RESUMO
N-terminal acetylation (NTA) is a highly abundant protein modification catalyzed by N-terminal acetyltransferases (NATs) in eukaryotes. However, the plant NATs and their biological functions have been poorly explored. Here we reveal that loss of function of CKRC3 and NBC-1, the auxiliary subunit (Naa25) and catalytic subunit (Naa20) of Arabidopsis NatB, respectively, led to defects in skotomorphogenesis and triple responses of ethylene. Proteome profiling and WB test revealed that the 1-amincyclopropane-1-carboxylate oxidase (ACO, catalyzing the last step of ethylene biosynthesis pathway) activity was significantly down-regulated in natb mutants, leading to reduced endogenous ethylene content. The defective phenotypes could be fully rescued by application of exogenous ethylene, but less by its precursor ACC. The present results reveal a previously unknown regulation mechanism at the co-translational protein level for ethylene homeostasis, in which the NatB-mediated NTA of ACOs render them an intracellular stability to maintain ethylene homeostasis for normal growth and responses.
Assuntos
Aminoácido Oxirredutases/metabolismo , Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Etilenos/metabolismo , Homeostase , Acetiltransferase N-Terminal B/metabolismo , Acetilação , Sequência de Aminoácidos , Arabidopsis/crescimento & desenvolvimento , Proteínas de Arabidopsis/química , Proteínas de Arabidopsis/genética , Biocatálise , Regulação para Baixo/genética , Regulação da Expressão Gênica de Plantas , Morfogênese , Mutação/genética , Proteoma/metabolismo , Regulação para Cima/genéticaRESUMO
Light plays an important role in pileus differentiation in Pleurotus eryngii cultivation, and pileus morphology is influenced by light quality. To understand the effects of light quality on pileus morphology at the transcriptional level, we performed a comparative transcriptomic analysis of pilei grown under blue and red light irradiation. We identified 3959 differentially expressed genes (DEGs) between the blue and red light-treated pilei, which included 1664 up-regulated and 2295 down-regulated genes. These DEGs were significantly associated with light sensing, signal transduction, cell wall degradation and melanogenesis, suggesting that these processes are involved in pileus morphogenesis. Multiple DEGs related to respiratory functions were differentially expressed, suggesting that respiratory activity increased during pileus development regardless of light quality. These results provide a valuable view of the transcriptional changes and molecular processes involved in pileus morphogenesis under different light conditions and provide a foundation for yield improvement and quality control of P. eryngii.
Assuntos
Regulação Fúngica da Expressão Gênica , Morfogênese , Pleurotus/genética , Transcriptoma , Luz , Melaninas/biossíntese , Pleurotus/crescimento & desenvolvimento , Pleurotus/metabolismo , Pleurotus/efeitos da radiaçãoRESUMO
Pleurotus eryngii, a highly valued edible fungus, is one of the major commercially cultivated mushrooms in China. The development of P. eryngii, especially during the stage of primordium differentiation, is easily affected by light. However, the molecular mechanism underlying the response of primordium differentiation to light remains unknown. In the present study, primordium expression profiles under blue-light stimulation, red-light stimulation, and exposure to darkness were compared using high-throughput sequencing. A total of 16,321 differentially expressed genes (DEGs) were identified from three comparisons. GO enrichment analysis showed that a large number of DEGs were related to light stimulation and amino acid biosynthesis. KEGG analyses demonstrated that the MAPK signaling pathway, oxidative phosphorylation pathway, and RNA transport were most active during primordium differentiation. Furthermore, it was predicted that the blue-light photoreceptor WC-1 and Deoxyribodipyrimidine photolyase PHR play important roles in the primordium differentiation of P. eryngii. Taken together, the results of this study provide a speculative mechanism that light induces primordium differentiation and a foundation for further research on fruiting body development in P. eryngii.
