Single-cell RNA sequencing reveals a high-resolution cell atlas of petals in Prunus mume at different flowering development stages.

Prunus mume (mei), a traditional ornamental plant in China, is renowned for its fragrant flowers, primarily emitted by its petals. However, the cell types of mei petals and where floral volatile synthesis occurs are rarely reported. The study used single-cell RNA sequencing to characterize the gene expression landscape in petals of P. mume 'Fenhong Zhusha' at budding stage (BS) and full-blooming stage (FS). Six major cell types of petals were identified: epidermal cells (ECs), parenchyma cells (PCs), xylem parenchyma cells, phloem parenchyma cells, xylem vessels and fibers, and sieve elements and companion cells complex. Cell-specific marker genes in each cell type were provided. Floral volatiles from mei petals were measured at four flowering development stages, and their emissions increased from BS to FS, and decreased at the withering stage. Fifty-eight differentially expressed genes (DEGs) in benzenoid/phenylpropanoid pathway were screened using bulk RNA-seq data. Twenty-eight DEGs expression increased from BS to FS, indicating that they might play roles in floral volatile synthesis in P. mume, among which PmBAHD3 would participate in benzyl acetate synthesis. ScRNA-seq data showed that 27 DEGs mentioned above were expressed variously in different cell types. In situ hybridization confirmed that PmPAL2, PmCAD1, PmBAHD3,5, and PmEGS1 involved in floral volatile synthesis in mei petals are mainly expressed in EC, PC, and most vascular tissues, consistent with scRNA-seq data. The result indicates that benzyl acetate and eugenol, the characteristic volatiles in mei, are mostly synthesized in these cell types. The first petal single-cell atlas was constructed, offering new insights into the molecular mechanism of floral volatile synthesis.

Widely metabolomic combined with transcriptome analysis to build a bioactive compound regulatory network for the fruit growth cycle in Pseudocydonia sinensis.

Neglected and underutilised plants such as Pseudocydonia sinensis (Chinese quince) have garnered global interest as invaluable sources of natural bioactive compounds. Herein, a wide-targeted metabolomics-based approach revealed 1199 concurrent metabolites, with further analysis of their fluctuations across with the five stages of fruit growth. The bioactive compounds in Chinese quince primarily comprised sugars and organic acids, flavonoids, and terpenoids. Moreover, 395 metabolites were identified as having medicinal properties and rutin was the most content of them. Transcriptome analysis further provided a molecular basis for the metabolic changes observed during fruit development. By thoroughly analysing metabolite and transcriptome data, we revealed changes in bioactive compounds and related genes throughout fruit development. This study has yielded valuable insights into the ripening process of Chinese quince fruit, presenting substantial implications for industrial applications, particularly in quality control.

Efficacy and mechanism of enhanced Sb(V) removal from textile wastewater using ferric flocs in aerobic biological treatment.

Antimony contamination from textile industries has been a global environmental concern and the existing treatment technologies could not reduce Sb(V) to meet the discharge standards. To overcome this shortcoming, ferric flocs were introduced to expedite the biological process for enhanced Sb(V) removal in wastewater treatment plant (WWTP). For this purpose, a series of laboratorial-scale sequential batch reactor activated sludge processes (SBRs) were applied for Sb(V) removal with varied reactor conditions and the transformation of Fe and Sb in SBR system was investigated. Results showed a significant improvement in Sb(V) removal and the 20 mg L-1 d-1 iron ions dosage and iron loss rate was found to be only 15.2%. The influent Sb(V) concentration ranging 153-612 µg L-1 was reduced to below 50 µg L-1, and the maximum Sb(V) removal rate of the enhanced system reached about 94.3%. Furthermore, it exhibited high stability of Sb(V) removal in the face of antimonate load, Fe strike and matrix change of wastewater. Sludge total Sb determination and capacity calculation revealed decreasing in Sb adsorption capacity and desorption without fresh Fe dosage. While sludge morphology analysis demonstrated the aging and crystallization of iron hydroxides. These results verify the distinct effects of fresh iron addition and iron aging on Sb(V) removal. High-throughput gene pyrosequencing results showed that the iron addition changed microbial mechanisms and effect Fe oxidized bacterial quantity, indicating Sb(V) immobilization achieved by microbial synergistic iron oxidation. The present study successfully established a simple and efficient method for Sb(V) removal during biological treatment, and the modification of biological process by iron supplement could provide insights for real textile wastewater treatment.

