April 21, 2020  |  

Nephromyces encodes a urate metabolism pathway and predicted peroxisomes, demonstrating that these are not ancient losses of apicomplexans.

The phylum Apicomplexa is a quintessentially parasitic lineage, whose members infect a broad range of animals. One exception to this may be the apicomplexan genus Nephromyces, which has been described as having a mutualistic relationship with its host. Here we analyze transcriptome data from Nephromyces and its parasitic sister taxon, Cardiosporidium, revealing an ancestral purine degradation pathway thought to have been lost early in apicomplexan evolution. The predicted localization of many of the purine degradation enzymes to peroxisomes, and the in silico identification of a full set of peroxisome proteins, indicates that loss of both features in other apicomplexans occurred multiple times. The degradation of purines is thought to play a key role in the unusual relationship between Nephromyces and its host. Transcriptome data confirm previous biochemical results of a functional pathway for the utilization of uric acid as a primary nitrogen source for this unusual apicomplexan.


April 21, 2020  |  

Midrib Sucrose Accumulation and Sugar Transporter Gene Expression in YCS-Affected Sugarcane Leaves

Sucrose accumulation and decreased photosynthesis are early symptoms of yellow canopy syndrome (YCS) in sugarcane (Saccharum spp.), and precede the visual yellowing of the leaves. To investigate broad-scale gene expression changes during YCS-onset, transcriptome analyses coupled to metabolome analyses were performed. Across leaf tissues, the greatest number of differentially expressed genes related to the chloroplast, and the metabolic processes relating to nitrogen and carbohydrates. Five genes represented 90% of the TPM (Transcripts Per Million) associated with the downregulation of transcription during YCS-onset, which included PSII D1 (PsbA). This differential expression was consistent with a feedback regulatory effect upon photosynthesis. Broad-scale gene expression analyses did not reveal a cause for leaf sugar accumulation during YCS-onset. Interestingly, the midrib showed the greatest accumulation of sugars, followed by symptomatic lamina. To investigate if phloem loading/reloading may be compromised on a gene expression level – to lead to leaf sucrose accumulation – sucrose transport-related proteins of SWEETs, Sucrose Transporters (SUTs), H+-ATPases and H+-pyrophosphatases (H+-PPases) were characterised from a sugarcane transcriptome and expression analysed. Two clusters of Type I H+-PPases, with one upregulated and the other downregulated, were evident. Although less pronounced, a similar pattern of change was observed for the H+-ATPases. The disaccharide transporting SWEETs were downregulated after visual symptoms were present, and a monosaccharide transporting SWEET upregulated preceding, as well as after, symptom development. SUT gene expression was the least responsive to YCS development. The results are consistent with a reduction of photoassimilate movement through the phloem leading to sucrose build-up in the leaf.


April 21, 2020  |  

Methylome and Metabolome Analyses Reveal Adaptive Mechanisms in Geobacter sulfurreducens Grown on Different Terminal Electron Acceptors.

The Geobacter species evolved respiratory versatility to utilize a wide range of terminal electron acceptors. To explore this adaptive mechanism, Fe(III) citrate, hydrous ferric oxide, and fumarate were selected as electron acceptors, and the methylome and metabolome of Geobacter sulfurreducens PCA grown on each electron acceptor were investigated via third-generation, single-molecule real-time DNA sequencing and gas chromatography/time-of-flight mass spectrometry-based metabolomics, respectively. Results showed that the patterns of 4-methylcytosine (m4C) and 6-methyladenine (m6A) modification, the concentrations of fatty acids (e.g., caprylic acid, capric acid, and squalene), and the activity of antioxidant enzymes (e.g., superoxide dismutase, catalase, and glutathione reductase) were all varied in different electron acceptor cultures. Moreover, genes (e.g., GSU0466 and GSU1467) with low expression levels generally had high methylation levels. These findings suggest that m4C and m6A modifications, fatty acids, and antioxidant enzymes all play a role in the adaptation of G. sulfurreducens to diverse electron acceptors, and DNA methylation may be involved in the adaptation mainly via gene expression regulation.


April 21, 2020  |  

Identification of putative genes for polyphenol biosynthesis in olive fruits and leaves using full-length transcriptome sequencing.

