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Vegetative Tissues (vegetative + tissue)
Selected AbstractsPresence Of Nemathecia In Parachaetetes Asvapatii Pia, 1936 (Rhodophyta, Gigartinales?): Reproduction In ,Solenoporaceans' RevisitedPALAEONTOLOGY, Issue 6 2001J. Aguirre Parachaetetes asvapatii is a very common algal species in the Palaeogene deposits of the Tethyan realm and has been considered as a member of the heterogeneous family Solenoporaceae. This attribution is exclusively based on features of the vegetative tissue, since no reproductive structures have ever been recovered. However, detailed analysis of Late Cretaceous,Eocene material from Turkey has revealed nemathecia-like structures in one specimen attributable to P. asvapatii. These nemathecia are small wart-like structures protruding on the thallus surface that formed by enlargement of the most peripheral cells of the plant. Nemathecia only occur in three families of the order Gigartinales (Rhodophyta): Rhizophyllidaceae, Peyssonneliaceae and Polyideaceae. Since reproductive structures are stable characters, the presence of nemathecia leads us to tentatively refer P. asvapatii and related species (probably Elianella elegans) to the Gigartinales. [source] Biochemical and molecular responses to water stress in resurrection plantsPHYSIOLOGIA PLANTARUM, Issue 2 2004Giovanni Bernacchia A small group of angiosperms, known as resurrection plants, can tolerate extreme dehydration. They survive in arid environments because they are able to dehydrate, remain quiescent during long periods of drought, and then resurrect upon rehydration. Dehydration induces the expression of a large number of transcripts in resurrection plants. Gene products with a putative protective function such as LEA proteins have been identified; they are expressed at high levels in the cytoplasm or in chloroplasts upon dehydration and/or ABA treatment of vegetative tissue. An increase in sugar concentration is usually observed at the onset of desiccation in vegetative tissue of resurrection plants. These sugars may be effective in osmotic adjustment or they may stabilize membrane structures and proteins. Regulatory genes such as a protein translation initiation factor, homeodomain-leucine zipper genes and a gene probably working as a regulatory RNA have been isolated and characterized. The knowledge of the biochemical and molecular responses that occur during the onset of drought may help to improve water stress tolerance in plants of agronomic importance. [source] Plant profilin isovariants are distinctly regulated in vegetative and reproductive tissuesCYTOSKELETON, Issue 1 2002Muthugapatti K. Kandasamy Abstract Profilin is a low-molecular weight, actin monomer-binding protein that regulates the organization of actin cytoskeleton in eukaryotes, including higher plants. Unlike the simple human or yeast systems, the model plant Arabidopsis has an ancient and highly divergent multi-gene family encoding five distinct profilin isovariants. Here we compare and characterize the regulation of these profilins in different organs and during microspore development using isovariant-specific monoclonal antibodies. We show that PRF1, PRF2, and PRF3 are constitutive, being strongly expressed in all vegetative tissues at various stages of development. These profilin isovariants are also predominant in ovules and microspores at the early stages of microsporogenesis. In contrast, PRF4 and PRF5 are late pollen-specific and are not detectable in other cell types of the plant body including microspores and root hairs. Immunocytochemical studies at the subcellular level reveal that both the constitutive and pollen-specific profilins are abundant in the cytoplasm. In vegetative cell types, such as root apical cells, profilins showed localization to nuclei in addition to the cytoplasmic staining. The functional diversity of profilin isovariants is discussed in light of their spatio-temporal regulation during vegetative development, pollen maturation, and pollen tube growth. Cell Motil. Cytoskeleton 52:22,32, 2002. © 2002 Wiley-Liss, Inc. [source] Biochemical characterization of rice trehalose-6-phosphate phosphatases supports distinctive functions of these plant enzymesFEBS JOURNAL, Issue 5 2007Shuhei Shima Substantial levels of trehalose accumulate in bacteria, fungi, and invertebrates, where it serves as a storage carbohydrate or as a protectant against environmental stresses. In higher plants, trehalose is detected at fairly low levels; therefore, a regulatory or signaling function has been proposed for this molecule. In many organisms, trehalose-6-phosphate phosphatase is the enzyme governing the final step of trehalose biosynthesis. Here we report that OsTPP1 and OsTPP2 are the two major trehalose-6-phosphate phosphatase genes