Mutational profile evaluates metastatic capacity of Chinese colorectal cancer patients, revealed by whole-exome sequencing.

Colorectal cancer (CRC) is the third most common cancer and the prevalence rate of CRC is increasing in the China. In this study, whole-exome sequencing (WES) was performed on primary tissues of 47 CRC Chinese patients including 22 metastatic and 25 non-metastatic patients. By comparison with data from western colorectal cancer patients in the Cancer Genome Atlas (TCGA), we identified a number of genes that are more likely to be mutated in Chinese colorectal cancer patients, such as MUC12, MUC12, MUC2, MUC4, HYDIN and KMT2C. Interestingly, MUC family genes including MUC12, MUC2 and MUC4, have mutation rates of >20%, while the mutation frequency was extremely low in western colorectal cancer patients, which were <3% in TCGA and 0% in Memorial Sloan Kettering Cancer Center (MSKCC). We detected metastasis-specific mutated genes including TCF7L2, MST1L, HRNR and SMAD4, while MUC4, NEB, FLG and RFPL4A alteration is more prevalent in the non-metastasis group. Further analysis reveals mutation genes in metastasis group are more focus in the Wnt and Hippo signaling pathway. APC, SMAD4 and TCF7L2 accounted for the major genetic abnormalities in this pathway. In conclusion, this study identified the unique characteristics of gene mutations in Chinese patients with colorectal cancer, and is a valuable reference for personalized treatment in Chinese CRC patients.

Nano-TiO2 regulates the MAPK (ERK, P38) pathway to promote apoptosis and inhibit proliferation of human colon cells.

BACKGROUND: Nano titanium dioxides (TiO2) are widely used in drug development, food additives and packaging materials. Although several studies have demonstrated the poisonousness of TiO2 in vivo and in vitro, the underlying molecular mechanisms have not been fully revealed. METHODS: Characterization of TiO2 by FTIR, XRD, TEM and DLS. The NCM460 cell line, representing normal colon epithelial cells, was utilized as a model to assess the impact of TiO2 nanoparticles (TiO2-NPs) on cell proliferation and apoptosis. The potential molecular mechanisms underlying its toxic effects were investigated through transcriptome analysis, RT-qPCR, and western blot experiments. RESULTS: The particle size of the TiO2-NPs used is about 25 nm, which has typical characteristics of anatase. TiO2-NPs at a concentration of 30-60 µg/mL will cause changes in colon cell morphology, decreased proliferation ability, and increased number of apoptotic cells. TiO2-NPs at a concentration of 6 µg/mL did not significantly modify the transcriptome expression profile of colon cells; while 30 µg/mL had a significant effect, leading to up-regulation of gene expression. The differentially expressed genes predominantly modulate the MAPK signaling pathway, TNF signaling pathway, cytokine-cytokine receptor interaction, and other related pathways. Further, western blot analysis revealed that higher concentrations of TiO2-NPs (30-60 µg/mL) could up-regulate the expression of P53, P21 and Bax, while down-regulating the expression of Bcl2 by regulating the MAPK (ERK, P38) signaling pathway. Simultaneously, it also promoted the decreased in Fos protein expression and inhibited the phosphorylation of Jun and Fos. CONCLUSION: This study demonstrates that TiO2-NPs may exert potential toxic effects on colon cells, and therefore the intake of TiO2-NPs should be strictly regulated in practical applications.

NF-κB downstream miR-1262 disturbs colon cancer cell malignant behaviors by targeting FGFR1.

