Plant Journal
1365-313X
0960-7412
Anh Quốc
Cơ quản chủ quản: WILEY , Wiley-Blackwell Publishing Ltd
Lĩnh vực:
GeneticsCell BiologyPlant Science
Các bài báo tiêu biểu
<b>Floral dip: a simplified method for</b><i><b>Agrobacterium</b></i><b>‐mediated transformation of</b><i><b>Arabidopsis thaliana</b></i> Summary The
Agrobacterium
vacuum infiltration method has made it possible to transform
Arabidopsis thaliana
without plant tissue culture or regeneration. In the present study, this method was evaluated and a substantially modified transformation method was developed. The labor‐intensive vacuum infiltration process was eliminated in favor of simple dipping of developing floral tissues into a solution containing
Agrobacterium tumefaciens
, 5% sucrose and 500 microliters per litre of surfactant Silwet L‐77. Sucrose and surfactant were critical to the success of the floral dip method. Plants inoculated when numerous immature floral buds and few siliques were present produced transformed progeny at the highest rate. Plant tissue culture media, the hormone benzylamino purine and pH adjustment were unnecessary, and
Agrobacterium
could be applied to plants at a range of cell densities. Repeated application of
Agrobacterium
improved transformation rates and overall yield of transformants approximately twofold. Covering plants for 1 day to retain humidity after inoculation also raised transformation rates twofold. Multiple ecotypes were transformable by this method. The modified method should facilitate high‐throughput transformation of
Arabidopsis
for efforts such as T‐DNA gene tagging, positional cloning, or attempts at targeted gene replacement.
Tập 16 Số 6 - Trang 735-743 - 1998
Microalgal triacylglycerols as feedstocks for biofuel production: perspectives and advances Summary Microalgae represent an exceptionally diverse but highly specialized group of micro‐organisms adapted to various ecological habitats. Many microalgae have the ability to produce substantial amounts (e.g. 20–50% dry cell weight) of triacylglycerols (TAG) as a storage lipid under photo‐oxidative stress or other adverse environmental conditions. Fatty acids, the building blocks for TAGs and all other cellular lipids, are synthesized in the chloroplast using a single set of enzymes, of which acetyl CoA carboxylase (ACCase) is key in regulating fatty acid synthesis rates. However, the expression of genes involved in fatty acid synthesis is poorly understood in microalgae. Synthesis and sequestration of TAG into cytosolic lipid bodies appear to be a protective mechanism by which algal cells cope with stress conditions, but little is known about regulation of TAG formation at the molecular and cellular level. While the concept of using microalgae as an alternative and renewable source of lipid‐rich biomass feedstock for biofuels has been explored over the past few decades, a scalable, commercially viable system has yet to emerge. Today, the production of algal oil is primarily confined to high‐value specialty oils with nutritional value, rather than commodity oils for biofuel. This review provides a brief summary of the current knowledge on oleaginous algae and their fatty acid and TAG biosynthesis, algal model systems and genomic approaches to a better understanding of TAG production, and a historical perspective and path forward for microalgae‐based biofuel research and commercialization.
Tập 54 Số 4 - Trang 621-639 - 2008
Efficient transformation of rice (<i>Oryza sativa</i> L.) mediated by <i>Agrobacterium</i> and sequence analysis of the boundaries of the T‐DNA Summary A large number of morphologically normal, fertile, transgenic rice plants were obtained by co‐cultivation of rice tissues with Agrobacterium tumefaciens . The efficiency of transformation was similar to that obtained by the methods used routinely for transformation of dicotyledons with the bacterium. Stable integration, expression and inheritance of transgenes were demonstrated by molecular and genetic analysis of transformants in the R0 , R1 and R2 generations. Sequence analysis revealed that the boundaries of the T‐DNA in transgenic rice plants were essentially identical to those in transgenic dicotyledons. Calli induced from scutella were very good starting materials. A strain of A. tumefaciens that carried a so‐called ‘super‐binary’ vector gave especially high frequencies of transformation of various cultivars of japonica rice that included Koshihikari, which normally shows poor responses in tissue culture.
