Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0038187 (starvation)
 24,951 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Proton/sulfate cotransporters in the plasma membranes are responsible for uptake of the environmental sulfate used in the sulfate assimilation pathway in plants. Here we report the cloning and characterization of an Arabidopsis thaliana gene, AST68, a new member of the sulfate transporter gene family in higher plants. Sequence analysis of cDNA and genomic clones of AST68 revealed that the AST68 gene is composed of 10 exons encoding a 677-aa polypeptide (74.1 kDa) that is able to functionally complement a Saccharomyces cerevisiae mutant lacking a sulfate transporter gene. Southern hybridization and restriction fragment length polymorphism mapping confirmed that AST68 is a single-copy gene that maps to the top arm of chromosome 5. Northern hybridization analysis of sulfate-starved plants indicated that the steady-state mRNA abundance of AST68 increased specifically in roots up to 9-fold by sulfate starvation. In situ hybridization experiments revealed that AST68 transcripts were accumulated in the central cylinder of sulfate-starved roots, but not in the xylem, endodermis, cortex, and epidermis. Among all the structural genes for sulfate assimilation, sulfate transporter (AST68), APS reductase (APR1), and serine acetyltransferase (SAT1) were inducible by sulfate starvation in A. thaliana. The sulfate transporter (AST68) exhibited the most intensive and specific response in roots, indicating that AST68 plays a central role in the regulation of sulfate assimilation in plants.
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PMID:Regulation of sulfur assimilation in higher plants: a sulfate transporter induced in sulfate-starved roots plays a central role in Arabidopsis thaliana. 938 Jul 66

Penicillium chrysogenum uses sulfate as a source of sulfur for the biosynthesis of penicillin. Sulfate uptake and the mRNA levels of the sulfate transporter-encoding sutB and sutA genes are all reduced by high sulfate concentrations and are elevated by sulfate starvation. In a high-penicillin-yielding strain, sutB is effectively transcribed even in the presence of excess sulfate. This deregulation may facilitate the efficient incorporation of sulfur into cysteine and penicillin.
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PMID:Sulfur regulation of the sulfate transporter genes sutA and sutB in Penicillium chrysogenum. 1101 Sep 12

Effects of plant hormones on a sulfur-deficiency responsive element (betaSR) from the promoter region of the beta subunit gene of beta-conglycinin, a major seed storage protein of soybean, were investigated using transgenic Arabidopsis thaliana. Among the hormones tested, the cytokinins, trans-zeatin (Z) and trans-zeatin riboside, upregulated gene expression directed by the betaSR element both in the presence and in the absence of sulfate in the medium. Z also increased transcript accumulation of two endogenous sulfur-responsive genes, the adenosine 5'-phosphosulfate reductase (APR1) and the Sultr2;2, a sulfate transporter. Concentrations of cytokinins were unaltered during early stages of sulfur starvation when expression of these genes was upregulated. Z did not alter concentrations of O-acetyl-L-serine, a positive regulator of gene expression in sulfur starvation response. Concentrations of sucrose, which is known to upregulate expression of APR1, were increased in rosette leaves by Z. Sucrose application to the medium also increased expression directed by the betaSR element, although sucrose concentrations in tissues were not significantly altered by sulfur availability. These results suggest that exogenously applied cytokinins positively regulate expression of these sulfur responsive genes through a pathway independent of that from sulfur starvation, possibly through increasing sucrose concentrations in tissues.
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PMID:Regulation of sulfur-responsive gene expression by exogenously applied cytokinins in Arabidopsis thaliana. 1251 46

A high-affinity-type sulfate transporter (Group 1: ZmST1;1, Accession No. AF355602) has been cloned from maize seedlings by RT-PCR. Tissue and cell specific localisation of this sulfate transporter has been determined along the developmental gradient of the root and in leaves of different ages. In S-sufficient conditions there was uniform low expression of ZmST1;1 in the root and very low expression in the leaves. Increased mRNA abundance and sulfate influx capacity indicated that S-starvation increased ZmST1;1 expression in roots, especially at the top of the root (just behind the seed, the area possessing most laterals and root hairs) compared to the root tip. Similarly a group 2, probable low affinity-type sulfate transporter, ZmST2;1, and also ATP-sulfurylase and APS-reductase but not OAS(thiol)lyase were induced by S-starvation and showed highest expression in the upper section of the root. S-starvation increased root/shoot ratio by 20 % and increased root lateral length and abundance in the region closest to the root tip. As the increase in root proliferation was not as great as the increase in mRNA pools, it was clear that there was a higher cellular abundance of the mRNAs for sulfate transporters, ATP-sulfurylase, and APS-reductase in response to sulfur starvation. In the leaves, the sulfate transporters, ATP-sulfurylase and APS-reductase were induced by S-starvation with the most mature leaf showing increased mRNA abundance first. In situ hybridization indicated that ZmST1;1 was expressed in epidermal and endodermal cell layers throughout the root whilst OAS(thiol)lyase was highly expressed in the root cortex.
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PMID:Coordinated expression of sulfate uptake and components of the sulfate assimilatory pathway in maize. 1524 23

