Effect of Aspartate‐derived Amino Acids and Aminoethyl Cysteine on Growth of Excised Mature Embryos of Maize<sup>1</sup>

Green, C. E.; Donovan, Christopher

doi:10.2135/cropsci1980.0011183x002000030018x

Cited by 14 publications

(6 citation statements)

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“…Two months after initiation, ca. 30-mg (fresh weight) pieces of these cultures were tested for growth on 0, 1.25, and 2.5 mm LT. Inheritance of LT resistance also was determined by using a bioassay based on seedling root length (9). Seeds sterilized for 20 min in 2.5% (wt/vol) sodium hypochlorite were soaked overnight in Orthocide (1 mg/ml; Chevron, San Francisco).…”

Section: Methodsmentioning

confidence: 99%

“…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).…”

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confidence: 99%

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

Hibberd

Green

1982

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

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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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Section: Methodsmentioning

confidence: 99%

mentioning

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.

Self Cite

103

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“…Secondly, the amide glutamine serves as an efficient source of nitrogen for the growth in culture of embryos of a number of plants (Rijven, 1956;Matsubara, 1964). Thirdly, mutual antagonism and synergism has been shown to exist between different amino acids in the growth of embryos (Sanders and Burkholder, 1948;Harris, 1956;Bright et al, 1978;Green and Donovan, 1980).…”

Section: Metabolic and Morphogenetic Studiesmentioning

confidence: 99%

One hundred years of zygotic embryo culture investigations

Raghavan

2003

In Vitro Cell. Dev. Biol. - Plant

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SummaryIsolation of zygotic embryos from seeds and their culture in a defined medium, initiated by Hannig in 1904, has proved to be a promising method to study the factors that control growth and differentiation of embryos. Using this technique, several investigations have focused on the carbohydrate and nitrogen nutrition during germination of cultured seed embryos and on the effects of plant hormones on their morphogenesis. Culture of immature embryos leads to their germination into weak seedlings, skipping the later stages of embryogenesis, by a process known as precocious germination. Progressively smaller embryos have been cultured by supplementation of the medium with coconut milk or hormonal additives or by osmotic adjustment of the medium by high concentrations of sucrose or mannitol. Although methods have not been developed for large-scale isolation and culture of zygotes, zygotes of maize isolated from embryo sacs and those obtained by in vitro fertilization have been grown in culture into full-term embryos. Embryo culture techniques are widely used to rescue embryos from seeds of wide crosses which usually abort and to overcome dormancy of recalcitrant seeds.

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“…4 94% ai, provided by American Cyanamid Co., Princeton, NJ. 5 1210 Ci/mmol, New England Nuclear. 6 55 Ci/mmol, ICN Pharmaceuticals, Inc.…”

Section: Introductionmentioning

confidence: 99%

Evidence for the Interaction of an Imidazolinone Herbicide with Leucine, Valine, and Isoleucine Metabolism

Anderson¹,

Hibberd²

1985

Weed sci.

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Effects of the imidazolinone herbicide AC243 997 [2-(5-isopropyl)-5-methyl-4-oxo-2-imidazolin-2-yl) nicotinic acid] on the growth of corn (Zea mays L. ‘Black Mexican Sweet’) cell suspension cultures were characterized. The herbicide caused half maximal growth inhibition at concentrations in the range of 10 nM to 30 nM. Significant reductions in protein synthesis were observed following treatment of cells with 10 μM herbicide. Analysis of free amino acid pool sizes indicated that levels of the biosyn-thetically related amino acids leucine and valine were substantially decreased in cells exposed to 10 μM herbicide. Supplementation of suspension culture growth media with leucine and valine plus isoleucine (1 mM each) reversed growth inhibitory effects of AC243 997 at levels ranging from 10 nM to 1 mM. The results suggest a specific interaction of this imidazolinone herbicide with leucine, valine, and isoleucine metabolism.

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Effect of Aspartate‐derived Amino Acids and Aminoethyl Cysteine on Growth of Excised Mature Embryos of Maize¹

Cited by 14 publications

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

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

One hundred years of zygotic embryo culture investigations

Evidence for the Interaction of an Imidazolinone Herbicide with Leucine, Valine, and Isoleucine Metabolism

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Effect of Aspartate‐derived Amino Acids and Aminoethyl Cysteine on Growth of Excised Mature Embryos of Maize1

Cited by 14 publications

References 0 publications

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

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

One hundred years of zygotic embryo culture investigations

Evidence for the Interaction of an Imidazolinone Herbicide with Leucine, Valine, and Isoleucine Metabolism

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Effect of Aspartate‐derived Amino Acids and Aminoethyl Cysteine on Growth of Excised Mature Embryos of Maize¹