expressed in vegetative tissues of rice. Similar to results obtained from our previous OsTPP1 study, complementation analysis of a yeast trehalose-6-phosphate phosphatase mutant and activity measurement of the recombinant protein demonstrated that OsTPP2 encodes a functional trehalose-6-phosphate phosphatase enzyme. OsTPP2 expression is transiently induced in response to chilling and other abiotic stresses. Enzymatic characterization of recombinant OsTPP1 and OsTPP2 revealed stringent substrate specificity for trehalose 6-phosphate and about 10 times lower Km values for trehalose 6-phosphate as compared with trehalose-6-phosphate phosphatase enzymes from microorganisms. OsTPP1 and OsTPP2 also clearly contrasted with microbial enzymes, in that they are generally unstable, almost completely losing activity when subjected to heat treatment at 50 °C for 4 min. These characteristics of rice trehalose-6-phosphate phosphatase enzymes are consistent with very low cellular substrate concentration and tightly regulated gene expression. These data also support a plant-specific function of trehalose biosynthesis in response to environmental stresses. [source] LC-MSMS identification of Arabidopsis thaliana heat-stable seed proteins: Enriching for LEA-type proteins by acid treatmentJOURNAL OF MASS SPECTROMETRY (INCORP BIOLOGICAL MASS SPECTROMETRY), Issue 11 2007E. Oliveira Abstract Protein identification in systems containing very highly abundant proteins is not always efficient and usually requires previous enrichment or fractionation steps in order to uncover minor proteins. In plant seeds, identification of late embryogenesis abundant (LEA) proteins is often masked by the presence of the large family of storage proteins. LEA-proteins are predicted to play a role in plant stress tolerance. They are highly hydrophilic proteins, generally heat-stable, and correlate with dehydration in seeds or vegetative tissues. In the present work, we analyze the protein composition of heat-stable Arabidopsis thaliana seed extracts after treatment with trichloroacetic acid (TCA). The composition of the proteins that precipitate and those that remain in solution in 3% TCA was analyzed by two different approaches: 1D SDS-PAGE coupled to LC-ESI-MSMS analysis and a gel-free protocol associated with LC-MALDI-MSMS. Our results indicate that treating total heat-soluble extracts with 3% TCA is an effective procedure to remove storage proteins by selective precipitation and this fractionation step provides a soluble fraction highly enriched in Lea-type proteins. The analysis and determination of protein identities in this acid-soluble fraction by MS technology is a suitable system for large-scale identification of Lea-proteins present in seeds. Copyright © 2007 John Wiley & Sons, Ltd. [source] A protein phosphatase 2A from Fagus sylvatica is regulated by GA3 and okadaic acid in seeds and related to the transition from dormancy to germinationPHYSIOLOGIA PLANTARUM, Issue 1 2006Mary Paz González-García Several gibberellic acid (GA3)-induced cDNA fragments encoding putative serine/threonine protein phosphatase (PP) 2A catalytic subunits were obtained by means of differential reverse transcriptase-PCR approach. The full-length clone, named FsPP2A1, isolated from a beechnut cDNA library, exhibited all the features of and homology to members of the PP2A family. By transient expression of FsPP2A1 in tobacco and Arabidopsis cells as a green fluorescent fusion protein, we have obtained evidence supporting the subcellular localization of this protein in both the cytosol and the nucleus. Analysis of FsPP2A1 expression during seed stratification shows that these transcripts increase in the presence of GA3, a treatment proved to be efficient in breaking the dormancy of Fagus sylvatica seeds, but they are almost undetectable in dormant seeds or when dormancy is maintained after treatment with either abscisic acid or the gibberellin biosynthesis inhibitor paclobutrazol. The PP inhibitor okadaic acid (OKA) has a clear effect in decreasing both seed germination and FsPP2A1 expression. Furthermore, FsPP2A1 is specifically expressed in seed tissues, not being detected in other vegetative tissues examined. These results show the regulation of this PP by GA3 and OKA in these seeds. Its relationship with the processes taking place during the transition from dormancy to germination is also discussed. [source] Expression of CP4 EPSPS in microspores and tapetum cells of cotton (Gossypium hirsutum) is critical for male reproductive development in response to late-stage glyphosate applicationsPLANT BIOTECHNOLOGY JOURNAL, Issue 5 2006Yun-Chia Sophia Chen Summary Plants expressing Agrobacterium sp. strain CP4 5-enolpyruvylshikimate-3-phosphate synthase (CP4 EPSPS) are known to be resistant to glyphosate, a potent