Lack of the Golgi phosphate transporter PHT4;6 causes strong developmental defects, constitutively activated disease resistance mechanisms and altered intracellular phosphate compartmentation in Arabidopsis
The Golgi-located phosphate exporter PHT4;6 has been described as involved in salt tolerance but further analysis on the physiological impact of PHT4;6 remained elusive. Here we show that PHT4;6-GFP is targeted to the trans-Golgi compartment and that loss of function of this carrier protein has a dr...
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| Main Authors: | , , |
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| Format: | Article (Journal) |
| Language: | English |
| Published: |
12 October 2012
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| In: |
The plant journal
Year: 2012, Volume: 72, Issue: 5, Pages: 732-744 |
| ISSN: | 1365-313X |
| DOI: | 10.1111/j.1365-313X.2012.05106.x |
| Online Access: | Verlag, kostenfrei, Volltext: http://dx.doi.org/10.1111/j.1365-313X.2012.05106.x Verlag, kostenfrei, Volltext: http://onlinelibrary.wiley.com/doi/10.1111/j.1365-313X.2012.05106.x/abstract 
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| Author Notes: | Sebastian Hassler, Lilia Lemke, Benjamin Jung, Torsten Möhlmann, Falco Krüger, Karin Schumacher, Luca Espen, Enrico Martinoia, H. Ekkehard Neuhaus |
| Summary: | The Golgi-located phosphate exporter PHT4;6 has been described as involved in salt tolerance but further analysis on the physiological impact of PHT4;6 remained elusive. Here we show that PHT4;6-GFP is targeted to the trans-Golgi compartment and that loss of function of this carrier protein has a dramatic impact on plant growth and development. Knockout mutants of pht4;6 exhibit a dwarf phenotype that is complemented by the homologous gene from rice (Oryza sativa). Interestingly, pht4;6 mutants show altered characteristics of several Golgi-related functions, such as an altered abundance of certain N-glycosylated proteins, altered composition of cell-wall hemicelluose, and higher sensitivity to the Golgi α-mannosidase and the retrograde transport inhibitors kifunensine and brefeldin A, respectively. Moreover, pht4;6 mutants exhibit a ‘mimic disease’ phenotype accompanied by constitutively activated pathogen defense mechanisms and increased resistance against the virulent Pseudomonas syringae strain DC3000. Surprisingly, pht4;6 mutants also exhibit phosphate starvation symptoms, as revealed at the morphological and molecular level, although total Pi levels in wild-type and pht4;6 plants are similar. This suggested that subcellular Pi compartmentation was impaired. By use of nuclear magnetic resonance (NMR), increased Pi concentration was detected in acidic compartments of pht4;6 mutants. We propose that impaired Pi efflux from the trans-Golgi lumen results in accumulation of inorganic phosphate in other internal compartments, leading to low cytoplasmic phosphate levels with detrimental effects on plant performance. |
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| Item Description: | Gesehen am 10.05.2017 |
| Physical Description: | Online Resource |
| ISSN: | 1365-313X |
| DOI: | 10.1111/j.1365-313X.2012.05106.x |