Assuntos
Perfilação da Expressão Gênica , Genes Fúngicos , Estudos de Associação Genética , Luz , Pleurotus/citologia , Pleurotus/genética , Regulação Fúngica da Expressão Gênica/efeitos da radiação , Ontologia Genética , Anotação de Sequência Molecular , Pleurotus/efeitos da radiação , Mapas de Interação de Proteínas/genéticaRESUMO
F4(+) enterotoxigenic Escherichia coli (ETEC) strains cause diarrheal disease in neonatal and post-weaned piglets. Several different host receptors for F4 fimbriae have been described, with porcine aminopeptidase N (APN) reported most recently. The FaeG subunit is essential for the binding of the three F4 variants to host cells. Here we show in both yeast two-hybrid and pulldown assays that APN binds directly to FaeG, the major subunit of F4 fimbriae, from three serotypes of F4(+) ETEC. Modulating APN gene expression in IPEC-J2 cells affected ETEC adherence. Antibodies raised against APN or F4 fimbriae both reduced ETEC adherence. Thus, APN mediates the attachment of F4(+) E. coli to intestinal epithelial cells.
Assuntos
Antígenos CD13/metabolismo , Escherichia coli Enterotoxigênica/fisiologia , Infecções por Escherichia coli/veterinária , Fímbrias Bacterianas/fisiologia , Doenças dos Suínos/imunologia , Adesinas de Escherichia coli/genética , Adesinas de Escherichia coli/metabolismo , Animais , Anticorpos Antibacterianos/imunologia , Antígenos CD13/genética , Células Epiteliais/enzimologia , Células Epiteliais/imunologia , Células Epiteliais/microbiologia , Infecções por Escherichia coli/imunologia , Infecções por Escherichia coli/microbiologia , Expressão Gênica , Mucosa Intestinal/enzimologia , Mucosa Intestinal/imunologia , Mucosa Intestinal/microbiologia , Suínos , Doenças dos Suínos/microbiologiaRESUMO
Infection with F4(+) enterotoxigenic Escherichia coli (ETEC) responsible for diarrhea in neonatal and post-weaned piglets leads to great economic losses in the swine industry. These pathogenic bacteria express either of three fimbrial variants F4ab, F4ac, and F4ad, which have long been known for their importance in host infection and initiating protective immune responses. The initial step in infection for the bacterium is to adhere to host enterocytes through fimbriae-mediated recognition of receptors on the host cell surface. A number of receptors for ETEC F4 have now been described and characterized, but their functions are still poorly understood. The current review summarizes the latest research addressing the characteristics of F4 fimbriae receptors and the interactions of F4 fimbriae and their receptors on host cells. These include observations that as follows: (1) FaeG mediates the binding activities of F4 and is an essential component of the F4 fimbriae, (2) the F4 fimbrial receptor gene is located in a region of chromosome 13, (3) the biochemical properties of F4 fimbrial receptors that form the binding site of the bacterium are now recognized, and (4) specific receptors confer susceptibility/resistance to ETEC F4 infection in pigs. Characterizing the host-pathogen interaction will be crucial to understand the pathogenicity of the bacteria, provide insights into receptor activation of the innate immune system, and develop therapeutic strategies to prevent this illness.
