Biologia plantarum, an international journal for experimental botany founded in 1959 by Professor Bohumil Němec. Covers all branches of experimental botany ranging from molecular biology and biotechnology to whole-plant and stand functioning.

Biologia plantarum, an international journal for experimental botany founded in 1959 by Professor Bohumil Němec. Covers all branches of experimental botany ranging from molecular biology and biotechnology to whole-plant and stand functioning.

Biologia plantarum, an international journal for experimental botany founded in 1959 by Professor Bohumil Němec. Covers all branches of experimental botany ranging from molecular biology and biotechnology to whole-plant and stand functioning.

Biologia plantarum, an international journal for experimental botany founded in 1959 by Professor Bohumil Němec. Covers all branches of experimental botany ranging from molecular biology and biotechnology to whole-plant and stand functioning.

Environmental and Molecular MutagenesisVolume 30, Issue 1 p. 91-93 Brief CommunicationFull Access Tobacco cotyledons: A novel system for testing mutagenicity in plants Ivan Babůrek, Ivan Babůrek Institute of Experimental Botany, Praha, Czech RepublicSearch for more papers by this authorBlanka Stibůrkovaá, Blanka Stibůrkovaá Institute of Experimental Botany, Praha, Czech RepublicSearch for more papers by this authorAvi Levy, Avi Levy Weizmann Institute of Science, Department of Plant Genetics, Rehovot, IsraelSearch for more papers by this authorKarel J. Angelis, Corresponding Author Karel J. Angelis [email protected] Institute of Experimental Botany, Praha, Czech RepublicInstitute of Experimental Botany, Na Karlovce 1a, 160 00 Praha 6, Czech RepublicSearch for more papers by this author Ivan Babůrek, Ivan Babůrek Institute of Experimental Botany, Praha, Czech RepublicSearch for more papers by this authorBlanka Stibůrkovaá, Blanka Stibůrkovaá Institute of Experimental Botany, Praha, Czech RepublicSearch for more papers by this authorAvi Levy, Avi Levy Weizmann Institute of Science, Department of Plant Genetics, Rehovot, IsraelSearch for more papers by this authorKarel J. Angelis, Corresponding Author Karel J. Angelis [email protected] Institute of Experimental Botany, Praha, Czech RepublicInstitute of Experimental Botany, Na Karlovce 1a, 160 00 Praha 6, Czech RepublicSearch for more papers by this author First published: 21 December 1998 https://doi.org/10.1002/(SICI)1098-2280(1997)30:1<91::AID-EM12>3.0.CO;2-LCitations: 1AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onEmailFacebookTwitterLinkedInRedditWechat No abstract is available for this article. References Angelis KJ, Brdřèza J, Šatava J, Skaákal I, Velemĺnský J, Vlasaák J, Kleibl K, Margison GP (1993): Increased resistance to the toxic effects of alkylating agents in tobacco expressing E. coli DNA repair gene ada. Mutat Res 273: 271–280. Britt A (1996): DNA damage and repair in plants. Annu Rev Plant Phys Plant Mol Biol 47: 75–100. Brdřèza J, Angelis KJ, Šatava J, Babůrek I, Velemĺnský J (1993): Resistance to ACNU induced toxicity in transgenic tobacco suspension cultures with ada gene transferred from Escherichia coli. Biol Plantarum 35: 125–129. Carlson F (1974): Mitotic crossing-over in a higher plant. Genet Res 24: 109–112. Dulieu HL, Dalebroux MA (1975): Spontaneous and induced reversion severrate in a double heterozygous mutant of Nicotiana tabacum var. xanthi N.C.-dose-response relationship. Mutat Res 30: 63–70. Friedlender M, Lev-Yadun S, Babůrek I, Angelis KJ, Levy A (1996): Cell divisions in cotyledons of germinating seeds of Nicotiana tabacum, Petunia hybrida, and Arabidopsis thaliana. Planta 199: 307–313. Horsch RB, Fry JE, Hoffmann NL, Eichholtz D, Rogers SG, Fraley RT (1985): A general and simple method for transferring genes into plants. Science 227: 1229–1231. Velemĺnský J, Angelis KJ, Babůrek I, Gichner T, Šatava J, Brdřèza J, Margison GP (1994): An E. coli ada transgenic clone of Nicotiana tabacum var. xanthi has an increased sensitivity to the mutagenic action of alkylating agents, maleic hydrazide and γ-rays. Mutat Res 307: 193–200. Citing Literature Volume30, Issue11997Pages 91-93 ReferencesRelatedInformation

Two transgenic clones X3 and X15 of Nicotiana tabacum var. Xanthi, heterozygous in two genes (a1 and a2) for chloroplast differentiation and transformed with the E. coli DNA repair gene ada cloned downstream from the 1' direction of the dual mas promoter, differed in the expression of the ada gene, in the number of copies of integrated T-DNA and in the response to the mutagenic action of alkylating and non-alkylating agents. The X3 genome contained four copies and the X15 genome one copy of T-DNA, nevertheless the expression of the ada gene, measured by the activity of O6-alkylguanine DNA alkyltransferase (ATase), was about six times higher in X15 than in X3. ATase activity in both clones was highest in extracts from callus whereas very low (X15) or no (X3) activity was detected in leaf extracts. This may explain the lack of difference between X15 and non-transformed tobacco (NTX) in the frequency of N-methyl-N-nitrosourea (MNU)-induced somatic mutations in leaves. In contrast, the frequency of somatic mutations in X3 was about 2-5 times higher than in NTX and X15 after the same doses of MNU, methyl methanesulfonate, maleic hydrazide and gamma-rays. Alteration of plant gene(s) essential in mutation pathway(s) by insertion of T-DNA or by somaclonal variation may explain the higher sensitivity of the X3 clone.

The protein coding region of theE. coli DNA repair geneada combined with the CaMV 35S promoter has been transferred to tobacco by means ofAgrobacterium tumefaciens Ti plasmid. In transgenic plants having theada gene in a sense orientation, detectable amounts of O6-alkylguanine-DNA-alkyltransferase has been found whereas in non-transformed plants this activity is absent. Cell suspension cultures derived from the former plants showed lower sensitivity to the toxic (growth inhibiting) effects of the bifunctional alkylating agent 1-(2-chloroethyl)-1-nitroso-3-(aminomethyl-1,3-diazinylo)-methylurea compared with cell cultures derived from a control non-transformed plant or from transgenic plants harbouring theada gene in an opposite, non-sense orientation.

UV-irradiation (254 nm, 10 or 20 J/cm2) of p-aminobenzoic acid (PABA) and p-aminosalicylic acid (NaPAS) potentiated their antimutagenicity towards N-methyl-N'-nitro-N-nitrosoguanidine mutagenesis in Salmonella typhimurium. Their inhibitory action towards the formation of the mutagen N-methyl-N-nitrosourea from the nitrosation mixture of N-methylurea and nitrite was also increased by UV-irradiation. In contrast, UV-irradiated PABA exhibited no inhibitory effects towards the mutagenicity of sodium azide or 3-azidoglycerol. Neither PABA nor NaPAS nor their UV-irradiation products were themselves mutagenic in the Ames assay.

In biological experiments the ionizing radiation is usually defined by the type, energy and total absorbed dose, as well as by the dose rate. If radiation generated by a physical particle accelerator is employed, we consider it necessary to supplement these data with the value for frequency of pulses of the ionizing radiation jet. As follows from our experiments, this parameter expressively affects the relative biological effect of ionizing radiation.