RESUMO
Advances in biological engineering are likely to have substantial impacts on global society. To explore these potential impacts we ran a horizon scanning exercise to capture a range of perspectives on the opportunities and risks presented by biological engineering. We first identified 70 potential issues, and then used an iterative process to prioritise 20 issues that we considered to be emerging, to have potential global impact, and to be relatively unknown outside the field of biological engineering. The issues identified may be of interest to researchers, businesses and policy makers in sectors such as health, energy, agriculture and the environment.
Assuntos
Bioengenharia/tendências , Pesquisa/tendências , Mudança Climática , Conservação dos Recursos Naturais , HumanosRESUMO
Sulfur is an essential nutrient for all organisms. Plants are able to take up inorganic sulfate and assimilate it into a range of bio-organic molecules either after reduction to sulfide or activation to 3'-phosphoadenosine 5'-phosphosulfate. While the regulation of the reductive part of sulfate assimilation and the synthesis of cysteine has been studied extensively in the past three decades, much less attention has been paid to the control of synthesis of sulfated compounds. Only recently the genes and enzymes activating sulfate and transferring it onto suitable acceptors have been investigated in detail with emphasis on understanding the diversity of the sulfotransferase gene family and the control of partitioning of sulfur between the two branches of sulfate assimilation. Here, the recent progress in our understanding of these processes will be summarized.
RESUMO
In plants, microRNAs play an important role in many regulatory circuits, including responses to environmental cues such as nutrient limitations. One such microRNA is miR395, which is strongly up-regulated by sulfate deficiency and targets two components of the sulfate uptake and assimilation pathway. Here we show that miR395 levels are affected by treatments with metabolites regulating sulfate assimilation. The precursor of cysteine, O-acetylserine, which accumulates during sulfate deficiency, causes increase in miR395 accumulation. Feeding plants with cysteine, which inhibits sulfate uptake and assimilation, induces miR395 levels while buthionine sulfoximine, an inhibitor of glutathione synthesis, lowers miR395 expression. Thus, miR395 is an integral part of the regulatory network of sulfate assimilation.
Assuntos
Arabidopsis/genética , Arabidopsis/metabolismo , MicroRNAs/genética , MicroRNAs/metabolismo , RNA de Plantas/genética , RNA de Plantas/metabolismo , Sulfatos/metabolismo , Proteínas de Transporte de Ânions/genética , Proteínas de Transporte de Ânions/metabolismo , Arabidopsis/efeitos dos fármacos , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Butionina Sulfoximina/farmacologia , Cisteína/metabolismo , Cisteína/farmacologia , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Regulação da Expressão Gênica de Plantas , Genes de Plantas , Redes e Vias Metabólicas/efeitos dos fármacos , Redes e Vias Metabólicas/genética , Modelos Biológicos , Plantas Geneticamente Modificadas , Serina/análogos & derivados , Serina/farmacologia , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismoRESUMO
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.
Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Proteínas de Ligação a DNA/metabolismo , MicroRNAs/metabolismo , Sulfatos/metabolismo , Fatores de Transcrição/metabolismo , Arabidopsis/genética , Regulação da Expressão Gênica de Plantas , Loci Gênicos , MicroRNAs/genética , Folhas de Planta/genética , Folhas de Planta/metabolismo , Raízes de Plantas/genética , Raízes de Plantas/metabolismo , Brotos de Planta/genética , Brotos de Planta/metabolismo , Plantas Geneticamente Modificadas/genética , Plantas Geneticamente Modificadas/metabolismo , Estresse Fisiológico , Sulfato Adenililtransferase/metabolismoRESUMO
In Arabidopsis thaliana, adenosine-5'-phosphosulfate kinase (APK) provides activated sulfate for sulfation of secondary metabolites, including the glucosinolates. We have successfully isolated three of the four possible triple homozygous mutant combinations of this family. The APK1 isoform alone was sufficient to maintain WT levels of growth and development. Analysis of apk1 apk2 apk3 and apk1 apk3 apk4 mutants suggests that APK3 and APK4 are functionally redundant, despite being located in cytosol and plastids, respectively. We were, however, unable to isolate apk1 apk3 apk4 mutants, most probably because the apk1 apk3 apk4 triple mutant combination is pollen lethal. Therefore, we conclude that APS kinase is essential for plant reproduction and viability.
