Biosynthesis Of Bioactive Metabolites Research Articles

Assessment of pharmacological activities of specialized metabolites of Withania somnifera (L.)

Withania somnifera is a revered herb in the Indian medicinal system due to the presence of pharmacologically bioactive compounds. The roots and leaves of Ashwagandha contain various phytochemicals like phenols, flavonoids, quinones, steroids, etc. These phytochemicals are distributed among various tissues of this plant in varying concentrations. Since location and environmental factors (biotic and abiotic) play a key role in the biosynthesis of bioactive metabolites, the agro-climatic conditions are conducive to introducing and domesticating new exotic plant varieties with enhanced phytochemicals and withanolide contents. The present study focuses on the assessment of these bioactive compounds in different commercially available varieties for the cultivation of elite germplasm from the perspective of hill agriculture and sustainable development.In the study, total phenols were found to be highest in Jawahar-20 root, i.e., 82.714 mg/g (DW), followed by Poshita root, i.e., 64.02 mg/g (DW), while the least was found in Pratap leaf, i.e., 2.33 mg/g (DW). The concentration of total flavonoids varied significantly (p ≤ 0.05) from 1.98 ± 0.0.01 to 80.735 ± 4.33 mg QE/g (DW). Total flavonoids were found to be highest in Jawahar-20 root, i.e., 80.735 mg/g (DW), followed by Poshita leaf, i.e., 60.02 mg/g (DW), and least in Nimithli stem, i.e., 1.98 mg/g (DW). The total tannin content varied significantly (p ≤ 0.05) among the five varieties of Withania somnifera under the present study. The concentration of total tannin varied significantly (p ≤ 0.05) from 0.691 ± 0.51 to 36.09 ± 0.61 mg TAE/g (DW). Tannins were found to be highest in Jawahar-20 root, i.e., 36.09 mg/g (DW), followed by Poshita root, i.e., 29.287 mg/g (DW), while the least was found to be in Pratap seed, i.e., 0.682 mg/g (DW). Ortho-dihydroxy phenol was found to be highest in Jawahar-20 leaf, i.e., 40.081 mg/g (DW), followed by Jawahar-20 root, 19.31 mg/g (DW), and Poshita leaf, i.e., 19.02 mg/g (DW). Both recorded the same, and the least was found in Nimithli leaf, i.e., 0.95 mg/g (DW). Total antioxidant capacity was found to be highest in Jawahar-20 leaf, i.e., 16.70 mg/g (DW), followed by Jawahar-20 leaf, i.e., 11.51 mg/g (DW), and Poshita leaf, i.e., 11.31 mg/g (DW), both of which recorded the same almost least in Pratap leaf, i.e., 0.257 mg/g (DW). The DPPH activity was found to be highest in Poshita root, i.e., 92.39 at 1000 μg concentration, which was very near the ascorbic acid, i.e., 98.9 (a natural antioxidant), followed by Pratap leaf, i.e., 88.04, and least in Nimithli root, i.e., 58.36. The IC50 value of Pratap leaf was the least, i.e., 369.42, followed by Jawahar-20 stem, i.e., 370.32, and the highest IC50 value was found in Nimithli root, i.e., 877.22. The reducing power of five different varieties increased with increasing concentration. The varieties differed w.r.t. their total reducing power activity, i.e., the reducing power activity was highest in Poshita stem with an R2 value of 0.992, followed by Poshita root with an R2 value of 0.982, and least in Pratap seed with an R2 value of 0.565. Thus, Jawahar-20 and Poshita not only recorded higher phytochemicals but also withanolide A and withaferin A.

Whole Genome Sequencing of the Novel Probiotic Strain Lactiplantibacillus plantarum FCa3L.

Lactiplantibacillus plantarum is best known for its significant adaptive potential and ability to colonize different ecological niches. Different strains of L. plantarum are widely used as probiotics. To characterize the probiotic potential of the novel L. plantarum FCa3L strain isolated from fermented cabbage, we sequenced its whole genome using the Illumina MiSeq platform. This bacterial isolate had a circular chromosome of 3,365,929 bp with 44.3% GC content and a cyclic phage phiX174 of 5386 bp with 44.7% GC content. The results of in vitro studies showed that FCa3L was comparable with the reference probiotic strain L. plantarum 8PA3 in terms of acid and bile tolerance, adhesiveness, H2O2 production, and acidification rate. The strain 8PA3 possessed higher antioxidant activity, while FCa3L demonstrated superior antibacterial properties. The antibiotic resistance of FCa3L was more relevant to the probiotic strain than that of 8PA3, although a number of silent antibiotic resistance genes were identified in its genome. Genomic evidence to support adhesive and antibacterial properties, biosynthesis of bioactive metabolites, and safety of FCa3L was also presented. Thus, this study confirmed the safety and probiotic properties of L. plantarum FCa3L via complete genome and phenotype analysis, suggesting its potential as a probiotic, although further in vivo investigations are still necessary.