Despite substantial advancements in screening, surgery, and chemotherapy, colorectal cancer remains the second most lethal form of the disease. Nuclear factor kappa B (NF-κB) signaling is a critical driver facilitating the malignant transformation of chronic inflammatory bowel diseases. In this study, deregulated miRNAs that could play a role in colon cancer are analyzed and investigated for specific functions in vitro using cancer cells and in vivo using a subcutaneous xenograft model. miRNA downstream targets are analyzed, and predicted binding and regulation are verified. miR-1262, an antitumor miRNA, is downregulated in colon cancer tissue samples and cell lines. miR-1262 overexpression suppresses colon cancer malignant behaviors in vitro and tumor development and metastasis in a subcutaneous xenograft model and a lung metastasis mouse model in vivo. miR-1262 directly targets fibroblast growth factor receptor 1 (FGFR1) and inhibits FGFR1 expression. FGFR1 overexpression shows oncogenic functions through the regulation of cancer cell proliferation, invasion, and migration; when cotransfected, lv-FGFR1 partially attenuates the antitumor effects of agomir-1262. NF-κB binds to the miR-1262 promoter region and inhibits transcription activity. The NF-κB inhibitor CAPE exerts antitumor effects; miR-1262 inhibition partially reverses CAPE effects on colon cancer cells. Conclusively, miR-1262 serves as an antitumor miRNA in colon cancer by targeting FGFR1. The NF-κB/miR-1262/FGFR1 axis modulates colon cancer cell phenotypes, including proliferation, invasion, and migration.

Laparoscopic D3 lymph node dissection with left colic artery and first sigmoid artery preservation in rectal cancer.

BACKGROUND: D3 lymph node dissection with left colic artery (LCA) preservation in rectal cancer surgery seems to have little effect on reducing postoperative anastomotic leakage. So we first propose D3 lymph node dissection with LCA and first sigmoid artery (SA) preservation. This novel procedure deserves further study. METHODS: Rectal cancer patients who underwent laparoscopic D3 lymph node dissection with LCA preservation or with LCA and first SA preservation between January 2017 and January 2020 were retrospectively assessed. The patients were categorized into two groups: the preservation of the LCA group and the preservation of the LCA and first SA group. A 1:1 propensity score-matched analysis was performed to decrease confounding. RESULTS: Propensity score matching yielded 56 patients in each group from the eligible patients. The rate of postoperative anastomotic leakage in the preservation of the LCA and first SA group was significantly lower than that in the LCA preservation group (7.1% vs. 0%, P=0.040). No significant differences were observed in operation time, length of hospital stay, estimated blood loss, length of distal margin, lymph node retrieval, apical lymph node retrieval, and complications. A survival analysis showed patients' 3-year disease-free survival (DFS) rates of group 1 and group 2 were 81.8% and 83.5% (P=0.595), respectively. CONCLUSION: D3 lymph node dissection with LCA and first SA preservation for rectal cancer may help reduce the incidence of anastomotic leakage without compromising oncological outcomes compare with D3 lymph node dissection with LCA preservation alone.

Study of carbon nanotube embedded honey as a resistive switching material.

In this paper, natural organic honey embedded with carbon nanotubes (CNTs) was studied as a resistive switching material for biodegradable nonvolatile memory in emerging neuromorphic systems. CNTs were dispersed in a honey-water solution with the concentration of 0.2 wt% CNT and 30 wt% honey. The final honey-CNT-water mixture was spin-coated and dried into a thin film sandwiched in between Cu bottom electrode and Al top electrode to form a honey-CNT based resistive switching memory (RSM). Surface morphology, electrical characteristics and current conduction mechanism were investigated. The results show that although CNTs formed agglomerations in the dried honey-CNT film, both switching speed and the stability in SET and RESET process of honey-CNT RSM were improved. The mechanism of current conduction in CNT is governed by Ohm's law in low-resistance state and the low-voltage range in high-resistance state, but transits to the space charge limited conduction at high voltages approaching the SET voltage.

S100A1 is Involved in Myocardial Injury Induced by Exhaustive Exercise.

Many studies have confirmed that exhaustive exercise has adverse effects on the heart by generating reactive oxygen species (ROS). S100A1 calcium-binding protein A1 (S100A1) is a regulator of myocardial contractility and a protector against myocardial injury. However, few studies have investigated the role of S100A1 in the regulation of myocardial injury induced by exhaustive exercise. In the present study, we suggested that exhaustive exercise led to increased ROS, downregulation of S100a1, and myocardial injury. Downregulation of S100a1 promoted exhaustive exercise-induced myocardial injury and overexpression of S100A1 reversed oxidative stress-induced cardiomyocyte injury, indicating S100A1 is a protective factor against myocardial injury caused by exhaustive exercise. We also found that downregulation of S100A1 promoted damage to critical proteins of the mitochondria by inhibiting the expression of Ant1, Pgc1a, and Tfam under exhaustive exercise. Our study indicated S100A1 as a potential prognostic biomarker or therapeutic target to improve the myocardial damage induced by exhaustive exercise and provided new insights into the molecular mechanisms underlying the myocardial injury effect of exhaustive exercise.

