ORCID Profile
0000-0003-1835-5339
Current Organisations
Edith Cowan University - Mount Lawley Campus
,
Friedrich-Alexander-Universität Erlangen-Nürnberg
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Publisher: Elsevier BV
Date: 04-2022
DOI: 10.1016/J.JPLPH.2022.153661
Abstract: Preprint servers allow rapid publication of research findings by eliminating the time gap between submission and publication associated with editorial and peer review of scientific works. Consequently, non-peer-reviewed articles are essentially accessible immediately to researchers and the public. There are many valid justifications for sharing work on preprint servers, such as the ability to collect feedback from the research community and improve work prior to journal submission and a reduced risk of work being "scooped" by competitors. Rapid access to the latest scientific developments can furthermore expedite progress in important research areas. Significant downsides of preprint servers, however, are that the public, including members of the media and policy makers, cannot judge the quality of such non-reviewed publications and that misinformation may be spread. Balancing the good and the bad of preprint servers as opposed to classic peer review, we provide guidance for authors of the Journal of Plant Physiology.
Publisher: Wiley
Date: 20-02-0086
DOI: 10.1111/PCE.12060
Abstract: Hexokinase (HXK) is present in all virtually living organisms and is central to carbohydrate metabolism catalysing the ATP-dependent phosphorylation of hexoses. In plants, HXKs are supposed to act as sugar sensors and/or to interact with other enzymes directly supplying metabolic pathways such as glycolysis, the nucleotide phosphate monosaccharide (NDP-glucose) pathway and the pentose phosphate pathway. We identified nine members of the tobacco HXK gene family and observed that among RNAi lines of these nine NtHXKs, only RNAi lines of NtHXK1 showed an altered phenotype, namely stunted growth and leaf chlorosis. NtHXK1 was also the isoform with highest relative expression levels among all NtHXKs. GFP-tagging and immunolocalization indicated that NtHXK1 is associated with mitochondrial membranes. Overexpression of NtHXK1 resulted in elevated glucose phosphorylation activity in leaf extracts or chloroplasts. Moreover, NtHXK1 was able to complement the glucose-insensitive Arabidopsis mutant gin2-1 suggesting that NtHXK1 can take over glucose sensing functions. RNAi lines of NtHXK1 showed severely damaged leaf and chloroplast structure, coinciding with an excess accumulation of starch. We conclude that NtHXK1 is not only essential for maintaining glycolytic activity during respiration but also for regulating starch turnover, especially during the night.
Publisher: Springer Science and Business Media LLC
Date: 12-2012
Abstract: Maize is a major crop plant, grown for human and animal nutrition, as well as a renewable resource for bioenergy. When looking at the problems of limited fossil fuels, the growth of the world’s population or the world’s climate change, it is important to find ways to increase the yield and biomass of maize and to study how it reacts to specific abiotic and biotic stress situations. Within the OPTIMAS systems biology project maize plants were grown under a large set of controlled stress conditions, phenotypically characterised and plant material was harvested to analyse the effect of specific environmental conditions or developmental stages. Transcriptomic, metabolomic, ionomic and proteomic parameters were measured from the same plant material allowing the comparison of results across different omics domains. A data warehouse was developed to store experimental data as well as analysis results of the performed experiments. The OPTIMAS Data Warehouse (OPTIMAS-DW) is a comprehensive data collection for maize and integrates data from different data domains such as transcriptomics, metabolomics, ionomics, proteomics and phenomics. Within the OPTIMAS project, a 44K oligo chip was designed and annotated to describe the functions of the selected unigenes. Several treatment- and plant growth stage experiments were performed and measured data were filled into data templates and imported into the data warehouse by a Java based import tool. A web interface allows users to browse through all stored experiment data in OPTIMAS-DW including all data domains. Furthermore, the user can filter the data to extract information of particular interest. All data can be exported into different file formats for further data analysis and visualisation. The data analysis integrates data from different data domains and enables the user to find answers to different systems biology questions. Finally, maize specific pathway information is provided. With OPTIMAS-DW a data warehouse for maize was established, which is able to handle different data domains, comprises several analysis results that will support researchers within their work and supports systems biological research in particular. The system is available at ptimas_dw .
Publisher: Elsevier BV
Date: 04-2005
Publisher: Cold Spring Harbor Laboratory
Date: 05-08-2022
DOI: 10.1101/2022.08.04.502830
Abstract: Companion cells and sieve elements play an essential role in vascular plants and yet the details of the metabolism that underpins their function remain largely unknown. Here we construct a tissue-scale flux balance analysis (FBA) model to describe the metabolism of phloem loading in a mature Arabidopsis leaf. We explore the potential metabolic interactions between mesophyll cells, companion cells, and sieve elements based on current understanding of the physiology of phloem tissue and through the use of cell-type-specific transcriptome data as a weighting in our model. We find that companion cell chloroplasts likely play a very different role to mesophyll chloroplasts. Our model suggests that, rather than carbon capture, the most crucial function of companion cell chloroplasts is to provide photosynthetically-generated ATP to the cytosol. Additionally, our model predicts that the metabolites imported into the companion cell are not necessarily the same metabolites that are exported in phloem sap phloem loading is more efficient if certain amino acids are synthesised in the phloem tissue. Surprisingly, in our model predictions the H + -PP i ase is the more important contributor than the H + ATPase to the energisation of the companion cell plasma membrane.
No related grants have been discovered for Uwe Sonnewald.