Comparative Analysis of Chloroplast Genomes for the Genus Manglietia Blume (Magnoliaceae): Molecular Structure and Phylogenetic Evolution.

Manglietia Blume, belonging to the Magnoliaceae family and mainly distributed in tropical and subtropical regions of Asia, has great scientific and economic value. In this study, we employed next-generation sequencing followed by de novo assembly to investigate the adaptive evolution of Manglietia using plastid genetic information. We newly sequenced the complete or nearly complete plastomes of four Manglietia species (Manglietia aromatica, Manglietia calcarea, Manglietia kwangtungensis, and Manglietia glauca) and conducted comparative analysis with seventeen published plastomes to examine the evolutionary pattern within this genus. The plastomes of these five newly sequenced Manglietia species range from 157,093 bp (M. calcarea2) to 160,493 bp (M. kwangtungensis), all exhibiting circular structures when mapped. Nucleotide diversity was observed across the plastomes, leading us to identify 13 mutational hotspot regions, comprising eight intergenic spacer regions and five gene regions. Our phylogenetic analyses based on 77 protein-coding genes generated phylogenetic relationships with high support and resolution for Manglietia. This genus can be divided into three clades, and the previously proposed infrageneric classifications are not supported by our studies. Furthermore, the close affinity between M. aromatica and M. calcarea is supported by the present work, and further studies are necessary to conclude the taxonomic treatment for the latter. These results provide resources for the comparative plastome, breeding, and plastid genetic engineering of Magnoliaceae and flowering plants.

The CsMYB123 and CsbHLH111 are involved in drought stress-induced anthocyanin biosynthesis in Chaenomeles speciosa.

Drought stress has been demonstrated to enhance the biosynthesis of anthocyanins in the leaves, resulting in an increased aesthetic appeal. However, the molecular mechanisms underlying drought-induced anthocyanin biosynthesis in Chaenomeles speciosa remain unclear. In this study, the metabolites of C. speciosa leaves were analyzed, and it was found that the content of cyanidin-3-O-rutinoside increased significantly under drought stress. The differentially expressed genes CsMYB123 and CsbHLH111 were isolated by transcriptomics data analysis and gene cloning, and gene overexpression and VIGS experiments verified that both play important roles in anthocyanin biosynthesis. Subsequently, Y1H and Dual-luciferase reporter assay showed that CsMYB123 binds to the promoters of anthocyanin biosynthesis-related structural genes (such as CsCHI, CsF3H, and CsANS), while CsbHLH111 was shown to bind to the promoter of CsCHI, positively regulating its activity. Furthermore, BIFC and Y2H assays unveiled potential protein-protein interactions between CsMYB123 and CsbHLH111 at the cell nucleus. Collectively, these results shed light on the critical roles played by CsMYB123 and CsbHLH111 in anthocyanin biosynthesis, thus providing a valuable insight into understanding the molecular mechanisms of how the MYB and bHLH genes regulate anthocyanin biosynthesis in the process of leaf coloration in C. speciosa.

Anthocyanins from Malus spp. inhibit the activity of Gymnosporangium yamadae by downregulating the expression of WSC, RLM1, and PMA1.

Malus plants are frequently devastated by the apple rust caused by Gymnosporangium yamadae Miyabe. When rust occurs, most Malus spp. and cultivars produce yellow spots, which are more severe, whereas a few cultivars accumulate anthocyanins around rust spots, forming red spots that inhibit the expansion of the affected area and might confer rust resistance. Inoculation experiments showed that Malus spp. with red spots had a significantly lower rust severity. Compared with M. micromalus, M. 'Profusion', with red spots, accumulated more anthocyanins. Anthocyanins exhibited concentration-dependent antifungal activity against G. yamadae by inhibiting teliospores germination. Morphological observations and the leakage of teliospores intracellular contents evidenced that anthocyanins destroyed cell integrity. Transcriptome data of anthocyanins-treated teliospores showed that differentially expressed genes were enriched in cell wall and membrane metabolism-related pathways. Obvious cell atrophy in periodical cells and aeciospores was observed at the rust spots of M. 'Profusion'. Moreover, WSC, RLM1, and PMA1 in the cell wall and membrane metabolic pathways were progressively downregulated with increasing anthocyanins content, both in the in vitro treatment and in Malus spp. Our results suggest that anthocyanins play an anti-rust role by downregulating the expression of WSC, RLM1, and PMA1 to destroy the cell integrity of G. yamadae.