Assuntos
Escherichia coli Enterotoxigênica/metabolismo , Infecções por Escherichia coli/metabolismo , Proteínas de Escherichia coli/metabolismo , Fímbrias Bacterianas/metabolismo , Receptores de Superfície Celular/metabolismo , Doenças dos Suínos/metabolismo , Animais , Escherichia coli Enterotoxigênica/genética , Infecções por Escherichia coli/genética , Infecções por Escherichia coli/microbiologia , Proteínas de Escherichia coli/genética , Fímbrias Bacterianas/genética , Receptores de Superfície Celular/genética , Suínos , Doenças dos Suínos/genética , Doenças dos Suínos/microbiologiaRESUMO
The FaeG subunit is the major constituent of F4(+) fimbriae, associated with glycoprotein and/or glycolipid receptor recognition and majorly contributes to the pathogen attachment to the host cells. To investigate the key factor involved in the fimbrial binding of F4(+) Escherichia coli, both the recombinant E. coli SE5000 strains carrying the fae operon gene clusters that express the different types of fimbriae in vitro, named as rF4ab, rF4ac, and rF4ad, respectively, corresponding to the fimbrial types F4ab, F4ac, and F4ad, and the three isogenic in-frame faeG gene deletion mutants were constructed. The adhesion assays and adhesion inhibition assays showed that ΔfaeG mutants had a significant reduction in the binding to porcine brush border as well as the intestinal epithelial cell lines, while the complemented strain ΔfaeG/pfaeG restored the adhesion function. The recombinant bacterial strains rF4ab, rF4ac, and rF4ad have the same binding property as wild-type F4(+) E. coli strains do and improvement in terms of binding to porcine brush border and the intestinal epithelial cells, and the adherence was blocked by the monoclonal antibody anti-F4 fimbriae. These data demonstrate that the fimbrial binding of F4(+) E. coli is directly mediated by the major FaeG subunit.
Assuntos
Adesinas de Escherichia coli/metabolismo , Aderência Bacteriana , Escherichia coli Enterotoxigênica/fisiologia , Fímbrias Bacterianas/metabolismo , Adesinas de Escherichia coli/genética , Animais , Anticorpos Monoclonais/metabolismo , Escherichia coli Enterotoxigênica/genética , Células Epiteliais , Fímbrias Bacterianas/genética , Fímbrias Bacterianas/imunologia , Suínos/microbiologiaRESUMO
NhaH is a novel Na(+)/H(+) antiporter identified from the moderate halophile Halobacillus dabanensis. In this study, six conserved charged residues located in the putative transmembrane segments (TMS) including TMSV, TMSVI, TMSVIII and TMSXI of NhaH as well as two His residues in Loop III were replaced by site-directed mutagenesis for the identification of their potential roles in the antiport activity and pH regulation. Substitutions D137A, D166A and R325A caused a complete loss of Na(+)(Li(+))/H(+) antiport activity, revealing that D137, D166 and R325 are indispensable for the antiport activity. Substitution D137E led to a significant increase of the apparent Km values for Na(+) and Li(+) without affecting the changes of pH profile, confirming that D137 plays vital roles in alkali cation binding/translocation. Substitution D166E resulted in not only a significant increase of the apparent Km values for Na(+) and Li(+) but also an alkaline shift of pH profile, suggesting that D166 is involved in alkali cation binding/translocation as well as H(+) binding or pH regulation. Substitutions E161N, D224A and D224E caused a significant increase of Km for Na(+) and Li(+), indicating that E161 and D224 partly contribute to alkali cation binding/translocation. Substitution E229K caused an over 50% elevation of the apparent Km for Li(+), without affecting that for Na(+), suggesting that E229 may be mainly responsible for Li(+) binding/translocation. Substitutions H87A and H88A resulted in an acidic shift of pH profile without an effect on Km for Na(+) and Li(+), indicating that H87 and H88 are involved in H(+) binding or pH regulation.
