Microbiological research最新文献_第4页

Exploring the multifaceted role of pehR in Ralstonia solanacearum pathogenesis: enzyme activity, motility, and biofilm formation 探索 pehR 在 Ralstonia solanacearum 致病机理中的多方面作用：酶活性、运动性和生物膜形成

IF 6.1 1区生物学 Q1 MICROBIOLOGY

Microbiological research

Pub Date : 2024-10-17 DOI: 10.1016/j.micres.2024.127925

Sharmilee Sarkar , Mohit Yadav , Upalabdha Dey, Manoj Sharma , Rupak Mukhopadhyay , Aditya Kumar

PehR is a transcriptional regulator among the various response regulators found in Ralstonia solanacearum, a bacterium that causes lethal wilt disease in over 450 plant species worldwide, including economically important crops such as tomato, chilli, and brinjal. PehR regulates the production of polygalacturonase, an extracellular enzyme that degrades plant cell walls, playing a significant role in bacterial wilt. Despite its significance, the precise function and regulatory mechanism of PehR in R. solanacearum are yet to be thoroughly investigated. The goal of this research is to better understand the role of PehR in R. solanacearum pathogenicity by identifying the genes and pathways that it regulates. By disrupting the pehR gene, we created the ΔpehR mutant of R. solanacearum F1C1, a strain isolated from Tezpur, Assam, India. Transcriptomic analysis revealed 667 differentially expressed genes (DEGs) in the ΔpehR mutant, with 320 upregulated and 347 downregulated compared to the wild-type F1C1 strain. GO and KEGG analyses indicated the downregulation of genes related to flagellum-dependent cell motility, membrane function, and amino acid degradation pathways in the ΔpehR mutant. EPS estimation, biochemical assays for biofilm production, motility, and enzymatic assays for cellulase and pectinase production were all used in the further characterization process. The ΔpehR mutant showed lower virulence in tomato seedlings compared to the wild-type F1C1 strain. The findings suggest that PehR could be a promising target for bacterial wilt disease control, as well as provide critical information for ensuring crop production safety around the world.

PehR 是 Ralstonia solanacearum 中发现的各种反应调节因子中的一种转录调节因子，这种细菌在全球 450 多种植物中引起致命的枯萎病，其中包括番茄、辣椒和青江菜等具有重要经济价值的作物。PehR 可调节聚半乳糖醛酸酶的产生，这是一种能降解植物细胞壁的胞外酶，在细菌枯萎病中发挥着重要作用。尽管 PehR 意义重大，但其在 R. solanacearum 中的确切功能和调控机制仍有待深入研究。本研究的目标是通过确定 PehR 调控的基因和途径，更好地了解 PehR 在 R. solanacearum 致病性中的作用。通过破坏 pehR 基因，我们创建了 R. solanacearum F1C1 的 ΔpehR 突变体。转录组分析显示，与野生型 F1C1 菌株相比，ΔpehR 突变体中有 667 个差异表达基因（DEGs），其中 320 个基因上调，347 个基因下调。GO和KEGG分析表明，在ΔpehR突变体中，与依赖鞭毛的细胞运动、膜功能和氨基酸降解途径相关的基因下调。在进一步的表征过程中，还使用了 EPS 估算、生物膜生成和运动的生化检测以及纤维素酶和果胶酶生成的酶学检测。与野生型 F1C1 菌株相比，ΔpehR 突变体对番茄幼苗的毒力较低。研究结果表明，PehR可能是细菌性萎蔫病防治的一个有前途的靶标，同时也为确保全球作物生产安全提供了重要信息。

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引用次数: 0

Expression, regulation and physiological roles of the five Rsm proteins in Pseudomonas syringae pv. tomato DC3000 五种 Rsm 蛋白在假单胞菌 Syringae pv. tomato DC3000 中的表达、调控和生理作用。

IF 6.1 1区生物学 Q1 MICROBIOLOGY

Microbiological research

Pub Date : 2024-10-16 DOI: 10.1016/j.micres.2024.127926

Adriana Vásquez , María-Dolores Ferreiro , Laura Martínez-Rodríguez, María-Trinidad Gallegos

