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AtTRP1 encodes a novel TPR protein that interacts with the ethylene receptor ERS1 and modulates development in Arabidopsis.

Lin Z, Ho CW, Grierson D - J. Exp. Bot. (2009)

Bottom Line: This association was confirmed by in vivo co-immunoprecipitation.Plants overexpressing AtTRP1 also showed a reduced response to exogenous IAA and altered expression of a subset of auxin early responsive genes.A model for AtTRP1 action is proposed.

View Article: PubMed Central - PubMed

Affiliation: Plant and Crop Sciences Division, School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough, UK.

ABSTRACT
Arabidopsis AtTRP1 is an orthologue of SlTPR1, a tomato tetratricopeptide repeat protein that interacts with the tomato ethylene receptors LeETR1 and NR in yeast 2-hybrid assays and in vitro, and modulates plant development. AtTRP1 is encoded by a single copy gene in the Arabidopsis genome, and is related to TCC1, a human protein that competes with Raf-1 for Ras binding, and distantly related to the immunophilin-like FK-binding proteins TWD1 and PAS1. The former is involved in auxin transport and the latter is translocated to the nucleus in response to auxin. AtTRP1 interacted preferentially with the Arabidopsis ethylene receptor ERS1 in yeast two-hybrid assays. This association was confirmed by in vivo co-immunoprecipitation. AtTRP1 promoter-GUS was highly expressed in vascular tissue, mature anthers, the abscission zone, and was induced by ACC. Overexpression of AtTRP1 in wild-type Arabidopsis resulted in dwarf plants with reduced fertility, altered leaf/silique morphology, and enhanced expression of the ethylene responsive gene AtChitB. Exogenous GA did not reverse the dwarf habit. Etiolated transgenic seedlings overexpressing AtTRP1 displayed enhanced sensitivity to low ACC and this was correlated with the transgene expression. Seedlings overexpressing AtTRP1 at high levels exhibited shortened and swollen hypocotyls, inhibited root growth, and an altered apical hook. Plants overexpressing AtTRP1 also showed a reduced response to exogenous IAA and altered expression of a subset of auxin early responsive genes. These results indicated that overexpression of AtTRP1 affects cross-talk between ethylene and auxin signalling and enhances some ethylene responses and alters some auxin responses. A model for AtTRP1 action is proposed.

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Characterization of the ethylene responses of transgenic plants overexpressing AtTRP1F–GFP. (A) Responses of etiolated seedlings to ACC. Wild-type and transgenic seedlings were grown on MS medium with or without 0.5 μM ACC in the dark and photographed in white light under an Olympus microscope at 3-d-old. (B) Enlarged images of the apical hooks of wild type (Col) and lines 2 and 3 from (A) grown in the absence of ACC. (C) Enlarged image of line 3 in response to ACC from (A), showing shortened and swollen hypocotyls and inhibited root growth. (D) Responses of light-grown seedlings to ACC. Wild-type and transgenic seedlings were grown on MS medium with or without 0.5 μM ACC in the light and photographed at 7-d-old.
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fig6: Characterization of the ethylene responses of transgenic plants overexpressing AtTRP1F–GFP. (A) Responses of etiolated seedlings to ACC. Wild-type and transgenic seedlings were grown on MS medium with or without 0.5 μM ACC in the dark and photographed in white light under an Olympus microscope at 3-d-old. (B) Enlarged images of the apical hooks of wild type (Col) and lines 2 and 3 from (A) grown in the absence of ACC. (C) Enlarged image of line 3 in response to ACC from (A), showing shortened and swollen hypocotyls and inhibited root growth. (D) Responses of light-grown seedlings to ACC. Wild-type and transgenic seedlings were grown on MS medium with or without 0.5 μM ACC in the light and photographed at 7-d-old.

Mentions: The ethylene responses of the transgenic seedlings that overexpressed AtTRP1F-GFP were investigated. Seeds from lines 2, 3, 4, 5, and 6 (Fig. 5B, C) were grown on MS medium with or without 0.5 μM ACC in the dark or light (Fig. 6). Line 4 did not germinate well. In the dark, lines 2 and 3 displayed great growth inhibition, with shortened and swollen hypocotyls (2–3 mm versus 9 mm in the wild type; Table 1), inhibited root growth, and altered apical hook in the absence of ACC, although lines 5 and 6 displayed normal growth (Fig. 6A, B). Etiolated seedlings from all lines exhibited enhanced responses to 0.5 μM ACC, with shortened roots and hypocotyls and altered apical hook, and hypocotyls of lines 2 and 3 were swollen (Fig. 6A, C, which shows an enlarged image of line 3 in response to 0.5 μM ACC; Table 1). In the light, seedlings of all transgenic lines exhibited a reduction in cotyledon expansion and greening in the absence of ACC, and enhanced responses to 0.5 μM ACC, with a great reduction in root length compared to the wild type (Fig. 6D; Table 2). Taken together, both dark- and light-grown AtTRP1 overexpressing seedlings showed enhanced responses to low concentration of exogenous ACC, although the seedlings did not always display swollen hypocotyls or exaggerated apical hooks.


