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1.
BMC Plant Biol ; 20(1): 206, 2020 May 11.
Artigo em Inglês | MEDLINE | ID: mdl-32393173

RESUMO

BACKGROUND: Fungus infection in staple grains affects the food storage and threatens food security. The Aspergillus flavus is known to infect multiple grains and produce mycotoxin Aflatoxin B1, which is mutagenic, teratogenic and causes immunosuppression in animals. However, the molecular mechanism of maize resistance to A. flavus is largely unknown. RESULTS: Here we used corn kernels to investigate resistance genes to A. flavus using genome-wide association study (GWAS) of 313 inbred lines. We characterized the resistance levels of kernels after inoculating with A. flavus. The GWAS with 558,529 SNPs identified four associated loci involving 29 candidate genes that were linked to seed development, resistance or infection, and involved in signal pathways, seed development, germination, dormancy, epigenetic modification, and antimicrobial activity. In addition, a few candidate genes were also associated with several G-protein signaling and phytohormones that might involve in synergistic work conferring different resistance during seed development. Expression of 16 genes out of 29 during kernel development was also associated with resistance levels. CONCLUSIONS: We characterized the resistance levels of 313 maize kernels after inoculating with A. flavus, and found four associated loci and 16 candidate maize genes. The expressed 16 genes involved in kernel structure and kernel composition most likely contribute to mature maize kernels' resistance to A. flavus, and in particular, in the development of pericarp. The linked candidate genes could be experimentally transformed to validate and manipulate fungal resistance. Thus this result adds value to maize kernels in breeding programs.

2.
Artigo em Inglês | MEDLINE | ID: mdl-32407241

RESUMO

Cancer-induced wasting is accompanied by disruptions to muscle oxidative metabolism and protein turnover that have been associated with systemic inflammation, whereas exercise and stimulated muscle contractions can positively regulate muscle protein synthesis and mitochondrial homeostasis. In preclinical cancer cachexia models a single bout of eccentric contractions (ECC) can induce protein synthesis while repeated ECC bouts prevent myofiber atrophy. The cellular mechanisms providing this protection from atrophy have not been resolved. Therefore, the purpose of this study was to determine if repeated stimulated eccentric contraction bouts effect basal muscle oxidative metabolism and protein synthesis during cancer cachexia, and if these changes were associated with plasma IL-6 levels. Male ApcMin/+ (MIN; N=10) mice initiating cachexia and healthy C57BL/6 (B6; N=11) controls performed repeated ECC bouts over 2 weeks. MIN mice exhibited body weight loss and elevated plasma IL-6 prior to and during repeated ECC bouts. Control MIN muscle demonstrated disrupted signaling related to inflammation, oxidative capacity and protein synthesis regulation, which were all improved by repeated ECC bouts. With cachexia plasma IL-6 levels were negatively correlated with myofiber cross-sectional area, oxidative capacity and protein synthesis. Interestingly, ECC improvements in these outcomes were positively correlated with plasma IL-6 levels in MIN mice. There was also a positive relationship between muscle oxidative capacity and protein synthesis following repeated ECC bouts in MIN mice. Collectively, repeated ECC bouts altered the cachectic muscle phenotype independent to systemic wasting, and there was a strong association between muscle oxidative capacity and protein synthesis in this adaptive response.