Proteins belonging to the RsmA (regulator of secondary metabolism)/CsrA (carbon storage regulator) family are small RNA-binding proteins that play crucial roles post-transcriptionally regulating gene expression in many Gram-negative and some Gram-positive bacteria. Although most of the bacteria studied have a single RsmA/CsrA gene, Pseudomonas syringae pv. tomato (Pto) DC3000 encodes five Rsm proteins: RsmA/CsrA2, RsmC/CsrA1, RsmD/CsrA4, RsmE/CsrA3, and RsmH/CsrA5. This work aims to provide a comprehensive analysis of the expression of these five rsm protein-encoding genes, elucidate the regulatory mechanisms governing their expression, as well as the physiological relevance of each variant. To achieve this, we examined the expression of rsmA, rsmE, rsmC, rsmD, and rsmH within their genetic contexts, identified their promoter regions, and assessed the impact of both their deletion and overexpression on various Pto DC3000 phenotypes. A novel finding is that rsmA and rsmC are part of an operon with the upstream genes, whereas rsmH seems to be co-transcribed with two downstream genes. We also observed significant variability in expression levels and RpoS dependence among the five rsm paralogs. Thus, despite the extensive repertoire of rsm genes in Pto DC3000, only rsmA, rsmE and rsmH were significantly expressed under all tested conditions (swarming, minimal and T3SS-inducing liquid media). Among these, RsmE and RsmA were corroborated as the most important paralogs at the functional level, whereas RsmH played a minor role in regulating free life and plant-associated phenotypes. Conversely, RsmC and RsmD did not seem to be functional under the conditions tested.

属于 RsmA（次生代谢调节因子）/CsrA（碳储存调节因子）家族的蛋白质是小型 RNA 结合蛋白，在许多革兰氏阴性菌和一些革兰氏阳性菌中发挥着转录后调节基因表达的关键作用。虽然研究的大多数细菌只有一个 RsmA/CsrA 基因，但西红柿假单胞菌（Pseudomonas syringae pv. tomato，Pto）DC3000 编码五个 Rsm 蛋白：RsmA/CsrA2、RsmC/CsrA1、RsmD/CsrA4、RsmE/CsrA3 和 RsmH/CsrA5。本研究旨在全面分析这五个 rsm 蛋白编码基因的表达，阐明其表达的调控机制以及每个变体的生理相关性。为此，我们研究了 rsmA、rsmE、rsmC、rsmD 和 rsmH 在其遗传背景下的表达，确定了它们的启动子区域，并评估了它们的缺失和过表达对 Pto DC3000 各种表型的影响。一个新发现是，rsmA 和 rsmC 与上游基因组成一个操作子，而 rsmH 似乎与两个下游基因共转录。我们还观察到五个 rsm 准同源物之间在表达水平和 RpoS 依赖性方面存在很大差异。因此，尽管 Pto DC3000 中有大量 rsm 基因，但只有 rsmA、rsmE 和 rsmH 在所有测试条件（蜂群、最小和 T3SS 诱导液体培养基）下都有显著表达。其中，RsmE 和 RsmA 在功能水平上被证实为最重要的旁系亲属，而 RsmH 在调节自由生活和植物相关表型方面作用较小。相反，RsmC 和 RsmD 在测试条件下似乎不起作用。

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引用次数: 0

Emerging concepts in mucosal immunity and oral microecological control of respiratory virus infection-related inflammatory diseases 呼吸道病毒感染相关炎症疾病的粘膜免疫和口腔微生态控制的新概念。

IF 6.1 1区生物学 Q1 MICROBIOLOGY

Microbiological research

Pub Date : 2024-10-12 DOI: 10.1016/j.micres.2024.127930

Ying Wang , Jiaxuan Li , Ruyi Chen , Qiuyi Xu , Di Wang , Chenxi Mao , Ziyi Xiang , Guangshang Wu , Ying Yu , Jianhua Li , Yuejuan Zheng , Keda Chen

