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Variety Of Plant Species (variety + of_plant_species)
Selected AbstractsExpression of a High Mobility Group Protein Isolated from Cucumis sativus Affects the Germination of Arabidopsis thaliana under Abiotic Stress ConditionsJOURNAL OF INTEGRATIVE PLANT BIOLOGY, Issue 5 2008Ji Young Jang Abstract Although high mobility group B (HMGB) proteins have been identified from a variety of plant species, their importance and functional roles in plant responses to changing environmental conditions are largely unknown. Here, we investigated the functional roles of a CsHMGB isolated from cucumber (Cucumis sativus L.) in plant responses to environmental stimuli. Under normal growth conditions or when subjected to cold stress, no differences in plant growth were found between the wild-type and transgenic Arabidopsis thaliana overexpressing CsHMGB. By contrast, the transgenic Arabidopsis plants displayed retarded germination compared with the wild-type plants when grown under high salt or dehydration stress conditions. Germination of the transgenic plants was delayed by the addition of abscisic acid (ABA), implying that CsHMGB affects germination through an ABA-dependent way. The expression of CsHMGB had affected only the germination stage, and CsHMGB did not affect the seedling growth of the transgenic plants under the stress conditions. The transcript levels of several germination-responsive genes were modulated by the expression of CsHMGB in Arabidopsis. Taken together, these results suggest that ectopic expression of a CsHMGB in Arabidopsis modulates the expression of several germination-responsive genes, and thereby affects the germination of Arabidopsis plants under different stress conditions. [source] Chewing sticks: timeless natural toothbrushes for oral cleansingJOURNAL OF PERIODONTAL RESEARCH, Issue 5 2001C. D. Wu It is generally accepted that oral hygiene maintenance through regular removal of dental plaque and food deposits is an essential factor in the prevention of dental caries and periodontal disease. Methods for oral hygiene vary from country to country and from culture to culture. Despite the widespread use of toothbrushes and toothpastes, natural methods of tooth cleaning using chewing sticks selected and prepared from the twigs, stems or roots from a variety of plant species have been practised for thousands of years in Asia, Africa, the Middle East and the Americas. Selected clinical studies have shown that chewing sticks, when properly used, can be as efficient as toothbrushes in removing dental plaque due to the combined effect of mechanical cleaning and enhanced salivation. It has also been suggested that antimicrobial substances that naturally protect plants against various invading microorganisms or other parasites may leach out into the oral cavity, and that these compounds may benefit the users by protection against cariogenic and periodontopathic bacteria. Some clinical epidemiological studies are in support of this, and many laboratory investigations have suggested the presence of heterogeneous antimicrobial components extractable using different chemical procedures. A few recent studies have identified some of the active antimicrobial compounds. Today, chewing sticks are still used in many developing countries because of religion and/or tradition, and because of their availability, low cost and simplicity. The World Health Organization also encourages their use. The Year 2000 Consensus Report on Oral Hygiene states that chewing sticks may have a role to play in the promotion of oral hygiene, and that evaluation of their effectiveness warrants further research. [source] A leucine-rich repeat protein is required for growth promotion and enhanced seed production mediated by the endophytic fungus Piriformospora indica in Arabidopsis thalianaTHE PLANT JOURNAL, Issue 1 2007Bationa Shahollari Summary Piriformospora indica, a basidiomycete of the Sebacinaceae family, promotes the growth, development and seed production of a variety of plant species. Arabidopsis plants colonized with the fungus produce 22% more seeds than uncolonized plants. Deactivating the Arabidopsis single-copy gene DMI-1, which encodes an ion carrier required for mycorrihiza formation in legumes, does not affect the beneficial interaction between the two symbiotic partners. We used cellular and molecular responses initiated during the establishment of the interaction between P. indica and Arabidopsis roots to isolate mutants that fail to respond to the fungus. An ethylmethane sulfonate mutant (Piriformospora indica - insensitive-2; pii-2), and a corresponding insertion line, are impaired in a leucine-rich repeat protein (At1g13230). The protein pii-2, which contains a putative endoplasmic reticulum retention signal, is also found in Triton X-100-insoluble plasma membrane microdomains, suggesting that it is present in the endoplasmic reticulum/plasma membrane continuum in Arabidopsis roots. The microdomains also contain an atypical receptor protein (At5g16590) containing leucine-rich repeats, the message of which is transiently upregulated in Arabidopsis roots in response to P. indica. This response is not detectable in At1g13230 mutants, and the protein is not detectable in the At1g13230 mutant microdomains. Partial deactivation of a gene for a sphingosine kinase, which is required for the biosynthesis of sphingolipid found in plasma membrane microdomains, also affects the Arabidopsis/P. indica interaction. Thus, pii-2, and presumably also At5g16590, two proteins present in plasma membrane microdomains, appear to be involved in P. indica -induced growth promotion and enhanced seed production in Arabidopsis thaliana. [source] Morphological and Molecular Evidence of Arbuscular Mycorrhizal Fungal Associations in Costa Rican Epiphytic Bromeliads,BIOTROPICA, Issue 2 2005Annette R. Rowe ABSTRACT Arbuscular mycorrhizal fungi influence the growth, morphology, and fitness of a variety of plant species, but little is known of the arbuscular mycorrhizal (AM) fungal associations of plant species in forest canopies. Plant species' associations with AM fungi are most often elucidated by examining the roots for fungal structures; however, morphological data may provide a limited resolution on a plant's mycorrhizal status. We combined a traditional staining technique with a molecular marker (the 18S ribosomal gene) to determine whether or not a variety of epiphytic bromeliads form arbuscular mycorrhizal fungal associations. Using these methods we show that the epiphytic bromeliad Vriesea werkleana forms arbuscular mycorrhizal fungal associations with members of the genus Glomus. AM fungal sequences of this plant species formed three distinct clades nested within a larger Glomus clade; two of the clades did not group with any previously sequenced lineage of Glomus. Novel clades may represent novel species. Although Vriesea werkleana is associated with multiple AM fungal species, each individual plant is colonized by a single lineage. The combination of morphological and molecular methods provides a practical approach to the characterization of the mycorrhizal status of epiphytic bromeliads, and perhaps other tropical epiphytes. [source] | ||||||||||