cDNAs encoding a high-affinity sulfate transporter and an adenosine 5'-phosphosulfate reductase from potato (Solanum tuberosum L. cv Desiree) have been cloned and used to examine the hypothesis that sulfate uptake and assimilation is transcriptionally regulated and that this is mediated via intracellular O-acetylserine (OAS) pools. Gas chromotography coupled to mass spectrometry was used to quantify OAS and its derivative, N-acetylserine. Treatment with external OAS increased sulfate transporter and adenosine 5'-phosphosulfate reductase gene expression consistent with a model of transcriptional induction by OAS. To investigate this further, the Escherichia coli gene cysE (serine acetyltransferase EC 2.3.1.30), which synthesizes OAS, has been expressed in potato to modify internal metabolite pools. Transgenic lines, with increased cysteine and glutathione pools, particularly in the leaves, had increased sulfate transporter expression in the roots. However, the small increases in the OAS pools were not supportive of the hypothesis that this molecule is the signal of sulfur (S) nutritional status. In addition, although during S starvation the content of S-containing compounds decreased (consistent with derepression as a mechanism of regulation), OAS pools increased only following extended starvation, probably as a consequence of the S starvation. Taken together, expression of these genes may be induced by a demand-driven model, via a signal from the shoots, which is not OAS. Rather, the signal may be the depletion of intermediates of the sulfate assimilation pathway, such as sulfide, in the roots. Finally, sulfate transporter activity did not increase in parallel with transcript and protein abundance, indicating additional posttranslational regulatory mechanisms.
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PMID:O-acetylserine and the regulation of expression of genes encoding components for sulfate uptake and assimilation in potato. 1580 76

A putative sulfate transporter gene, RSultr3.2A, was identified from radish (Raphanus sativus L.). The RSultr3.2A gene encodes a polypeptide of 651 amino acids with a calculated molecular mass of 71701 Da. The deduced amino acid sequence preserves the common motifs of the sulfate transporters and exhibits a high degree of homology to other plant sulfate transporters. RSultr3.2A was not induced by sulfur starvation and was expressed in roots, stems, leaves, flowers and young pods, suggesting a possible need for the nonregulated and constitutive sulfate transport system of the plant. The RSultr3.2A is a single copy gene in the radish genome. A genomic sequence information corresponding to RSultr3.2A cDNA was found by PCR and sequencing. Comparison of cDNA and genomic sequences revealed that the coding sequence of RSultr3.2A consisted of 12 exons. In addition, another cDNA (RSultr3.2B) from radish young pods was found. As compared with RSultr3.2A, RSultr3.2B encodes a 499 amino acid protein with modifications in the carboxy-terminus. Sequence analysis suggested an occasional donor splicing site mutation (GT to TT) in the RSultr3.2A gene from radish young pods leading to the truncated cDNA RSultr3.2B.
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PMID:Cloning and characterization of a novel sulfate transporter gene from radish (Raphanus sativus L.). 1728 35

High-affinity sulfate transporters SULTR1;1 and SULTR1;2 are expressed at epidermis and cortex of Arabidopsis (Arabidopsis thaliana) roots during sulfur limitation. Here, we report that SULTR1;1 and SULTR1;2 are two essential components of the sulfate uptake system in roots and are regulated at posttranscriptional levels together with the previously reported transcriptional control. Double knockout of SULTR1;1 and SULTR1;2 by T-DNA insertion gene disruption resulted in complete lack of sulfate uptake capacity and severely affected plant growth under low-sulfur conditions. Expression of epitope-tagged proteins SULTR1;1mycHis and SULTR1;2mycHis, under the control of the cauliflower mosaic virus 35S promoter, rescued the uptake of sulfate and the growth of the sultr1;1 sultr1;2 double knockout mutant. The recovery of the double knockout phenotypes was attributable to the posttranscriptional accumulation of sulfate transporter proteins that derive from the epitope-tagged transgenic constructs. Both SULTR1;1mycHis and SUTLR1;2mycHis mRNAs were predominantly found in roots and slightly induced by long-term sulfur limitation. SULTR1;1mycHis and SULTR1;2mycHis proteins were found exclusively in roots, and significantly accumulated by sulfur limitation, correlating with the induction of sulfate uptake activities. In the time course of short-term sulfate starvation treatment, SULTR1;1mycHis and SULTR1;2mycHis proteins were significantly accumulated during the 8- to 72-h period, causing substantial induction of sulfate uptake activities, while their corresponding mRNAs were expressed constantly around the initial levels, except for the transient induction in the first 2 h. This study suggested the importance of root-specific and sulfur deficiency-inducible accumulation of SULTR1;1 and SULTR1;2 sulfate transporter proteins for the acquisition of sulfate from low-sulfur environment.
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PMID:Posttranscriptional regulation of high-affinity sulfate transporters in Arabidopsis by sulfur nutrition. 1772 Jul 55

