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A genetic and biochemical analysis of a mutant of Arabidopsis thaliana resistant to alpha-methyltryptophan

Kreps, Joel Andrew
http://rave.ohiolink.edu/etdc/view?acc_num=case1060870885

Abstract Details

1993, Doctor of Philosophy, Case Western Reserve University, Biology.
Mutants of Arabidopsis thaliana have been selected for resistance to growth inhibition at the seedling stage by alpha-methyltryptophan (αMT). One mutant, amt-1 has been characterized in detail. The appearance and growth rate of the mutant in the absence of the inhibitor are similar to wild-type, both as plants and callus. However mutant plant growth is unaffected by 25 μM αMT and mutant callus growth by 50 μM αMT, concentrations which completely inhibit the growth of wild-type plants and callus respectively. Tryptophan levels in mutant and wild-type plants are 24.3 ± 2.7 and 4.7 ± 1.2 μg/g freshweight respectively and in the corresponding callus 64.0 ± 2.6 and 31.8 ± 8.4 μg/g fresh weight, respectively. Anthranilate synthase activity levels (nmol/mg protein hr) in crude extracts from whole plants are 3.09 ± 0.54 in amt-1 and 1.32 ± 0.21 in wild-type plants. In crude extracts from callus, anthranilate synthase levels are 11.54 ± 2.05 in amt-1 and 7.74 ± 1.58 in wild-type. Enzyme extracts from plants and callus are inhibited by L-tryptophan; IC50 values are 4.6 ± 0.6 μM for amt-1 plants and 1.5 ± 0.5 μM for wild-type plant extracts and 6.9 ± 0.4 and 3.4 ± 0.5 for mutant and wil d-type callus extracts respectively. The mutation segregates as a single nuclear allele, shows incomplete dominance, and maps to the top of Chromosome V within 1.5 map units of ASA1, a gene for the large subunit of anthranilate synthase. The concommitant increases in both anthranilate synthase activity and its IC50 for tryptophan suggest that the mutation amt-1 resides either in one of the anthranilate synthase structural genes or in a gene whose product modifies anthranilate synthase activity
Christopher Town (Advisor)
114 p.
Biology, Plant Physiology
Arabidopsis; Alpha-methyltryptophan

Recommended Citations

Citations

  • Kreps, J. A. (1993). A genetic and biochemical analysis of a mutant of Arabidopsis thaliana resistant to alpha-methyltryptophan [Doctoral dissertation, Case Western Reserve University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=case1060870885

    APA Style (7th edition)

  • Kreps, Joel. A genetic and biochemical analysis of a mutant of Arabidopsis thaliana resistant to alpha-methyltryptophan. 1993. Case Western Reserve University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=case1060870885.

    MLA Style (8th edition)

  • Kreps, Joel. "A genetic and biochemical analysis of a mutant of Arabidopsis thaliana resistant to alpha-methyltryptophan." Doctoral dissertation, Case Western Reserve University, 1993. http://rave.ohiolink.edu/etdc/view?acc_num=case1060870885

    Chicago Manual of Style (17th edition)

case1060870885
543
© 1993, all rights reserved.
This open access ETD is published by Case Western Reserve University School of Graduate Studies and OhioLINK.