Olive (Olea europaea) is a rich source of valuable bioactive polyphenols, which has attracted widespread interest. In this study, we combined targeted metabolome, Pacbio ISOseq transcriptome, and Illumina RNA-seq transcriptome to investigate the association between polyphenols and gene expression in the developing olive fruits and leaves. A total of 12 main polyphenols were measured, and 122 transcripts of 17 gene families, 101 transcripts of 9 gene families, and 106 transcripts of 6 gene families that encode for enzymes involved in flavonoid, oleuropein, and hydroxytyrosol biosynthesis were separately identified. Additionally, 232 alternative splicing events of 18 genes related to polyphenol synthesis were analyzed. This is the first time that the third generations of full-length transcriptome technology were used to study the gene expression pattern of olive fruits and leaves. The results of transcriptome combined with targeted metabolome can help us better understand the polyphenol biosynthesis pathways in the olive.Copyright © 2019 Elsevier Ltd. All rights reserved.


April 21, 2020  |  

Comparative analysis of proteomic and metabolomic profiles of different species of Paris.

An extract prepared from species of Paris is the most widely consumed herbal product in China. The genus Paris includes a variety of genotypes with different medicinal component contents but only two are defined as official sources. Closely related species have different medicinal properties because of differential expression of proteins and metabolites. To better understand the molecular basis of these differences, we examined proteomic and metabolomic changes in rhizomes of P. polyphylla var. chinensis, P. polyphylla var. yunnanensis, and P. fargesii var. fargesii using a technique known as sequential window acquisition of all theoretical mass spectra as well as gas chromatography-time-of-flight mass spectrometry. In total, 419 proteins showed significant abundance changes, and 33 metabolites could be used to discriminate Paris species. A complex analysis of proteomic and metabolomic data revealed a higher efficiency of sucrose utilization and an elevated protein abundance in the sugar metabolic pathway of P. polyphylla var. chinensis. The pyruvate content and efficiency of acetyl-CoA-utilization in saponin biosynthesis were also higher in P. polyphylla var. chinensis than in the other two species. The results expand our understanding of the proteome and metabolome of Paris and offer new insights into the species-specific traits of these herbaceous plants. SIGNIFICANCE: The traditional Chinese medicine Paris is the most widely consumed herbal product for the treatment of joint pain, rheumatoid arthritis and antineoplastic. All Paris species have roughly the same morphological characteristics; however, different members have different medicinal compound contents. Efficient exploitation of genetic diversity is a key factor in the development of rare medicinal plants with improved agronomic traits and malleability to challenging environmental conditions. Nevertheless, only a partial understanding of physiological and molecular mechanisms of different plants of Paris can be achieved without proteomics. To better understand the molecular basis of these differences and facilitate the use of other Paris species, we examine proteomic metabolomic changes in rhizomes of Paris using the technique known as SWATH-MS and GC/TOF-MS. Our research has provided information that can be used in other studies to compare metabolic traits in different Paris species. Our findings can also serve as a theoretical basis for the selection and cultivation of other Paris species with a higher medicinal value. Copyright © 2019 Elsevier B.V. All rights reserved.


April 21, 2020  |  

Modulation of metabolome and bacterial community in whole crop corn silage by inoculating homofermentative Lactobacillus plantarum and heterofermentative Lactobacillus buchneri.

The present study investigated the species level based microbial community and metabolome in corn silage inoculated with or without homofermentative Lactobacillus plantarum and heterofermentative Lactobacillus buchneri using the PacBio SMRT Sequencing and time-of-flight mass spectrometry (GC-TOF/MS). Chopped whole crop corn was treated with (1) deionized water (control), (2) Lactobacillus plantarum, or (3) Lactobacillus buchneri. The chopped whole crop corn was ensiled in vacuum-sealed polyethylene bags containing 300 g of fresh forge for 90 days, with three replicates for each treatment. The results showed that a total of 979 substances were detected, and 316 different metabolites were identified. Some metabolites with antimicrobial activity were detected in whole crop corn silage, such as catechol, 3-phenyllactic acid, 4-hydroxybenzoic acid, azelaic acid, 3,4-dihydroxybenzoic acid and 4-hydroxycinnamic acid. Catechol, pyrogallol and ferulic acid with antioxidant property, 4-hydroxybutyrate with nervine activity, and linoleic acid with cholesterol lowering effects, were detected in present study. In addition, a flavoring agent of myristic acid and a depression mitigation substance of phenylethylamine were also found in this study. Samples treated with inoculants presented more biofunctional metabolites of organic acids, amino acids and phenolic acids than untreated samples. The Lactobacillus species covered over 98% after ensiling, and were mainly comprised by the L. acetotolerans, L. silagei, L. parafarraginis, L. buchneri and L. odoratitofui. As compared to the control silage, inoculation of L. plantarum increased the relative abundances of L. acetotolerans, L. buchneri and L. parafarraginis, and a considerable decline in the proportion of L. silagei was observed; whereas an obvious decrease in L. acetotolerans and increases in L. odoratitofui and L. farciminis were observed in the L. buchneri inoculated silage. Therefore, inoculation of L. plantarum and L. buchneri regulated the microbial composition and metabolome of the corn silage with different behaviors. The present results indicated that profiling of silage microbiome and metabolome might improve our current understanding of the biological process underlying silage formation.


