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Summary: Vietnam is one of the countries with the highest diversity of golden camellias in the world, with more than forty endemic species. However, studies on Vietnamese golden camellias need to be expanded to fill a knowledge gap on these species' chemical profiles and pharmacological properties. This qualitative study focuses on six golden camellias: four endemic species from Tam Dao district, Vinh Phuc province, including Camellia hakodae, Camellia phanii, Camellia tamdaoensis, Camellia tienii and two species commonly cultivated in Quang Ninh province including Camellia petelotii and Camellia euphlebia. A mutual profile of 131 metabolites was obtained by using widely targeted metabolomics analysis using ultra‐performance liquid chromatography coupled with tandem mass spectrometry. Comparative metabolomics was performed among leaf extracts of six golden teas, between young and mature leaves and between freeze‐drying and oven‐drying leaves to discriminate these species, and determine the effect of developmental stage and post‐harvesting method on the plant metabolism. The PLS‐DA model successfully illustrated a clear separation of the six species and suggested apigenin C‐glycoside derivatives as chemical markers for the diversity. Young and mature leaves of all six species also produced distinguished metabolomes, differentiated by mostly amino acid derivatives. The multivariate analysis also indicated the conversion of some flavonoids and amino acids induced by heat in the drying process. These results offer metabolite markers for quality control of Vietnamese golden camellias and recommendations for their usage and preparation. [ABSTRACT FROM AUTHOR]

SUMMARY: Glutathione (GSH) is required for various physiological processes in plants, including redox regulation and detoxification of harmful compounds. GSH also functions as a repository for assimilated sulfur and is actively catabolized in plants. In Arabidopsis, GSH is mainly degraded initially by cytosolic enzymes, γ‐glutamyl cyclotransferase, and γ‐glutamyl peptidase, which release cysteinylglycine (Cys‐Gly). However, the subsequent enzyme responsible for catabolizing this dipeptide has not been identified to date. In the present study, we identified At4g17830 as a Cys‐Gly dipeptidase, namely cysteinylglycine peptidase 1 (CGP1). CGP1 complemented the phenotype of the yeast mutant that cannot degrade Cys‐Gly. The Arabidopsis cgp1 mutant had lower Cys‐Gly degradation activity than the wild type and showed perturbed concentrations of thiol compounds. Recombinant CGP1 showed reasonable Cys‐Gly degradation activity in vitro. Metabolomic analysis revealed that cgp1 exhibited signs of severe sulfur deficiency, such as elevated accumulation of O‐acetylserine (OAS) and the decrease in sulfur‐containing metabolites. Morphological changes observed in cgp1, including longer primary roots of germinating seeds, were also likely associated with sulfur starvation. Notably, At4g17830 has previously been reported to encode an N2‐acetylornithine deacetylase (NAOD) that functions in the ornithine biosynthesis. The cgp1 mutant did not show a decrease in ornithine content, whereas the analysis of CGP1 structure did not rule out the possibility that CGP1 has Cys‐Gly dipeptidase and NAOD activities. Therefore, we propose that CGP1 is a Cys‐Gly dipeptidase that functions in the cytosolic GSH degradation pathway and may play dual roles in GSH and ornithine metabolism. Significance Statement: In this study, we identified At4g17830 (CGP1) as a Cys‐Gly dipeptidase that functions in the glutathione (GSH) degradation pathway and revealed its importance in plant metabolism and growth, especially under sulfur starvation. Notably, CGP1 has been reported as an N2‐acetylornithine deacetylase (NAOD) that participates in the ornithine biosynthesis pathway; therefore, our findings imply that CGP1 is a bifunctional enzyme that plays vital roles in both sulfur and nitrogen metabolism. [ABSTRACT FROM AUTHOR]

