[Background]Galium spurium,one of the main noxious weeds in crop fields,is mainly controlled by chemicals,which causes serious harm to the human body and the environment.Microbial herbicides with precise targets and environmental safety have practical significance for agricultural modernization.[Objective]To screen out the non-polluting and harmless strains with strong weed-controlling activities and provide new strain resources for the development of microbial herbicides.[Methods]The strains were isolated and purified by tissue culture method.The herbicidal activity and selectivity of the isolate were determined by the spore suspension method.Internal transcribed spacer(ITS)and EF-1/EF-2 gene sequencing was used to identify the isolate.The phylogenetic tree was constructed in MEGA 7.0 to reveal the phylogenetic relationship of the strain.Finally,the environmental conditions suitable for growth and sporulation of the strain were analyzed based on colony diameter and mycelial dry weight combined with blood cell counting.[Results]A strain DT-08C was isolated and identified as Fusarium paeoniae.The incidence rate of DT-08C infection in G.spurium reached 47.22%-93.93%,and the strain was safe to broad bean,pea,maize,Chinese cabbage,tomato,cucumber,and pepper.The optimum media for colony growth and sporulation of DT-08C was PSA and OA,respectively.[Conclusion]F.paeoniae DT-08C is highly pathogenic to G.spurium but safe to broad bean,pea,maize,Chinese cabbage,tomato,cucumber,and pepper,and it has wide adaptability to the environment.The results provide strain resources for the further field application.
The development and spread of antibiotic resistance in the environment pose potential risks to human health. With the advances in high-throughput sequencing and bioinformatics, metagenomics has been widely used in the study of antibiotic resistomes in different environmental samples. This paper introduces two metagenomic methods for environmental resistome screening, summarizes the current mainstream bioinformatic tools and databases, and describes the risk assessment framework of environmental resistome and the related practice based on metagenomic technology. We aim to provide a feasible roadmap for the monitoring, risk assessment, and control of environmental resistome.
Medium and long-chain alkanes are key parts of petroleum hydrocarbons. They are the main cause of the high viscosity of underground crude oil, low oil recovery, and long-term pollution of the ecological environment after leakage due to their strong hydrophobicity, high viscosity, low chemical activity, and difficulty in degradation. As a result, they are important degradation targets in terms of improving oil recovery and treating petroleum pollution in the environment. As a new and efficient green technology, microbial degradation of medium and long-chain alkanes has gained popularity. This paper summarized the interphase adaptation and transport process of medium and long-chain alkanes in microbial degradation, membrane proteins related to the transport process, metabolic pathways of aerobic and anaerobic microorganism degradation, gene regulation mechanism in aerobic degradation, and putative gene regulation mechanism in anaerobic degradation. Furthermore, prospects for the research direction of microbial degradation of medium and long-chain alkanes were presented, serving as references for subsequent related research.
[背景]三七根际微生物群落特征与其土传根腐病害密切相关,而针对自然林下根腐三七的相关研究鲜见报道.[目的]比较分析自然林下与田间根腐三七根际土壤微生物群落的组成特征,结合土壤理化性质与酶活性分析,为三七根腐病害防治与仿野生栽培提供科学依据.[方法]采集自然林下与田间根腐三七根际土壤,利用高通量测序技术,分析土壤细菌与真菌群落的物种组成与多样性,并测定土壤理化性质和酶活性.[结果]自然林下与田间根腐三七根际土壤中细菌和真菌群落组成具有明显差异,自然林下根腐三七根际土壤中担子菌门(Basidiomycota)、酸杆菌门(Acidobacteria)和疣微菌门(Verrucomicrobia)的相对丰度较高,而田间根腐三七根际土壤中子囊菌门(Ascamycota)、变形菌门(Proteobacteria)和绿弯菌门(Chloroflexi)的相对丰度较高.在属分类水平,镰刀菌属(Fusarium)是自然林下根腐三七根际土壤中的优势菌群,相对丰度为17.30％,而癣囊腔菌属(Plectosphaerella)是田间根腐三七根际土壤中的优势菌群,相对丰度为22.55％;Candidatus Bacilloplasma在自然林下非三七根际土壤中的相对丰度达8.05％,而在三七根际土壤中的相对丰度大幅降低(0-1.25％).与自然林下三七根际土壤相比较,田间根腐三七根际土壤有机质含量、酶活性与微生物多样性均显著降低(P＜0.05).冗余分析(redundancy analysis,RDA)表明,自然林下与田间根腐三七根际土壤细菌和真菌群落存在明显分化,与土壤有机质含量和酶活性密切相关.[结论]自然林下与田间根腐三七根际微生物群落组成存在明显差异;针对田间种植三七需要采取有效措施提高土壤有机质含量、酶活性与微生物多样性,除镰刀菌属外,还需特别关注癣囊腔菌属真菌对三七的侵害.
[背景]A型塞内卡病毒(Senecavirus A,SVA)是新发猪塞内卡病毒病的病原,属于小核糖核酸病毒科(Picornaviridae)塞内卡病毒属(Senecavirus)的单股正链RNA病毒.可引起新生仔猪死亡和成年猪口、蹄部出现水泡.先天免疫是宿主抵御病毒入侵的第一道防线,但SVA与宿主抗病毒先天免疫的相互作用机制尚不清楚.[目的]探究SVA非结构蛋白2C在先天免疫应答中的作用机制.[方法]利用SVA感染和通过在猪PK-15细胞中过表达SVA 2C蛋白,利用RT-qPCR和Western blotting分析2C蛋白对细胞因子表达及其关键信号通路的影响.[结果]RT-qPCR检测发现,SVA感染PK-15细胞导致IFNβ、TNF-α和IL-6表达的显著升高;同时,SVA感染导致TBK1和NF-κB的磷酸化.进一步的研究发现,SVA的2C蛋白能够激活TBK1和NF-κB磷酸化,并诱导IFNβ、TNF-α和IL-6的表达;2C蛋白能够激活抗DNA病毒感染关键蛋白干扰素基因刺激因子(stimulator of interferon genes,STING)磷酸化,敲除 STING 抑制 TBK1、NF-κB 的磷酸化和 IFNβ、TNF-α、IL-6的表达.[结论]本研究初步揭示了 SVA2C蛋白通过激活STING诱导天然免疫应答的作用机制,揭示了 STING参与调控RNA病毒SVA介导的免疫应答的功能,为抗病毒药物和疫苗的研发提供了理论基础.