herbicide that inhibits the activity of the endogenous plant EPSPS. The RR1445 transgenic cotton line (current commercial line for Roundup Ready® Cotton) was generated using the figwort mosaic virus (FMV) 35S promoter to drive the expression of the CP4 EPSPS gene, and has excellent vegetative tolerance to glyphosate. However, with high glyphosate application rates at developmental stages later than the four-leaf stage (late-stage applications: applications that are inconsistent with the Roundup® labels), RR1445 shows male sterility. Another transgenic cotton line, RR60, was generated using the FMV 35S promoter and the Arabidopsis elongation factor-1, promoter (AtEF1,) for the expression of CP4 EPSPS. RR60 has excellent vegetative and reproductive tolerance to applications of glyphosate at all developmental stages. Histochemical analyses were conducted to examine the male reproductive development at the cellular level of these cotton lines in response to glyphosate applications, and to investigate the correlation between glyphosate injury and the expression of CP4 EPSPS in male reproductive tissues. The expression of CP4 EPSPS in RR60 was found to be strong in all male reproductive cell types. Conversely, CP4 EPSPS expression in RR1445 was low in pollen mother cells, male gametophytes and tapetum, three crucial male reproductive cell types. Our results indicate that the FMV 35S promoter, although expressing strongly in most vegetative tissues in plants, has extremely low activity in these cell types. [source] Insights into the cellular mechanisms of desiccation tolerance among angiosperm resurrection plant speciesPLANT CELL & ENVIRONMENT, Issue 11 2004M. VICRÉ ABSTRACT Water is a major limiting factor in growth and reproduction in plants. The ability of tissues to survive desiccation is commonly found in seeds or pollen but rarely present in vegetative tissues. Resurrection plants are remarkable as they can tolerate almost complete water loss from their vegetative tissues such as leaves and roots. Metabolism is shut down as they dehydrate and the plants become apparently lifeless. Upon rehydration these plants recover full metabolic competence and ,resurrect'. In order to cope with desiccation, resurrection plants have to overcome a number of stresses as water is lost from the cells, among them oxidative stress, destabilization or loss of membrane integrity and mechanical stress. This review will mainly focus on the effect of dehydration in angiosperm resurrection plants and some of the strategies developed by these plants to tolerate desiccation. Resurrection plants are important experimental models and understanding the physiological and molecular aspects of their desiccation tolerance is of great interest for developing drought-tolerant crop species adapted to semi-arid areas. [source] Expression of a celery mannose 6-phosphate reductase in Arabidopsis thaliana enhances salt tolerance and induces biosynthesis of both mannitol and a glucosyl-mannitol dimerPLANT CELL & ENVIRONMENT, Issue 2 2003G. ZHIFANG ABSTRACT Mannitol, a sugar alcohol that may serve as a compatible solute to cope with salt stress, is synthesized via the action of a mannose-6-phosphate reductase (M6PR) in celery (Apium graveolens L). In contrast to previous approaches that have used a bacterial gene to engineer mannitol biosynthesis in plants and other organisms, Arabidopsis thaliana, a non-mannitol producer, was transformed with the celery leaf M6PR gene under control of the CaMV 35S promotor. In all independent Arabidopsis M6PR transformants, mannitol accumulated throughout the plants in amounts ranging from 0·5 to 6 µmol g,1 fresh weight. A novel compound, not found in either celery or Arabidopsis, 1-O- , - d -glucopyranosyl- d -mannitol, also accumulated in vegetative tissues of mature plants in amounts up to 4 µmol g,1 fresh weight, but not in flowers and seeds. In the absence of NaCl, all transformants were phenotypically the same as the wild type; however, in the presence of NaCl, mature transgenic plants showed a high level of salt tolerance, i.e. growing, completing normal development, flowering, and producing seeds in soil irrigated with 300 mm NaCl in the nutrient solution. These results demonstrate a major role in developing salt-tolerant plants by means of introducing mannitol biosynthesis using M6PR. [source] Over-expression of SOB5 suggests the involvement of a novel plant protein in cytokinin-mediated developmentTHE PLANT JOURNAL, Issue 5 2006Jingyu Zhang Summary Cytokinins are a class of phytohormones that play a critical role in plant growth and development. sob5-D, an activation-tagging mutant, shows phenotypes typical of transgenic plants expressing the Agrobacterium tumefaciens isopentenyltransferase (ipt) gene that encodes the enzyme catalyzing the