Oral microecological imbalance is closely linked to oral mucosal inflammation and is implicated in the development of both local and systemic diseases, including those caused by viral infections. This review examines the critical role of the interleukin (IL)-17/helper T cell 17 (Th17) axis in regulating immune responses within the oral mucosa, focusing on both its protective and pathogenic roles during inflammation. We specifically highlight how the IL-17/Th17 pathway contributes to dysregulated inflammation in the context of respiratory viral infections. Furthermore, this review explores the potential interactions between respiratory viruses and the oral microbiota, emphasizing how alterations in the oral microbiome and increased production of proinflammatory factors may serve as early, non-invasive biomarkers for predicting the severity of respiratory viral infections. These findings provide insights into novel diagnostic approaches and therapeutic strategies aimed at mitigating respiratory disease severity through monitoring and modulating the oral microbiome.

口腔微生态失衡与口腔粘膜炎症密切相关，并与局部和全身性疾病（包括由病毒感染引起的疾病）的发生有关。本综述探讨了白细胞介素（IL）-17/辅助 T 细胞 17（Th17）轴在调节口腔粘膜免疫反应中的关键作用，重点关注其在炎症过程中的保护和致病作用。我们特别强调了在呼吸道病毒感染的情况下，IL-17/Th17 通路是如何导致炎症失调的。此外，本综述还探讨了呼吸道病毒与口腔微生物群之间的潜在相互作用，强调了口腔微生物群的改变和促炎因子的增加可作为早期非侵入性生物标志物，用于预测呼吸道病毒感染的严重程度。这些发现为新型诊断方法和治疗策略提供了启示，这些方法和策略旨在通过监测和调节口腔微生物组来减轻呼吸道疾病的严重程度。

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引用次数: 0

From probiotic chassis to modification strategies, control and improvement of genetically engineered probiotics for inflammatory bowel disease 从益生菌底盘到改造策略，控制和改进用于治疗炎症性肠病的基因工程益生菌

IF 6.1 1区生物学 Q1 MICROBIOLOGY

Microbiological research

Pub Date : 2024-10-10 DOI: 10.1016/j.micres.2024.127928

Yuewen Huang , Shan Peng , Rong Zeng , Hao Yao , Guangfu Feng , Jun Fang

With the rising morbidity of inflammatory bowel disease (IBD) year by year, conventional therapeutic drugs with systemic side effects are no longer able to meet the requirements of patients. Probiotics can improve gut microbiota, enhance intestinal barrier function, and regulate mucosal immunity, making them a potential complementary or alternative therapy for IBD. To compensate for the low potency of probiotics, genetic engineering technology has been widely used to improve their therapeutic function. In this review, we systematically summarize the genetically engineered probiotics used for IBD treatment, including probiotic chassis, genetic modification strategies, methods for controlling probiotics, and means of improving efficacy. Finally, we provide prospects on how genetically engineered probiotics can be extended to clinical applications.

随着炎症性肠病（IBD）发病率的逐年上升，具有全身副作用的传统治疗药物已无法满足患者的要求。益生菌可以改善肠道微生物群，增强肠道屏障功能，调节粘膜免疫，是治疗 IBD 的潜在补充或替代疗法。为了弥补益生菌效力低的缺陷，基因工程技术已被广泛用于改善益生菌的治疗功能。在这篇综述中，我们系统地总结了用于 IBD 治疗的基因工程益生菌，包括益生菌底盘、基因修饰策略、控制益生菌的方法以及提高疗效的手段。最后，我们对如何将基因工程益生菌推广到临床应用进行了展望。

引用次数: 0

Transcriptomics reveals the regulation of the immune system of the mushroom-forming fungus Schizophyllum commune during interaction with four competitors 转录组学揭示了形成蘑菇的真菌五味子在与四种竞争者相互作用过程中对免疫系统的调控

IF 6.1 1区生物学 Q1 MICROBIOLOGY

Microbiological research

Pub Date : 2024-10-09 DOI: 10.1016/j.micres.2024.127929

Erik P.W. Beijen, Marieke H. van Maanen, Ioana M. Marian, Janieke X. Klusener, Emmeline van Roosmalen, Koen C. Herman, Margot C. Koster, Robin A. Ohm

