Comparison of cytokinin-binding proteins from wheat and oat grains.

Cytokinin-binding proteins (CBPs) isolated from mature grains of oat (Avena sativa L.) and wheat (Triticum aestivum L.) by acid precipitation, ion-exchange and affinity chromatography had similar characteristics, although they differed somewhat in apparent molecular weight of the native protein as determined by gel filtration (109 and 133 kDa, respectively) and subunit size as estimated by SDS-polyacrylamide gel electrophoresis (47 and 55 kDa, respectively).

Cytokinin oxidase from wheat: partial purification and general properties.

As part of the study of the possible role(s) of CBF-1, a cytokinin-binding protein abundant in wheat embryo, a cytokinin oxidase was found in wheat (Triticum aestivum L.) germ and partially purified by conventional purification techniques and high performance chromatofocusing. This preparation catalyzes conversion of N(6)-(Delta(2)-isopentenyl)adenosine to adenosine at a V(max) of 0.

Characterization of a benzyladenine binding-site peptide isolated from a wheat cytokinin-binding protein: sequence analysis and identification of a single affinity-labeled histidine residue by mass spectrometry.

A wheat embryo cytokinin-binding protein was covalently modified with the radiolabeled photoaffinity ligand 2-azido-N6-[14C]benzyladenine. A single labeled peptide was obtained after proteolytic digestion and isolation by reversed-phase and anion-exchange HPLC. Sequencing by classical Edman degradation identified 11 of the 12 residues but failed to identify the labeled amino acid.

Inhibition of Mung Bean UDP-Glucose: (1-->3)-beta-Glucan Synthase by UDP-Pyridoxal: Evidence for an Active-Site Amino Group.

UDP-pyridoxal competitively inhibits the Ca(2+)-, cellobiose-activated (1-->3)-beta-glucan synthase activity of unfractionated mung bean (Vigna radiata) membranes, with a K(i) of 3.8 +/- 0.7 micromolar, when added simultaneously with the substrate UDP-glucose in brief (3 minute) assays.

Homology of Saccharomyces cerevisiae ADH4 to an iron-activated alcohol dehydrogenase from Zymomonas mobilis.

Insertion of the transposable element Ty at the ADH4 locus results in increased levels of a new alcohol dehydrogenase (ADH) activity in Saccharomyces cerevisiae. The DNA sequence of this locus has been determined. It contains a long open reading frame which is not homologous to the other ADH isozymes that have been characterized in S.

Chilling sensitivity of cucumber cotyledon protoplasts and seedlings.

Cucumber (Cucumis sativus L.) seedlings are more sensitive to chilling stress when transferred to low temperature from the night cycle than from the day cycle. However, greater damage occurs when chilling is carried out in light than in dark.

Identification of a receptor protein in cotton fibers for the herbicide 2,6-dichlorobenzonitrile.

The herbicide 2,6-dichlorobenzonitrile (DCB) is an effective and apparently specific inhibitor of cellulose synthesis in higher plants. We have synthesized a photoreactive analog of DCB (2,6-dichlorophenylazide [DCPA]) for use as an affinity-labeling probe to identify the DCB receptor in plants. This analog retains herbicide activity and inhibits cellulose synthesis in cotton fibers and tobacco cells in a manner similar to DCB.

Purification and properties of Acid phosphatase-1 from a nematode resistant tomato cultivar.

In tomato the acid phosphatase-1 isozyme (Apase-1) is inherited as a single locus linked to the nematode resistance gene (Mi). The Apase-1(1) electrophoretic variant has been purified from a tomato cell suspension culture using ion exchange and concanavalin A sepharose affinity chromatography. A cellulose acetate electrophoresis method was used to distinguish Apase-1(1) rapidly from other Apase isozymes in tomato.

Cloning and sequence analysis of a cDNA encoding a Brazil nut protein exceptionally rich in methionine.

The primary amino acid sequence of an abundant methionine-rich seed protein found in Brazil nut (Bertholletia excelsa H.B.K.

Ri-plasmid as a helper for introducing vector DNA into alfalfa plants.