Fabrication of field-effect transistors with transfer-free nanostructured carbon as the semiconducting channel material.

Carbon nanostructures used as the active channel material in field effect transistors (FETs) are appealing in microelectronics for their improved performance, such as their high speed and low energy dissipation. However, these devices require the incorporation of nanostructure transfer steps in the fabrication process flow, which makes their application difficult in large scale integrated circuits. Here we present a novel method for the fabrication of FETs with nanostructured carbon in the channel with p-type semiconducting properties and intermediate drain-source current (IDS ) on/off ratio. The method is based on the use of Ni nanoparticles in the source-drain gap region as the seed material for the formation of carbon nanostructures in the FET channel. FETs without Ni nanoparticles in the channel showed no modulation of IDS as a function of gate voltage. The device fabrication process does not require any carbon nanostructure transfer steps since it directly forms carbon nanostructures electrically connected to the device's source and drain electrodes via electron-beam evaporation of carbon and conventional lithographic processes. Since all device fabrication steps are compatible with existing Si technology processes, they are capable of being further optimized following process development protocols practiced by the semiconductor industry.

Modification of Rhizosphere Bacterial Community Structure and Functional Potentials to Control Pseudostellaria heterophylla Replant Disease.

Replant disease caused by negative plant-soil feedback commonly occurs in a Pseudostellaria heterophylla monoculture regime. Here, barcoded pyrosequencing of 16S ribosomal DNA amplicons combined with phylogenetic investigation of communities by reconstruction of unobserved states (PICRUSt) analysis was applied to study the shifts in soil bacterial community structure and functional potentials in the rhizosphere of P. heterophylla under consecutive monoculture and different soil amendments (i.e., bio-organic fertilizer application [MF] and paddy-upland rotation [PR]). The results showed that the yield of tuberous roots decreased under P. heterophylla consecutive monoculture and then increased after MF and PR treatments, which was consistent with the changes in soil bacterial diversity. Both principal coordinate analysis and the unweighted pair-group method with arithmetic means cluster analysis showed the distinct difference in bacterial community structure between the consecutively monocultured soil (relatively unhealthy soil) and other relatively healthy soils (i.e., newly planted soil, MF, and PR). Furthermore, taxonomic analysis showed that consecutive monoculture of P. heterophylla significantly decreased the relative abundances of the families Burkholderiaceae and Acidobacteriaceae (subgroup 1), whereas it increased the population density of families Xanthomonadaceae, Phyllobacteriaceae, Sphingobacteriaceae, and Alcaligenaceae, and Fusarium oxysporum. In contrast, the MF and PR treatments recovered the soil microbiome and decreased F. oxysporum abundance through the different ways; for example, the introduction of beneficial microorganisms (in MF) or the switching between anaerobic and aerobic conditions (in PR). In addition, PICRUSt analysis revealed the higher abundances of membrane transport, cell motility, and DNA repair in the consecutively monocultured soil, which might contribute to the root colonization and survival for certain bacterial pathogens under monoculture. These findings highlight the close association between replant disease of P. heterophylla and the variations in structure and potential functions of rhizosphere bacterial community.

Fabrication and characterization of emulsion stabilized by table egg-yolk granules at different pH levels.

