An altered chloroplast ribosomal protein in a streptomycin resistant tobacco mutant

Yurina, N. P.; Odintsova, M. S.; Maliga, Pál

doi:10.1007/bf00264745

Cited by 35 publications

(2 citation statements)

References 12 publications

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“…Only a few studies have demonstrated expression in regenerated plants and sexual transmission of selected traits to progeny. These include resistance to methionine sulfoximine (1), streptomycin (2,3), Helminthosporium maydis race T toxin (4), picloram (5), and valine (6).…”

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confidence: 99%

Inheritance and expression of lysine plus threonine resistance selected in maize tissue culture

Hibberd

Green

1982

Proc. Natl. Acad. Sci. U.S.A.

103

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Selection for resistance to growth inhibition by lysine plus threonine in equimolar concentrations (LT) The heritability and expression in plants of traits selected in tissue culture are of particular concern to those using these methods for genetic modification of plants. Only a few studies have demonstrated expression in regenerated plants and sexual transmission of selected traits to progeny. These include resistance to methionine sulfoximine (1), streptomycin (2, 3), Helminthosporium maydis race T toxin (4), picloram (5), and valine (6).Selection for resistance to growth inhibition by lysine plus threonine in equimolar concentrations (LT) has been proposed as a means ofobtaining feedback-resistant mutants in the lysinethreonine-methionine-isoleucine (aspartate family) biosynthetic pathway (7). Reversal of LT inhibition by the addition of methionine or the methionine precursor, homoserine, indicates that inhibition is the result of methionine starvation (8, 9) and that altered phenotypes which increase methionine synthesis should provide resistance to LT inhibition. Aspartokinase and homoserine dehydrogenase, in the aspartate pathway, are subject to feedback inhibition by lysine and threonine, respectively, in maize (10, 11).In a recent report from this laboratory, we described the selection from tissue cultures ofmaize ofa stable LT-resistant line (D33) that contained aspartokinase with decreased sensitivity to lysine inhibition (12). Analysis offree amino acid pools in D33 cultures showed substantial increases in methionine and threonine and small increases for lysine and isoleucine. Attempts to determine the inheritance of LT resistance failed because of complete sterility in plants regenerated from D33 cultures.Additional LT-resistant lines have now been selected from which we have obtained regenerated plants and progeny. In this report, we describe the inheritance of LT resistance and the expression of this trait in tissue cultures and progeny of regenerated plants. METHODSThe initiation, maintenance, and incubation of tissue cultures from immature embryos were as described (13,14). Immature embryos, 1-2 mm in length, were obtained from a cross between inbred lines A188 and W22. Cultures were grown on Murashige and Skoog (MS) medium (50 ml per 25 X 100 mm Petri dish) containing 0.5 mg of2,4-dichlorophenoxyacetic acid (2,4-D) per liter. The cultures were transferred to fresh medium after 1 month, and after 2 months they were subdivided into pieces of ca. 20 mg of fresh weight and placed on 50 ml of MS medium. One drop of 0.1 M phosphate buffer (pH 3.0) containing 0, 0.1, 1, or 10 mM sodium azide was applied to each explant. This solution was completely absorbed into the tissue or growth medium after 1 hr. Eight days after azide treatment, lysine and threonine were added to the culture plates to give a final concentration of 2 mM for each. At monthly intervals, sectors of cultures which appeared to be alive (nonnecrotic) were transferred to fresh MS medium containing 2 mM LT.Plant regeneration wa...

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confidence: 99%

Inheritance and expression of lysine plus threonine resistance selected in maize tissue culture

Hibberd

Green

1982

Proc. Natl. Acad. Sci. U.S.A.

103

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“…Plant regeneration was possible only in two N. tabacum lines, SRI (Maliga et al, 1973;1975) and St-R701 (Umiel, 1978) and maternal inheritance of the resistance trait was demonstrated. In the SRI mutant, no other changes than alteration of the chloroplast ribosomes (Bourque et al, 1977;Yurina et al, 1978) could be shown.…”

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confidence: 99%