3.
New Phytol ; 2020 Mar 07.
Artigo em Inglês | MEDLINE | ID: mdl-32145071

RESUMO

Root growth control plays an important role in plant adaptation to drought stress, but the underlying molecular mechanisms of this control remain largely elusive. Here, a root-specific nuclear factor Y (NF-Y) transcription factor PdNF-YB21 was isolated from Populus. The functional mechanism of PdNF-YB21 was characterised by various morphological, physiological, molecular, biochemical and spectroscopy techniques. Overexpression of PdNF-YB21 in poplar promoted root growth with highly lignified and enlarged xylem vessels, resulting in increased drought resistance. By contrast, CRISPR/Cas9-mediated poplar mutant nf-yb21 exhibited reduced root growth and drought resistance. PdNF-YB21 interacted with PdFUSCA3 (PdFUS3), a B3 domain transcription factor. PdFUS3 directly activated the promoter of the abscisic acid (ABA) synthesis key gene PdNCED3, resulting in a significant increase in root ABA content in poplars subjected to water deficit. Coexpression of poplar NF-YB21 and FUS3 significantly enhanced the expression of PdNCED3. Furthermore, ABA promoted indoylacetic acid transport in root tips, which ultimately increased root growth and drought resistance. Taken together, our data indicate that NF-YB21-FUS3-NCED3 functions as an important avenue in auxin-regulated poplar root growth in response to drought.

4.
Environ Int ; 138: 105675, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32213427

RESUMO

Eutrophication and global warming are two main urgent environmental problems around the world. Nitrate-dependent Anaerobic Methane Oxidation (NdAMO) is a bioprocess coupling nitrate reduction with anaerobic methane oxidation, which could mitigate of these two environmental issues simultaneously. In this study, a newly granular active carbon-NdAMO-membrane bioreactor (GAC-NdAMO-MBR) system was established to evaluate its nitrogen removal efficiency, membrane fouling property and the probable strengthening mechanism was also uncovered. Results indicated that the nitrate removal rate in GAC-NdAMO-MBR reached 31.85 ± 3.19 mgN·L-1·d-1 while it was only 10.35 ± 2.02 mgN·L-1·d-1 in NdAMO-MBR system (lack of GAC), which was multiplied three-fold. The membrane flux decay rate of GAC- NdAMO -MBR was 0.15 L/m2·h·d while it was 0.49 L/m2·h·d without GAC, and the addition of GAC could extend membrane fouling time for 2.5 times. Notablely, the relative abundance of NdAMO bacteria sharply increased from 27.15% to 56.91% after GAC addition while the NdAMO archaea showed similar variation trend. The physicochemical property of GAC mainly contributed the strengthening effect. The porous structure of GAC absorbed methane and adhered by microorganism, which enhance microorganism amount and metabolic activity. The mechanical strength of GAC scoured membrane surface to mitigate external fouling and pores absorbed EPS to reduce internal fouling. The combined effects could improve NdAMO microorganism growth and metabolism activity and finally improved nitrogen removal performance and controlled membrane fouling. These findings could deep the knowledge of NdAMO process and help extend its application potential in environment science and engineering.

5.
Sci Total Environ ; 713: 136739, 2020 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-32019052

RESUMO

Nitrate-dependent anaerobic methane oxidation (N-DAMO), a bioprocess that couples the oxidation of green gas and the removal of nitrogen oxides in a microbial group, has gained much attention as a potential economical method of biological removal of nitrates and methane from wastewater. Low-temperature (20 °C) operation of N-DAMO would be beneficial to utilize the methane dissolved in the effluent and thus decrease the cost of maintaining the bioreactor temperature in wastewater treatment. Here, the long-term (>350 days) operational activities of N-DAMO were evaluated to assess the performance of N-DAMO from stepwise cooling (30-20 °C) to ambient temperatures (13-38 °C). Under stepwise cooling conditions, the activity of the N-DAMO community was first inhibited and then rapidly adjusted. Notably, a similar N-DAMO activity was observed at 30 °C and 20 °C. Under ambient temperature conditions, the highest nitrate removal rate observed at the beginning of the test was 7.14 mg-N/L/d, which was 5.3 times higher than that recorded at the end of the test. This indicates that the long-term temperature fluctuation irreversibly inhibited N-DAMO activity. 16S rRNA gene sequencing analyses found that the functional archaea were ANME-2D, which has been deemed as the dominant culture in the N-DAMO process. The abundance of ANME-2D on the last day at stepwise cooling temperature conditions was much higher than on day 0, but disappeared after a long period of operation at ambient temperature. It was assumed that N-DAMO would stabilize at stepwise cooling temperature conditions, but not at ambient temperature. Our findings could offer a promising technology for anaerobic wastewater treatment plants (WWTPs) in temperate and warm climate zones.