BACKGROUND: The egg yolk is complex, which makes it difficult to understand why mayonnaise can be stabilized into a high internal-phase emulsion. This study aimed to assess the possibility of developing oil-in-water emulsions through unmodified natural egg-yolk granules (EYGs) at various pH levels, to further understand the precise mechanism of mayonnaise. RESULTS: Egg-yolk granules were obtained from hen egg yolk by centrifugation. The sizes of the EYGs were characterized using dynamic light scattering (DLS). Zeta potential of EYGs was detected by DLS and its microstructure was observed by microscope and scanning electron microscope (SEM). Oil / water emulsions were made with EYGs and the size distribution and creaming index of those emulsions were measured at different storage times (1 h and 14 days). The interfacial morphology of EYGs was observed using the emulsion polymerization method. Our results suggested that the prepared EYGs were mainly in an aggregated state but individual EYGs displayed spherical shapes, with a size of 1.0 ± 0.2 µm. The emulsion stabilized by EYGs displayed better stability against creaming at acidic pH (<4.0). At the same time, the interfacial morphology and microscopic observation of the emulsions strongly demonstrated that the emulsions were of the Pickering type. CONCLUSION: The above results are of great importance for an understanding of the mechanism by which mayonnaise is stabilized by egg, together with the applications of egg in food formulations. © 2019 Society of Chemical Industry.

lncRNA B4GALT1-AS1 promotes colon cancer cell stemness and migration by recruiting YAP to the nucleus and enhancing YAP transcriptional activity.

Here, an RNA-sequencing assay revealed long noncoding RNAs (lncRNAs) with an ectopic expression between colon cancer (CC) and normal colon epithelial cells, in which lncRNA B4GALT1-AS1 exhibited the highest change. A 3-(4,5-dimethythiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay indicated that B4GALT1-AS1 knockdown had no effect on CC cell viability, however, cell clone formation analysis showed that B4GALT1-AS1 knockdown attenuated the capacity of cell clone formation. Additionally, gene set enrichment analysis of this data set revealed that positive enrichment of stem cell-differentiated signatures and negative embryonic stem cell function and adult tissue stem module were observed in CC cells with B4GALT1-AS1 knockdown. Furthermore, B4GALT1-AS1 knockdown suppressed the stemness-marker expression, the ability of cell spheroid formation, and ALDH1 activity in CC cells. Mechanistically, RNA-sequencing data found that the Hippo pathway in cancer was shown on pathways mostly upregulated by B4GALT1-AS1 knockdown, and B4GALT1-AS1 directly bound to the yes-associated protein (YAP), a downstream executor of the Hippo pathway, and B4GALT1-AS1 knockdown promoted the nuclear cytoplasm translocation of YAP and decreased YAP transcriptional activity. Notably, YAP overexpression attenuated the inhibitory effects mediated by B4GALT1-AS1 knockdown. Our results identify the direct binding of lncRNA B4GALT1-AS1 to YAP, which is responsible for CC cell stemness.

Technologies for enhancement of bioactive components and potential health benefits of cereal and cereal-based foods: Research advances and application challenges.

Cereal grains are a major source of human food and their production has steadily been increased during the last several decades to meet the demand of our increasing world population. The modernized society and the expansion of the cereal food industry created a need for highly efficient processing technologies, especially flour production. Earlier scientific research efforts have led to the invention of the modern steel roller mill, and the refined flour of wheat has become a basic component in most of cereal-based foods such as breads and pastries because of the unique functionality of wheat protein. On the other hand, epidemiological studies have found that consumption of whole cereal grains was health beneficial. The health benefit of whole cereal grain is attributed to the combined effects of micronutrients, phytochemicals, and dietary fibre, which are mainly located in the outer bran layer and the germ. However, the removal of bran and germ from cereal grains during polishing and milling results in refined flour and food products with lower bioactive compounds and dietary fibre contents than those from whole grain. Also, the level of bioactive compounds in cereal food is influenced by other food preparation procedures such as baking, cooking, extrusion, and puffing. Therefore, food scientists and nutritionists are searching for strategies and processing technologies to enhance the content and bioavailability of nutrients, bioactive compounds, and dietary fibre of cereal foods. The objective of this article was to review the research advances on technologies for the enhancement of bioactive compounds and dietary fibre contents of cereal and cereal-based foods. Bioactivities or biological effects of enhanced cereal and cereal-based foods are presented. Challenges facing the application of the proposed technologies in the food industry are also discussed.

