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Plant senescence is regulated by a coordinated genetic program mediated in part by changes in ethylene, abscisic acid (ABA), and cytokinin content. Transgenic plants with delayed senescence are useful for studying interactions between these signaling mechanisms. Expression of ipt, a cytokinin biosynthetic gene from Agrobacterium tumefaciens, under the(More)
To investigate ethylene's role in petal senescence, a comparative analysis of age-related changes in total protein, protease activity, and the expression of nine cysteine protease genes in the corollas of ethylene-sensitive Petuniaxhybrida cv. Mitchell Diploid (MD) and ethylene-insensitive (35S:etr1-1; line 44568) transgenic petunias was conducted. The(More)
BACKGROUND Although numerous factors can influence gene expression, promoters are perhaps the most important component of the regulatory control process. Promoter regions are often defined as a region upstream of the transcriptional start. They contain regulatory elements that interact with regulatory proteins to modulate gene expression. Most genes possess(More)
The senescence of carnation (Dianthus caryophyllus L.) flower petals is regulated by the phytohormone ethylene and is associated with considerable catabolic activity including the loss of protein. In this paper we present the molecular cloning of a cysteine proteinase and show that its expression is regulated by ethylene and associated with petal(More)
Virus-induced gene silencing (VIGS) is used to down-regulate endogenous plant genes. VIGS efficiency depends on viral proliferation and systemic movement throughout the plant. Although tobacco rattle virus (TRV)-based VIGS has been successfully used in petunia (Petunia × hybrida), the protocol has not been thoroughly optimized for efficient and uniform gene(More)
Personality profiles and the motivations for seeking orthodontic treatment were investigated in a sample of adult patients. An improvement in dental esthetics was found to be the prime motivating factor, and the decision to seek treatment was usually made by the adult patients themselves. Questionnaires to assess personality traits revealed an atypical(More)
Alpha-galactosidase (alpha-Gal; EC is involved in many aspects of plant metabolism, including hydrolysis of the alpha-1,6 linkage of raffinose oligosaccharides during deacclimation. To examine the relationship between endogenous sugars and freezing stress, the expression of alpha-Gal was modified in transgenic petunia (Petunia x hybrida cv(More)
Senescence represents the last phase of petal development during which macromolecules and organelles are degraded and nutrients are recycled to developing tissues. To understand better the post-transcriptional changes regulating petal senescence, a proteomic approach was used to profile protein changes during the senescence of Petuniaxhybrida 'Mitchell(More)
The programmed senescence of flower petals has been shown to involve the fragmentation of nuclear DNA. Nuclear DNA fragmentation, as determined by the TUNEL assay, was detected in Petunia x hybrida corollas during both pollination-induced and age-related senescence. DNA fragmentation was detected late in the lifespan of the flower when corollas were wilting(More)
The programmed degradation of macromolecules during petal senescence allows the plant to remobilize nutrients from dying to developing tissues. Ethylene is involved in regulating the timing of nucleic acid degradation in petunia, but it is not clear if ethylene has a role in the remobilization of phosphorus during petal senescence. To investigate ethylene's(More)