first step of cytokinin biosynthesis. The sob5-D mutant phenotypes are caused by over-expression of a novel gene, SOB5. Sequence analysis places SOB5 in a previously uncharacterized family of plant-specific proteins. A translational fusion between SOB5 and the green fluorescent protein reporter was localized in the cytoplasm as well as associated with the plasma membrane when transiently expressed in onion epidermal cells. Analysis of transgenic plants harboring an SOB5:SOB5,, -glucuronidase (GUS) translational fusion under the control of the SOB5 promoter region showed GUS activity in vegetative tissues (hydathodes and trichomes of leaves, shoot meristems and roots) as well as in floral tissues (pistil tips, developing anthers and sepal vasculature). Cytokinin quantification analysis revealed that adult sob5-D plants accumulated higher levels of trans -zeatin riboside, trans -zeatin riboside monophosphate and isopentenyladenine 9-glucoside when compared to the wild-type. Consistent with this result, AtIPT3 and AtIPT7 were found to be up-regulated in a tissue-specific manner in sob5-D mutants. Physiological analysis of the sob5-D mutant demonstrated reduced responsiveness to exogenous cytokinin in both root-elongation and callus-formation assays. Taken together, our data suggest a role for the novel gene SOB5 in cytokinin-mediated plant development. [source] Stress-induced somatic embryogenesis in vegetative tissues of Arabidopsis thalianaTHE PLANT JOURNAL, Issue 1 2003Miho Ikeda-Iwai Summary Somatic embryogenesis is an obvious experimental evidence of totipotency, and is used as a model system for studying the mechanisms of de-differentiation and re-differentiation of plant cells. Although Arabidopsis is widely used as a model plant for genetic and molecular biological studies, there is no available tissue culture system for inducing somatic embryogenesis from somatic cells in this plant. We established a new tissue culture system using stress treatment to induce somatic embryogenesis in Arabidopsis. In this system, stress treatment induced formation of somatic embryos from shoot-apical-tip and floral-bud explants. The somatic embryos grew into young plantlets with normal morphology, including cotyledons, hypocotyls, and roots, and some embryo-specific genes (ABI3 and FUS3) were expressed in these embryos. Several stresses (osmotic, heavy metal ion, and dehydration stress) induced somatic embryogenesis, but the optimum stress treatment differed between different stressors. When we used mannitol to cause osmotic stress, the optimal conditions for somatic embryogenesis were 6,9 h of culture on solid B5 medium containing 0.7 m mannitol, after which the explants were transferred to B5 medium containing 2,4-dichlorophenoxyacetic acid (2,4-D, 4.5 µm), but no mannitol. Using this tissue culture system, we induced somatic embryogenesis in three major ecotypes of Arabidopsis thaliana, Ws, Col, and Ler. [source] Maize Rabl7 overexpression in Arabidopsis plants promotes osmotic stress toleranceANNALS OF APPLIED BIOLOGY, Issue 3 2004M FIGUERAS Summary Rabl7 is a Late Embryogenesis Abundant (LEA) protein from maize, which accumulates largely during embryogenesis and also in vegetative tissues when subjected to stress conditions. We have analysed the effect of Rab 17 expression under a constitutive promoter in vegetative tissues of transgenic Arabidopsis thaliana plants. These transgenic plants have higher sugar and proline contents, and also higher water loss rate under water stress. In addition, these plants are more tolerant than non-transformed controls to high salinity and recover faster from mannitol treatment. Our results point to a protective effect of Rabl7 protein in vegetative tissues under osmotic stress conditions. [source] Crystallization of the plant hormone receptors PYL9/RCAR1, PYL5/RCAR8 and PYR1/RCAR11 in the presence of (+)-abscisic acidACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 4 2010Nobuyuki Shibata Abscisic acid (ABA) is a plant hormone that plays key regulatory roles in physiological pathways for the adaptation of vegetative tissues to abiotic stresses such as water stress in addition to events pertaining to plant growth and development. The Arabidopsis ABA receptor proteins PYR/PYLs/RCARs form a START family that contains 14 members which are classified into three subfamilies (I,III). Here, purification, crystallization and X-ray data collection are reported for a member of each of the subfamilies, PYL9/RCAR1 from subfamily I, PYL5/RCAR8 from subfamily II and PYR1/RCAR11 from subfamily III, in the presence of (+)-abscisic acid. The three proteins crystallize in space groups P3121/P3221, P2 and P1, respectively. X-ray intensity data were collected to 1.9,2.6,Ĺ resolution. 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