Brown Rice Versus White Rice: Nutritional Quality, Potential Health Benefits, Development of Food Products, and Preservation Technologies.

Obesity and chronic diet-related diseases such as type 2 diabetes, hypertension, cardiovascular disease, cancers, and celiac are increasing worldwide. The increasing prevalence of these diseases has led nutritionists and food scientists to pay more attention to the relationship between diet and different disease risks. Among different foods, rice has received increasing attention because it is a major component of billions of peoples' diets throughout the world. Rice is commonly consumed after polishing or whitening and the polished grain is known a high glycemic food because of its high starch content. In addition, the removal of the outer bran layer during rice milling results in a loss of nutrients, dietary fiber, and bioactive components. Therefore, many studies were performed to investigate the potential health benefits for the consumption of whole brown rice (BR) grain in comparison to the milled or white rice (WR). The objective of this work was to review the recent advances in research performed for purposes of evaluation of nutritional value and potential health benefits of the whole BR grain. Studies carried out for purposes of developing BR-based food products are reviewed. BR safety and preservation treatments are also explored. In addition, economic and environmental benefits for the consumption of whole BR instead of the polished or WR are presented. Furthermore, challenges facing the commercialization of BR and future perspectives to promote its utilization as food are discussed.

Effect of protein aggregates on properties and structure of rice bran protein-based film at different pH.

Rice bran protein (RBP) aggregates were prepared by heating of RBP solution at 90 °C for 4 h at pH 2, 7, or 11 and used for preparing of packaging films. The structure and properties of RBP aggregates and RBP-based films were characterized with sodium dodecyl sulfate-polyacrylamide gel electrophoresis, transmission electron microscopy, scanning electron microscope, differential scanning calorimetry, Fourier transform infrared spectroscopy and circular dichroism. The results showed formation of fibrillar, globular, and large molecular protein aggregates during the heating at pH 2, 7 and 11. The heat-aggregated RBP-based films exhibited lower opacity, moisture content, water solubility, and water vapor permeability than those of untreated RBP-based films. Also, improved mechanical and thermal properties were found for the heat-aggregated RBP-based films. In addition, the heat-aggregated RBP-based film at pH 11 showed homogenous and smooth surface as well as compact appearance compared with the untreated RBP-based films or heat-aggregated RBP-based film at pH 2 or 7. Furthermore, the secondary structure of heat-aggregated RBP film exhibited an increase in ß-sheet content and molecular interactions through non-covalent bonds. The obtained results indicated that formation of protein aggregates could improve physical, mechanical, and thermal properties of RBP-based film, especially at pH 11.

Rs13293512 polymorphism located in the promoter region of let-7 is associated with increased risk of radiation enteritis in colorectal cancer.

RE (Radiation enteritis) has been characterized by the inflammation reaction, and in this study, we aim to explore inflammatory cytokines and underlying mechanism involved in the pathogenesis of RE. Luciferase assay was performed to explore whether polymorphism affected the expression of let-7, and also validated let-7 directly regulated f IL-6 expression. Then Elisa was performed to study the mechanism of rs13293512 polymorphism associated with enteritis occurrence. And Western-blot and real-time PCR were performed to verify the relationship between let-7 and IL-6. 380 colorectal cancer patients were recruited, and all participants were genotyped. We found that occurrence probability of enteritis patients carried CC genotype (32%) was much higher than that in TT and TC groups (15%). In addition, we showed that the presence of the minor (C) allele of the polymorphism in the promoter region of let-7 substantially reduced the transcription activity of let-7, furthermore, we validated that let-7 directly regulated IL-6 expression by using luciferase reporter system. Moreover, IL-6 was highly expressed in peripheral blood and colonic mucosa samples genotyped as CC compared to those in TT and TC groups, furthermore, IL-6 was highly expressed in peripheral blood and colonic mucosa samples from participants with enteritis than without enteritis, whereas let-7 was highly expressed in peripheral blood and colonic mucosa samples genotyped as TT and TC compared to those in CC groups. Let-7 polymorphism (rs13293512) was associated with risk of RE in the colorectal cancer patients who received radiotherapy.

