Showing papers by "Ray A. Bressan published in 1994"

Plant Defense Genes Are Synergistically Induced by Ethylene and Methyl Jasmonate.

Abstract: Combinations of ethylene and methyl jasmonate (E/MeJA) synergistically induced members of both groups 1 and 5 of the pathogenesis-related (PR) superfamily of defense genes. E/MeJA caused a synergistic induction of PR-1b and osmotin (PR-5) mRNA accumulation in tobacco seedlings. E/MeJA also synergistically activated the osmotin promoter fused to a [beta]-glucuronidase marker gene in a tissue-specific manner. The E/MeJA responsiveness of the osmotin promoter was localized on a -248 to +45 fragment that exhibited responsiveness to several other inducers. E/MeJA induction also resulted in osmotin protein accumulation to levels similar to those induced by osmotic stress. Of the several known inducers of the osmotin gene, including salicylic acid (SA), fungal infection is the only other condition known to cause substantial osmotin protein accumulation in Wisconsin 38, a tobacco cultivar that does not respond hypersensitively to tobacco mosaic virus. Based on the ability of the protein kinase C inhibitor 1-(5-isoquinolinylsulfonyl)-2-methylpiperazine to block ethylene induction of PR-1b mRNA accumulation and its inability to block osmotin mRNA induction by ethylene, these two PR gene groups appeared to have at least partially separate signal transduction pathways. Stimulation of osmotin mRNA accumulation by okadaic acid indicated that another protein kinase system is involved in regulation of the osmotin gene. SA, which is known to induce pathogen resistance in tobacco, could not induce the osmotin gene as much as E/MeJA and neither could it induce PR-1b as much as SA and MeJA combined.

Osmotin overexpression in potato delays development of disease symptoms.

Abstract: Transgenic potato and tobacco plants carrying the osmotin gene under the control of the cauliflower mosaic virus 35S promoter constitutively overexpressed osmotin to a level of approximately 2% of total cellular protein. Leaves of transgenic potato plants exhibited delayed development of disease symptoms after inoculation with spore suspensions of Phytophthora infestans, which is the cause of late blight disease of potato. In contrast, transgenic tobacco plants did not display any change in the development of disease symptoms when challenged with either spore suspensions or fungal mycelia of Phytophthora parasitica var. nicotianae. Using in vitro assays, purified osmotin was found to be more effective against P. infestans. Some inhibition of P. parasitica also was observed in vitro even though no in vivo effect could be established.

A higher plant extracellular vitronectin-like adhesion protein is related to the translational elongation factor-1 alpha.

Abstract: Higher plant proteins immunologically related to the animal substrate adhesion molecule vitronectin have recently been observed and implicated in a variety of biological processes, such as plasma membrane-cell wall adhesion, pollen tube extension, and bacterium-plant interaction. We provide evidence that, similar to vitronectin, one of these proteins, PVN1 (plant vitronectin-like 1), isolated from 428 mM NaCl-adapted tobacco cells binds to glass surfaces an heparin. PVN1 was isolated by glass bead affinity chromatography. Isolated PVN1 has adhesive activity based on results from a baby hamster kidney cell-spreading assay. This plant adhesion protein was detected in all tissues examined but was most abundant in roots and salt-adapted cultured cells. Immunogold labeling indicated that PVN1 is localized in the cell wall of cortical and transmitting tissue cells of pollinated mature styles. A partial amino acid sequence of PVN1 revealed no similarity with vitronectin but, instead, was nearly identical to the translational elongation factor-1 alpha (EF-1 alpha). A clone isolated by screening a tobacco cDNA expression library with anti-PVN1 encoded a protein with greater than 93% identity to sequences of EF-1 alpha from plants of numerous species. Immunological cross-reactivity between tobacco PVN1 and EF-1 alpha as well as the reaction between the EF-1 alpha antibody and the 65- and 75-kD vitronectin-like proteins of a fucoidal alga supported the conclusion that the plant extracellular adhesion protein PVN1 is related to EF-1 alpha.