Genetic engineering of legumes and other important dicotyledonous plants is limited because of the difficulty of regenerating plants via cell culture. Since a considerable number of crop plants can be regenerated only from root culture, the introduction of foreign genes into Agrobacterium rhizogenes-induced hairy roots may expand the list of crop plants that could be genetically engineered. Here we report genetic transformation of alfalfa (Medicago sativa L.

Role of benzoxazinones in allelopathy by rye (Secale cereale L.).

Two phytotoxic compounds [2,4-dihydroxy-1,4(2H)-benzoxazin-3-one (DIBOA) and 2(3H)-benzoxazolinone (BOA)] were previously isolated and identified in 35-day-old greenhouse-grown rye shoot tissue. Both compounds were also detected by TLC in greenhouse-grown root and fieldgrown shoot tissue. The concentration of DIBOA varied in the tissues, with the greatest quantity detected in greenhouse-grown shoots.

UDP-Glucose: (1-->3)-beta-Glucan Synthases from Mung Bean and Cotton: Differential Effects of Ca and Mg on Enzyme Properties and on Macromolecular Structure of the Glucan Product.

A re-examination of the kinetic properties of UDP-glucose: (1-->3)-beta-glucan (callose) synthases from mung bean seedlings (Vigna radiata) and cotton fibers (Gossypium hirsutum) shows that these enzymes have a complex interaction with UDP-glucose and various effectors. Stimulation of activity by micromolar concentrations of Ca(2+) and millimolar concentrations of beta-glucosides or other polyols is highest at low (<100 micromolar) UDP-glucose concentrations. These effectors act both by raising the V(max) of the enzyme, and by lowering the apparent K(m) for UDP-glucose from >1 millimolar to 0.

Pea Xyloglucan and Cellulose: VI. Xyloglucan-Cellulose Interactions in Vitro and in Vivo.

Since xyloglucan is believed to bind to cellulose microfibrils in the primary cell walls of higher plants and, when isolated from the walls, can also bind to cellulose in vitro, the binding mechanism of xyloglucan to cellulose was further investigated using radioiodinated pea xyloglucan. A time course for the binding showed that the radioiodinated xyloglucan continued to be bound for at least 4 hours at 40 degrees C. Binding was inhibited above pH 6.

Identification of restriction fragment length polymorphisms linked to genes controlling soluble solids content in tomato fruit.

Gene(s) conferring high soluble solids (SS) in tomato fruit had been backcrossed previously from a wild tomato species, Lycopersicon chmielewskii LA1028 (∼ 10% SS), into a L. esculentum cultivar, VF36 (∼ 5% SS), to derive a BC5S5 line, LA1563, similar to 'VF 36' but with 7-8% SS. DNAs from these lines and a tomato breeding line, H2038, were screened for restriction fragment length polymorphisms (RFLPs) using four restriction endonucleases and sixty clones chosen at random from a tomato cDNA library.

A single dominant gene for Fusarium wilt resistance in protoplast-derived tomato plants.

Tomato plants resistant to the fungal pathogen, Fusarium oxysporum f. sp. lycopersici, race 2, were obtained using in vitro selection against fusaric acid, a non-specific toxin, as well as non-challenged cells.

Transformation of cucumber (Cucumis sativus L.) plants with Agrobacterium rhizogenes.

Transgenic cucumber plants (Cucumis sativus L., cv. 'Straight Eight') were regenerated from roots induced by inoculation of inverted hypocotyl sections with Agrobacterium rhizogenes containing the vector pARC8 in addition to the resident Ri-plasmid.

Transformation of cultivated tomato by a binary vector in Agrobacterium rhizogenes: transgenic plants with normal phenotypes harbor binary vector T-DNA, but no Ri-plasmid T-DNA.

Cultivated tomato was genetically transformed using two procedures. In the first procedure, punctured cotyledons were infected with "disarmed" Agrobacterium tumefaciens strain LBA4404 or with A. rhizogenes strain A4, each containing the binary vector pARC8.

The metabolism of sunflower phytoalexins ayapin and scopoletin: plant-fungus interactions.

