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The Tinkerbell (Tink) Mutation Identifies the Dual-Specificity MAPK Phosphatase INDOLE-3-BUTYRIC ACID-RESPONSE5 (IBR5) as a Novel Regulator of Organ Size in Arabidopsis.

Johnson KL, Ramm S, Kappel C, Ward S, Leyser O, Sakamoto T, Kurata T, Bevan MW, Lenhard M - PLoS ONE (2015)

Bottom Line: Organ size and shape regulation by IBR5 acts independently of the KLU growth-regulatory pathway.Microarray analysis of tink/ibr5-6 mutants identified a likely role for this phosphatase in male gametophyte development.We show that IBR5 may influence the size and shape of petals through auxin and TCP growth regulatory pathways.

View Article: PubMed Central - PubMed

Affiliation: ARC Centre of Excellence in Plant Cell Walls, School of Botany, University of Melbourne, Royal Parade, Parkville, Victoria, 3010, Australia.

ABSTRACT
Mitogen-activated dual-specificity MAPK phosphatases are important negative regulators in the MAPK signalling pathways responsible for many essential processes in plants. In a screen for mutants with reduced organ size we have identified a mutation in the active site of the dual-specificity MAPK phosphatase indole-3-butyric acid-response5 (IBR5) that we named tinkerbell (tink) due to its small size. Analysis of the tink mutant indicates that IBR5 acts as a novel regulator of organ size that changes the rate of growth in petals and leaves. Organ size and shape regulation by IBR5 acts independently of the KLU growth-regulatory pathway. Microarray analysis of tink/ibr5-6 mutants identified a likely role for this phosphatase in male gametophyte development. We show that IBR5 may influence the size and shape of petals through auxin and TCP growth regulatory pathways.

No MeSH data available.


Related in: MedlinePlus

Above ground phenotypes of tink/ibr5-6 mutants.a. Mutants in tink1/ibr5-6 (right) display reduced plant height and bushier phenotypes compared to Ler plants (left). An increased number of flowers in the inflorescence (c) and narrow petals (e) are observed in tink1/ibr5-6 compared to Ler (b, d) flowers. f. Measurement of tink1/ibr5-6 and Ler petal size showing statistically significant (shown by *) reduction in petal area (p value ≤ 4.5e-14) and petal width (p value ≤ 2e-37) in two tailed t-tests assuming unequal variance. g. Kinematic analysis of tink1/ibr5-6 and Ler petal size during development. Scale bar is 1 mm. Values are shown as mean ± SEM where n = 20.
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pone.0131103.g001: Above ground phenotypes of tink/ibr5-6 mutants.a. Mutants in tink1/ibr5-6 (right) display reduced plant height and bushier phenotypes compared to Ler plants (left). An increased number of flowers in the inflorescence (c) and narrow petals (e) are observed in tink1/ibr5-6 compared to Ler (b, d) flowers. f. Measurement of tink1/ibr5-6 and Ler petal size showing statistically significant (shown by *) reduction in petal area (p value ≤ 4.5e-14) and petal width (p value ≤ 2e-37) in two tailed t-tests assuming unequal variance. g. Kinematic analysis of tink1/ibr5-6 and Ler petal size during development. Scale bar is 1 mm. Values are shown as mean ± SEM where n = 20.

Mentions: EMS mutagenesis of the klu-2 mutant in the Arabidopsis thaliana Landsberg erecta background was undertaken and approximately 2500 individual M2 lines were screened for reduced plant height and reduced petal size. Petals were used for screening as growth of floral organs is more consistent than leaf growth [21]. A mutant line that displayed significantly reduced petal and leaf size compared to klu-2 single mutants was selected for further investigation and backcrossed three times to wild type to separate the novel mutation and the klu-2 mutation. The novel mutation was named tinkerbell (tink) for its small stature (Fig 1A–1E and S1A Fig). Homozygous tink single-mutant plants show a 20% reduction in petal size compared to wild-type and this was due to a reduction in petal width (Fig 1F). Size of petals in heterozygous TINK/tink plants was indistinguishable from wild-type indicating this is a recessive mutation. To investigate the cause of the reduced petal size we measured cell size in mature petals of tink and wild-type plants. Cell size is not altered in tink plants compared to wild-type indicating that the reduced size of tink petals results from fewer cells (Fig 1F).