Assuntos
Metano/química , Anaerobiose , Reatores Biológicos , Desnitrificação , Nitritos , Oxirredução , RNA Ribossômico 16S , Temperatura
6.
Nat Commun ; 11(1): 884, 2020 02 14.
Artigo em Inglês | MEDLINE | ID: mdl-32060277

RESUMO

Teff (Eragrostis tef) is a cornerstone of food security in the Horn of Africa, where it is prized for stress resilience, grain nutrition, and market value. Here, we report a chromosome-scale assembly of allotetraploid teff (variety Dabbi) and patterns of subgenome dynamics. The teff genome contains two complete sets of homoeologous chromosomes, with most genes maintaining as syntenic gene pairs. TE analysis allows us to estimate that the teff polyploidy event occurred ~1.1 million years ago (mya) and that the two subgenomes diverged ~5.0 mya. Despite this divergence, we detect no large-scale structural rearrangements, homoeologous exchanges, or biased gene loss, in contrast to many other allopolyploids. The two teff subgenomes have partitioned their ancestral functions based on divergent expression across a diverse expression atlas. Together, these genomic resources will be useful for accelerating breeding of this underutilized grain crop and for fundamental insights into polyploid genome evolution.

7.
BMC Genomics ; 21(1): 141, 2020 Feb 10.
Artigo em Inglês | MEDLINE | ID: mdl-32041544

RESUMO

BACKGROUND: Foxtail millet (Setaria italica) has been developed into a model genetical system for deciphering architectural evolution, C4 photosynthesis, nutritional properties, abiotic tolerance and bioenergy in cereal grasses because of its advantageous characters with the small genome size, self-fertilization, short growing cycle, small growth stature, efficient genetic transformation and abundant diverse germplasm resources. Therefore, excavating QTLs of yield component traits, which are closely related to aspects mentioned above, will further facilitate genetic research in foxtail millet and close cereal species. RESULTS: Here, 164 Recombinant inbreed lines from a cross between Longgu7 and Yugu1 were created and 1,047,978 SNPs were identified between both parents via resequencing. A total of 3413 bin markers developed from SNPs were used to construct a binary map, containing 3963 recombinant breakpoints and totaling 1222.26 cM with an average distance of 0.36 cM between adjacent markers. Forty-seven QTLs were identified for four traits of straw weight, panicle weight, grain weight per plant and 1000-grain weight. These QTLs explained 5.5-14.7% of phenotypic variance. Thirty-nine favorable QTL alleles were found to inherit from Yugu1. Three stable QTLs were detected in multi-environments, and nine QTL clusters were identified on Chromosome 3, 6, 7 and 9. CONCLUSIONS: A high-density genetic map with 3413 bin markers was constructed and three stable QTLs and 9 QTL clusters for yield component traits were identified. The results laid a powerful foundation for fine mapping, identifying candidate genes, elaborating molecular mechanisms and application in foxtail millet breeding programs by marker-assisted selection.