Characterization and in situ localization of a salt-induced tomato peroxidase mRNA.

Abstract: NaCl treatment of tomato plants in hydroponic culture at concentrations as low as 50 mM resulted in enhanced accumulation of transcripts of TPX1, a full-length cDNA clone that we had isolated from a library of NaCl-treated tomato plants using a peroxidase-specific oligonucleotide probe. Although the overall amino acid sequence identity of TPX1 to other peroxidase genes was less than 45%, there was a very high degree of identity in all of the conserved domains. The deduced amino acid sequence included the presence of a N-terminal signal peptide but not the C-terminal extension present in peroxidases targeted to the vacuole. The mature protein has a theoretical pI value of 7.5. Transcripts that hybridized to TPX1 were detected only in the roots with higher levels of mRNA in epidermal and subepidermal cell layers. Isoelectric focusing of root extracts showed two major bands of peroxidase activity at pI 5.9 and 6.2. Both activities increased with salt treatment. Southern analysis indicated the presence of only a single TPX1 gene in tomato.

A NaCl‐regulated plant gene encoding a brain protein homolog that activates ADP ribosyltransferase and inhibits protein kinase C

Abstract: Summary A cDNA clone pCZ1, with a 1.1 kb insert, was isolated from a NaCI-adapted tobacco cell cDNA library that encodes an apparently full-length 29 kDa protein (251 amino acids) with a calculated pl of 5.7. The encoded peptide had a high amino acid sequence identity with bovine 14-3-3 protein which was originally found as an abundant protein in the animal central nervous system. Recently, proteins with sequence identity to 14-3-3 protein have also been found in plants, insects and yeast, and appear to have diverse physiological functions. Similar to the bovine brain 14-3-3 protein, the recombinant pCZ1 protein stimulated ADP-ribosylation of protein substrate by ADP-ribosyl-transferase from the plant and animal pathogenic bacterium Pseudomonas aeruginosa. This recombinant protein also inhibited protein kinase C activity in vitro. Southern blot analyses indicated that most likely five genes encoding 14-3-3-like proteins are present in tobacco. The pCZ1 cDNA insert hybridized to a single mRNA of 1.1 kb from cultured tobacco cells. The level of this mRNA transcript in tobacco cells was downregulated upon adaptation to NaCl but was unaffected by short-term treatment with NaCl, ABA or ethylene. In tobacco plants, expression of transcript that hybridized to pCZ1 was tissue specific, and was most abundant in roots and flower parts. Monoclonal antibody raised against GF14 protein, a maize protein with substantial sequence identity with 14-3-3 protein detected two bands on SDS-PAGE of total proteins from unadapted tobacco cells and only a single band from cells adapted to NaCl. The GF14 antibody was also used to illustrate that the G-box element of a salt-induced gene is associated with a 14-3-3-type protein.

Tissue Culture in the Improvement of Salt Tolerance in Plants

Abstract: The use of tissue culture for improving osmotic (water and salt) stress tolerance in plants has been envisaged primarily on the assumed agricultural potential that will arise from the unique genetic manipulations that can be imposed on cells and tissues in vitro (Nabors 1976; Stavarek and Rains 1984; Raghava Ram and Nabors 1985; Spiegel-Roy and Ben-Hayyim 1985; Hasegawa et al. 1986; Tal 1990). Plant scientists who are predisposed to this philosophy, and not all are, typically view the application of tissue culture from the perspective of how it could augment traditional breeding approaches directed towards the improvement of salinity tolerance in plants. This includes the utilisation of techniques, such as embryo or ovule rescue, that would substantially support efforts to introgress genetic determinants of stress tolerance through wide crosses and interspecific hybridisation. However, substantially greater utility of tissue culture to achieve this goal is hypothesised as a result of potential to exploit effectively sources of useful genetic variation through highly efficient cell or tissue selection strategies, parasexual hybridisation and gene transformation.