LncRNA HOTAIR is a Prognostic Biomarker for the Proliferation and Chemoresistance of Colorectal Cancer via MiR-203a-3p-Mediated Wnt/ß-Catenin Signaling Pathway.

BACKGROUND/AIMS: HOX transcript antisense RNA (HOTAIR) plays a vital role in carcinogenesis. However, its functional and regulatory roles remain unclear. In this study, we aimed to investigate its biological function and clinical significance in human colorectal cancer (CRC). METHODS: We examined the expression levels of lncRNA HOTAIR and miR-203a-3p in CRC tissues and CRC cell lines by qRT-PCR. Gain and loss-of-function assays were performed to examine the effects of HOTAIR and miR-203a-3p on the proliferation and chemoresistance of CRC cells. The possible mechanisms of HOTAIR were also explored by fluorescence reporter assay and Western blot. RESULTS: The expressions of HOTAIR were upregulated in CRC tissue tissues compared to adjacent control tissues. We also found HOTAIR was downregulated by miR-203a-3p in CRC cell lines. Both HOTAIR knockdown and miR-203a-3p overexpression in CRC cell lines led to inhibited cell proliferation and reduced chemoresistance. We also determined that ß-catenin and GRG5 were inhibitory targets of miR-203a-3p, and that Wnt/ß-catenin signaling was inhibited by both HOTAIR knockdown and miR-203a-3p overexpression. Significantly, we found that increased expression of miR-203a-3p is essential for cell proliferation repression, chemoresistance reduction, and Wnt/ß-catenin signaling inhibition induced by HOTAIR knockdown. CONCLUSIONS: Our study demonstrated that the lncRNA HOTAIR could regulate the progression and chemoresistance of CRC via modulating the expression levels of miR-203a-3p and the activity of Wnt/ß-catenin signaling pathway.

New Experimental Limits on Exotic Spin-Spin-Velocity-Dependent Interactions by Using SmCo_{5} Spin Sources.

Despite the great success of the standard model (SM), there still exist mysteries like the nature of dark matter, the strong CP problems, etc. To solve them, many theories proposed new bosons beyond the SM that can mediate new forces. Here, we report the latest results of searching for possible new long-range spin-spin-velocity-dependent forces (SSVDFs), based on specially designed iron-shielded SmCo_{5} spin sources and a spin exchange relaxation free comagnetometer. With help from the similarity analysis method, new constraints on some forms of SSVDFs between electrons have been obtained, which represent up to more than 11 orders of magnitude tighter limits than previous experiments for the force range of 5 cm-1 km.

Rhizosphere Fungal Community Dynamics Associated with Rehmannia glutinosa Replant Disease in a Consecutive Monoculture Regime.

Consecutive monoculture of Rehmannia glutinosa in the same field leads to a severe decline in both quality and yield of tuberous roots, the most useful part in traditional Chinese medicine. Fungi are an important and diverse group of microorganisms in the soil ecosystem and play crucial roles in soil health. In this study, high-throughput pyrosequencing of internal transcribed spacer 2 ribosomal DNA amplicons was applied to gain insight into how consecutive monoculture practice influence and stimulate R. glutinosa rhizosphere and bulk soil fungal communities. The results from nonmetric multidimensional scaling ordination and clustering analysis revealed distinctive differences between rhizosphere and bulk soil fungal communities. However, longer-term monocultured bulk soils were more similar to the rhizosphere soils in comparison with the shorter-term monocultured bulk soils. Moreover, consecutive monoculture caused a gradual shift in the composition and structure of the soil fungal community. The cultivation of this plant led to the appearance of some exclusive operational taxonomic units in rhizosphere or bulk soils that were assigned to the genera Fusarium, Rhizoctonia, and so on. Furthermore, the sum of the relative abundance of species of Fusarium, Cylindrocarpon, and Gibberella (belonging to the family Nectriaceae); Rhizoctonia, Thanatephorus, and Ceratobasidium (belonging to the family Ceratobasidiaceae); and Lectera and Plectosporium (belonging to the family Plectosphaerellaceae) was significantly higher in consecutively monocultured (CM) than in newly planted (NP) soil in both rhizosphere and bulk soils. In particular, Fusarium abundance was significantly higher in CM than in NP in the rhizosphere, and higher in rhizosphere soils than in bulk soils for each treatment. A pathogenicity test showed that both Fusarium strains isolated were pathogenic to R. glutinosa seedlings. In addition, the culture filtrate and mycotoxins produced by Fusarium oxysporum significantly repressed the growth of the antagonistic bacterium, Pseudomonas aeruginosa. In conclusion, consecutive monoculture of R. glutinosa restructured the fungal communities in both rhizosphere and bulk soils but bulk effects developed more slowly over time in comparison with rhizosphere effects. Furthermore, microbial interactions might lead to a reduction in the abundance of beneficial microbes.