8.
Drug Deliv ; 27(1): 309-322, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32037895

RESUMO

Amentoflavone, robustaflavone, 2″,3″-dihydro-3',3‴-biapigenin, 3',3‴-binaringenin, and delicaflavone are five major hydrophobic components in the total biflavonoids extract from Selaginella doederleinii (TBESD) that display favorable anticancer properties. The purpose of this study was to develop a new oral delivery formulation to improve the solubilities, dissolution rates, and oral bioavailabilities of the main ingredients in TBESD by the solid dispersion technique. Solid dispersions of TBESD with various hydrophilic polymers were prepared, and different technologies were applied to select the suitable carrier and method. TBESD amorphous solid dispersion (TBESD-ASD) with polyvinylpyrrolidone K-30 was successfully prepared by the solvent evaporation method. The physicochemical properties of TBESD-ASD were investigated by scanning electron microscopy, differential scanning calorimetry, and Fourier-transform infrared spectroscopy. As a result, TBESD was found to be molecularly dispersed in the amorphous carrier. The solubilities and dissolution rates of all five ingredients in the TBESD-ASD were significantly increased (nearly 100% release), compared with raw TBESD. Meanwhile, TBESD-ASD showed good preservation stability for 3 months under accelerated conditions of 40 °C and 75% relative humidity. A subsequent pharmacokinetic study in rats revealed that Cmax and AUC0-t of all five components were significantly increased by the solid dispersion preparation. An in vivo study clearly revealed that compared to raw TBESD, a significant reduction in tumor size and microvascular density occurred after oral administration of TBESD-ASD to xenograft-bearing tumor mice. Collectively, the developed TBESD-ASD with the improved solubility, dissolution rates and oral bio-availabilities of the main ingredients could be a promising chemotherapeutic agent for cancer treatment.

9.
Nat Commun ; 11(1): 57, 2020 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-31896753

RESUMO

Atom-thin transition metal dichalcogenides (TMDs) have emerged as fascinating materials and key structures for electrocatalysis. So far, their edges, dopant heteroatoms and defects have been intensively explored as active sites for the hydrogen evolution reaction (HER) to split water. However, grain boundaries (GBs), a key type of defects in TMDs, have been overlooked due to their low density and large structural variations. Here, we demonstrate the synthesis of wafer-size atom-thin TMD films with an ultra-high-density of GBs, up to ~1012 cm-2. We propose a climb and drive 0D/2D interaction to explain the underlying growth mechanism. The electrocatalytic activity of the nanograin film is comprehensively examined by micro-electrochemical measurements, showing an excellent hydrogen-evolution performance (onset potential: -25 mV and Tafel slope: 54 mV dec-1), thus indicating an intrinsically high activation of the TMD GBs.

10.
ACS Nano ; 14(1): 175-184, 2020 Jan 28.
Artigo em Inglês | MEDLINE | ID: mdl-31789497

RESUMO

Structural asymmetry of materials plays a crucial role in developing multipurpose devices. Layered metallic transition metal dichalcogenides (MTMDCs) have been proposed as promising materials in electronics. However, they are still subject to native surface oxidation, limiting their practical applications. Combination of surface protection and native surface oxidation of MTMDCs will create asymmetric structures for devices but has yet to be explored. Here, we report a bifunctional NbS2-based vertical heterostructure derived from epitaxially grown NbS2 on MoS2 followed by a natural oxidation (MoS2-NbS2-NbOx), which simultaneously exhibits both high-efficiency tunneling conductive and memristive surfaces. With the tunneling conductive surface, the heterostructure functions as nearly ohmic contact electrodes with a two-dimensional (2D) channel in lateral transistors, delivering an enhanced mobility ∼140 times higher than that of the exfoliated NbS2-contacted device. With the memristive surface, the heterostructure can be used to build high-performance lateral or vertical memristors with low working voltages and synaptic functions. By combining both types of surfaces, a memristor array for nonvolatile memory is further developed. Moreover, the memristors show a good endurance for 2000 cycles of bending as flexible devices. The bifunctional heterostructure based on NbS2 offers a strategy toward the future applications of layered metallic materials.

11.
Sci Rep ; 9(1): 18545, 2019 Dec 06.
Artigo em Inglês | MEDLINE | ID: mdl-31811156

RESUMO

Healthy aging results in cardiac structural and electrical remodeling that increases susceptibility to cardiovascular diseases. Relaxin, an insulin-like hormone, suppresses atrial fibrillation, inflammation and fibrosis in aged rats but the mechanisms-of-action are unknown. Here we show that relaxin treatment of aged rats reverses pathological electrical remodeling (increasing Nav1.5 expression and localization of Connexin43 to intercalated disks) by activating canonical Wnt signaling. In isolated adult ventricular myocytes, relaxin upregulated Nav1.5 (EC50 = 1.3 nM) by a mechanism inhibited by the addition of Dickkopf-1. Furthermore, relaxin increased the levels of connexin43, Wnt1, and cytosolic and nuclear ß-catenin. Treatment with Wnt1 or CHIR-99021 (a GSK3ß inhibitor) mimicked the relaxin effects. In isolated fibroblasts, relaxin blocked TGFß-induced collagen elevation in a Wnt dependent manner. These findings demonstrate a close interplay between relaxin and Wnt-signaling resulting in myocardial remodeling and reveals a fundamental mechanism of great therapeutic potential.