The Tinkerbell (Tink) Mutation Identifies the Dual-Specificity MAPK Phosphatase INDOLE-3-BUTYRIC ACID-RESPONSE5 (IBR5) as a Novel Regulator of Organ Size in Arabidopsis.

Johnson KL, Ramm S, Kappel C, Ward S, Leyser O, Sakamoto T, Kurata T, Bevan MW, Lenhard M - PLoS ONE (2015)

Above ground phenotypes of tink/ibr5-6 mutants.a. Mutants in tink1/ibr5-6 (right) display reduced plant height and bushier phenotypes compared to Ler plants (left). An increased number of flowers in the inflorescence (c) and narrow petals (e) are observed in tink1/ibr5-6 compared to Ler (b, d) flowers. f. Measurement of tink1/ibr5-6 and Ler petal size showing statistically significant (shown by *) reduction in petal area (p value ≤ 4.5e-14) and petal width (p value ≤ 2e-37) in two tailed t-tests assuming unequal variance. g. Kinematic analysis of tink1/ibr5-6 and Ler petal size during development. Scale bar is 1 mm. Values are shown as mean ± SEM where n = 20.
© Copyright Policy
Related In: Results  -  Collection

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Show All Figures
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pone.0131103.g001: Above ground phenotypes of tink/ibr5-6 mutants.a. Mutants in tink1/ibr5-6 (right) display reduced plant height and bushier phenotypes compared to Ler plants (left). An increased number of flowers in the inflorescence (c) and narrow petals (e) are observed in tink1/ibr5-6 compared to Ler (b, d) flowers. f. Measurement of tink1/ibr5-6 and Ler petal size showing statistically significant (shown by *) reduction in petal area (p value ≤ 4.5e-14) and petal width (p value ≤ 2e-37) in two tailed t-tests assuming unequal variance. g. Kinematic analysis of tink1/ibr5-6 and Ler petal size during development. Scale bar is 1 mm. Values are shown as mean ± SEM where n = 20.
Mentions: EMS mutagenesis of the klu-2 mutant in the Arabidopsis thaliana Landsberg erecta background was undertaken and approximately 2500 individual M2 lines were screened for reduced plant height and reduced petal size. Petals were used for screening as growth of floral organs is more consistent than leaf growth [21]. A mutant line that displayed significantly reduced petal and leaf size compared to klu-2 single mutants was selected for further investigation and backcrossed three times to wild type to separate the novel mutation and the klu-2 mutation. The novel mutation was named tinkerbell (tink) for its small stature (Fig 1A–1E and S1A Fig). Homozygous tink single-mutant plants show a 20% reduction in petal size compared to wild-type and this was due to a reduction in petal width (Fig 1F). Size of petals in heterozygous TINK/tink plants was indistinguishable from wild-type indicating this is a recessive mutation. To investigate the cause of the reduced petal size we measured cell size in mature petals of tink and wild-type plants. Cell size is not altered in tink plants compared to wild-type indicating that the reduced size of tink petals results from fewer cells (Fig 1F).

Bottom Line: Organ size and shape regulation by IBR5 acts independently of the KLU growth-regulatory pathway.Microarray analysis of tink/ibr5-6 mutants identified a likely role for this phosphatase in male gametophyte development.We show that IBR5 may influence the size and shape of petals through auxin and TCP growth regulatory pathways.

View Article: PubMed Central - PubMed

Affiliation: ARC Centre of Excellence in Plant Cell Walls, School of Botany, University of Melbourne, Royal Parade, Parkville, Victoria, 3010, Australia.

ABSTRACT
Mitogen-activated dual-specificity MAPK phosphatases are important negative regulators in the MAPK signalling pathways responsible for many essential processes in plants. In a screen for mutants with reduced organ size we have identified a mutation in the active site of the dual-specificity MAPK phosphatase indole-3-butyric acid-response5 (IBR5) that we named tinkerbell (tink) due to its small size. Analysis of the tink mutant indicates that IBR5 acts as a novel regulator of organ size that changes the rate of growth in petals and leaves. Organ size and shape regulation by IBR5 acts independently of the KLU growth-regulatory pathway. Microarray analysis of tink/ibr5-6 mutants identified a likely role for this phosphatase in male gametophyte development. We show that IBR5 may influence the size and shape of petals through auxin and TCP growth regulatory pathways.

No MeSH data available.


Related in: MedlinePlus