Showing papers by "Ray A. Bressan published in 1992"
TL;DR: Osmotin was found to be most abundant in tobacco roots and in tissues of the outer stem comprised primarily of epidermis, and it was less abundant in the corolla.
Abstract: Accumulation of both osmotin mRNA and osmotin protein in tissues of tobacco (Nicotiana tabacum L. var Wisconsin 38) is subject to complex developmental control. Osmotin was found to be most abundant in tobacco roots and in tissues of the outer stem comprised primarily of epidermis, and it was less abundant in the corolla. It was a minor protein in other tissues and was undetectable in some tissues, including those of developing and mature seeds. The mRNA abundances did not always reflect the amount of protein accumulation because in some tissues high levels of mRNA but not protein were measured and vice versa. Accumulation of osmotin mRNA but not protein occurred in some plant tissues due to treatment with abscisic acid, wounding, and tobacco mosaic virus infection. Ethylene induced the accumulation of osmotin mRNA and, to a small extent, protein in seedlings, but was ineffective with cultured cells. Exposure of cultured cells and plants to NaCl caused high levels of both mRNA and the protein to accumulate. Thus, the accumulation of osmotin mRNA is controlled developmentally and by at least five hormonal or environmental signals. However, posttranscriptional processes can limit osmotin accumulation.
111 citations
TL;DR: It is found that the osmotin promoter has a very high natural level of activity in mature pollen grains during anther dehiscence and in pericarp tissue at the final, desiccating stages of fruit development.
Abstract: By introducing a chimeric gene fusion of the osmotin promoter and [beta]-glucuronidase into tobacco by Agrobacterium-mediated transformation, we have demonstrated a very specific pattern of temporal and spatial regulation of the osmotin promoter during normal plant development and after adaptation to NaCl. We have found that the osmotin promoter has a very high natural level of activity in mature pollen grains during anther dehiscence and in pericarp tissue at the final, desiccating stages of fruit development. GUS activity was rapidly lost after pollen germination. The osmotin promoter thus appears to be unique among active pollen promoters described to date in that it is active only in dehydrated pollen. The osmotin promoter was also active in corolla tissue at the onset of senescence. Adaptation of plants to NaCl highly stimulated osmotin promoter activity in epidermal and cortex parenchyma cells in the root elongation zone; in epidermis and xylem parenchyma cells in stem internodes; and in epidermis, mesophyll, and xylem parenchyma cells in developed leaves. The spatial and temporal expression pattern of the osmotin gene appears consistent with both osmotic and pathogen defense functions of the gene.
110 citations
TL;DR: The sensitivity of the osmotin promoter to ABA applied exogenously decreased with age in both roots and shoots of young seedlings and in transformed plants carrying copies of a fusion of the cloned promoter to the β-glucuronidase reporter gene.
Abstract: A Nicotiana tabacum gene encoding the basic PR-like protein osmotin was isolated and characterized. The gene is derived from the N. sylvestris parent of N. tabacum. In cell suspension cultures of tobacco, the osmotin gene was shown to be transcriptionally activated by treatment with ABA.
89 citations
TL;DR: The deduced peptide had the greatest homology to the endoplasmic reticulum Ca(2+)-ATPases of Drosophila and Artemia, followed by the mammalian and avian enzymes (SERCA2 and 3), and was 3- to 4-fold higher in 428 mm NaCl-adapted cells growing in salt than in unadapted Cells growing without salt.
Abstract: A cDNA clone was isolated that encodes the partial sequence of a putative endoplasmic reticulum Ca2+-ATPase of tobacco. The 1.497-kb insert had an open reading frame of 1.149 kb. The deduced peptide had the greatest homology to the endoplasmic reticulum Ca2+-ATPases of Drosophila and Artemia, followed by the mammalian and avian enzymes (SERCA2 and 3). The cDNA insert hybridized to a single mRNA of 4.4 kb from tobacco cultured cells or plant tissues. The level of this transcript was induced about 2-fold by NaCl shock in 428 mm NaCl-deadapted tobacco cells that were maintained in medium without salt, but not in unadapted cells. The level of this transcript was 3- to 4-fold higher in 428 mm NaCl-adapted cells growing in salt than in unadapted cells growing without salt.
82 citations
TL;DR: A peptide (molecular mass 50 kilodaltons) that is immunologically related to tobacco osmotin was detected in cells of the halophyte Atriplex nummularia as mentioned in this paper.
Abstract: A peptide (molecular mass 50 kilodaltons) that is immunologically related to tobacco osmotin was detected in cells of the halophyte Atriplex nummularia. This protein was constitutively expressed in both unadapted and NaCl-adapted cells. A predominant osmotin-like peptide (molecular mass 24 kilodaltons) was also found in culture media after cell growth. Two unique A. nummularia cDNA clones, pA8 and pA9, encoding osmotin-like proteins have been isolated. The pA8 and pA9 inserts are 952 and 792 base pairs and encode peptides of 222 and 224 amino acids, respectively. The peptide deduced from pA8 has a molecular mass of 23,808 daltons and theoretical isoelectric point of 8.31, whereas the peptide derived from pA9 has a molecular mass of 23,827 daltons and an isoelectric point of 6.88. Unique transcripts were detected by the inserts of the cDNA clones, two (1.2 and 1.0 kilobases) by pA8 and one (0.9 kilobase) by pA9. The pA8 transcripts were constitutively accumulated in unadapted and NaCl-adapted cells, whereas the mRNA levels were up-regulated by abscisic acid treatment. The level of pA9 mRNA was induced by NaCl treatment and increased in cells as a function of NaCl adaptation. Southern analysis of the genomic DNA indicated the presence of osmotin-like multigene families in A. nummularia.
41 citations
TL;DR: An Atriplex nummularia cDNA sequence is described that encodes a predicted peptide with high sequence identity to caltractin, a Ca2"-binding protein that is required for spindle pole body formation.
Abstract: Calcium controls numerous cellular processes with a high degree of spatial and temporal precision. One way by which these controls are effected is through the transduction of a Ca2\" signal by an interaction of the cation with Ca2\"-binding proteins. Among the Ca2\"-binding proteins that are presumed to function in the modulation of cellular processes are calmodulin, troponin C, myosin light chain, parvalbumin, and caltractin (2, 3, 7, 8, 10). Caltractin is a 20-kD Ca2\"-binding protein that was isolated from basal body complexes of the unicellular green alga Chlamydomonas reinhardtii (6). The primary structure of caltractin, deduced from peptide fragments and cDNA sequences (5, 6), has 45 to 48% identity with calmodulins and 50% identity with Saccharomyces cerevisiae CDC31-encoded protein (1) that is required for spindle pole body formation. We describe here an Atriplex nummularia cDNA sequence that encodes a predicted peptide with high sequence identity to caltractin (Table I). The 970-base pair cDNA contains a longest open reading frame of 501 nucleotides, with a translated peptide of 167 amino acids that has a molecular mass of 20.3 kD (Fig. 1). The predicted protein is hydrophilic and has a theoretical isoelectric point of 4.7. It is of similar size (167 versus 169 amino acids) to caltractin and has an analogous predicted isoelectric point (4.7 versus 5.3). The sequence identities/similarities between the A. nummularia peptide and caltractin, yeast CDC31 gene product, animal calmodulins, plant calmodulins, and troponin C are 62/82, 42/64, 48/66, 46/65, and 38/68%, respectively. The A. nummularia cDNA contains a CTGCAC sequence that is tandemly repeated seven times just downstream from the putative TGA stop codon (Fig. 1). No discernable consen-
30 citations