12.
J Vasc Access ; : 1129729819891336, 2019 Dec 10.
Artigo em Inglês | MEDLINE | ID: mdl-31820667

RESUMO

INTRODUCTION: Central venous catheter insertion for long-term vascular access is not recommended in clinical practice. However, since arteriovenous fistula creation is difficult to perform in some patients, central venous catheter insertion for long-term vascular access is performed. This study aimed to assess the complications and service time of central venous catheters replaced using different methods and to determine the influencing factors of service time. METHODS: Study design: A retrospective observational cohort study. Setting and participants: Patients who underwent tunneled dialysis catheter malfunction (2009-2019) and had to undergo another dialysis catheter insertion were enrolled. Exposures: Ectopic replacement and in situ replacement. Outcomes: Factors such as age, sex, primary patency rate, secondary patency rate, early complications, and late complications were considered. Analytical approach: This study used a Cox proportional hazards regression model. RESULTS: The first and the newly replaced catheter service time were 37.779 ± 24.563 months and 32.468 ± 26.638 (25) months in the ectopic group and 37.075 ± 20.550 months and 26.349 ± 22.672 months in the in situ group, respectively. In the early service time, the newly replaced catheter resulted in significant bleeding from the tunnel. The first catheter had the least complications, most adequate blood flow, and longest service time. Ectopic catheter replacement and the tip shape of the catheter were the independent factors for catheter service time. Catheter service time increased with age. CONCLUSION: Ectopic catheter replacement can improve the primary patency rate and auxiliary primary patency rate of catheters. Ectopic catheter replacement may require sufficient surgical skills with digital subtraction angiography, resulting in a better prognosis.

13.
Genes (Basel) ; 10(11)2019 11 14.
Artigo em Inglês | MEDLINE | ID: mdl-31739562

RESUMO

Leaves are one of the most important organs of plants, and yet, the association between leaf color and consumable traits remains largely unclear. Tea leaves are an ideal study system with which to investigate the mechanism of how leaf coloration affects palatability, since tea is made from the leaves of the crop Camellia sinensis. Our genomic resequencing analysis of a tea cultivar ZiJuan (ZJ) with purple leaves and altered flavor revealed genetic variants when compared with the green-leaf, wild type cultivar YunKang(YK). RNA-Seq based transcriptomic comparisons of the bud and two youngest leaves in ZJ and YK identified 93%, 9% and 5% expressed genes that were shared in YK- and ZJ-specific cultivars, respectively. A comparison of both transcript abundance and particular metabolites revealed that the high expression of gene UFGT for anthocyanin biosynthesis is responsible for purple coloration, which competes with the intermediates for catechin-like flavanol biosynthesis. Genes with differential expression are enriched in response to stress, heat and defense, and are casually correlated with the environmental stress of ZJ plant origin in the Himalayas. In addition, the highly expressed C4H and LDOX genes for synthesizing flavanol precursors, ZJ-specific CLH1 for degrading chlorophyll, alternatively spliced C4H and FDR and low photosynthesis also contributed to the altered color and flavor of ZJ. Thus, our study provides a better molecular understanding of the effect of purple coloration on leaf flavor, and helps to guide future engineering improvement of palatability.