Plants incorporate acquired carbon and nitrogen into amino acid metabolism, whereby the building blocks of proteins and the precursors of various metabolites are produced. This fundamental demand requires tight amino acid metabolism to sustain physiological homeostasis. There is increasing evidence that amino acid metabolism undergoes plastic alteration to orchestrate specific growth and developmental events. Consequently, there has been a gradual exploration of the interface at which amino acid metabolism and plant morphogenesis are mutually affected. This research progress offers an opportunity to explore amino acid metabolism, with the goal to understand how it can be modulated to serve special cellular needs and regulate specific growth and developmental pathways. Continuous improvements in the sensitivity and coverage of metabolomics technology, along with the development of chemoinformatics, have allowed the investigation of these research questions. In this review, we summarize the roles of threonine, serine, arginine and γ-aminobutyric acid as representative examples of amino acids relevant to specific developmental processes in plants ('functional amino acids'). Our objective is to expand perspectives regarding amino acid metabolism beyond the conventional view that it is merely life-supporting machinery. [ABSTRACT FROM AUTHOR]

Plants are a treasure trove of metabolic compounds. The chemical diversity of plant cells has developed and been maintained through evolution and metabolic regulation, and plays a crucial role in plant physiology, development, and adaption to changing environmental situations. Metabolomics, when combined with genomics and proteomics, has opened up unprecedented opportunities to address the biological importance of metabolic diversity. It has also provided an avenue for metabolic engineering to produce a particular compound of interest to meet societal and economical demands, an important effort to achieve sustainable development. This Special Issue therefore focuses on current trends in plant metabolomics research, providing examples in the development of analytical technologies, the functional study of plant metabolism, and applications to synthetic and engineering biology. [ABSTRACT FROM AUTHOR]

This article discusses the classification and functions of plant metabolites. Traditionally, plant metabolites have been categorized as primary metabolites, specialized secondary metabolites, and plant hormones based on their attributes. However, emerging evidence suggests that many plant metabolites have more significant and widespread roles than previously thought, blurring the boundaries between these categories. The article includes reviews and original research papers that explore the evolution of metabolic pathways, the structural diversity of metabolites, and the unexpected functions of metabolites. It also highlights the distinct biological functions of common primary metabolites and the fine-tuning of carbon metabolism and development. The authors suggest that future research should focus on the spatial distribution and compartmentalization of metabolites and metabolic enzymes to further understand plant metabolism. [Extracted from the article]

Highlights • Plant metabolic engineering is still a challenge compared to microbial engineering. • Metabolic engineering requires system-level understanding of metabolism by modeling. • Time-series metabolome data enables construction of dynamic in vivo models. • New modeling approaches overcome limitations of current metabolome data. • Modeling leads to hypothesis generation and predictive metabolic engineering. Plant metabolism is characterized by a wide diversity of metabolites, with systems far more complicated than those of microorganisms. Mathematical modeling is useful for understanding dynamic behaviors of plant metabolic systems for metabolic engineering. Time-series metabolome data has great potential for estimating kinetic model parameters to construct a genome-wide metabolic network model. However, data obtained by current metabolomics techniques does not meet the requirement for constructing accurate models. In this article, we highlight novel strategies and algorithms to handle the underlying difficulties and construct dynamic in vivo models for large-scale plant metabolic systems. The coarse but efficient modeling enables the prediction of unknown mechanisms regulating plant metabolism. [ABSTRACT FROM AUTHOR]

Molybdenum (Mo) is a micronutrient essential for plant growth, as several key enzymes of plant metabolic pathways contain Mo cofactor in their catalytic centres. Mo-containing oxidoreductases include nitrate reductase, sulphite oxidase, xanthine dehydrogenase, and aldehyde oxidase. These are involved in nitrate assimilation, sulphite detoxification, purine metabolism or the synthesis of abscisic acid, auxin and glucosinolates in plants. To understand the effects of Mo deficiency and a mutation in a molybdate transporter, MOT1, on nitrogen and sulphur metabolism in Arabidopsis thaliana, transcript and metabolite profiling of the mutant lacking MOT1 was conducted in the presence or absence of Mo. Transcriptome analysis revealed that Mo deficiency had impacts on genes involved in metabolisms, transport, stress responses, and signal transductions. The transcript level of a nitrate reductase NR1 was highly induced under Mo deficiency in mot1-1. The metabolite profiles were analysed further by using gas chromatography time-of-flight mass spectrometry, capillary electrophoresis time-of-flight mass spectrometry, and ultra high performance liquid chromatography. The levels of amino acids, sugars, organic acids, and purine metabolites were altered significantly in the Mo-deficient plants. These results are the first investigation of the global effect of Mo nutrition and MOT1 on plant gene expressions and metabolism. [ABSTRACT FROM PUBLISHER]