Mushroom-forming fungi frequently encounter competitors during their lifecycle, but their defense mechanisms remain largely unexplored. We studied the response of the mushroom-forming fungus Schizophyllum commune during interaction with the fungal competitors Trichoderma harzianum, Trichoderma aggressivum and Purpureocillium lilacinum and the bacterial competitor Serratia quinivorans. Transcriptomics revealed 632 up-regulated genes in the direct interaction zone, which were enriched in small secreted proteins and transporters. A set of 26 genes were up-regulated during all interactions, indicating a core transcriptomic defense response. In the non-interacting edge of the mycelium of S. commune, there were 154 up-regulated genes, suggesting that there is a systemic response due to a signal that reaches unaffected areas. The GATA zinc finger transcription factor gene gat1 was up-regulated during interaction and a Δgat1 strain displayed increased colonization by T. harzianum. Previously linked to mushroom development, this transcription factor apparently has a dual role. Moreover, 138 genes were up-regulated during both interaction and mushroom development, indicating priming of the defense response during development to prepare the fruiting body for future interactions. Overall, we unveiled a defensive response of S. commune during interaction with fungal and bacterial competitors and identified a regulator of this response.

蘑菇真菌在其生命周期中经常会遇到竞争者，但它们的防御机制在很大程度上仍未得到探索。我们研究了形成蘑菇的真菌牛肝菌在与真菌竞争者哈茨真菌（Trichoderma harzianum）、侵袭性毛霉（Trichoderma aggressivum）、紫色毛霉（Purpureocillium lilacinum）以及细菌竞争者奎尼沃氏沙雷氏菌（Serratia quinivorans）相互作用过程中的反应。转录组学发现，在直接相互作用区有 632 个上调基因，其中富含小型分泌蛋白和转运体。一组 26 个基因在所有相互作用过程中都被上调，表明存在核心转录组防御反应。在 S. commune 菌丝体的非交互作用边缘，有 154 个基因上调，表明由于信号到达未受影响的区域而产生了系统反应。在相互作用过程中，GATA 锌指转录因子基因 gat1 被上调，Δgat1 菌株被 T. harzianum 定殖的数量增加。这种转录因子以前与蘑菇的发育有关，显然具有双重作用。此外，138 个基因在交互作用和蘑菇发育过程中均上调，这表明防御反应在发育过程中启动，为子实体未来的交互作用做好准备。总之，我们揭示了牛肝菌在与真菌和细菌竞争者相互作用期间的防御反应，并确定了这种反应的调节因子。

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引用次数: 0

Christensenellaceae minuta modulates epithelial healing via PI3K-AKT pathway and macrophage differentiation in the colitis Christensenellaceae minuta 通过 PI3K-AKT 通路和巨噬细胞分化调节结肠炎的上皮愈合。

IF 6.1 1区生物学 Q1 MICROBIOLOGY

Microbiological research

Pub Date : 2024-10-09 DOI: 10.1016/j.micres.2024.127927

Ting Yao , Youhe Wu , Liyun Fu, Jiawen Lv, Longxian Lv, Lanjuan Li

Ulcerative colitis (UC) is a chronic inflammatory disorder with an unsatisfactory cure rate and mucosal healing is a key treatment objective. Christensenellaceae minuta (C. minuta) has emerged as a next-generation of probiotic for maintaining intestinal health. We investigated the therapeutic efficacy of C. minuta in dextran sulfate sodium (DSS)-induced colitis, focusing on mucosal healing and the underlying mechanisms. C. minuta effectively alleviated colitis and promoted the regeneration of intestinal epithelial cells (IECs). Using 16S rRNA sequencing and metabolomics, we found that C. minuta administration increased beneficial bacteria, decreased pathogenic bacteria, and significantly elevated propionic acid levels. Additionally, C. minuta activated the PI3K-AKT pathway by upregulating systemic and local IGF-1 expression. Inhibiting the PI3K-AKT pathway reduced the therapeutic effects of C. minuta and impaired IEC regeneration. Furthermore, C. minuta promoted macrophage differentiation into the M2 phenotype and decreased proinflammatory factors. We propose that C. minuta alleviates colitis by regulating the gut microbiota, modulating macrophage differentiation, and enhancing mucosal healing by activating the PI3K-AKT pathway via IGF-1 secretion induced by short-chain fatty acids. Our findings provide evidence from animal experiments to support future clinical trials and the therapeutic translation of C. minuta.

