دانلود رایگان مقاله انگلیسی پمپ پروتونی گیاهان به همراه ترجمه فارسی
| عنوان فارسی مقاله | پمپ پروتونی گیاهان |
| عنوان انگلیسی مقاله | Plant proton pumps |
| رشته های مرتبط | زیست شناسی، علوم گیاهی و بیوشیمی |
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| کیفیت ترجمه | کیفیت ترجمه این مقاله متوسط میباشد |
| نشریه | الزویر – Elsevier |
| مجله | FEBS اسناد |
| سال انتشار | 2007 |
| کد محصول | F863 |
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| جستجوی ترجمه مقالات | جستجوی ترجمه مقالات زیست شناسی |
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فهرست مقاله: چکیده |
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بخشی از ترجمه فارسی مقاله: 1. H+-ATPase غشای پلاسمایی: نقش های فیزیولوژیکی |
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بخشی از مقاله انگلیسی: 1. Plasma membrane H+-ATPases: Physiological roles 1.1. Specific PM H+ -ATPases are expressed in cells specialized for transport Solute flux across the plasma membrane depends to a large extent on the proton motive force available. As such, PM H+- ATPases are important molecular players that determine and control plant nutrient acquisition and partitioning at the whole plant level (reviewed in Refs. [1–4]). Structure–function relationships of this pump have been reviewed recently [3]. Here we will focus on recent developments that throw new light on the physiological function and regulation of PM H+-ATPases. Since the completion of the sequencing of the genome of the model plant Arabidopsis thaliana in 2000, the Arabidopsis transcriptome has been characterized in a large number of gene array experiments. An overview of the expression profiles of members of the Arabidopsis PM H+-ATPase family (AHA1- 11) [5] can be found in the Genevestigator database (www.genevestigator.org). Two genes, AHA1 and AHA2, are expressed in virtually all tissues and organs. Thus, these genes appear to function as housekeeping genes required for ion homeostasis. Relatively more AHA1 transcript is found in shoots, whereas AHA2 is predominantly expressed in roots, especially in root hairs. AHA3, AHA4 and AHA11 also show broad expression throughout the plant, but are not expressed to the same degree. Some degree of specialization is seen as AHA4 has high expression in root endodermis in accordance with reporter gene analysis studies [6]. Real time RT PCR analysis has confirmed that AHA1, AHA2, AHA3 and AHA11 are the major transcripts found in leaves [7]. Reporter gene analyses show that the AHA3promoter is active in leaf phloem companion cells [8]. Expression patterns of AHA5 (low expression throughout the plant), AHA6 and AHA9 (predominantly expressed in anthers), AHA7and AHA8 (almost exclusive expression in pollen) and AHA10 (highest transcript levels in siliques) suggest that the pumps encoded by these genes have more specialized function. Reporter gene analyses have verified the expression of AHA9 in anthers [9] and AHA10 in the endothelium of the developing seed coat [10]. Are all these transcripts translated into proteins? All isoforms, except AHA8, have been detected by mass spectrometry-based proteomics, either in cotyledons, whole seedlings, leaves or stems [11–16]. Four isoforms have been detected by mass spectrometry in most investigations, namely AHA1, AHA2, AHA4 and AHA11 [11,13–16]. These isoforms correspond to the major gene transcripts in seedlings and leaves. 1.2. Single cells may contain more than one isoform of PM H+- ATPase Transcriptome analysis and cDNA library screening of Vicia faba stomatal guard cells detected expression of at least two plasma membrane H+ -ATPases, but none of these iso forms are unique to guard cells [17]. Likewise, by fusing endogenous PM H+-ATPase promoters with the GUS reporter gene and expressing the chimeric genes in transgenic plants, it could be shown that the promoters of two different tobacco PM H+-ATPases, NpPMA2 and NpPMA4, are active in guard cells [18]. In a recent study, RT-PCR was employed to amplify AHA sequences in isolated Arabidopsis guard cell protoplasts [19]. Surprisingly, all members of the Arabidopsis PM H+ -ATPase gene family (AHA1-11) were identified in this particular cell type. The major guard cell transcripts are AHA1, AHA2 and AHA5. This confirms the presence of AHA1 and AHA2 as house-keeping genes in guard cells and points to AHA5 as a candidate guard cell specific PM H+-ATPase. However, as the method employed is very sensitive and not quantitative, it is not clear to what extent each AHA isoform is present in guard cells. The male gametophyte of the plant is an independent haploid organism that expresses a specific subset of genes [20]. Nicotiana plumbaginifolia NpPMA5 H+-ATPase is expressed in pollen tubes but in many cell types of the sporophyte as well [21]. Four different AHA transcripts have been identified in Arabidopsis pollen grains at different stages of development: AHA6, AHA8, AHA9 and AHA12 [20], the latter being a pseudogene [6]. AHA12 is expressed at very low levels at the microspore and bicellular states, AHA6 and AHA9 peak at the tricellular state, whereas in mature pollen the AHA8 isogene takes over as the all-dominant transcript. This suggests that during development one AHA isogene can take over the role of another. Lastly, in barley aleurone cells, two isoforms of PM H+- ATPase have been identified in proteomic analyses [22]. We can conclude that the plasma membrane of individual cells may harbor several PM H+-ATPases. The reason for this diversity is not known, but might reflect a specific need for ATPases at specific times of development or with specialized functions [23,24]. |