Assuntos
Antiporters/química , Proteínas de Bactérias/química , Halobacillus/metabolismo , Trocadores de Sódio-Hidrogênio/química , Sequência de Aminoácidos , Proteínas de Bactérias/metabolismo , Sequência de Bases , Cátions , Membrana Celular/metabolismo , Clonagem Molecular , DNA/química , Concentração de Íons de Hidrogênio , Cinética , Lítio/química , Dados de Sequência Molecular , Mutagênese Sítio-Dirigida , Ligação Proteica , Transporte Proteico , Homologia de Sequência de Aminoácidos , Sódio/química , Trocadores de Sódio-Hidrogênio/metabolismoRESUMO
The white rot fungi Pleurotus eryngii are environmental microorganisms that can effectively break down lignocellulosic biomass. However, understanding of the mechanisms by which P. eryngii is effective in degrading lignocellulose is still limited. This work aimed to examine the extracellular secretory proteins implicated in the breakdown of lignocellulose in P. eryngii and identify degradation tactics across various cultivation substrates. Thus, a comparative analysis of the secretory proteins based on Nanoliquid chromatography combined with tandem mass spectrometry was conducted among P. eryngii cultivated on sawdusts, bagasse, peanut shells, and glucose. In total, 647, 616, 604, and 511 proteins were identified from the four samples, respectively. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway analysis of protein expression differences identified pathways (hydrolytic enzymes, catalytic activity, metabolic processes, cellular processes, and response to stimuli) significantly enriched in proteins associated with lignocellulose degradation in P. eryngii. An integrated analysis of proteome data revealed specifically or differentially expressed genes secreted by P. eryngii in different cultivation substrates. The most prevalent carbohydrate-active enzymes involved in lignocellulose degradation in the secretome of the four samples were laccase (Lac), manganese peroxidase (MnP), aryl alcohol oxidase (AaO), and copper radical oxidase (CRO). Among them, Lac 2 mainly involved in the lignin degradation of sawdust peanut shells, and bagasse by P. eryngii, and Mnp 3 was mainly involved in the degradation of peanut shells. AaO and Lac 4 were mainly involved in glucose substrate defense and oxidative stress. It was found that exogenous addition of sawdust and peanut shells significantly increased lignolytic enzyme abundance. These findings provide insight and guidance for improving agricultural waste resource recovery. In this study, the secretomes of P. eryngii grown on four different carbon sources were compared. The findings revealed the extracellular enzymes implicated in the degradation of lignocellulose, offering avenues for further investigation into the biotransformation mechanisms of P. eryngii biomass and the potential utilization of agricultural wastes. SIGNIFICANCE: The cost of the substrate for mushroom cultivation has increased as the production of edible fungus has risen year after year. Therefore, the use of these locally available lignocellulosic wastes as substrates offers a cost-cutting option. Further, the overuse of wood for the cultivation of edible mushrooms is also detrimental to the conservation of forest resources or the ecological environment. Consequently, the use of other agricultural wastes as an alternative to sawdust or other woody substrates is a viable approach for cultivating P. eryngii. The distribution of extracellular lignocellulosic degrading enzymes, inferred in the present study could help improve the cultivation efficiency of P. eryngii vis-à-vis managing agricultural waste.
Assuntos
Arachis , Celulose , Pleurotus , Madeira , Arachis/metabolismo , Madeira/metabolismo , Proteômica/métodos , Lignina/metabolismo , Glucose/metabolismoRESUMO
Pleurotus ostreatus is one of the most consumed mushroom species, as it serves as a high-quality food, favors a rich secondary metabolism, and has remarkable adaptability to the environment and predators. In this study, we investigated the function of two key reactive oxygen species producing enzyme NADPH oxidase (PoNoxA and PoNoxB) in P. ostreatus hyphae growth, metabolite production, signaling pathway activation, and immune responses to different stresses. Characterization of the Nox mutants showed that PoNoxB played an important role in the hyphal formation of the multicellular structure, while PoNoxA regulated apical dominance. The ability of P. ostreatus to tolerate a series of abiotic stress conditions (e.g., osmotic, oxidative, membrane, and cell-wall stresses) and mechanical damage repair was enhanced with PoNoxA over-expression. PoNoxB had a greater responsibility in regulating the polysaccharide composition of the cell wall and methyl jasmonate and gibberellin GA1 biosynthesis, and improved mushroom resistance against Tyrophagus putrescentiae. Moreover, mutants were involved in the jasmonate and GA signaling pathway, and toxic protein defense metabolite production. Our findings shed light on how the oyster mushroom senses stress signals and responds to adverse environments by the complex regulators of Noxs.