溃疡性结肠炎（UC）是一种慢性炎症性疾病，治愈率不尽人意，粘膜愈合是治疗的关键目标。Christensenellaceae minuta（C. minuta）已成为维护肠道健康的新一代益生菌。我们研究了C. minuta对葡聚糖硫酸钠（DSS）诱导的结肠炎的疗效，重点关注粘膜愈合及其内在机制。C. minuta能有效缓解结肠炎并促进肠上皮细胞（IECs）的再生。通过 16S rRNA 测序和代谢组学研究，我们发现服用 C. minuta 能增加有益菌，减少致病菌，并显著提高丙酸水平。此外，C. minuta 通过上调全身和局部 IGF-1 的表达激活了 PI3K-AKT 通路。抑制 PI3K-AKT 通路会降低 C. minuta 的治疗效果，阻碍 IEC 再生。此外，C. minuta 还能促进巨噬细胞向 M2 表型分化并减少促炎因子。我们认为，C. minuta 可通过调节肠道微生物群、调节巨噬细胞分化以及通过短链脂肪酸诱导的 IGF-1 分泌激活 PI3K-AKT 通路来促进粘膜愈合，从而缓解结肠炎。我们的研究结果为未来的临床试验和 C. minuta 的治疗转化提供了动物实验证据。

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引用次数: 0

Brassinosteroids mediate arbuscular mycorrhizal symbiosis through multiple potential pathways and partial identification in tomato 芸苔素类固醇通过多种潜在途径介导丛枝菌根共生，并在番茄中进行了部分鉴定

IF 6.1 1区生物学 Q1 MICROBIOLOGY

Microbiological research

Pub Date : 2024-10-05 DOI: 10.1016/j.micres.2024.127924

Ying Ren , Brian Tobin , Shuyi Yang , Tingying Xu , Hui Chen , Ming Tang

Currently, little is known regarding the specific processes through which brassinosteroids (BR) affect arbuscular mycorrhizal (AM) symbiosis. Understanding this relationship is vital for advancing plant physiology and agricultural applications. In this study, we aimed to elucidate the regulatory mechanisms of BR in AM symbiosis. According to the log2 fold change-value and adjP-value, we integrated the common differentially expressed genes (DEGs) in maize (Zea mays L.) treated with BR and AM, Arabidopsis (Arabidopsis thaliana) mutants deficient in BR receptors, and tomato (Solanum lycopersicum) plants inoculated with AM fungi. In addition, we characterized the symbiotic performance of tomato plants with BR receptor defects and overexpression. The results indicated that the common differential genes induced by BR and AM were involved in metabolic processes, such as cell wall modification, cytoskeleton remodeling, auxin and ethylene signaling, photosynthesis, mineral nutrient transport, and stress defense. Specifically, these include the BR1 gene, which modifies the cell wall. However, the fungal colonization rate of BR receptor-deficient tomato plants was significantly reduced, and the total phosphorus concentration was increased. Conversely, the performance of the overexpressing tomato transformation plants demonstrated a significant contrast. Additionally, the mild rescue of mycorrhizal attenuation in mutants treated with exogenous BR suggests the possibility of direct feedback from BR synthesis to AM. Notably, the cell wall modification gene (SlBR1) and calcium spike gene (SlIPD3) were induced by both BR and AM, suggesting that BR may influence cell penetration during the early stages of AM colonization. Synthesis: Our results demonstrated that BR positively regulates AM symbiosis through multiple pathways. These findings pave the way for future research, including isolation of the individual contributions of each pathway to this complex process and exploration of possible agricultural applications.