Drought-induced CsMYB6 interacts with CsbHLH111 to regulate anthocyanin biosynthesis in Chaenomeles speciosa.

Chaenomeles speciosa is a plant with high ornamental value, and the color of its petals deepens obviously under drought stress. To understand the mechanism of drought-induced reddening of C. speciosa petal color, the metabolites and transcriptomics of petals from 4% PEG-8000-treated and control cuttings were analyzed. In this study, the analysis of metabolites revealed the accumulation of anthocyanins in petals of PEG-treated cuttings, indicating anthocyanins might be the reason for the deepening of petal color. By using transcriptomics, we identified CsMYB6 as an overexpressed transcription factor in PEG-treated samples. Transient overexpression and suppression of CsMYB6 revealed that it is a key transcription factor for anthocyanin synthesis. We identified genes related to anthocyanin biosynthesis and constructed a network of drought- and anthocyanin-related genes (such as CsMYB6, CsbHLH111, CsANS, CsDFR, and CsUFGT). Further experiments indicated that CsMYB6 directly interacted with CsbHLH111, and this interaction increased the binding ability of CsMYB6 to the promoter regions of three structural genes of anthocyanin biosynthesis: CsANS, CsDFR, and CsUFGT. Our findings provide a molecular basis and new insight into drought-induced anthocyanin biosynthesis in C. speciosa.

The synergy of thanatin and cathelicidin-BF-15a3 combats Escherichia coli O157:H7.

Escherichia coli O157:H7 is a pathogen that commonly causes foodborne illness and represents a health hazard to consumers. The combined use of synergistic antimicrobial peptides (AMPs) is a promising way to improve the microbiological safety of foods. In this study, we detected the synergistic interactions between thanatin and BF-15a3 to reduce their usage and obtain more efficient antibacterial activity. The minimal inhibitory concentrations (MICs) of thanatin and BF-15a3 against 49 E. coli O157:H7 strains were ranged from 2 to 8 µg/mL and 4-32 µg/mL, showed a general inhibitory effect on E. coli O157:H7 strains, respectively, even multidrug-resistant strains. Their fractional inhibitory concentration index (FICI) was 0.375, which suggested that their combination presented synergistic antibacterial effect against E. coli O157:H7. The killing kinetic curves indicated that the 0.25 × MIC combination had equivalent bactericidal effects to 1 × MIC thanatin or BF-15a3. When AMP combinations were used to treat eukaryotic cells to evaluate the hemolytic characteristics against rabbit erythrocytes and cytotoxicity against human embryonic kidney 293T (HEK-293T) cells and intestinal porcine enterocyte J2 (IPEC-J2) cells, no magnified adverse effects were observed, exhibiting higher specificity to bacteria and lower toxicity to eukaryotic cells. Compared with bacteriostasis of thanatin or BF-15a3 alone, the proportion of membrane-damaged bacteria treated with the synergetic combination did not appear a significant rise, interestingly the Zeta potential of them greatly decreased and their cell membrane permeability significantly increased. Besides, more release of ions and cytoplasm were detected, confirming a more severe loss of membrane integrity. These results suggested that the synergistic action mode of thanatin and BF-15a3 is likely attributed to damage aggravation to E. coli membrane. When applying in fresh-cut lettuce and cucumber, their combination allowed for 2.5 log CFU/piece reductions of E. coli O157:H7 in 24 h. In conclusion, the combination of thanatin and BF-15a3 showed excellent synthetic efficacy to kill E. coli O157:H7 in vitro under lower MICs than single use of them.

A Dual-Channel Microfluidic Chip for Single Tobacco Protoplast Isolation and Dynamic Capture.