The coumarin phytoalexins ayapin and scopoletin accumulate in longitudinal stem sections of sunflower (Helianthus annuus L., Compositae) following inoculation with fungi both pathogenic (Alternaria helianthi) and nonpathogenic (Helminthosporium carbonum) to this plant. Both compounds were induced more rapidly, and they attained higher levels in tissue inoculated with the heterologous pathogen H.

Gel-Electrophoretic Separation, Detection, and Characterization of Plant and Bacterial UDP-Glucose Glucosyltransferases.

We have developed procedures for detection and characterization of UDP-glucose: glucosyltransferases following electrophoretic separation in nondenaturing polyacrylamide gels. Using digitonin-solubilized membrane protein preparations from a variety of plants and two cellulose-producing bacteria, activity can be demonstrated for several UDP-glucose:beta-glucan synthases with an in situ assay following gel electrophoresis. These enzymes can be characterized within the gels with respect to effector requirements and products produced, and several advantages of this assay over solution assays are demonstrated.

Molecular properties of phosphoenolpyruvate carboxylase from C3, C 3-C 4 intermediate, and C 4 Flaveria species.

Phosphoenolpyruvate carboxylase (PEPCase; EC 4.1.1.

Biosynthesis and Degradation of a Wheat Embryo Cytokinin-Binding Protein during Embryogenesis and Germination.

The accumulation and degradation of a wheat (Triticum durum) embryo cytokinin-binding protein (CBF-1) was followed during embryo development and germination by its N(6)-benzyladenine (BA) binding activity and immunological reactivity (rocket immunoelectrophoresis and Western blotting). Both BA binding activity and CBF-1 appeared at 2 weeks post-anthesis and rose sharply between 2 to 4 weeks before leveling off to approximately 47 micrograms per embryo (9% of the soluble embryo protein at maturity). In vitro translation of polyadenylated RNA from 20-day-old embryos yielded a polypeptide which was immunoprecipitable with anti-CBF-1 IgG and migrated closely to the 54-kilodalton CBF-1 polypeptide on sodium dodecyl sulfate-polyacrylamide gel electrophoresis.

The Biosynthesis of the Pyrenocines in Cultures of Pyrenochaeta terrestris.

[(14)C]Acetate, [(14)C]formate, and methyl[(14)C]methionine all serve as precursors of pyrenocines A, B, and C when added to cultures of Pyrenochaeta terrestris (Hansen) Gorenz, Walker, and Larson, the pathogen responsible for disease known as pink root of onion (Allium cepa L.). This information supports the hypothesis that these metabolites are methyl-substituted polyketides in origin.

Phosphatidylglycerol synthesis in pea chloroplasts: pathway and localization.

Isolated intact pea chloroplasts synthesized phosphatidylglycerol from either [(14)C]acetate or [(14)C]glycerol 3-phosphate. Both time-course and pulse-chase labeling studies demonstrated a precursor-product relationship between newly synthesized phosphatidic acid and newly synthesized phosphatidylglycerol.The synthesis both of CDP-diacylglycerol from exogenous phosphatidic acid and CTP, and of phosphatidylglycerol from exogenous CDP-diacylglycerol and glycerol 3-phosphate, could be assayed in fractions obtained from disrupted chloroplasts.

Totipotency of tomato protoplasts.

An efficient and reliable protocol for tomato protoplast isolation, culture, and plant regeneration has been developed. Fourteen diverse cultivars were tested. Fertile plants were regenerated from all 14 cultivars without any modification in the protocol.

Characterization of the mRNA transcripts of the maize, ribulose-1,5-bisphosphate carboxylase, large subunit gene.

The analysis of RNA isolated from maize leaves indicates that there are two mRNA transcripts which are homologous to the chloroplast encoded gene for the large subunit of ribulose-1,5-bisphosphate carboxylase (rbcL). The 5' end of the smaller transcript, 1.62 Kb in length, begins at a position which is 60 nucleotides upstream from the coding sequence of the gene, corresponding to the position mapped by earlier workers.