目前，人们对铜绿素类固醇（BR）影响丛枝菌根（AM）共生的具体过程知之甚少。了解这种关系对于促进植物生理学和农业应用至关重要。在本研究中，我们旨在阐明 BR 在 AM 共生中的调控机制。根据对折变化值（log2 fold change-value）和P值（adjP-value），我们整合了经BR和AM处理的玉米（Zea mays L.）、缺乏BR受体的拟南芥（Arabidopsis thaliana）突变体以及接种了AM真菌的番茄（Solanum lycopersicum）植株中常见的差异表达基因（DEGs）。此外，我们还研究了BR受体缺陷和过表达的番茄植株的共生表现。结果表明，BR和AM诱导的共同差异基因参与了代谢过程，如细胞壁修饰、细胞骨架重塑、辅助素和乙烯信号转导、光合作用、矿质养分运输和胁迫防御。具体来说，其中包括改造细胞壁的 BR1 基因。然而，BR 受体缺陷番茄植株的真菌定植率显著降低，总磷浓度增加。相反，过表达番茄转化植株的表现却呈现出明显的反差。此外，用外源 BR 处理的突变体对菌根衰减的轻度挽救表明，可能存在从 BR 合成到 AM 的直接反馈。值得注意的是，细胞壁修饰基因（SlBR1）和钙穗基因（SlIPD3）同时被BR和AM诱导，这表明BR可能会在AM定殖的早期阶段影响细胞渗透。综述：我们的研究结果表明，BR 通过多种途径积极调控 AM 的共生。这些发现为今后的研究铺平了道路，包括分离出每种途径对这一复杂过程的贡献，以及探索可能的农业应用。

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引用次数: 0

Chemoreceptor MCP4580 of Vibrio splendidus mediates chemotaxis toward L-glutamic acid contributing to bacterial virulence 绚丽弧菌的化学感受器 MCP4580 介导了对 L-谷氨酸的趋化作用，从而增强了细菌的毒力。

IF 6.1 1区生物学 Q1 MICROBIOLOGY

Microbiological research

Pub Date : 2024-10-01 DOI: 10.1016/j.micres.2024.127917

Ya Li , Weibo Shi , Zihao Sun , Weiwei Zhang

Chemotaxis has an essential function in flagellar bacteria that allows them to sense and respond to specific environmental signals, enabling their survival and colonization. Vibrio splendidus is an important opportunistic pathogen that infects a wide range of hosts including fish, bivalve, and sea cucumber. Our study demonstrated that V. splendidus AJ01 exhibited chemotaxis toward L-glutamic acid (L-Glu), an abundant amino acid in the intestinal and respiratory tree tissues of the sea cucumber. Bacterial samples collected from two locations in soft agar swimming plates were subjected to RNA-sequencing (RNA-Seq) analysis to identify the methyl-accepting chemotaxis protein (MCP) respond to L-Glu. Among the 40 annotated chemoreceptors, MCP4580 was identified as the MCP that mediates L-Glu-response. Molecular docking and site-directed mutagenesis revealed that L-arginine at residue 81 (R81) and L-glutamine at residue 88 (Q88) in the ligand-binding domain (LBD) are crucial for L-Glu recognition. Bacterial two-hybrid assay (BTH) showed that MCP4580 forms dimers and interacts with the histidine kinase CheA via the coupling protein CheW1 and CheW2. Phosphorylation analysis showed that the binding of L-Glu to MCP4580 results in the inhibition of CheA phosphorylation mainly via CheW1. Notably, sea cucumbers stimulated with each mutant strain of chemotaxis protein exhibited reduced mortality, highlighting the importance of chemotaxis in V. splendidus virulence. The present study provides valuable insights into the molecular components and signal transduction involved in the chemotaxis of V. splendidus toward L-Glu, and highlights the importance of chemotaxis in its virulence.