Metabolic profiling, in-situ spatial distribution, and biosynthetic pathway of functional metabolites in Dendrobium nobile stem revealed by combining UPLC-QTOF-MS with MALDI-TOF-MSI.

The stem of Dendrobium nobile Lindl. (Orchidaceae), called "Shihu" in traditional Chinese medicine, is a well-known medicinal and edible plant material in China. It is used as an antipyretic, analgesic, and tonic to nourish the stomach and Yin (i.e., to improve the production of body fluids). These therapeutic properties are attributed to its alkaloids, sesquiterpenoids, bibenzyls, fluorenones, and phenanthrenes. However, a comprehensive understanding of these metabolites and their spatial distribution in stems is lacking. In this study, ultra-performance liquid chromatography/quadrupole time-of-flight mass spectrometry (UPLC-QTOF-MS) was performed to obtain detailed metabolites information about D. nobile stems. Then, the spatial distributions of diverse metabolites, including alkaloids and sesquiterpenoids, were characterized and visualized by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry imaging (MALDI-TOF-MSI). Based on the spatial and metabolic profiling data, sesquiterpene alkaloid dendrobine was chosen for the exhaustive study of a biosynthetic pathway in D. nobile. This is the first report on mass spectrometry imaging for Dendrobium species. As a result, critical bioactive metabolites such as 11 alkaloids, 10 sesquiterpenes, and 13 other metabolites were putatively identified and relatively quantified. The identified alkaloids were distributed in the parenchyma or vascular bundle, and sesquiterpenes were present in all regions of the stem with higher abundance in the vascular bundle and cuticle, or in the cuticle and epidermis. The biosynthetic pathway and accumulation pattern of dendrobine in D. nobile stem were also proposed. Our findings not only provided a critical methodology for the thorough understanding of physiological changes in metabolites and precise utilization of D. nobile stem, but also displayed an effective strategy for insight into the biosynthesis of bioactive metabolites in plants.

Gene-Metabolite Network Analysis Revealed Tissue-Specific Accumulation of Therapeutic Metabolites in Mallotus japonicus.

Mallotus japonicus is a valuable traditional medicinal plant in East Asia for applications as a gastrointestinal drug. However, the molecular components involved in the biosynthesis of bioactive metabolites have not yet been explored, primarily due to a lack of omics resources. In this study, we established metabolome and transcriptome resources for M. japonicus to capture the diverse metabolite constituents and active transcripts involved in its biosynthesis and regulation. A combination of untargeted metabolite profiling with data-dependent metabolite fragmentation and metabolite annotation through manual curation and feature-based molecular networking established an overall metabospace of M. japonicus represented by 2129 metabolite features. M. japonicus de novo transcriptome assembly showed 96.9% transcriptome completeness, representing 226,250 active transcripts across seven tissues. We identified specialized metabolites biosynthesis in a tissue-specific manner, with a strong correlation between transcripts expression and metabolite accumulations in M. japonicus. The correlation- and network-based integration of metabolome and transcriptome datasets identified candidate genes involved in the biosynthesis of key specialized metabolites of M. japonicus. We further used phylogenetic analysis to identify 13 C-glycosyltransferases and 11 methyltransferases coding candidate genes involved in the biosynthesis of medicinally important bergenin. This study provides comprehensive, high-quality multi-omics resources to further investigate biological properties of specialized metabolites biosynthesis in M. japonicus.

Comparative genomics and association analysis identifies virulence genes of Cercospora sojina in soybean

BackgroundRecently, a new strain of Cercospora sojina (Race15) has been identified, which has caused the breakdown of resistance in most soybean cultivars in China. Despite this serious yield reduction, little is known about why this strain is more virulent than others. Therefore, we sequenced the Race15 genome and compared it to the Race1 genome sequence, as its virulence is significantly lower. We then re-sequenced 30 isolates of C. sojina from different regions to identifying differential virulence genes using genome-wide association analysis (GWAS).ResultsThe 40.12-Mb Race15 genome encodes 12,607 predicated genes and contains large numbers of gene clusters that have annotations in 11 different common databases. Comparative genomics revealed that although these two genomes had a large number of homologous genes, their genome structures have evolved to introduce 245 specific genes. The most important 5 candidate virulence genes were located on Contig 3 and Contig 1 and were mainly related to the regulation of metabolic mechanisms and the biosynthesis of bioactive metabolites, thereby putatively affecting fungi self-toxicity and reducing host resistance. Our study provides insight into the genomic basis of C. sojina pathogenicity and its infection mechanism, enabling future studies of this disease.ConclusionsVia GWAS, we identified five candidate genes using three different methods, and these candidate genes are speculated to be related to metabolic mechanisms and the biosynthesis of bioactive metabolites. Meanwhile, Race15 specific genes may be linked with high virulence. The genes highly prevalent in virulent isolates should also be proposed as candidates, even though they were not found in our SNP analysis. Future work should focus on using a larger sample size to confirm and refine candidate gene identifications and should study the functional roles of these candidates, in order to investigate their potential roles in C. sojina pathogenicity.