Sodium azide mutagenesis: preferential generation of A.T--&gt;G.C transitions in the barley Ant18 gene.

Olsen, Ole; Wang, Xingzhi; Wettstein, Diter von

doi:10.1073/pnas.90.17.8043

Cited by 91 publications

(48 citation statements)

References 28 publications

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“…GC base pair substitutions three times more frequent than GC ? AT (Olsen et al 1993). Sodium azide was used to mutagenize barnyard grass in this study, although we expected low mutation frequency due to the polyploidy nature of the species (allohexaploidy) that renders mutagenesis harder because of the buffering effect of multiple genomes (Stebbins 1971).…”

Section: Discussionmentioning

confidence: 99%

Vegetative salt tolerance of barnyard grass mutants selected for salt tolerant germination

Abogadallah

Quick

2009

Acta Physiol Plant

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Improving salt tolerance of economically important plants is imperative to cope with the increasing soil salinity in many parts of the world. Mutation breeding has been widely used to improve plant performance under salinity stress. In this study, we have mutagenized Echinochloa crusgalli L. with sodium azide and three selected mutants (designated fows A) with salt tolerant germination. Their vegetative growth was compared to that of the wild type after short-term and long-term salt stress. The germination of the three fows A mutants in the presence of inhibitory concentrations of NaCl, KCL, and mannitol was better than that of the wild type. Early growth of the mutants in the presence of 200 mM NaCl was also better than that of the wild type perhaps due to improved K ? uptake and enhanced accumulation of sugars particularly sucrose at least in two mutants. But the three mutants and the wild type responded similarly to long-term salt stress. The tolerance mechanisms during short-term and long-term salt stress are discussed.

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Section: Discussionmentioning

confidence: 99%

Vegetative salt tolerance of barnyard grass mutants selected for salt tolerant germination

Abogadallah

Quick

2009

Acta Physiol Plant

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“…NaN 3 and 4NOP were identified for this purpose. NaN 3 is known to induce missense mutations (Olsen et al 1993) while 4NOP primarily induces deletions and insertions (Ames et al 1975). Because TA1535 contains a missense allele (of HisG) and TA1538 contains a frameshift allele (of HisD), each mutagen should produce a different reversion frequency with the two Salmonella strains.…”

Section: Resultsmentioning

confidence: 99%

Reinventing the Ames Test as a Quantitative Lab That Connects Classical and Molecular Genetics

Goodson-Gregg

Stasio

2009

Genetics

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While many institutions use a version of the Ames test in the undergraduate genetics laboratory, students typically are not exposed to techniques or procedures beyond qualitative analysis of phenotypic reversion, thereby seriously limiting the scope of learning. We have extended the Ames test to include both quantitative analysis of reversion frequency and molecular analysis of revertant gene sequences. By giving students a role in designing their quantitative methods and analyses, students practice and apply quantitative skills. To help students connect classical and molecular genetic concepts and techniques, we report here procedures for characterizing the molecular lesions that confer a revertant phenotype. We suggest undertaking reversion of both missense and frameshift mutants to allow a more sophisticated molecular genetic analysis. These modifications and additions broaden the educational content of the traditional Ames test teaching laboratory, while simultaneously enhancing students' skills in experimental design, quantitative analysis, and data interpretation. While data analysis has long been a staple of student learning, recent research demonstrates that students become most engaged and learn best when they have a hand in the design of experiments as well as in the execution and analysis of resulting data (Hake 1998;Merkel 2003;Handelsman et al. 2007). Inquiry-based labs have been shown to improve students' research skills in biology (Myers and Burgess 2003). Further, as suggested by BIO2010 (National Research Council 2003), biology curricula should explicitly build the quantitative skills of budding biologists. Hack and Kendall (2005) argue that biology curricula should change because current life science students must learn to use models, to apply appropriate mathematic tools and statistics to solve problems, and to manage and integrate data. That these tools are best taught in the context of biology courses themselves has been demonstrated by Metz (2008), who has shown that undergraduate biology students do not make connections between quantitative concepts taught in mathematics and statistics courses and their application to biological problems. Metz (2008) demonstrates that inclusion of quantitative and statistical analyses in biology laboratory courses led to significant gains in long-term retention of such knowledge, regardless of whether students also had taken courses in statistics.To address the issue of connecting quantitative analysis and biological problem solving, we have extended the open-ended Ames test for the undergraduate genetics lab to allow students to practice quantitative skills during student-driven experimental design and analysis. Students bring to the lab potential mutagens of their choice, and they are charged both with creating methods to determine the number of colony-forming units (CFUs) per bacterial culture and with using that figure to determine reversion frequencies. We find that this is a difficult task for students, but having them conclude what sort of s...

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“…The largely unpredictable relative yields of the mutants compared to their mother genotypes could also have resulted from mutations at additional loci. Sodium azide has a high capacity to induce multiple mutations (Olsen et al 1993). The presence of side effects produced by unwanted additional mutations in mutants selected for breeding purposes has long been documented (Sigurbjörnsson 1977), and backcrossing to the mother genotype is almost always required.…”

Section: Discussionmentioning

confidence: 99%

Mildew-resistant mutants induced in North American two- and six-rowed malting barley cultivars

Molina-Cano

Simiand²,

Sopena

et al. 2003

Theor Appl Genet

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Mildew-resistant mutants were induced with sodium azide in three North American malting barley cultivars, two in the six-rowed Ursula (URS1 and URS2), one in the six-rowed Gertrud (GER1), and one in the two-rowed Prudentia (PRU1). Two of the mutants, URS1 and PRU1, showed complete resistance and were shown to have two new alleles at the mlo locus; these were designated, respectively, mlo31 and mlo32. Mutant URS2, showing partial resistance, was inherited as a dominant gene, but was not an allele at the Mla locus. The mean yield of each mutant was higher than that of its parental line, but yield levels varied across environments, although this was independent of the severity of the mildew attack. Other reasons, for example, the severity of the necrotic lesions in the mutants, may account for yield variations. The malting quality of the GER1 mutant proved similar to that of Gertrud, but both URS1 and URS2 showed lower malt extract than Ursula. This lower extract might be due to the smaller grain size of the mutants that could, in turn, result from necrotic lesions in the leaves, as implied by the effects on grain yield.

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Sodium azide mutagenesis: preferential generation of A.T-->G.C transitions in the barley Ant18 gene.

Cited by 91 publications

References 28 publications

Vegetative salt tolerance of barnyard grass mutants selected for salt tolerant germination

Vegetative salt tolerance of barnyard grass mutants selected for salt tolerant germination

Reinventing the Ames Test as a Quantitative Lab That Connects Classical and Molecular Genetics

Mildew-resistant mutants induced in North American two- and six-rowed malting barley cultivars

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