趋化作用是鞭毛细菌的一项基本功能，它能使细菌感知特定的环境信号并做出反应，从而使细菌得以生存和定殖。白芨弧菌是一种重要的机会性病原体，可感染鱼类、双壳贝类和海参等多种宿主。我们的研究表明，白芨弧菌 AJ01 对 L-谷氨酸（L-Glu）具有趋化性，而 L-谷氨酸是海参肠道和呼吸树组织中含量丰富的氨基酸。对从软琼脂游泳板两个位置采集的细菌样本进行了RNA测序（RNA-Seq）分析，以确定对L-谷氨酸有反应的甲基接受趋化蛋白（MCP）。在 40 个已注释的趋化感受器中，MCP4580 被确定为介导 L-Glu 反应的 MCP。分子对接和定点突变显示，配体结合结构域（LBD）中残基81（R81）处的L-精氨酸和残基88（Q88）处的L-谷氨酰胺对L-Glu的识别至关重要。细菌双杂交试验（BTH）显示，MCP4580 形成二聚体，并通过偶联蛋白 CheW1 和 CheW2 与组氨酸激酶 CheA 相互作用。磷酸化分析表明，L-Glu 与 MCP4580 结合后，主要通过 CheW1 抑制 CheA 的磷酸化。值得注意的是，用每种趋化蛋白突变株刺激的海参死亡率都有所降低，这突出表明了趋化作用在白芨弧菌毒力中的重要性。本研究对白芨趋化L-Glu的分子成分和信号转导提供了有价值的见解，并强调了趋化在其毒力中的重要性。

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引用次数: 0

The global transcription factor Clp exerts positive regulatory effects in the walnut bacterial black spot pathogen, Xanthomonas arboricola pv. juglandis 全局转录因子 Clp 在核桃细菌性黑斑病病原体 Xanthomonas arboricola pv. juglandis 中发挥积极的调控作用。

IF 6.1 1区生物学 Q1 MICROBIOLOGY

Microbiological research

Pub Date : 2024-10-01 DOI: 10.1016/j.micres.2024.127921

Feng Li , Wenzhong Yang , Benzhong Fu , Yonghong Yu , Yahui Mao

Walnut blight caused by the bacterium Xanthomonas arboricola pv. juglandis (Xaj) is one of the most common diseases of walnut (Juglans spp.), resulting in serious yield decline and significant economic losses. Crp-like protein (Clp) is an important global regulatory transcription factor in bacteria. In this study, we sought to elucidate the role of Clp in the pathogenicity of Xaj strain DW3F3 and the associated regulatory mechanism. The results indicated that clp gene deficiency significantly reduced the pathogenicity of Xaj DW3F3 in walnut without affecting the growth of the bacterium. We found that Clp positively regulates biofilm formation, extracellular polysaccharide production, exoenzyme secretion, and motility of Xaj, which was consistent with the transcript levels of virulence factor-encoding genes. However, overexpression of clp does not enhance the expression of all virulence genes, it may inhibit the expression of a part of virulence factor-related genes. EMSA assay further showed that Clp specifically binds to the promoters of these genes and regulates their expression, and CD spectra test certified that the ligand of Clp was c-di-GMP. Our findings contribute to the in-depth understanding of the pathogenic mechanism of Xaj and highlight the potential of Clp as a drug target for the development of agents to prevent and control walnut diseases.

由核桃黄单胞菌（Xanthomonas arboricola pv. juglandis，Xaj）引起的核桃枯萎病是核桃（Juglans spp.）最常见的病害之一，会导致严重减产和重大经济损失。Crp 样蛋白（Clp）是细菌中一种重要的全球调控转录因子。本研究试图阐明 Clp 在 Xaj 菌株 DW3F3 致病性中的作用及相关调控机制。结果表明，Clp 基因缺失会显著降低 Xaj DW3F3 在核桃中的致病性，而不会影响细菌的生长。我们发现 Clp 对 Xaj 的生物膜形成、胞外多糖产生、外酵素分泌和运动有正向调控作用，这与毒力因子编码基因的转录水平一致。然而，过表达 clp 并不会增强所有毒力基因的表达，它可能会抑制部分毒力因子相关基因的表达。EMSA测定进一步表明，Clp能特异性地与这些基因的启动子结合并调控它们的表达，CD光谱检测证明Clp的配体是c-di-GMP。我们的研究结果有助于深入了解 Xaj 的致病机理，并凸显了 Clp 作为药物靶点开发预防和控制核桃疾病的潜力。

