scholarly journals A plant cation–chloride co-transporter promoting auxin-independent tobacco protoplast division

1997 ◽  
Vol 16 (19) ◽  
pp. 5855-5866 ◽  
Author(s):  
Hinrich Harling ◽  
Inge Czaja ◽  
Jeff Schell ◽  
Richard Walden
Keyword(s):  
Tobacco Protoplast ◽  
Protoplast Division

Isolation, Culture and Plant Regeneration From Protoplasts of Nicotiana debneyi

1980 ◽  
Vol 7 (6) ◽  
pp. 635 ◽  
Author(s):  
WR Scowcroft ◽  
PJ Larkin
Keyword(s):  
Acetic Acid ◽  
Plant Regeneration ◽  
Indole Acetic Acid ◽  
High Efficiency ◽  
Protoplast Culture ◽  
Callus Cultures ◽  
Dna Uptake ◽  
Mesophyll Protoplasts ◽  
Nicotiana Debneyi ◽  
Protoplast Division

Mesophyll protoplasts of two genetically distinct genotypes of N. debneyi were cultured with sustained division following a plating efficiency in excess of 50%. Fully fertile mature plants were regenerated from callus cultures derived from protoplasts. Shoots were induced in medium containing 1 mg/l 6-benzylaminopurine and 0.5 mg/I indole acetic acid. The repeatably high efficiency of protoplast culture was used to evaluate the quantitative effects of two drugs, kanamycin and trimethoprim, which effectively inhibited colony formation at concentrations of 100 and 50 �g/ml, respectively. An enhancer of DNA uptake, poly-L-ornithine, had virtually no effect on sustained protoplast division at a concentration of 7.5 �g/ml or less.

scholarly journals Some properties of tobacco protoplast chromatin

1976 ◽  
Vol 3 (9) ◽  
pp. 2315-2330 ◽  
Author(s):  
C. Gigot ◽  
G. Philipps ◽  
A. Nicolaieff ◽  
L. Hirth
Keyword(s):  
Tobacco Protoplast

scholarly journals Lipopeptide Phytotoxins Produced by Pseudomonas syringae pv. syringae: Comparison of the Biosurfactant and Ion Channel-Forming Activities of Syringopeptin and Syringomycin

1997 ◽  
Vol 10 (3) ◽  
pp. 347-354 ◽  
Author(s):  
Michael L. Hutchison ◽  
Dennis C. Gross
Keyword(s):  
Ion Channel ◽  
Pseudomonas Syringae ◽  
Lipid Membranes ◽  
Divalent Cations ◽  
Critical Micellar Concentration ◽  
Threshold Concentration ◽  
Phytopathogenic Bacterium ◽  
Black Lipid Membranes ◽  
Tobacco Protoplast ◽  
Plant Membranes

The phytopathogenic bacterium Pseudomonas syringae pv. syringae produces two classes of necrosis-inducing lipodepsipeptide toxins commonly referred to as the syringomycins and syringopeptins. Members of the syringomycin class are pore-forming cytotoxins that act by promoting passive transmembrane ion flux. In this study, we test the hypothesis that syringopeptin forms SP22A and SP22B likewise function as pore-forming cytotoxins and are similar in activity to syringomycin in artificial and plant membranes. Correspondingly, syringopeptin increased the conductance of black-lipid membranes in a manner indicative of ion channel formation. In tobacco protoplast assays, syringopeptin forms SP22A and SP22B were equivalent in activity causing lysis of protoplasts and measurable 45Ca2+ influx at a threshold concentration of 50 ng/ml. A mixture of three forms of syringomycin did not show cytotoxic activity appreciably different from that of SP22A or SP22B in tobacco protoplast assays. Both forms of syringopeptin also displayed potent biosurfactant properties demonstrated by lowering of the interfacial tension of high-pressure liquid chromatography-grade water to 36 and 34.5 nm/m, respectively; the critical micellar concentration was 0.8 mg/ml for both forms of toxin. These results demonstrate that both classes of pore-forming lipodepsipeptides secreted by P. syringae pv. syringae are cytotoxic to plant cells at nanomolar concentrations and cause necrosis by forming ion channels that are freely permeable to divalent cations.

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