April 21, 2020  |  

Closing the Yield Gap for Cannabis: A Meta-Analysis of Factors Determining Cannabis Yield.

Until recently, the commercial production of Cannabis sativa was restricted to varieties that yielded high-quality fiber while producing low levels of the psychoactive cannabinoid tetrahydrocannabinol (THC). In the last few years, a number of jurisdictions have legalized the production of medical and/or recreational cannabis with higher levels of THC, and other jurisdictions seem poised to follow suit. Consequently, demand for industrial-scale production of high yield cannabis with consistent cannabinoid profiles is expected to increase. In this paper we highlight that currently, projected annual production of cannabis is based largely on facility size, not yield per square meter. This meta-analysis of cannabis yields reported in scientific literature aimed to identify the main factors contributing to cannabis yield per plant, per square meter, and per W of lighting electricity. In line with previous research we found that variety, plant density, light intensity and fertilization influence cannabis yield and cannabinoid content; we also identified pot size, light type and duration of the flowering period as predictors of yield and THC accumulation. We provide insight into the critical role of light intensity, quality, and photoperiod in determining cannabis yields, with particular focus on the potential for light-emitting diodes (LEDs) to improve growth and reduce energy requirements. We propose that the vast amount of genomics data currently available for cannabis can be used to better understand the effect of genotype on yield. Finally, we describe diversification that is likely to emerge in cannabis growing systems and examine the potential role of plant-growth promoting rhizobacteria (PGPR) for growth promotion, regulation of cannabinoid biosynthesis, and biocontrol.


April 21, 2020  |  

Genomics-driven discovery of a biosynthetic gene cluster required for the synthesis of BII-Rafflesfungin from the fungus Phoma sp. F3723.

Phomafungin is a recently reported broad spectrum antifungal compound but its biosynthetic pathway is unknown. We combed publicly available Phoma genomes but failed to find any putative biosynthetic gene cluster that could account for its biosynthesis.Therefore, we sequenced the genome of one of our Phoma strains (F3723) previously identified as having antifungal activity in a high-throughput screen. We found a biosynthetic gene cluster that was predicted to synthesize a cyclic lipodepsipeptide that differs in the amino acid composition compared to Phomafungin. Antifungal activity guided isolation yielded a new compound, BII-Rafflesfungin, the structure of which was determined.We describe the NRPS-t1PKS cluster ‘BIIRfg’ compatible with the synthesis of the cyclic lipodepsipeptide BII-Rafflesfungin [HMHDA-L-Ala-L-Glu-L-Asn-L-Ser-L-Ser-D-Ser-D-allo-Thr-Gly]. We report new Stachelhaus codes for Ala, Glu, Asn, Ser, Thr, and Gly. We propose a mechanism for BII-Rafflesfungin biosynthesis, which involves the formation of the lipid part by BIIRfg_PKS followed by activation and transfer of the lipid chain by a predicted AMP-ligase on to the first PCP domain of the BIIRfg_NRPS gene.


April 21, 2020  |  

Comparative Genomic Analyses Reveal Core-Genome-Wide Genes Under Positive Selection and Major Regulatory Hubs in Outlier Strains of Pseudomonas aeruginosa.

Genomic information for outlier strains of Pseudomonas aeruginosa is exiguous when compared with classical strains. We sequenced and constructed the complete genome of an environmental strain CR1 of P. aeruginosa and performed the comparative genomic analysis. It clustered with the outlier group, hence we scaled up the analyses to understand the differences in environmental and clinical outlier strains. We identified eight new regions of genomic plasticity and a plasmid pCR1 with a VirB/D4 complex followed by trimeric auto-transporter that can induce virulence phenotype in the genome of strain CR1. Virulence genotype analysis revealed that strain CR1 lacked hemolytic phospholipase C and D, three genes for LPS biosynthesis and had reduced antibiotic resistance genes when compared with clinical strains. Genes belonging to proteases, bacterial exporters and DNA stabilization were found to be under strong positive selection, thus facilitating pathogenicity and survival of the outliers. The outliers had the complete operon for the production of vibrioferrin, a siderophore present in plant growth promoting bacteria. The competence to acquire multidrug resistance and new virulence factors makes these strains a potential threat. However, we identified major regulatory hubs that can be used as drug targets against both the classical and outlier groups.


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