14.
Nanoscale ; 11(46): 22432-22439, 2019 Nov 28.
Artigo em Inglês | MEDLINE | ID: mdl-31742287

RESUMO

Strain is usually unavoidable in the fabrication of devices based on two-dimensional (2D) transition metal chalcogenides (TMDCs). When metals are deposited onto monolayer TMDCs, strain can be induced at metal-TMDC interfaces and evolves with elapsed time. However, the effect of the substrate on the strain evolution at the metal-TMDC interfaces is still unclear, which hinders the development of reliable 2D TMDC-based devices with perfect contacts. In this work, we investigated the evolution of metal-induced local strains for Ag-deposited monolayer MoS2 on three kinds of substrates with different interface interactions, i.e., sapphire, SiO2/Si, and mica. The interface interaction between MoS2 and sapphire is the strongest, while that between MoS2 and mica is the weakest. With the splitting of MoS2 Raman peaks as an indicator of local strain, the evolution behavior of the local strain at the Ag-MoS2 interfaces is found to greatly depend on the interface interactions from the underlying substrates. With elapsed time, the local strain is best preserved on sapphire but relaxed most easily on mica. Density-functional theory calculations show that the adsorption energies at the interfaces are different for MoS2 on different substrates, suggesting that the interface interaction between monolayer MoS2 and the substrates is crucial for the strain evolution. Our work is of benefit for the study of stability and reliability of devices based on TMDCs, particularly for flexible electronic devices.

15.
Sci Rep ; 9(1): 16602, 2019 Nov 12.
Artigo em Inglês | MEDLINE | ID: mdl-31719639

RESUMO

Maintaining the viability of the apical shoot is critical for continued vertical growth in plants. Terminal shoot of tree species Paulownia cannot regrow in subsequent years. The short day (SD) treatment leads to apical growth cessation and dormancy. To understand the molecular basis of this, we further conducted global RNA-Seq based transcriptomic analysis in apical shoots to check regulation of gene expression. We obtained ~219 million paired-end 125-bp Illumina reads from five time-courses and de novo assembled them to yield 49,054 unigenes. Compared with the untreated control, we identified 1540 differentially expressed genes (DEGs) which were found to involve in 116 metabolic pathways. Expression of 87% of DEGs exhibited switch-on or switch-off pattern, indicating key roles in growth cessation. Most DEGs were enriched in the biological process of gene ontology categories and at later treatment stages. The pathways of auxin and circadian network were most affected and the expression of associated DEGs was characterised. During SD induction, auxin genes IAA, ARF and SAURs were down-regulated and circadian genes including PIF3 and PRR5 were up-regulated. PEPC in photosynthesis was constitutively upregulated, suggesting a still high CO2 concentrating activity; however, the converting CO2 to G3P in the Calvin cycle is low, supported by reduced expression of GAPDH encoding the catalysing enzyme for this step. This indicates a de-coupling point in the carbon fixation. The results help elucidate the molecular mechanisms for SD inducing dormancy and cessation in apical shoots.

16.
Int J Nanomedicine ; 14: 6691-6706, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31692515

RESUMO

Purpose: Amentoflavone, robustaflavone, 2'',3''-dihydro-3',3'''-biapigenin, 3',3'''-binaringenin and delicaflavone are five major active ingredients in the total biflavonoids extract from Selaginella doederleinii (TBESD) with favorable anticancer properties. However, the natural-derived potent antitumor agent of TBESD is undesirable due to its poor solubility. The present study was to develop and optimize a proliposomal formulation of TBESD (P-TBESD) to improve its solubility, oral bioavailability and efficacy. Materials and methods: P-TBESD containing a bile salt, a protective hydrophilic isomalto-oligosaccharides (IMOs) coating, were successfully prepared by thin film dispersion-sonication method. The physicochemical and pharmacokinetic properties of P-TBESD were characterized, and the antitumor effect was evaluated using the HT-29 xenograft-bearing mice models in rats. Results: Compared with TBESD, the relative bioavailability of amentoflavone, robustaflavone, 2'',3''-dihydro-3',3'''-biapigenin, 3',3'''-binaringenin and delicaflavone from P-TBESD were 669%, 523%, 761%, 955% and 191%, respectively. The results of pharmacodynamics demonstrated that both TBESD and P-TBESD groups afforded antitumor effect without systemic toxicity, and the antitumor effect of P-TBESD was significantly superior to that of raw TBESD, based on the tumor growth inhibition and histopathological examination. Conclusion: Hence, IMOs-modified proliposomes have promising potential for TBESD solving the problem of its poor solubility and oral bioavailability, which can serve as a practical oral preparation for TBESD in the future cancer therapy.