RESUMO
Light is a vital environmental factor that promotes the growth and development of edible fungi mycelium. Under white light, the mycelium color of Sanghuangporus vaninii shifts during its growth stages. To investigate the impact of visible light on mycelial morphogenesis, a comparative transcriptomic analysis was conducted. This analysis revealed the molecular processes that underpin mycelial growth and development in S. vaninii when cultured in both darkness and light conditions. From the analysis, 13,643 genes were aligned using Illumina raw reads. Of these, 596 genes exhibited significant expression changes under white light exposure. Specifically, 226 genes were upregulated and 370 downregulated, spanning 55 different metabolic pathways. We further classified differentially expressed genes (DEGs), these genes play roles in photomorphogenesis, signal transduction, carbohydrate metabolism, and melanin production, among other processes. Some are also implicated in cell cycle regulation and the differential expression of respiratory functions. The validation of the differentially expressed transcripts using qRT-PCR showed complete agreement with RNA-Seq data for 9 transcripts. Meanwhile, the light had an inhibitory effect on the bioactive components in S. vaninii. These findings offer valuable insights into the transcriptional shifts and molecular mechanisms driving the color change in S. vaninii under light exposure, providing a basis for further research into mechanisms of light-response regulation.
Assuntos
Perfilação da Expressão Gênica , Regulação Fúngica da Expressão Gênica , Luz , Regulação Fúngica da Expressão Gênica/efeitos da radiação , Transcriptoma , Micélio/genética , Micélio/efeitos da radiação , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Agaricales/genética , Agaricales/metabolismo , Estresse Fisiológico/genéticaRESUMO
The basic leucine zipper (bZIP) transcription factor (TF) is widespread among eukaryotes and serves different roles in fungal processes including nutrient utilization, growth, stress responses and development. The oyster mushroom (Pleurotus ostreatus) is an important and widely cultivated edible mushroom worldwide; nevertheless, reports are lacking on the identification or function of bZIP gene family members in P. ostreatus. Herein, 11 bZIPs on 6 P. ostreatus chromosomes were systematically identified, which were classified into 3 types according to their protein sequences. Phylogenetic analysis of PobZIPs with other fungal bZIPs indicated that PobZIPs may have differentiated late. Cis-regulatory element analysis revealed that at least one type of stress-response-related element was present on each bZIP promoter. RNA-seq and RT-qPCR analyses revealed that bZIP expression patterns were altered under heat stress and different developmental stages. We combined results from GST-Pull-down, EMSA and yeast two-hybrid assays to screen a key heat stress-responsive candidate gene PobZIP3. PobZIP3 overexpression in P. ostreatus enhanced tolerance to high temperature and cultivation assays revealed that PobZIP3 positively regulates the development of P. ostreatus. RNA-seq analysis showed that PobZIP3 plays a role in glucose metabolism pathways, antioxidant enzyme activity and sexual reproduction. These results may support future functional studies of oyster mushroom bZIP TFs.
Assuntos
Pleurotus , Pleurotus/genética , Filogenia , Resposta ao Choque Térmico , Fatores de Transcrição de Zíper de Leucina Básica/genética , Fatores de Transcrição de Zíper de Leucina Básica/metabolismo , Sequência de AminoácidosRESUMO
Ginkgo biloba is widely planted as a colorful foliage tree, and its leaf can be used as a biomass energy source, but it has been underutilized for a long time. The aim of this study was to investigate the potential of garden waste as a substrate component in the cultivation process of the king oyster mushroom (Pleurotus eryngii), with the goal of enhancing both the yield of P. eryngii and the efficiency of energy use. The percentages of G. biloba leaf powder in the substrate were 10.5% and 21% to replace sawdust or sugarcane bagasse in a typical substrate. A substrate formulation that could completely replace sawdust and sugarcane bagasse was selected by analyzing mycelial growth rate, days of production, fruiting body length, biological efficiency, yield, stipe thickness, pileus diameter and laccase activity. The results showed that Y1 (treatment with 21% G. biloba leaf powder and sugarcane bagasse) had the highest yield (303.1 ± 31.9 g), which was higher than that of CK (control) (259.3 ± 37.4 g). The crude fiber content of the samples grown on substrate Y1 (as 7.43%) was higher than CK (7.37%). In addition, P. eryngii grown on substrate Y1 had the highest laccase activity for the complete colonization of the mycelium. Thus, these findings suggest that G. biloba leaf powder represents a viable and economical supplement for enhancing both the yield and quality of P. eryngii.
