A combinatorial Interplay Among the ACC Synthase Isoforms Regulates Ethylene Biosynthesis in Arabidopsis thaliana
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ABSTRACT: ACC Synthase (ACS) is the key regulatory enzyme in the ethylene biosynthesis in plants. It catalyzes the conversion of s-adenosylmethionine (SAM) to 1-aminocyclopropane-1-carboxylic acid (ACC), the precursor of ethylene. Arabidopsis has nine ACS genes. The goal of the project is to inactivate each gene by insertional mutagenesis and amiRNA technology and eventually construct a null ACS mutant. We have been recently able to achieve this goal. Furthermore, we wanted to know how inactivation of individual ACS genes affects global gene expression. Keywords: ACS mutant comprrison; global gene expression.
Project description:ACC Synthase (ACS) is the key regulatory enzyme in the ethylene biosynthesis in plants. It catalyzes the conversion of s-adenosylmethionine (SAM) to 1-aminocyclopropane-1-carboxylic acid (ACC), the precursor of ethylene. Arabidopsis has nine ACS genes. The goal of the project is to inactivate each gene by insertional mutagenesis and amiRNA technology and eventually construct a null ACS mutant. We have been recently able to achieve this goal. Furthermore, we wanted to know how inactivation of individual ACS genes affects global gene expression. Keywords: ACS mutant comprrison; global gene expression. Triplicate samples of 10-day light grown seedling from each ACS mutant was used for microarray analysis.
Project description:ETR1 receptor mutants etr1-3 (loss-of-function) and etr1-7 (gain-of-function) were treated with either ethylene or its biosynthetic precursor, ACC (1-aminocyclopropane-1-carboxylate) for 0, 1, 4, and 24 hours.
Project description:The purpose of this experiment was to study the effects of a bacterial ACC deaminase transgene in the roots and its impact on nickel tolerance of canola. ACC deaminase breaks down 1-aminocyclopropane-1-carboxylic acid, the biosynthetic precursor to the plant hormone ethylene, lowering ethylene levels and improving plant tolerance to stress. Ethylene evolved during plant stress is thought to causes senescence and cell death and worsen stress symptoms. Transgenic plants expressing ACC deaminase from the plant growth-promoting bacteria Pseudomonas putida UW4 are more tolerant to heavy metals in the soil and this expression study helps to illuminate the pathways responsible for this tolerance.
Project description:The purpose of this experiment was to study the effects of the bacterial enzyme ACC deaminase on the transcriptional changes within canola seedlings. Seedlings from seeds treated with the plant growth-promoting bacteria Pseudomonas putida UW4 which expresses a high level of ACC deaminase and its ACC deaminase-minus mutant were compared to untreated seedlings along with a transgenic line of canola expressing the ACC deaminase enzyme in the roots. ACC deaminase breaks down 1-aminocyclopropane-1-carboxylic acid, the biosynthetic precursor to the plant hormone ethylene, lowering ethylene levels and improving plant fitness. Plants treated with the ACC deaminase-containing bacteria and transgenic plants expressing ACC deaminase are more tolerant to a variet of stresses and this expression study helps to illuminate the pathways responsible for the growth promotion provided by the beneficial bacteria and the role of the enzyme itself.
Project description:The goal of the experiments is to identify differential genes between the roots of Arabidopsis thaliana and roots treated for 3 h with 1-aminocyclopropane-1-carboxylic acid (ACC). ACC blocks the maximal cell elongation of the root cells. - Arabidopsis plants are grown for 5 days on MS medium and then we transfer them to a medium supplemented with ACC (5uM) or without ACC. After 3 h of growth, we isolate the RNA of the roots. Keywords: treated vs untreated comparison
Project description:The plant hormone ethylene is involved in plant developmental, stress and environmental signalling. The ethylene signalling pathway is modulated by the master transcription factor EIN3. Here we examined the involvement of proteasome-associated UPL3 and UPL4 ubiquitin ligases in ethylene-responsive gene expression. We reveal that in absence of functional UPL3 and UPL4, plants show constitutive and enhanced activation or repression of ethylene-responsive genes in an EIN3-dependent manner. Ten-day old Arabidopsis thaliana seedlings of wild-type Col-0, mutant upl3 upl4, mutant ein3-1, and mutant upl3 upl4 ein3-1 were grown on MS media in an environmental chamber with 16/8 hour day/night light regime (120 mol m-2 s-1 light intensity) and 22 degrees Celsius. Seedlings were then transferred to 6-well plates and floated on the surface of water or 50 uM 1-aminocyclopropane-1-carboxylic acid (ACC). After 3 hours seedlings were harvested and for each treatment ~50 seedlings were pooled together into a single biological repeat. In total three independent biological repeats were collected. After harvesting seedlings were briefly dried on tissue and immediately frozen in liquid nitrogen until further analysis.
Project description:Hormones effect various plant developmental processes by altering gene expression. The expression of several genes is regulated by plant hormones and many of these genes are regulated commonly and specifically by various hormones. We used microarrays to study the global effect of plant hormones on rice gene expression and identify the genes involved in operlapping and specific transcriptional responses. Rice seedlings of IR64 variety were grown hydroponically for 7-days in a culture room with a daily photoperiodic cycle of 14h light and 10h dark. Seedlings were incubated in water (control) or 50 µM solution of indole-3-acetic acid (auxin, IAA) and benzyl aminopurine (cytokinin, BAP) and 100 µM solution of abscisic acid (ABA), 1-aminocyclopropane-1-carboxylic acid (ethylene derivative, ACC), salicylic acid (SA) and jasmonic acid (JA) for 3h. The 5 micrograms of total RNA sample isolated from each tissue sample was processed for microarray analysis according to Affymetrix protocol. Two biological replicates for each sample (two controls, IAA, BAP, ABA, ACC, SA and JA) were used for microarray analysis.
Project description:Ethylene-dependent gene expression was assayed by treating with 1 uM ACC, an ethylene precursor, or a control treatment to Arabidopsis seedlings by transferring 6 day old Arabidopsis grown on a a nylon mesh to fresh ACC-containing or control media Seedling roots were harvested 0, .5, 1, 2, 4, 8, 12, and 24 hours after treatment and the resultant RNA was used for microarray analysis to determine the kinetic profiles of auxin-responsive gene expression
Project description:Arabidopsis plants are grown for 5 days on MS medium and then we transfer them to a medium supplemented with ACC (5uM) or without ACC. After 3 h of growth, we isolate the RNA of the roots.