Tập 6 Số 2 - Trang 271-282 - 1994
<scp>mapman</scp>: a user‐driven tool to display genomics data sets onto diagrams of metabolic pathways and other biological processes Summary mapman is a user‐driven tool that displays large data sets onto diagrams of metabolic pathways or other processes. SCAVENGER modules assign the measured parameters to hierarchical categories (formed ‘BINs’, ‘subBINs’). A first build of transcriptscavenger groups genes on the Arabidopsis Affymetrix 22K array into >200 hierarchical categories, providing a breakdown of central metabolism (for several pathways, down to the single enzyme level), and an overview of secondary metabolism and cellular processes. metabolitescavenger groups hundreds of metabolites into pathways or groups of structurally related compounds. An imageannotator module uses these groupings to organise and display experimental data sets onto diagrams of the users' choice. A modular structure allows users to edit existing categories, add new categories and develop SCAVENGER modules for other sorts of data. mapman is used to analyse two sets of 22K Affymetrix arrays that investigate the response of Arabidopsis rosettes to low sugar: one investigates the response to a 6‐h extension of the night, and the other compares wild‐type Columbia‐0 (Col‐0) and the starchless pgm mutant (plastid phosphoglucomutase) at the end of the night. There were qualitatively similar responses in both treatments. Many genes involved in photosynthesis, nutrient acquisition, amino acid, nucleotide, lipid and cell wall synthesis, cell wall modification, and RNA and protein synthesis were repressed. Many genes assigned to amino acid, nucleotide, lipid and cell wall breakdown were induced. Changed expression of genes for trehalose metabolism point to a role for trehalose‐6‐phosphate (Tre6P) as a starvation signal. Widespread changes in the expression of genes encoding receptor kinases, transcription factors, components of signalling pathways, proteins involved in post‐translational modification and turnover, and proteins involved in the synthesis and sensing of cytokinins, abscisic acid (ABA) and ethylene revealing large‐scale rewiring of the regulatory network is an early response to sugar depletion.
Tập 37 Số 6 - Trang 914-939 - 2004
Subcellular localization of H<sub>2</sub>O<sub>2</sub> in plants. H<sub>2</sub>O<sub>2</sub> accumulation in papillae and hypersensitive response during the barley—powdery mildew interaction Active oxygen species (AOS) are believed to have important roles in plants in general and in plant—pathogen interactions in particular. They are believed to be involved in signal transduction, cell wall reinforcement, hypersensitive response (HR) and phytoalexin production, and to have direct antimicrobial effects. Since current methods are inadequate for localizing AOS in intact plant tissue, most studies have been conducted using cell suspension culture/elicitors systems. 3,3‐diaminobenzidine (DAB) polymerizes instantly and locally as soon as it comes into contact with H2 O2 in the presence of peroxidase, and it was found that, by allowing the leaf to take up this substrate, in‐vivo and in‐situ detection of H2 O2 can be made at subcellular levels. This method was successfully used to detect H2 O2 in developing papillae and surrounding haloes (cell wall appositions) and whole cells of barley leaves interacting with the powdery mildew fungus. Thus, H2 O2 can be detected in the epidermal cell wall subjacent to the primary germ tube from 6 h after inoculation, and subjacent to the appressorium from 15 h. The earliest time point for observation of H2 O2 in relation to epidermal cells undergoing HR is 15 h after inoculation, first appearing in the zones of attachment to the mesophyll cells underneath, and eventually in the entire epidermal cell. Furthermore, it was observed that proteins in papillae and HR cells are cross‐linked, a process believed to be fuelled by H2 O2 . This cross‐linking reinforces the apposition, presumably assisting the arrest of the pathogen.
Tập 11 Số 6 - Trang 1187-1194 - 1997
Reactive oxygen species, abiotic stress and stress combination Summary Reactive oxygen species (ROS) play a key role in the acclimation process of plants to abiotic stress. They primarily function as signal transduction molecules that regulate different pathways during plant acclimation to stress, but are also toxic byproducts of stress metabolism. Because each subcellular compartment in plants contains its own set of ROS‐producing and ROS‐scavenging pathways, the steady‐state level of ROS, as well as the redox state of each compartment, is different at any given time giving rise to a distinct signature of ROS levels at the different compartments of the cell. Here we review recent studies on the role of ROS in abiotic stress in plants, and propose that different abiotic stresses, such as drought, heat, salinity and high light, result in different ROS signatures that determine the specificity of the acclimation response and help tailor it to the exact stress the plant encounters. We further address the role of ROS in the acclimation of plants to stress combination as well as the role of ROS in mediating rapid systemic signaling during abiotic stress. We conclude that as long as cells maintain high enough energy reserves to detoxify ROS, ROS is beneficial to plants during abiotic stress enabling them to adjust their metabolism and mount a proper acclimation response.
Tập 90 Số 5 - Trang 856-867 - 2017
Biosynthesis of plant pigments: anthocyanins, betalains and carotenoids Summary Plant compounds that are perceived by humans to have color are generally referred to as ‘pigments’. Their varied structures and colors have long fascinated chemists and biologists, who have examined their chemical and physical properties, their mode of synthesis, and their physiological and ecological roles. Plant pigments also have a long history of use by humans. The major classes of plant pigments, with the exception of the chlorophylls, are reviewed here. Anthocyanins, a class of flavonoids derived ultimately from phenylalanine, are water‐soluble, synthesized in the cytosol, and localized in vacuoles. They provide a wide range of colors ranging from orange/red to violet/blue. In addition to various modifications to their structures, their specific color also depends on co‐pigments, metal ions and pH. They are widely distributed in the plant kingdom. The lipid‐soluble, yellow‐to‐red carotenoids, a subclass of terpenoids, are also distributed ubiquitously in plants. They are synthesized in chloroplasts and are essential to the integrity of the photosynthetic apparatus. Betalains, also conferring yellow‐to‐red colors, are nitrogen‐containing water‐soluble compounds derived from tyrosine that are found only in a limited number of plant lineages. In contrast to anthocyanins and carotenoids, the biosynthetic pathway of betalains is only partially understood. All three classes of pigments act as visible signals to attract insects, birds and animals for pollination and seed dispersal. They also protect plants from damage caused by UV and visible light.