RESUMO
The laccase gene family encodes multiple isozymes that are crucial for the degradation of substrates and the regulation of developmental processes in fungi. Pleurotus eryngii is an important edible and medicinal fungus belonging to the Basidiomycota phylum and can grow on a variety of natural substrates. In the present study, genome-wide profiling of P. eryngii identified 10 genes encoding its laccase isoenzymes. Conservative sequence analysis demonstrated that all PeLacs possess classical laccase structural domains. Phylogenetic analysis yielded four major subgroups, the members of which are similar with respect to conserved gene organization, protein domain architecture, and consensus motifs. The 10 PeLacs formed three groups together with 12 PoLacs in Pleurotus ostreatus, indicating that they share a high level of evolutionary homology. Cis-responsive element analysis implied that PeLacs genes play a role in growth and development and lignocellulose degradation. Targeted overexpression of PeLac5 reduced the time to primordia formation and their development to fruiting bodies. Gene expression patterns in the presence of different lignocellulosic substrates indicate that three PeLacs genes (2, 4, and 9) are key to lignocellulose degradation. This work presents the first inventory of laccase genes in P. eryngii and preliminarily explores their functions, which may help to uncover the manner by which these proteins utilize substrates.
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Sanghuangporus vaninii is a profitable traditional and medicinal edible fungus with uncommon therapeutic properties and medicinal value. The accumulation of active ingredients in this fungus that is used in traditional Chinese medicine is affected by its years of growth, and their pharmacological activities are also affected. However, the effects of age on the medicinal value of fruiting bodies of S. vaninii cultivated on cut log substrate remain unclear. In this study, an untargeted liquid chromatography mass spectrometry (LC-MS)-based metabolomics approach was performed to characterize the profiles of metabolites from 1-, 2- and 3-year-old fruiting bodies of S. vaninii. A total of, 156 differentially accumulated metabolites (DAMs) were screened based on the criterion of a variable importance projection greater than 1.0 and p < 0.01, including 75% up regulated and 25% down regulated. The results of enrichment of metabolic pathways showed that the metabolites involved the biosynthesis of plant secondary metabolites, biosynthesis of amino acids, central carbon metabolism in cancer, steroid hormone biosynthesis, linoleic acid metabolism, prolactin signaling pathway, and arginine biosynthesis, and so on. The biosynthesis of plant secondary metabolites pathway was significantly activated. Five metabolites were significantly elevated within the growth of fruiting bodies, including 15-keto-prostaglandin F2a, (4S, 5R)-4,5,6-trihydroxy-2-iminohexanoate, adenylsuccinic acid, piplartine, and chenodeoxycholic acid. 15-keto-prostaglandin F2a is related to the pathway of arachidonic acid metabolism and was significantly increased up to 1,320- and 535-fold in the 2- and 3-year-old fruiting bodies, respectively, compared with those in the 1-year-old group. The presence of these bioactive natural products in S. vaninii is consistent with the traditional use of Sanghuang, which prompted an exploration of its use as a source of natural prostaglandin in the form of foods and nutraceuticals. These findings may provide insight into the functional components of S. vaninii to develop therapeutic strategies.