AtTRP1 encodes a novel TPR protein that interacts with the ethylene receptor ERS1 and modulates development in Arabidopsis.

Lin Z, Ho CW, Grierson D - J. Exp. Bot. (2009)

Characterization of the ethylene responses of transgenic plants overexpressing AtTRP1F–GFP. (A) Responses of etiolated seedlings to ACC. Wild-type and transgenic seedlings were grown on MS medium with or without 0.5 μM ACC in the dark and photographed in white light under an Olympus microscope at 3-d-old. (B) Enlarged images of the apical hooks of wild type (Col) and lines 2 and 3 from (A) grown in the absence of ACC. (C) Enlarged image of line 3 in response to ACC from (A), showing shortened and swollen hypocotyls and inhibited root growth. (D) Responses of light-grown seedlings to ACC. Wild-type and transgenic seedlings were grown on MS medium with or without 0.5 μM ACC in the light and photographed at 7-d-old.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC2736885&req=5

fig6: Characterization of the ethylene responses of transgenic plants overexpressing AtTRP1F–GFP. (A) Responses of etiolated seedlings to ACC. Wild-type and transgenic seedlings were grown on MS medium with or without 0.5 μM ACC in the dark and photographed in white light under an Olympus microscope at 3-d-old. (B) Enlarged images of the apical hooks of wild type (Col) and lines 2 and 3 from (A) grown in the absence of ACC. (C) Enlarged image of line 3 in response to ACC from (A), showing shortened and swollen hypocotyls and inhibited root growth. (D) Responses of light-grown seedlings to ACC. Wild-type and transgenic seedlings were grown on MS medium with or without 0.5 μM ACC in the light and photographed at 7-d-old.
Mentions: The ethylene responses of the transgenic seedlings that overexpressed AtTRP1F-GFP were investigated. Seeds from lines 2, 3, 4, 5, and 6 (Fig. 5B, C) were grown on MS medium with or without 0.5 μM ACC in the dark or light (Fig. 6). Line 4 did not germinate well. In the dark, lines 2 and 3 displayed great growth inhibition, with shortened and swollen hypocotyls (2–3 mm versus 9 mm in the wild type; Table 1), inhibited root growth, and altered apical hook in the absence of ACC, although lines 5 and 6 displayed normal growth (Fig. 6A, B). Etiolated seedlings from all lines exhibited enhanced responses to 0.5 μM ACC, with shortened roots and hypocotyls and altered apical hook, and hypocotyls of lines 2 and 3 were swollen (Fig. 6A, C, which shows an enlarged image of line 3 in response to 0.5 μM ACC; Table 1). In the light, seedlings of all transgenic lines exhibited a reduction in cotyledon expansion and greening in the absence of ACC, and enhanced responses to 0.5 μM ACC, with a great reduction in root length compared to the wild type (Fig. 6D; Table 2). Taken together, both dark- and light-grown AtTRP1 overexpressing seedlings showed enhanced responses to low concentration of exogenous ACC, although the seedlings did not always display swollen hypocotyls or exaggerated apical hooks.

Bottom Line: This association was confirmed by in vivo co-immunoprecipitation.Plants overexpressing AtTRP1 also showed a reduced response to exogenous IAA and altered expression of a subset of auxin early responsive genes.A model for AtTRP1 action is proposed.

View Article: PubMed Central - PubMed

Affiliation: Plant and Crop Sciences Division, School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough, UK.

ABSTRACT
Arabidopsis AtTRP1 is an orthologue of SlTPR1, a tomato tetratricopeptide repeat protein that interacts with the tomato ethylene receptors LeETR1 and NR in yeast 2-hybrid assays and in vitro, and modulates plant development. AtTRP1 is encoded by a single copy gene in the Arabidopsis genome, and is related to TCC1, a human protein that competes with Raf-1 for Ras binding, and distantly related to the immunophilin-like FK-binding proteins TWD1 and PAS1. The former is involved in auxin transport and the latter is translocated to the nucleus in response to auxin. AtTRP1 interacted preferentially with the Arabidopsis ethylene receptor ERS1 in yeast two-hybrid assays. This association was confirmed by in vivo co-immunoprecipitation. AtTRP1 promoter-GUS was highly expressed in vascular tissue, mature anthers, the abscission zone, and was induced by ACC. Overexpression of AtTRP1 in wild-type Arabidopsis resulted in dwarf plants with reduced fertility, altered leaf/silique morphology, and enhanced expression of the ethylene responsive gene AtChitB. Exogenous GA did not reverse the dwarf habit. Etiolated transgenic seedlings overexpressing AtTRP1 displayed enhanced sensitivity to low ACC and this was correlated with the transgene expression. Seedlings overexpressing AtTRP1 at high levels exhibited shortened and swollen hypocotyls, inhibited root growth, and an altered apical hook. Plants overexpressing AtTRP1 also showed a reduced response to exogenous IAA and altered expression of a subset of auxin early responsive genes. These results indicated that overexpression of AtTRP1 affects cross-talk between ethylene and auxin signalling and enhances some ethylene responses and alters some auxin responses. A model for AtTRP1 action is proposed.

Show MeSH
Related in: MedlinePlus