Assuntos
Antineoplásicos Fitogênicos/administração & dosagem , Biflavonoides/administração & dosagem , Lipossomos/administração & dosagem , Extratos Vegetais/administração & dosagem , Selaginellaceae/química , Administração Oral , Animais , Antineoplásicos Fitogênicos/química , Antineoplásicos Fitogênicos/farmacocinética , Biflavonoides/farmacocinética , Biflavonoides/farmacologia , Ácidos e Sais Biliares/química , Disponibilidade Biológica , Células HT29 , Humanos , Lipossomos/química , Lipossomos/farmacocinética , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Oligossacarídeos/química , Extratos Vegetais/química , Ratos Sprague-Dawley , Solubilidade , Ensaios Antitumorais Modelo de Xenoenxerto
17.
Front Plant Sci ; 10: 1096, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31572415

RESUMO

Anthracnose disease is caused by Colletotrichum gloeosporioides, and is common in leaves of the tea plant (Camellia sinensis). MicroRNAs (miRNAs) have been known as key modulators of gene expression in response to environmental stresses, disease resistance, defense responses, and plant immunity. However, the role of miRNAs in responses to C. gloeosporioides remains unexplored in tea plant. Therefore, in the present study, six miRNA sequencing data sets and two degradome data sets were generated from C. gloeosporioides-inoculated and control tea leaves. A total of 485 conserved and 761 novel miRNAs were identified. Of those, 239 known and 369 novel miRNAs exhibited significantly differential expression under C. gloeosporioides stress. One thousand one hundred thirty-four and 596 mRNAs were identified as targets of 389 conserved and 299 novel miRNAs by degradome analysis, respectively. Based on degradome analysis, most of the predicted targets are negatively correlated with their corresponding conserved and novel miRNAs. The expression levels of 12 miRNAs and their targets were validated by quantitative real-time PCR. A negative correlation between expression profiles of five miRNAs (PC-5p-80764_22, csn-miR160c, csn-miR828a, csn-miR164a, and csn-miR169e) and their targets (WRKY, ARF, MYB75, NAC, and NFY transcription factor) was observed. The predicted targets of five interesting miRNAs were further validated through 5'RLM-RACE. Furthermore, Gene Ontology and metabolism pathway analysis revealed that most of the target genes were involved in the regulation of auxin pathway, ROS scavenging pathway, salicylic acid mediated pathway, receptor kinases, and transcription factors for plant growth and development as well as stress responses in tea plant against C. gloeosporioides stress. This study enriches the resources of stress-responsive miRNAs and their targets in C. sinensis and thus provides novel insights into the miRNA-mediated regulatory mechanisms, which could contribute to the enhanced susceptibility of C. gloeosporioides in tea plant.