Comparative Metagenomic Analysis of Rhizosphere Microbial Community Composition and Functional Potentials under Rehmannia glutinosa Consecutive Monoculture.

Consecutive monoculture of Rehmannia glutinosa, highly valued in traditional Chinese medicine, leads to a severe decline in both quality and yield. Rhizosphere microbiome was reported to be closely associated with the soil health and plant performance. In this study, comparative metagenomics was applied to investigate the shifts in rhizosphere microbial structures and functional potentials under consecutive monoculture. The results showed R. glutinosa monoculture significantly decreased the relative abundances of Pseudomonadaceae and Burkholderiaceae, but significantly increased the relative abundances of Sphingomonadaceae and Streptomycetaceae. Moreover, the abundances of genera Pseudomonas, Azotobacter, Burkholderia, and Lysobacter, among others, were significantly lower in two-year monocultured soil than in one-year cultured soil. For potentially harmful/indicator microorganisms, the percentages of reads categorized to defense mechanisms (i.e., ATP-binding cassette (ABC) transporters, efflux transporter, antibiotic resistance) and biological metabolism (i.e., lipid transport and metabolism, secondary metabolites biosynthesis, transport and catabolism, nucleotide transport and metabolism, transcription) were significantly higher in two-year monocultured soil than in one-year cultured soil, but the opposite was true for potentially beneficial microorganisms, which might disrupt the equilibrium between beneficial and harmful microbes. Collectively, our results provide important insights into the shifts in genomic diversity and functional potentials of rhizosphere microbiome in response to R. glutinosa consecutive monoculture.

Barcoded Pyrosequencing Reveals a Shift in the Bacterial Community in the Rhizosphere and Rhizoplane of Rehmannia glutinosa under Consecutive Monoculture.

The production and quality of Rehmannia glutinosa can be dramatically reduced by replant disease under consecutive monoculture. The root-associated microbiome, also known as the second genome of the plant, was investigated to understand its impact on plant health. Culture-dependent and culture-independent pyrosequencing analysis was applied to assess the shifts in soil bacterial communities in the rhizosphere and rhizoplane under consecutive monoculture. The results show that the root-associated microbiome (including rhizosphere and rhizoplane microbiomes) was significantly impacted by rhizocompartments and consecutive monoculture. Consecutive monoculture of R. glutinosa led to a significant decline in the relative abundance of the phyla Firmicutes and Actinobacteria in the rhizosphere and rhizoplane. Furthermore, the families Flavobacteriaceae, Sphingomonadaceae, and Xanthomonadaceae enriched while Pseudomonadaceae, Bacillaceae, and Micrococcaceae decreased under consecutive monoculture. At the genus level, Pseudomonas, Bacillus, and Arthrobacter were prevalent in the newly planted soil, which decreased in consecutive monocultured soils. Besides, culture-dependent analysis confirmed the widespread presence of Pseudomonas spp. and Bacillus spp. in newly planted soil and their strong antagonistic activities against fungal pathogens. In conclusion, R. glutinosa monoculture resulted in distinct root-associated microbiome variation with a reduction in the abundance of beneficial microbes, which might contribute to the declined soil suppressiveness to fungal pathogens in the monoculture regime.