Engineered abiotic stress resistance is an important target for increasing agricultural productivity.There are concerns, however, regarding possible ecological impacts of transgenic crops. In contrast to the first wave of transgenic crops, many abiotic stress resistance genes can initiate
Comparison of salt stress resistance genes in transgenic Arabidopsis thaliana indicates that extent of transcriptomic change may not predict secondary phenotypic or fitness effects.
Age, Specimen part, Treatment
View SamplesTranscriptional variation, also called expression level polymorphism (ELP), contributes to intra-specific phenotypic variation in many organisms. Differentially expressed transcripts are typically enriched for stress-related genes, suggesting that differences in response to the environment are a particularly common point of divergence among gentoypes. Analysis of ELPs also has been suggested as a way to assess unintended consequences of transgene introduction; however, it is important that interpretation of transcriptional changes be performed within the context of potential fitness effects. In these studies we sought to examine differential gene expression in response to salinity for two widely used Arabidopsis thaliana ecotypes, Wassilewskija (Ws) and Columbia (Col), and a single gene mutation (glabrous, gl1-1) in the Col background (Col(gl)), in relation to genetic, phenotypic, and fitness differences.
Global gene expression analysis of transgenic, mannitol-producing, and salt-tolerant Arabidopsis thaliana indicates widespread changes in abiotic and biotic stress-related genes.
Age, Specimen part
View SamplesTranscriptional variation, also called expression level polymorphism (ELP), contributes to intra-specific phenotypic variation in many organisms. Differentially expressed transcripts are typically enriched for stress-related genes, suggesting that differences in response to the environment are a particularly common point of divergence among gentoypes. Analysis of ELPs also has been suggested as a way to assess unintended consequences of transgene introduction; however, it is important that interpretation of transcriptional changes be performed within the context of potential fitness effects. In these studies we sought to examine differential gene expression in response to cold for two widely used Arabidopsis thaliana ecotypes, C24 and Columbia (Col).
No associated publication
Specimen part
View SamplesMannitol is a putative osmoprotectant contributing to salt tolerance in several species. Arabidopsis plants transformed with the mannose-6-phosphate reductase (M6PR) gene from celery were dramatically more salt tolerant (at 100mM NaCl) as exhibited by reduced salt injury, less inhibition of vegetative growth, and increased seed production relative to the wild type (WT). When treated with 200mM NaCl, transformants produced no seeds, but did bolt, and exhibited less chlorosis/necrosis and greater survival and dry weights than the WT. Without salt there were no M6PR effects on growth or phenotype, but expression levels of 2272 genes were altered. Many fewer differences (1039) were observed between M6PR and WT plants in the presence of salt, suggesting that M6PR pre-conditioned the plants to stress. Previous work suggested that mannitol is an osmoprotectant, but mannitol levels are invariably quite low, perhaps inadequate for osmoprotectant effects. In this study, transcriptome analysis reveals that the M6PR transgene activated the downstream abscisic acid (ABA) pathway by up-regulation of ABA receptor genes (PYL4, PYL5, and PYL6) and down-regulation of protein phosphatase 2C genes (ABI1 and ABI2). In the M6PR transgenic lines there were also increases in transcripts related to redox and cell wall-strengthening pathways. These data indicate that mannitol-enhanced stress tolerance is due at least in part to increased expression of a variety of stress-inducible genes.
Global gene expression analysis of transgenic, mannitol-producing, and salt-tolerant Arabidopsis thaliana indicates widespread changes in abiotic and biotic stress-related genes.
Age, Specimen part
View SamplesThe growth and fruit quality of grapevine are widely affected by abnormal climatic conditions such as extreme temperature. But how grapevine responds to cold stress is still largely unknown. Here we found that VaMyb14, a member of R2R3 Myb transcription factor family, was up-regulated dramatically during cold, drought and salinity treatments in Vitis amurensis, a cold and drought-hardiness wild Vitis species. Overexpression VaMyb14 in Arabidopsis increased antioxidant enzyme activity, especially POD activity, than that of the wild type and decreased the MDA content. A series of ABA metabolism and signal transduction genes in transgenic Arabidopsiswere were up-regulated in microarry results, including several nsLTPs, PP2Cs, RD29B, COR78 and other structural genes, suggesting that VaMyb14 not only affect the ABA signaling pathways, but also activates the CBF-COR independent nsLTP genes. Collectively, these results illustrate that Vitis Myb14 could represent a node of convergence regulating grapevine stress responses, including improve defence induced phytoalexin resveratrol against necrotrophic as well as drought and/or cold stress tolerance, highlighting Myb14 as a potential gene resource in future grapevine breeding.