An improvement in plant production is increasingly important for a sustainable human society. For this purpose, understanding the mechanism of plant production, that is, the plant metabolic system, is an immediate necessity. After the sequencing of the Arabidopsis genome, it has become possible to obtain a bird’s eye view of its metabolism by means of omics such as transcriptomics and proteomics. Availability of thousands of transcriptome data points in the public domain has resulted in great advances in the methodology of functional genomics. Metabolome data can be a “gold mine” of biological findings. However, as the total throughput of metabolomics is far lower than that of transcriptomics due to technical difficulties, there is currently no publicly available large-scale metabolome dataset that is comparable in size to the transcriptome dataset. Recently, we established a novel methodology, termed widely targeted metabolomics, which can generate thousands of metabolome data points in a high-throughput manner. We previously conducted a targeted metabolite analysis of large-scale Arabidopsis bioresources, namely transposon-tagged mutants and accessions, to make a smaller dataset of metabolite accumulation. In this paper, we release approximately 3,000 metabolic profiles obtained by targeted analysis for 36 metabolites and discuss the possible regulation of amino acid accumulation. [ABSTRACT FROM AUTHOR]

Understanding plant metabolism as an integrated system is essential for metabolic engineering aimed at the effective production of compounds useful to human life and the global environment. The ‘omics’ approach integrates transcriptome and metabolome data into a single data set and can lead to the identification of unknown genes and their regulatory networks involved in metabolic pathways of interest. One of the intriguing, although poorly described metabolic pathways in plants is the biosynthesis of glucosinolates (GSLs), a group of bioactive secondary products derived from amino acids that are found in the family Brassicaceae. Here we report the discovery of two R2R3-Myb transcription factors that positively control the biosynthesis of GSLs in Arabidopsis thaliana by an integrated omics approach. Combined transcriptome coexpression analysis of publicly available, condition-independent data and the condition-specific (i.e., sulfur-deficiency) data identified Myb28 and Myb29 as candidate transcription factor genes specifically involved in the regulation of aliphatic GSL production. Analysis of a knockout mutant and ectopic expression of the gene demonstrated that Myb28 is a positive regulator for basal-level production of aliphatic GSLs. Myb29 presumably plays an accessory function for methyl jasmonate-mediated induction of a set of aliphatic GSL biosynthetic genes. Overexpression of Myb28 in Arabidopsis-cultured suspension cells, which do not normally synthesize GSLs, resulted in the production of large amounts of GSLs, suggesting the possibility of efficient industrial production of GSLs by manipulation of these transcription factors. A working model for regulation of GSL production involving these genes, renamed Production of Methionine-Derived Glucosinolate (PMG) 1 and 2, are postulated. [ABSTRACT FROM AUTHOR]

With the genome sequence of Arabidopsis and rice now available, plant science has stepped forward into a new phase. Post-genomics studies such as transcriptomics, proteomics, and metabolomics will bring about a breakthrough for the functional elucidation of genes and for an understanding of a whole process of living cells. Concerning studies of sulphur (S) metabolism, several reports have recently been published describing the transcript profiles of S-starved Arabidopsis. In this review, these -omics studies that have revealed the network linking several pathways related to jasmonic acid (JA), oxidative stress response, auxin, and flavonoid to S metabolic pathway are summarized. [ABSTRACT FROM PUBLISHER]