A cytokinin-resistant mutant of Nicotiana plumbaginifolia is wilty

Blonstein, Anne D.; Parry, Andrew D.; Horgan, R.; King, Patrick J.

doi:10.1007/bf00197795

Cited by 41 publications

(21 citation statements)

References 12 publications

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“…However, despite the vast literature on the description of cytokinin effects and progress in understanding its metabolism (for reviews see Horgan, 1992;Kaminek, 1992;McGaw, 1987), the mode of action of cytokinins is not understood. In particular, no mutants of cytokinin biosynthesis are known and only a few higher plant mutants, altered in their response to externally applied cytokinins have been described (Blonstein et aL, 1991;Jullien et al, 1992;Su and Howell, 1992). One of these cytokinin-insensitive mutants turned out to be defective in abscisic acid synthesis .…”

Section: Introductionmentioning

confidence: 99%

Promoter tagging with a promoterless ipt gene leads to cytokinin‐induced phenotypic variability in transgenic tobacco plants: implications of gene dosage effects

Hewelt

Prinsen

Schell³

et al. 1994

The Plant Journal

108

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Section: Introductionmentioning

confidence: 99%

Promoter tagging with a promoterless ipt gene leads to cytokinin‐induced phenotypic variability in transgenic tobacco plants: implications of gene dosage effects

Hewelt

Prinsen

Schell³

et al. 1994

The Plant Journal

108

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“…The ckrl mutant in N. plumbaginifolia was selected at high concentrations of cytokinin (2). The primary lesion in this mutant is not known, but it appears that the defect may be unrelated to cytokinin metabolism or perception.…”

Section: Cytokinin-resistant Mutantsmentioning

confidence: 99%

“…The defect in the mutant does not appear to be specific to cytokinin. Instead, the mutant seems to be less growth inhibited in response to general stresses produced by high cytokinin concentrations (2).…”

mentioning

confidence: 97%

A Single Genetic Locus, Ckr1, Defines Arabidopsis Mutants in which Root Growth Is Resistant to Low Concentrations of Cytokinin

Howell²

1992

Plant Physiol.

107

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Arabidopsis mutants resistant to cytokinin (benzyladenine [BA]) have been isolated with the intent to find plants defective in cytokinin perception or response. At low concentrations, BA produces a "cytokinin root syndrome" in which primary root elongation is inhibited, but root hair elongation is stimulated. Five independent mutants that did not express this syndrome in the presence of BA were selected. All five mutants were recessive, and crosses between them indicated that they were in the same complementation group. The genetic locus represented by these mutations has been designated ckrl and mapped to chromosome 5.The analysis of mutants with altered responses to hormones is an important approach to understanding hormonesignaling mechanisms in plants. Because to ABA and to an inhibitor of GA3 biosynthesis, paclobutrazol. The authors suggested that the cross-resistance was a result of the interaction of the hormones in promoting normal growth. Recently, new N. plumbaginifolia mutants have been isolated that are not resistant but are more sensitive to auxin (5).Less progress has been made in isolating mutant plants with altered responses to cytokinin. There is only one report of a higher plant mutant selected on the basis of its resistance to cytokinin. The defect in the mutant does not appear to be specific to cytokinin. Instead, the mutant seems to be less growth inhibited in response to general stresses produced by high cytokinin concentrations (2).In this report, we describe the isolation and characterization of cytokinin-resistant mutants in Arabidopsis. To avoid mutants with defects not specifically related to cytokinin responses, we selected mutants at relatively low concentrations of cytokinin. Five independent mutants were identified and found to be mutations in the same complementation group, defining a locus called ckrl in Arabidopsis. MATERIALS AND METHODS Plant Materials and Growth ConditionsAll mutant lines described in this report were derived from the Arabidopsis thaliana Columbia ecotype (Col-0). For growing sterile plants, seeds were sterilized and grown on 0.8% agar medium as described by Estelle and Somerville (6)

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“…Whereas cyrl and stpl seem to be specific to cytokinin, ckrl was shown to be insensitive to ethylene and allelic to the ethyleneinsensitive mutant ein2 (Cary et al, 1995). In N. plumbaginifolia the ckrllibalesg mutant was classified as cytokininresistant because it germinates on higher cytokinin concentrations than the wild type, and the mutant leaves continue to develop at cytokinin concentrations inhibitory to the wild type (Bitoun et al, 1990;Blonstein et al, 1991;Parry et al, 1991). As with the Arabidopsis ckrl mutant, the ckrllibalesg mutation is not cytokinin-specific.…”

mentioning

confidence: 99%

“…As with the Arabidopsis ckrl mutant, the ckrllibalesg mutation is not cytokinin-specific. This mutant has a defect in the last step of ABA biosynthesis and is also insensitive to auxin and to the GA, biosynthesis inhibitor paclobutrazol (Bitoun et al, 1990;Blonstein et al, 1991;Parry et al, 1991).…”

mentioning

confidence: 99%

ZEA3: A Negative Modulator of Cytokinin Responses in Plant Seedlings

et al. 1997

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In Nicotiana plumbaginifolia cytokinins affect seedling development by inhibiting root growth and hypocotyl elongation and by stimulating cotyledon expansion. The zea3.1 mutant was selected for its inability to grow in conditions of low nitrogen and for its ability to grow independently on inhibitory concentrations of zeatin (J.D. Faure, M. Jullien, M. Caboche [1994] Plant J 5: 481–491). The zea3.1 growth response to cytokinins is reflected by an increase in cotyledon expansion due to cell division and by a swelling of the hypocotyl due to cell enlargement. An analysis of the seedling's root length and fresh weight over a wide range of benzyladenine concentrations showed that zea3.1 plants exhibit a higher sensitivity and an amplified response to cytokinins. A similar response of zea3.1 to benzyladenine was also seen in the expression of msr1, a cytokinin-regulated gene. Regulation of msr1 expression by protein phosphorylation was unaffected by the zea3.1 mutation. No significant differences in cytokinin and auxin levels were found between zea3.1 and wild-type seedlings, suggesting that the mutant phenotype is not caused by an alteration of these hormone levels. The data presented suggest that ZEA3 negatively modulates cytokinin responses and may function as a broad regulator of seedling development.

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A cytokinin-resistant mutant of Nicotiana plumbaginifolia is wilty

Cited by 41 publications

References 12 publications

Promoter tagging with a promoterless ipt gene leads to cytokinin‐induced phenotypic variability in transgenic tobacco plants: implications of gene dosage effects

Promoter tagging with a promoterless ipt gene leads to cytokinin‐induced phenotypic variability in transgenic tobacco plants: implications of gene dosage effects

A Single Genetic Locus, Ckr1, Defines Arabidopsis Mutants in which Root Growth Is Resistant to Low Concentrations of Cytokinin

ZEA3: A Negative Modulator of Cytokinin Responses in Plant Seedlings

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