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引用次数: 0

Sterol regulatory element-binding proteins mediate intrinsic fungicide tolerance and antagonism in the fungal biocontrol agent Clonostachys rosea IK726 甾醇调节元件结合蛋白介导真菌生物控制剂 Clonostachys rosea IK726 对杀真菌剂的内在耐受性和拮抗性。

IF 6.1 1区生物学 Q1 MICROBIOLOGY

Microbiological research

Pub Date : 2024-09-28 DOI: 10.1016/j.micres.2024.127922

Edoardo Piombo , Georgios Tzelepis , Alma Gustavsson Ruus, Vahideh Rafiei, Dan Funck Jensen, Magnus Karlsson, Mukesh Dubey

Sterol regulatory element-binding proteins (SREBPs) are transcription factors governing various biological processes in fungi, including virulence and fungicide tolerance, by regulating ergosterol biosynthesis and homeostasis. While studied in model fungal species, their role in fungal species used for biocontrol remains elusive. This study delves into the biological and regulatory function of SREBPs in the fungal biocontrol agent (BCA) Clonostachys rosea IK726, with a specific focus on fungicide tolerance and antagonism. Clonostachys rosea genome contains two SREBP coding genes (sre1 and sre2) with distinct characteristics. Deletion of sre1 resulted in mutant strains with pleiotropic phenotypes, including reduced C. rosea growth on medium supplemented with prothioconazole and boscalid fungicides, hypoxia mimicking agent CoCl₂ and cell wall stressor SDS, and altered antagonistic abilities against Botrytis cinerea and Rhizoctonia solani. However, Δsre2 strains showed no significant effect. Consistent with the gene deletion results, overexpression of sre1 in Saccharomyces cerevisiae enhanced tolerance to prothioconazole. The functional differentiation between SRE1 and SRE2 was elucidated by the yeast-two-hybridization assay, which showed an interaction between SREBP cleavage-activating protein (SCAP) and SRE1 but not between SRE2 and SCAP. Transcriptome analysis of the Δsre1 strain unveiled SRE1-mediated expression regulation of genes involved in lipid metabolism, respiration, and xenobiotic tolerance. Notably, genes coding for antimicrobial compounds chitinases and polyketide synthases were downregulated, aligning with the altered antagonism phenotype. This study uncovers the role of SREBPs in fungal BCAs, providing insights for C. rosea IK726 application into integrated pest management strategies.

甾醇调节元件结合蛋白（SREBPs）是一种转录因子，通过调节麦角甾醇的生物合成和平衡，控制真菌的各种生物过程，包括毒力和杀真菌剂耐受性。虽然对模型真菌物种进行了研究，但它们在用于生物防治的真菌物种中的作用仍然难以捉摸。本研究深入研究了 SREBPs 在真菌生物控制剂（BCA）Clonostachys rosea IK726 中的生物学和调控功能，特别关注杀真菌剂的耐受性和拮抗性。Clonostachys rosea 基因组包含两个 SREBP 编码基因（sre1 和 sre2），它们具有不同的特征。缺失 sre1 会导致突变株具有多生物表型，包括在添加了丙硫菌唑和溴螨脲杀菌剂、缺氧模拟剂 CoCl2 和细胞壁应激剂 SDS 的培养基上生长能力降低，以及对灰霉病菌和根瘤菌的拮抗能力改变。然而，Δsre2 菌株没有明显的影响。与基因缺失结果一致的是，sre1 在酿酒酵母中的过表达增强了对丙硫菌唑的耐受性。酵母双杂交试验阐明了 SRE1 和 SRE2 之间的功能差异，结果表明 SREBP 裂解激活蛋白（SCAP）与 SRE1 之间存在相互作用，而 SRE2 与 SCAP 之间没有相互作用。对 Δsre1 菌株的转录组分析揭示了 SRE1 介导的脂质代谢、呼吸和异生物耐受基因的表达调控。值得注意的是，编码抗微生物化合物几丁质酶和多酮合成酶的基因被下调，这与拮抗表型的改变相一致。这项研究揭示了 SREBPs 在真菌 BCA 中的作用，为 C. rosea IK726 应用于害虫综合治理战略提供了启示。

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