Tập 54 Số 4 - Trang 733-749 - 2008
A multicolored set of <i>in vivo</i> organelle markers for co‐localization studies in Arabidopsis and other plants Summary Genome sequencing has resulted in the identification of a large number of uncharacterized genes with unknown functions. It is widely recognized that determination of the intracellular localization of the encoded proteins may aid in identifying their functions. To facilitate these localization experiments, we have generated a series of fluorescent organelle markers based on well‐established targeting sequences that can be used for co‐localization studies. In particular, this organelle marker set contains indicators for the endoplasmic reticulum, the Golgi apparatus, the tonoplast, peroxisomes, mitochondria, plastids and the plasma membrane. All markers were generated with four different fluorescent proteins (FP) (green, cyan, yellow or red FPs) in two different binary plasmids for kanamycin or glufosinate selection, respectively, to allow for flexible combinations. The labeled organelles displayed characteristic morphologies consistent with previous descriptions that could be used for their positive identification. Determination of the intracellular distribution of three previously uncharacterized proteins demonstrated the usefulness of the markers in testing predicted subcellular localizations. This organelle marker set should be a valuable resource for the plant community for such co‐localization studies. In addition, the Arabidopsis organelle marker lines can also be employed in plant cell biology teaching labs to demonstrate the distribution and dynamics of these organelles.
Tập 51 Số 6 - Trang 1126-1136 - 2007
Monitoring the expression profiles of 7000 <i>Arabidopsis</i> genes under drought, cold and high‐salinity stresses using a full‐length cDNA microarray Summary Full‐length cDNAs are essential for functional analysis of plant genes in the post‐sequencing era of the Arabidopsis genome. Recently, cDNA microarray analysis has been developed for quantitative analysis of global and simultaneous analysis of expression profiles. We have prepared a full‐length cDNA microarray containing ≈7000 independent, full‐length cDNA groups to analyse the expression profiles of genes under drought, cold (low temperature) and high‐salinity stress conditions over time. The transcripts of 53, 277 and 194 genes increased after cold, drought and high‐salinity treatments, respectively, more than fivefold compared with the control genes. We also identified many highly drought‐, cold‐ or high‐salinity‐ stress‐inducible genes. However, we observed strong relationships in the expression of these stress‐responsive genes based on Venn diagram analysis, and found 22 stress‐inducible genes that responded to all three stresses. Several gene groups showing different expression profiles were identified by analysis of their expression patterns during stress‐responsive gene induction. The cold‐inducible genes were classified into at least two gene groups from their expression profiles. DREB1A was included in a group whose expression peaked at 2 h after cold treatment. Among the drought, cold or high‐salinity stress‐inducible genes identified, we found 40 transcription factor genes (corresponding to ≈11% of all stress‐inducible genes identified), suggesting that various transcriptional regulatory mechanisms function in the drought, cold or high‐salinity stress signal transduction pathways.
Tập 31 Số 3 - Trang 279-292 - 2002
<i>OsDREB</i> genes in rice, <i>Oryza sativa</i> L., encode transcription activators that function in drought‐, high‐salt‐ and cold‐responsive gene expression Summary The transcription factors DREBs/CBFs specifically interact with the dehydration‐responsive element/C‐repeat (DRE/CRT) cis ‐acting element (core motif: G/ACCGAC) and control the expression of many stress‐inducible genes in Arabidopsis . In rice, we isolated five cDNAs for DREB homologs: OsDREB1A , OsDREB1B , OsDREB1C , OsDREB1D , and OsDREB2A . Expression of OsDREB1A and OsDREB1B was induced by cold, whereas expression of OsDREB2A was induced by dehydration and high‐salt stresses. The OsDREB1A and OsDREB2A proteins specifically bound to DRE and activated the transcription of the GUS reporter gene driven by DRE in rice protoplasts. Over‐expression of OsDREB1A in transgenic Arabidopsis induced over‐expression of target stress‐inducible genes of Arabidopsis DREB1A resulting in plants with higher tolerance to drought, high‐salt, and freezing stresses. This indicated that OsDREB1A has functional similarity to DREB1A. However, in microarray and RNA blot analyses, some stress‐inducible target genes of the DREB1A proteins that have only ACCGAC as DRE were not over‐expressed in the OsDREB1A transgenic Arabidopsis . The OsDREB1A protein bound to GCCGAC more preferentially than to ACCGAC whereas the DREB1A proteins bound to both GCCGAC and ACCGAC efficiently. The structures of DREB1‐type ERF/AP2 domains in monocots are closely related to each other as compared with that in the dicots. OsDREB1A is potentially useful for producing transgenic monocots that are tolerant to drought, high‐salt, and/or cold stresses.
Tập 33 Số 4 - Trang 751-763 - 2003