Accumulation of phytuberin and phytuberol in tobacco callus inoculated with Pseudomonas solanacearum or Pseudomonas syringae pv. Tabaci

Tobacco callus tissues inoculated with Pseudomonas solanacearum or Pseudomonas syringae pv. tabaci accumulated phytuberin and phytuberol. Accumulation of the two sesquiterpenoids was dependent upon: the source (cultivar) of the explant; the number of transfers; the period which had elapsed after transfer; the bacterial species, and the time after inoculation.     

Stress compounds in tobacco callus infiltrated by Pseudomonas solanacearum

Two sesquiterpenoids, phytuberin and phytuberol, have been identified in tobacco callus infiltrated by Pseudomonas solanacearum.     

Sesquiterpenoid stress compounds from Nicotiana rustica inoculated with TMV

Sesquiterpenoid stress compounds, occidol, occidol isomer-1 occidol isomer-2, occidol acetate and phytuberin have been isolated from the leaves of Nicotiana rustica inoculated with TMV. Isomers 1 and 2 and the acetate are sesquiterpenoids not previously reported in nature.     

Evidence for O-acetylserine in Nicotiana tabacum

O-Acetylserine, a precursor of cysteine in plants, was isolated from cells of Nicotiana tabacum cultured in liquid medium.     

Sesquiterpenoid stress compounds from Nicotiana species

Solavetivone, 3-hydroxysolavetivone, solanascone, phytuberin and phytuberol were identified as stress compounds in leaves of Nicotiana tabacum cv Samsun NN. N. sylvestris, which is the maternal progenitor of N. tabacum, produced all the above compounds except 3-hydroxysolavetivone. In the F₁, hybrid of N. tabacum and N. glutinosa, all the stress compounds produced by N. tabacum and N. glutinosa, respectively, were accumulated.     

A damascone derivative from Nicotiana tabacum

A new member of the damascone series, 4-hydroxy-β-damascone, was identified in the steam distillable oil from Virginia tobacco.     

Ferulic acid: a substrate for two isoperoxidases from Nicotiana tabacum tissue cultures

An anodic isoperoxidase (A₂) from tobacco tissue culture W-38 and a cathodic isoperoxidase (C₄) from tobacco tissue suspension culture WR-132 have been separated and characterized. Both isoperoxidases catalysed oxidation of ferulic acid in the presence of H₂O₂. When the reaction mixture was subjected to TLC, ferulic acid was found to have been converted to an unknown compound which, after treatment with ammonia, fluoresces green in UV light. Both the isoperoxidases A₂ and C₄ appear to follow simple Michaelis-Menten kinetics with respect to guaiacol as the substrate. The Kms for guaiacol are 4 and 4·5 mM for isoperoxidases C₄ and A₂, respectively. The pH optimum for both enzymes is about 6·0. The effect of various phenolic and related compounds on the activity of each isoperoxidase is reported and discussed.     

Stress compounds from Nicotiana rustica inoculated with TMV

Three new sesquiterpenoid stress compounds, occidenol, occidentalol and trans-occidentalol, have been isolated from the leaves of Nicotiana rustica inoculated with TMV.     

Pectolytic enzyme activity from Nicotiana tabacum pollen

Ungerminated pollen of Nicotiana tabacum contains a pectolytic enzyme which has its optimal activity between pH 5.5 and 6.5. Pectic lyase was not detected.     

β-d-glucosidase activity in developing leaves of Nicotiana tabacum

Tobacco (Nicotiana tabacum L. cv. Burley 21) leaves were assayed for β-d-glucosidase activity, using esculin as substrate. The enzymatically produced esculetin was silylated and quantitatively measured by GLC, using a tritium foil electron-capture detector. In field-grown plants, the activity in mid-stalk leaves increased with plant maturation; conversely, the activity in the top leaves decreased.     

An acidic xylan from extracellular polysaccharides of suspension-cultured cells of Nicotiana tabacum

An acidic xylan was isolated from the extracellular polysaccharides of suspension-cultured tobacco cells. Its structure was investigated by methylation analysis and ¹³C NMR spectroscopy and was shown to consist of a main chain of β-(1→4)-linked D-xylopyranosyl residues to which were attached as side-chains, α-D-glucuronic acid residues at O-2.     

Scopoletin: A substrate for an isoperoxidase from Nicotiana tabacum tissue culture W-38

Scopoletin was found to be a substrate for a single anodic isoperoxidase isolated from tobacco callus tissue W-38. Isolation of this peroxidase was accomplished using DEAE-cellulose chromatography. This isoperoxidase catalysed the destruction of scopoletin in the presence of H₂O₂ only. An enzyme assay for the scopoletin reaction was developed. The pH optimum of the enzyme was 5·5 and the apparent K_ms for scopoletin and H₂O₂ were 0·6 and 0·9 rnM respectively.     

Sesquiterpenoid phytoalexins from suspended callus cultures of Nicotiana tabacum

Treatment of suspended callus cultures of Nicotiana tabacum with commercial cellulase elicited four principal stress metabolites including the phytoalexin capsidiol and a second eremophilane-type diol, shown on the basis of chemical and spectroscopic evidence to be 4-epieremophil-9-ene-11 /gx, 12-diol (without assignment of absolute configuration). This diol appears to be structurally identical with debneyol isolated from N. debneyi (see accompanying paper). Among minor metabolites were an isomer and a dehydro-analogue of the diol. GC/MS of cyclic derivatives (boronates and di-t-butylsilylene derivatives) of vicinal diols was useful for their detection and characterisation. The remaining two major metabolites appeared to be phytuberol and phytuberin.     

Volatile acids of sun-cured greek Nicotiana tabacum

The volatile acids of sun-cured Greek tobacco have been studied. Examination of this material by GC-MS supplemented by other spectroscopic methods and in some instances by synthesis, has permitted the identification of nearly a hundred compounds. About half of them have not been encountered previously in tobacco or tobacco smoke, and the majority of the new compounds are straight and branched-chain unsaturated acids and aromatic acids. Five of the oxygenated acids are evidently seco- or nor-terpenoids.