18.
Int J Mol Sci ; 20(18)2019 Sep 11.
Artigo em Inglês | MEDLINE | ID: mdl-31514333

RESUMO

Recently, long noncoding RNAs (lncRNAs) have emerged as vital regulators of many biological processes in animals and plants. However, to our knowledge no investigations on plant lncRNAs which respond to arbuscular mycorrhizal (AM) fungi have been reported thus far. In this study, maize roots colonized with AM fungus were analyzed by strand-specific RNA-Seq to identify AM fungi-responsive lncRNAs and construct an associated regulatory network. A total of 1837 differentially expressed protein coding genes (DEGs) were identified from maize roots with Rhizophagus irregularis inoculation. Many AM fungi-responsive genes were homologs to MtPt4, STR, STR2, MtFatM, and enriched pathways such as fatty acid biosynthesis, response to phosphate starvation, and nitrogen metabolism are consistent with previous studies. In total, 5941 lncRNAs were identified, of which more than 3000 were new. Of those, 63 lncRNAs were differentially expressed. The putative target genes of differentially expressed lncRNAs (DELs) were mainly related to phosphate ion transmembrane transport, cellular response to potassium ion starvation, and lipid catabolic processes. Regulatory network analysis showed that DELs might be involved in the regulation of bidirectional nutrient exchange between plant and AM fungi as mimicry of microRNA targets. The results of this study can broaden our knowledge on the interaction between plant and AM fungi.


Assuntos
Redes Reguladoras de Genes , Micorrizas/crescimento & desenvolvimento , Micorrizas/genética , RNA Longo não Codificante/genética , Zea mays/microbiologia , Regulação para Baixo/genética , Regulação Fúngica da Expressão Gênica , Ontologia Genética , Genoma Fúngico , Fenótipo , RNA Longo não Codificante/metabolismo , Plântula/microbiologia , Regulação para Cima/genética
19.
Nanotechnology ; 31(1): 015503, 2019 Sep 13.
Artigo em Inglês | MEDLINE | ID: mdl-31519013

RESUMO

In this work, we demonstrate a highly effective method to generate and detect single-nanoparticle (NP) collision events on a nanoelectrode in aqueous solutions. The nanoelectrode of a nanopore-nanoelectrode nanopipette is first employed to accumulate NPs in solution by dielectrophoresis (DEP). Instead of using amperometric methods, the continuous individual NP collision events on the nanoelectrode are sensitively detected by monitoring the open-circuit potential changes of the nanoelectrode. Metallic gold NPs (GNPs) and insulating polystyrene (PS) NPs with various sizes are used as the model NPs. Due to the higher conductivity and polarizability of GNPs, the collision motion of a GNP is different from that of a PS NP. The difference is distinct in the shape of the transient potential change and its first time derivative detected by the nanoelectrode. Therefore, the collision events by metallic and insulating NPs on a nanoelectrode can be differentiated based on their polarizability. DEP induced NP separation and cluster formation can also be probed in detail in the concentrated mixture of PS NPs and GNPs.

20.
Int J Mol Sci ; 20(17)2019 Aug 25.
Artigo em Inglês | MEDLINE | ID: mdl-31450700

RESUMO

Herbivore-induced plant volatiles (HIPVs) play important ecological roles in defense against stresses. In contrast to model plants, reports on HIPV formation and function in crops are limited. Tea (Camellia sinensis) is an important crop in China. α-Farnesene is a common HIPV produced in tea plants in response to different herbivore attacks. In this study, a C. sinensis α-farnesene synthase (CsAFS) was isolated, cloned, sequenced, and functionally characterized. The CsAFS recombinant protein produced in Escherichia coli was able to transform farnesyl diphosphate (FPP) into α-farnesene and also convert geranyl diphosphate (GPP) to ß-ocimene in vitro. Furthermore, transient expression analysis in Nicotiana benthamiana plants indicated that CsAFS was located in the cytoplasm and could convert FPP to α-farnesene in plants. Wounding, to simulate herbivore damage, activated jasmonic acid (JA) formation, which significantly enhanced the CsAFS expression level and α-farnesene content. This suggested that herbivore-derived wounding induced α-farnesene formation in tea leaves. Furthermore, the emitted α-farnesene might act as a signal to activate antibacterial-related factors in neighboring undamaged tea leaves. This research advances our understanding of the formation and signaling roles of common HIPVs in crops such as tea plants.


Assuntos
Herbivoria , Folhas de Planta/metabolismo , Sesquiterpenos/metabolismo , Chá/metabolismo , Compostos Orgânicos Voláteis/metabolismo , Fenômenos Fisiológicos Vegetais , Transdução de Sinais , Chá/classificação , Chá/genética
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