育阶段启动 etr1-1 的表达。在这里，我们表明，没有化学诱导剂，转基因植物也能正常生长和发育。半定量 RT-PCR 表明，用 30 μM 地塞米松（DEX）处理后，拟南芥 etr1-1 基因的转录本丰度显著增加。因此，花朵的寿命几乎延长了一倍，乙烯的产生高峰也延迟了。我们通过微阵列比较了有 DEX 和没有 DEX 的花瓣在 24 小时和 48 小时的基因表达变化。我们的结果表明，许多假定的转录因子编码基因的转录本在早期阶段通过 etr1-1 诱导表达而被下调。此外，与 etr1-1 诱导表达相关，参与赤霉素生物合成、对茉莉酸/赤霉素刺激的反应、细胞壁修饰、乙烯生物合成和细胞死亡的假定基因也被下调。我们研究了时间过程基因表达谱，发现这两种处理下的两个谱显示出完全相反的表达模式。在这些图谱中，“转录调控”在 GO 类别中占主导地位。综合所有结果，我们得出结论，早期下调的这些转录因子可能在调节细胞壁修饰和细胞死亡的衰老过程中发挥主要作用。