Protoplasts are widely used in gene function verification, subcellular localization, and single-cell sequencing because of their complete physiological activities. The traditional methods based on tissues and organs cannot satisfy the requirement. Therefore, the isolation and capture of a single protoplast are most important to these studies. In this study, a dual-channel microfluidic chip based on PDMS with multi-capture cavities was designed. The design theory of the dual-channel microfluidic chip's geometry was discussed. The capture mechanism of the single cell in a dual-channel microfluidic chip was studied by simulation analysis. Our results showed that a single polystyrene microsphere or tobacco protoplast was successfully isolated and trapped in this chip. The capture efficiency of the chip was 83.33% for the single tobacco protoplast when the inlet flow rate was 0.75 µL/min. In addition, the dynamic capture of the polystyrene microsphere and tobacco protoplasts was also presented. Overall, our study not only provided a new strategy for the subsequent high throughput single protoplast research, but also laid a theoretical foundation for the capture mechanism of the single cell.

The UV-B-Induced Transcription Factor HY5 Regulated Anthocyanin Biosynthesis in Zanthoxylum bungeanum.

Pericarp color is an important economic characteristic of Zanthoxylum bungeanum. Anthocyanins are the main reason for the pericarp's red appearance in Z. bungeanum. In this study, through the combined analysis of the metabolome and transcriptome, HY5, whose expression is highly correlated to changes in the anthocyanin content, was screened and identified. Under natural ripening conditions, the Z. bungeanum fruit gradually changed in color from green to red, while bagging resulted in the fruit maintaining its green color. After unbagging, the fruit gradually turned red, and the ZbHY5 expression and anthocyanin content increased. In addition, the leaves changed from green to red after exposure to UV-B radiation, and the ZbHY5 expression and anthocyanin content increased. The transient overexpression of ZbHY5 deepened the redness of the Z. bungeanum leaves and promoted the expression of ZbHY5 and ZbMYB113 as well as anthocyanin accumulation. Bimolecular fluorescence complementation (BIFC) showed that there was an interaction between ZbHY5 and ZbMYB113. These results revealed that under UV-B irradiation, ZbHY5 might regulate the expression levels of the structural genes related to anthocyanin biosynthesis through combination with ZbMYB113, thereby affecting anthocyanin accumulation. This finding provides useful insights for further studies focusing on UV-B-induced anthocyanin accumulation in Z. bungeanum.

Extracellular lipopeptide bacillomycin L regulates serial expression of genes for modulating multicellular behavior in Bacillus velezensis Bs916.

In wild strains of Bacillus, a handful of extracellular natural products act as signals that can regulate multicellular behavior, but relatively little is known about molecular mechanisms' detail. We proposed a previously unreported molecular mechanism for triggering multicellularity in B. velezensis Bs916 by an endogenous cyclic lipopeptide, bacillomycin L. The genome-wide effect on gene expression was caused by the disruption of bacillomycin L gene cluster, and 100 µg/mL bacillomycin L was revealed by quantitative transcriptomics. A total of 878 differentially expressed genes among Bs916, Δbl, and Δbl + 100BL were identified and grouped into 9 functional categories. The transcription levels of 40 candidate genes were further evaluated by RT-qPCR analysis. The expression of eight candidate genes regulated by bacillomycin L in a dose-dependent manner was revealed by LacZ fusion experiment. Although the addition of bacillomycin L could not completely restore the expression levels of the differentially regulated genes in △bl, our results strongly suggest that bacillomycin L acts as a tuning signal of swarming motility and complex biofilm formation by indirectly regulating the expression levels of some two-component systems (TCSs) connector genes, particularly including several Raps that potentially regulate the phosphorylation levels of three major regulators ComA, DegU, and Spo0A.Key points• Proposed model for bacillomycin L regulation in B. velezensis Bs916.• Bacillomycin L can act as an extracellular signal to regulate the phosphorylation levels of three major regulators, ComA, DegU, and Spo0A and control the multicellular processes of vegetative growth, competent, motility, matrix production, sporulation, and autolysis.

Impact of the Supervisor Feedback Environment on Creative Performance: A Moderated Mediation Model.

