title: Transcriptome changes associated with delayed flower senescence on transgenic petunia by inducing expression of etr1-1, a mutant ethylene receptor.
abstract: 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.
authors.affiliation: Institute of Horticulture, Jiangsu Academy of Agricultural Sciences, Nanjing, China.
authors.forename: Hong
authors.initials: H
authors.lastname: Wang
authors.forename: Genevieve
authors.initials: G
authors.lastname: Stier
authors.forename: Jing
authors.initials: J
authors.lastname: Lin
authors.forename: Gang
authors.initials: G
authors.lastname: Liu
authors.forename: Zhen
authors.initials: Z
authors.lastname: Zhang
authors.forename: Youhong
authors.initials: Y
authors.lastname: Chang
authors.forename: Michael S
authors.initials: MS
authors.lastname: Reid
authors.forename: Cai-Zhong
authors.initials: CZ
authors.lastname: Jiang
mesh_terms: D003907:Dexamethasone / Q000494:pharmacology; D005030:Ethylenes / Q000096:biosynthesis; D035264:Flowers / Q000187:drug effects / Q000235:genetics* / Q000254:growth & development*; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D009154:Mutation; D032306:Petunia / Q000502:physiology*; D010641:Phenotype; D010940:Plant Proteins / Q000235:genetics*; D030821:Plants, Genetically Modified; D011956:Receptors, Cell Surface / Q000235:genetics*; D015203:Reproducibility of Results; D059467:Transcriptome
chemical_list: D005030:Ethylenes; D010940:Plant Proteins; D011956:Receptors, Cell Surface; C083750:ethylene receptors, plant; D003907:Dexamethasone; C036216:ethylene