RESUMO
Spent mushroom substrate (SMS) is the by-products of mushroom production, which is mainly composed of disintegrated lignocellulosic biomass, mushroom mycelia and some minerals. The huge output and the lack of effective utilization methods make SMS becoming a serious environmental problem. In order to improve the application of SMS and SMS derived biochar (SBC), composted SMS (CSMS), SBC, combined plant growth-promoting rhizobacteria (PGPR, Bacillus subtilis BUABN-01 and Arthrobacter pascens BUAYN-122) and SBC immobilized PGPR (BCP) were applied in the lettuce seedling. Seven substrate treatments were used, including (1) CK, commercial control; (2) T1, CSMS based blank control; (3) T2, T1 with combined PGPR (9:1, v/v); (4) T3, T1 with SBC (19:1, v/v); (5) T4, T1 with SBC (9:1, v/v); (6) T5, T1 with BCP (19:1, v/v); (7) T6, T1 with BCP (9:1, v/v). The physicochemical properties of substrate, agronomic and physicochemical properties of lettuce and rhizospheric bacterial and fungal communities were investigated. The addition of SBC and BCP significantly (p < 0.05) improved the total nitrogen and available potassium content. The 5% (v/v) BCP addiction treatment (T5) represented the highest fresh weight of aboveground and underground, leave number, chlorophyll content and leaf anthocyanin content, and the lowest root malondialdehyde content. Moreover, high throughput sequencing revealed that the biochar immobilization enhanced the adaptability of PGPR. The addition of PGPR, SBC and BCP significantly enriched the unique bacterial biomarkers. The co-occurrence network analysis revealed that 5% BCP greatly increased the network complexity of rhizospheric microorganisms and improved the correlations of the two PGPR with other microorganisms. Furthermore, microbial functional prediction indicated that BCP enhanced the nutrient transport of rhizospheric microorganisms. This study showed the BCP can increase the agronomic properties of lettuce and improve the rhizospheric microbial community.
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High temperature is one of the major impediments limiting the growth and development of most edible fungi. While many efforts have been made in agricultural practice, the mechanism for resistance to high temperature remains elusive. Nitric oxide (NO) is considered as a signaling molecule involved in regulation of diverse physiological processes and stress responses in animals and plants. However, the role of NO in regulating fungal, particularly edible fungi, response to abiotic stresses, is unknown. The present study demonstrated that NO could effectively alleviate oxidative damage induced by heat stress in mycelia of Pleurotus eryngii var. tuoliensis. Heat stress induced increased thiobarbituric acid reactive substance (TBARS) content in mycelia, and the NO donor sodium nitroprusside (SNP) dramatically decreased TBARS content under high temperature. Moreover, the specific NO scavenger, 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-1-oxyl-3-oxide (cPTIO), could arrest the SNP action under the stress. Heat stress induced an increase in endogenous NO production in mycelial cells. However, the effect was significantly blocked by the NO synthase (NOS) inhibitor l-N(G)-nitroarginine methyl ester (l-NAME). In contrast, nitrate reductase (NR) activities were not obviously altered during heat stress. The NR suppressor tungstate had no effect on intracellular NO abundance under heat stress. These results suggest that NO can effectively protect mycelia of edible fungi from heat stress-induced oxidative damage and the NOS-dependent NO production may participate in the response to heat stress.
Assuntos
Óxido Nítrico/metabolismo , Estresse Oxidativo , Pleurotus/fisiologia , Pleurotus/efeitos da radiação , Estresse Fisiológico , Temperatura Alta , Micélio/fisiologia , Micélio/efeitos da radiaçãoRESUMO
Little is known about the mechanism of how trehalose responds to various abiotic stresses although trehalose is considered as an important protectant in fungi. We investigated the role of nitric oxide (NO) in regulating trehalose accumulation during heat stress in Pleurotus eryngii var. tuoliensis. The addition of 100 or 200 g trehalose/l significantly inhibited the production of thiobarbituric acid-reactive substance under heat stress in mycelial cells. High temperature induced endogenous trehalose accumulation and sodium nitroprusside, a NO donor, further enhanced trehalose accumulation. Finally, heat-induced trehalose accumulation could be arrested by the NO scavenger, 2-(4-carboxyphenyl)-4,4,5,5-tetramethyl-imidazoline-1-1-oxyl-3-oxide, at 250 µM by inhibiting the transcription of trehalose phosphate synthase gene. Thus NO plays an important role in the regulation of trehalose accumulation during abiotic stresses in P. eryngii var. tuoliensis.