The homocysteine synthase (tbhos) and putative sulfate transporter (tbsul1) genes have been characterized in order to understand the sulfate metabolism and regulation in the ectomycorrhizal fungus Tuber borchii. The analyses of tbsul1 and tbhos nucleotide and deduced amino acid sequences led to the identification of the typical domains shown in homologous proteins. Sulfate starvation condition upregulates both genes. The real-time PCR assay of tbsul1 revealed that gene expression was about threefold higher in mycelia grown under sulfate starvation for 2 days than in the mycelial control and in the same starvation condition, the sulfate uptake increased. Real-time PCR and enzymatic assays showed regulation of tbhos when sulfur sources were lacking, suggesting that a transcriptional regulation of this gene rather than a post-transcriptional one occurred. Furthermore, the tbsul1 and tbhos expression patterns were evaluated during the truffle life cycle, revealing an over-expression in the mature ascomata for both genes. In the ectomycorrhizal tissue, only tbhos was upregulated suggesting its substantial role in T. borchii cysteine synthesis. The regulation of tbsul1 and tbhos occurs primarily at the transcriptional level both during vegetative and fruiting phases and these genes could be directly involved in VOCs production.
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PMID:Sulfate metabolism in Tuber borchii: characterization of a putative sulfate transporter and the homocysteine synthase genes. 2003 42

MicroRNAs play a key role in the control of plant development and response to adverse environmental conditions. For example, microRNA395 (miR395), which targets three out of four isoforms of ATP sulfurylase, the first enzyme of sulfate assimilation, as well as a low-affinity sulfate transporter, SULTR2;1, is strongly induced by sulfate deficiency. However, other components of sulfate assimilation are induced by sulfate starvation, so that the role of miR395 is counterintuitive. Here, we describe the regulation of miR395 and its targets by sulfate starvation. We show that miR395 is important for the increased translocation of sulfate to the shoots during sulfate starvation. MiR395 together with the SULFUR LIMITATION 1 transcription factor maintain optimal levels of ATP sulfurylase transcripts to enable increased flux through the sulfate assimilation pathway in sulfate-deficient plants. Reduced expression of ATP sulfurylase (ATPS) alone affects both sulfate translocation and flux, but SULTR2;1 is important for the full rate of sulfate translocation to the shoots. Thus, miR395 is an integral part of the regulatory circuit controlling plant sulfate assimilation with a complex mechanism of action.
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PMID:Interplay of SLIM1 and miR395 in the regulation of sulfate assimilation in Arabidopsis. 2140 44

Characterization of the relationship between sulfur and iron in both Strategy I and Strategy II plants, has proven that low sulfur availability often limits plant capability to cope with iron shortage. Here it was investigated whether the adaptation to iron deficiency in tomato (Solanum lycopersicum L.) plants was associated with an increased root sulfate uptake and translocation capacity, and modified dynamics of total sulfur and thiols accumulation between roots and shoots. Most of the tomato sulfate transporter genes belonging to Groups 1, 2, and 4 were significantly upregulated in iron-deficient roots, as it commonly occurs under S-deficient conditions. The upregulation of the two high affinity sulfate transporter genes, SlST1.1 and SlST1.2, by iron deprivation clearly suggests an increased root capability to take up sulfate. Furthermore, the upregulation of the two low affinity sulfate transporter genes SlST2.1 and SlST4.1 in iron-deficient roots, accompanied by a substantial accumulation of total sulfur and thiols in shoots of iron-starved plants, likely supports an increased root-to-shoot translocation of sulfate. Results suggest that tomato plants exposed to iron-deficiency are able to change sulfur metabolic balance mimicking sulfur starvation responses to meet the increased demand for methionine and its derivatives, allowing them to cope with this stress.
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PMID:Iron deprivation results in a rapid but not sustained increase of the expression of genes involved in iron metabolism and sulfate uptake in tomato (Solanum lycopersicum L.) seedlings. 2411 7


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