No associated publication
Specimen part, Treatment
View SamplesThe growth and fruit quality of grapevine are widely affected by abnormal climatic conditions such as water deficit. But how grapevine responds to drought stress is still largely unknown. Here we found that VaNAC26, a member of NAC transcription factor family, was up-regulated dramatically during cold, drought and salinity treatments in Vitis amurensis, a cold and drought-hardiness wild Vitis species. Ectopic overexpression of VaNAC26 enhanced the drought and salt tolerances in transgenic Arabidopsis. Higher activities of antioxidant enzymes and the lower concentration of H2O2 and O2- were found in VaNAC26-OE lines than in wild type plants under drought stress. These results indicate that the reactive oxygen species (ROS) scavenging was enhanced by VaNAC26 in transgenic lines. Microarray based transcriptome analysis reveals that genes related to jasmonic acid (JA) synthesis and signaling were up-regulated in VaNAC26-OE lines under both normal and drought conditions. VaNAC26 showed a specific binding ability on NACRS motif, which was broadly existent in the promoter regions of up-regulated genes in transgenic lines. Endogenous JA content was found increased obviously in VaNAC26-OE-2/3 lines. Our data suggests that VaNAC26 responds to abiotic stresses and may enhance the drought tolerance by transcriptional regulation of JA synthesis in Arabidopsis.
Expression of Vitis amurensis NAC26 in Arabidopsis enhances drought tolerance by modulating jasmonic acid synthesis.
Specimen part
View SamplesThis SuperSeries is composed of the SubSeries listed below.
RDM4 modulates cold stress resistance in Arabidopsis partially through the CBF-mediated pathway.
Specimen part
View SamplesHaploid pluripotent stem cells, such as haploid embryonic stem cells (haESCs), facilitate the genetic study of recessive traits. In vitro, fish haESCs maintain haploidy in both undifferentiated and differentiated states, but whether mammalian haESCs can preserve pluripotency in the haploid state has not been tested. Here, we report that mouse haESCs can differentiate in vitro into haploid epiblast stem cells (haEpiSCs), which maintain an intact haploid genome, unlimited self-renewal potential, and durable pluripotency to differentiate into various tissues in vitro and in vivo. Mechanistically, the maintenance of self-renewal potential depends on the Activin/bFGF pathway. We further show that haEpiSCs can differentiate in vitro into haploid progenitor-like cells.
Durable pluripotency and haploidy in epiblast stem cells derived from haploid embryonic stem cells in vitro.
Specimen part
View SamplesIn plants, CCCH zinc finger proteins involved in secondary wall formation and anther development are poorly understood. We have functionally identified two homologous genes C3H14 and C3H15 and found that the two genes differentially regulate secondary wall formation and anther development. C3H14 contributes more to secondary wall thickening, whereas, C3H15 is more important for anther development.
Arabidopsis C3H14 and C3H15 have overlapping roles in the regulation of secondary wall thickening and anther development.
Specimen part
View SamplesThe C-REPEAT-BINDING FACTOR (CBF) pathway has important roles in plant responses to cold stress. Previous research documented that constitutively expressed upstream transcription factors are activated by cold stress to induce the expression of CBF genes and the resulting CBF proteins trigger the expression of downstream cold responsive genes that confer freezing tolerance. In the present study, we found that dysfunction of RNA-DIRECTED DNA METHYLATION 4 (RDM4), which encodes a protein that associates with RNA polymerases Pol IV and Pol V as well as Pol II, and is required for RNA-directed DNA methylation (RdDM) and proper plant development in Arabidopsis, reduced chilling and freezing tolerance in Arabidopsis as evidenced by decreased survival and increased electrolyte leakage under cold stress conditions. CBFs and CBF regulon genes were down-regulated in rdm4 but not nrpe1 (the largest subunit of PolV) mutant plants, suggesting that the role of RDM4 in cold stress responses is independent of the RdDM pathway. Overexpression of RDM4 increased the expression of CBFs and CBF regulon genes and decreased cold-induced membrane injury. The rdm4 mutants exhibited decreased antioxidant enzyme activities and increased accumulation of reactive oxygen species. Microarray analysis indicated that a great proportion of genes affected by rdm4 overlapped with those affected by CBF2 and CBF3 in Arabidopsis. Chromatin immunoprecipitation (ChIP) results suggested that RDM4 is important for Pol II occupancy at the promoters of CBF genes but not the promoters of up-stream regulators of CBFs. Together, these data indicate that RDM4 acts as a component of a Pol II transcription complex that regulates CBF gene expression and cold stress resistance in Arabidopsis.
RDM4 modulates cold stress resistance in Arabidopsis partially through the CBF-mediated pathway.
Specimen part
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