Growth cycle stage-dependent NaCl induction of plasma membrane H+-ATPase mRNA accumulation in de-adapted tobacco cells

Abstract: A cDNA clone encoding an isoform of the plasma membrane H+-ATPase was isolated from Nicotiana tabacum. The steady-state plasma membrane H+-ATPase message levels were the same in unadapted tobacco cells and tobacco cells adapted to 428 mol m−3 NaCl. When cells adapted to 428 mol m−3 NaCl maintained in the absence of NaCl (deadapted) for an excess of 100 passages were exposed to 400 mol m−3 NaCl for 24 h, there was an increased accumulation of plasma membrane H+-ATPase message. The NaCl responsiveness of the deadapted cells was dependent upon the growth cycle stage. Alterations in the levels of plasma membrane FT-ATPase message during the growth cycle support a role for the H+-ATPase in cell growth. These results document the induction by NaCl of plasma membrane FT-ATPase message accumulation in tobacco cells, and suggest that enhanced expression of the plasma membrane FT-ATPase has a role in the short term response of cells of NaCl, but is not necessarily involved in long-term adaptation.

Molecular Cloning and Expression of a Glyceraldehyde-3-Phosphate Dehydrogenase Gene in a Desert Halophyte, Atriplex nummularia L

Abstract: Plants must constantly respond to various environmental stresses during growth and development. Heat-shock and anaerobic stress are known to alter the expression of many genes (Sachs and Ho, 1986). Among them is the GAPDH gene that encodes an enzyme in the glycolytic pathway (Russell and Sachs, 1989; Yang et al., 1993). The enzyme catalyzes the NAD+-dependent oxidative phosphorylation of glyceraldehyde-3-P, generating a high-energy intermediate, 1,3-bisphosphoglycerate, one of the most important metabolic reactions in the glycolytic pathway (Mathews and van Holde, 1990). As an altemative ATP-producing pathway, the activation of the GAPDH gene may be an adaptative response to heat-stress-related mitochondrial damage or anaerobic stress-induced inhibition of oxidative phosphorylation. The elucidation of the functional significance of this induction will provide insight into primary carbon metabolism involved in cellular responses to environmental stresses. Atriplex nummularia L., a salt bush indigenous to the Negev desert, tolerates high temperature and osmotic stresses. We have obtained a cDNA done encoding the GAPDH from A . nummularia and characterized its regulation in response to heat and anaerobic stress. Comparison of the deduced amino acid sequence from the A. nummularia cDNA with those in data bases indicates a high degree of conservation for this enzyme among plants (Table I). The largest open reading frame within the 1339-bp cDNA encodes a polypeptide of 360 amino acids. The predicted peptide contains highly conserved domains for NAD+ binding (residues 1-151) and catalytic function (residues 152338), as well as functionally important residues: C Y S ' ~ ~ for glyceraldehyde-3-P binding and His'*' for thiol group activation during glycolysis (Martinez et al., 1989). A unique feature of the peptide encoded by this particular cDNA is the extension at the carboxyl terminus, resulting in a protein about 20 amino acids longer than other GAPDHs. The significance of the extra amino acids at the C terminus is unknown; however, it would be intriguing to determine its possible function in gene expression. Using the full-length cDNA as a probe, we detected

Structure, Regulation and Function of the Osmotin Gene

Abstract: Over the past years several genes have been reported to be osmotically regulated (Storey and Storey, 1981; Holtum and Winter, 1982; Singh et al, 1985; Singh et al, 1987a;Bedford et al, 1987; Close et al, 1989; Cushman et al, 1989; Singh et al, 1989a; 1989b; Delauney and Verma, 1990; Perez-Prat et al, 1990; Skriver and Mundy, 1990; Bartels et al, 1991; Dhindsa, 1991, Estragarcia et al, 1991; Narasimhan et al, 1991; Perez-Prat et al, 1992; Kononowicz et al, 1992; Nelson et al, 1992; Niu et al, 1993; Zhu et al, 1993b) These studies have been rationalized on the assumption that amongst these genes are molecular determinants of osmotic tolerance Although the products of many of these genes still remain unidentified there are a number that have been well characterized and are of interest of several laboratories One of these genes is osmotin (Singh et al, 1987a; LaRosa et al, 1989, Meeks-Wagner et al, 1989; Grosset et al, 1990; Roberts and Selitrennikoff, 1990; Stintzi et al, 1991; Woloshuk et al, 1991; Casas et al, 1992; LaRosa et al, 1992, Kononowicz et al, 1993)