Studies on the relationship between feedback and creative performance have only focused on the feedback-self and have underestimated the value of the feedback environment. Building on Self Determined Theory, the purpose of this article is to examine the relationship among feedback environment, creative personality, goal self-concordance and creative performance. Hierarchical regression analysis of a sample of 162 supervisor-employee dyads from nine industry firms. The results indicate that supervisor feedback environment is positively related to creative performance, the relationship between the supervisor feedback environment and creative performance is mediated by goal self-concordance perfectly and moderated by creative personality significantly. The mediation effort of goal self-concordance is significantly influenced by creative personality. The implication of improving employees' creative performance is further discussed. The present study advances several perspectives of previous studies, echoes recent suggestions that organizations interested in stimulating employee creativity might profitably focus on developing work contexts that support it.

Draft Genome Sequence of the Organophosphorus-Degrading Bacterium Pseudomonas sp. Strain 1-7, Isolated from Organophosphorus-Polluted Sludge.

Pseudomonas sp. strain 1-7, isolated from organophosphorus-polluted sludge, is able to degrade many organophosphorus compounds. Here, we report the draft genome sequence of Pseudomonas sp. strain 1-7.

Identification of the para-nitrophenol catabolic pathway, and characterization of three enzymes involved in the hydroquinone pathway, in Peudomonas sp. 1-7.

BACKGROUND: para-Nitrophenol (PNP), a priority environmental pollutant, is hazardous to humans and animals. However, the information relating to the PNP degradation pathways and their enzymes remain limited. RESULTS: Pseudomonas sp.1-7 was isolated from methyl parathion (MP)-polluted activated sludge and was shown to degrade PNP. Two different intermediates, hydroquinone (HQ) and 4-nitrocatechol (4-NC) were detected in the catabolism of PNP. This indicated that Pseudomonas sp.1-7 degraded PNP by two different pathways, namely the HQ pathway, and the hydroxyquinol (BT) pathway (also referred to as the 4-NC pathway). A gene cluster (pdcEDGFCBA) was identified in a 10.6 kb DNA fragment of a fosmid library, which cluster encoded the following enzymes involved in PNP degradation: PNP 4-monooxygenase (PdcA), p-benzoquinone (BQ) reductase (PdcB), hydroxyquinol (BT) 1,2-dioxygenase (PdcC), maleylacetate (MA) reductase (PdcF), 4-hydroxymuconic semialdehyde (4-HS) dehydrogenase (PdcG), and hydroquinone (HQ) 1,2-dioxygenase (PdcDE). Four genes (pdcDEFG) were expressed in E. coli and the purified pdcDE, pdcG and pdcF gene products were shown to convert HQ to 4-HS, 4-HS to MA and MA to ß-ketoadipate respectively by in vitro activity assays. CONCLUSIONS: The cloning, sequencing, and characterization of these genes along with the functional PNP degradation studies identified 4-NC, HQ, 4-HS, and MA as intermediates in the degradation pathway of PNP by Pseudomonas sp.1-7. This is the first conclusive report for both 4-NC and HQ- mediated degradation of PNP by one microorganism.

Identification of the transcriptional regulator NcrB in the nickel resistance determinant of Leptospirillum ferriphilum UBK03.

The nickel resistance determinant ncrABCY was identified in Leptospirillum ferriphilum UBK03. Within this operon, ncrA and ncrC encode two membrane proteins that form an efflux system, and ncrB encodes NcrB, which belongs to an uncharacterized family (DUF156) of proteins. How this determinant is regulated remains unknown. Our data indicate that expression of the nickel resistance determinant is induced by nickel. The promoter of ncrA, designated pncrA, was cloned into the promoter probe vector pPR9TT, and co-transformed with either a wild-type or mutant nickel resistance determinant. The results revealed that ncrB encoded a transcriptional regulator that could regulate the expression of ncrA, ncrB, and ncrC. A GC-rich inverted repeat sequence was identified in the promoter pncrA. Electrophoretic mobility shift assays (EMSAs) and footprinting assays showed that purified NcrB could specifically bind to the inverted repeat sequence of pncrA in vitro; this was confirmed by bacterial one-hybrid analysis. Moreover, this binding was inhibited in the presence of nickel ions. Thus, we classified NcrB as a transcriptional regulator that recognizes the inverted repeat sequence binding motif to regulate the expression of the key nickel resistance gene, ncrA.