Assuntos
Resposta ao Choque Térmico/fisiologia , Óxido Nítrico/metabolismo , Pleurotus/metabolismo , Trealose/metabolismo , Proteínas Fúngicas/metabolismo , Glucosiltransferases/metabolismo , Temperatura Alta , Estresse Oxidativo/fisiologiaRESUMO
As one of the innovative technologies of intelligent transportation systems (ITS), Connected and Autonomous Vehicles (CAVs) have been deployed gradually. Given that there will be a long transition period before reaching a fully CAVs environment, it is crucial to assess the potential impacts of CAVs on mixed traffic flow. Considering platoon formation process, this study develops a platoon cooperation strategy based on "catch-up" mechanism, and then analyzes the impact on fundamental diagram, traffic oscillation, and traffic safety within mixed traffic. Simulation results show that with an increasing market penetration rate (MPR) of CAVs, road capacity shows an increasing trend. Compared with base scenario, a clear increase in road capacity is also observed under platoon scenario. With an increasing MPR, traffic oscillation is shown to reduce largely. Furthermore, the proposed platoon strategy could dampen frequent shockwaves and shorten the propagation range of waves. Regarding traffic safety, multiple surrogate safety measures (SSMs) are used to evaluate the traffic risk: including Criticality Index Function (CIF), Potential Index for Collision with Urgent Deceleration (PICUD), and Deceleration Rate to Avoid a Crash (DRAC). With increasing MPR, collision risk identified by CIF and DRAC shows an increase tendency, while that identified by PICUD has no apparent trend. Furthermore, the platoon strategy is shown to increase the severity of traffic conflicts significantly. Overall, this study provides novel insights into CAVs deployment through the analysis of platoon strategy.
Assuntos
Acidentes de Trânsito , Condução de Veículo , Acidentes de Trânsito/prevenção & controle , Simulação por Computador , Humanos , SegurançaRESUMO
The auxin IAA (Indole-3-acetic acid) plays key roles in regulating plant growth and development, which depends on an intricate homeostasis that is determined by the balance between its biosynthesis, metabolism and transport. YUC flavin monooxygenases catalyze the rate-limiting step of auxin biosynthesis via IPyA (indole pyruvic acid) and are critical targets in regulating auxin homeostasis. Despite of numerous reports on the transcriptional regulation of YUC genes, little is known about those at the post-translational protein level. Here, we show that loss of function of CKRC3/TCU2, the auxiliary subunit (Naa25) of Arabidopsis NatB, and/or of its catalytic subunit (Naa20), NBC, led to auxin-deficiency in plants. Experimental evidences show that CKRC3/TCU2 can interact with NBC to form a NatB complex, catalyzing the N-terminal acetylation (NTA) of YUC proteins for their intracellular stability to maintain normal auxin homeostasis in plants. Hence, our findings provide significantly new insight into the link between protein NTA and auxin biosynthesis in plants.
Assuntos
Proteínas de Arabidopsis , Arabidopsis , Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Acetilação , Ácidos Indolacéticos/metabolismo , Plantas/metabolismo , HomeostaseRESUMO
Primordium formation is an important stage preceding the growth and development of the Pleurotus eryngii fruiting body. However, the molecular mechanisms underlying primordium formation remain unclear. In the present study, comparative transcriptomics was performed between mature mycelia and primordium to analyze the transcriptional properties during primordium formation in P. eryngii. A total of 19,655 differentially expressed genes (10,718 upregulated genes and 8937 downregulated genes) were identified. These differentially expressed genes were involved in cell wall degradation, carbohydrate hydrolysis, light perception, and cAMP signal transduction. These results aid further understanding of the transcriptional changes and the molecular processes underlying primordium formation and differentiation, which may lay the foundation for improving the cultivation and quality control of P. eryngii.