Osmotin gene promoter and use thereof

Abstract: Described are an isolated DNA fragment incorporating an osmotin gene promoter sequence, recombinant DNA incorporating a foreign structural gene under control of an osmotin gene promoter sequence, as well as methods and transformants involving the isolated DNA fragment and recombinant DNA. Also described are methods for the inhibition of fungal, insect, nematode, and viral pathogens in a plant using such recombinant DNA.

Planf Gene Regisfer Molecular Cloning and Expression of a Clyceraldehyde-3-Phosphate Dehydrogenase Gene in a Desert Halophyte, Atriplex nummularia 1.'

Abstract: Plants must constantly respond to various environmental stresses during growth and development. Heat-shock and anaerobic stress are known to alter the expression of many genes (Sachs and Ho, 1986). Among them is the GAPDH gene that encodes an enzyme in the glycolytic pathway (Russell and Sachs, 1989; Yang et al., 1993). The enzyme catalyzes the NAD+-dependent oxidative phosphorylation of glyceraldehyde-3-P, generating a high-energy intermediate, 1,3-bisphosphoglycerate, one of the most important metabolic reactions in the glycolytic pathway (Mathews and van Holde, 1990). As an altemative ATP-producing pathway, the activation of the GAPDH gene may be an adaptative response to heat-stress-related mitochondrial damage or anaerobic stress-induced inhibition of oxidative phosphorylation. The elucidation of the functional significance of this induction will provide insight into primary carbon metabolism involved in cellular responses to environmental stresses. Atriplex nummularia L., a salt bush indigenous to the Negev desert, tolerates high temperature and osmotic stresses. We have obtained a cDNA done encoding the GAPDH from A . nummularia and characterized its regulation in response to heat and anaerobic stress. Comparison of the deduced amino acid sequence from the A. nummularia cDNA with those in data bases indicates a high degree of conservation for this enzyme among plants (Table I). The largest open reading frame within the 1339-bp cDNA encodes a polypeptide of 360 amino acids. The predicted peptide contains highly conserved domains for NAD+ binding (residues 1-151) and catalytic function (residues 152338), as well as functionally important residues: C Y S ' ~ ~ for glyceraldehyde-3-P binding and His'*' for thiol group activation during glycolysis (Martinez et al., 1989). A unique feature of the peptide encoded by this particular cDNA is the extension at the carboxyl terminus, resulting in a protein about 20 amino acids longer than other GAPDHs. The significance of the extra amino acids at the C terminus is unknown; however, it would be intriguing to determine its possible function in gene expression. Using the full-length cDNA as a probe, we detected

Cloning of a Dna Fragment Encoding γ-Glutamyl Kinase and γ-Glutamyl Phosphate Reductase from a Tomato cDNA Library

Abstract: We cloned the gene encoding the first enzyme of proline synthesis from tomato (L esculentum) by complementation of a proB mutation in E coli with a λgt-11 cDNA library of tomato fruit We obtained seven phages which were able to restore proline prototrophy to the proB mutant The insert from one of the complementing phages, PRO1, was subcloned into plasmid pBluescript IIKS+ When transferred into a mutant ΔproBA (which is deficient in both the first and second enzymes of proline biosynthesis, γ-glutamyl kinase and γ-glutamyl phosphate reductase), the PRO1 gene was able to complement this deletion mutation Assays of the coupled γ-glutamyl kinase/γ-glutamyl phosphate reductase activity of E coli proB or ΔproBA mutant strains revealed that these strains have elevated levels of both γ-glutamyl kinase and γ-glutamyl phosphate reductase These results indicate that the PRO1 gene is a hybrid locus which specifies both enzymatic activities