抗感白粉病青稞的内生真菌群落差异分析

种子内生微生物组与种子的健康发育有着密切的关系。本研究收集对白粉病抗病和易感共11个品种的青稞种子,利用扩增子测序技术对内生真菌的群落、丰度和多样性进行研究。从不同品种的青稞种子中共鉴定4个门、17个纲、35个目、66个科、107个属的内生真菌,其中子囊菌门Ascomycota、担子菌门Basidiomycota和被孢菌门Mortierellomycota是优势菌门;链格孢属Alternaria、微座孢属Microdochium、亚隔孢壳属Didymella、镰刀菌属Fusarium和球腔菌属Mycosphaerella为优势菌属。根据生物信息学注释结果,在鉴定到的107个属中,抗病品种的青稞种子中特有的属有20个,感病品种的青稞种子中特有的属有50个;通过对两组样本的分析,发现感病品种中真菌物种多样性高于抗病品种。本研究通过扩增子测序技术初步确定了青稞抗、感白粉病两组样品中的真菌群落结构和优势菌群,为进一步研究青稞内携真菌与抗/感病的关系提供了基础,从内生菌的角度为青稞白粉病的防控提供新的策略。     

黑胫病感染对烟草茎秆及根际土壤真菌群落结构的影响

烟草黑胫病是由寄生疫霉烟草变种引起的一种对烟草生产造成巨大经济损失的土传病害。本文以健康烟株与感染黑胫病烟株茎秆和根际土壤为研究对象,通过PCR技术扩增样本中真菌转录间隔区的ITS1区域,采用Illumina Miseq高通量测序技术对扩增片段进行测序,旨在了解黑胫病感染对于烟草茎秆和根际土壤真菌群落结构与多样性的影响。本研究20个测序样品,共获得755 599条高质量序列片段,最短序列为200bp,最长序列为356bp,平均序列长度248bp。结果表明,健康烟株和发病烟株根际土壤的优势真菌为子囊菌门Ascomycota、接合菌门Zygomycota和担子菌门Basidiomycota,所有茎秆样品的优势真菌为子囊菌门、担子菌门。健康烟株与感染黑胫病烟株根际土壤样品相对丰度大于1%的属有镰刀菌属Fusarium、被孢霉属Mortierella、隐球菌属Cryptococcus、链格孢属Alternaria和赤霉菌属Gibberella等,其中,健康烟株根际土壤优势属为镰刀菌属（39.35%）和被孢霉属（14.19%）,发病烟株根际土壤镰刀菌属和被孢霉属相对丰度分别为40.26%和20.77%;健康茎秆样品优势属为隐球菌属（31.12%）、链格孢属（18.28%）、镰刀菌属（15.67%）和红酵母属Rhodotorula（13.34%）;病健交界茎秆样品优势属为镰刀菌属（41.36%）、隐球菌属（28.15%）和链格孢属（22.32%）;发病茎秆优势属为隐球菌属（62.14%）和链格孢属（27.75%）。烟株感染黑胫病后,其根际土壤与茎秆样品真菌优势属种类与健康烟株无明显变化,但属水平的相对丰度变化显著。发病烟株茎秆与根际土壤样品真菌群落Sobs、Chao1、Shannon指数较健康烟株降低,Simpson指数上升,表明烟株发病后根际土壤真菌与茎秆内生真菌群落丰富度与多样性降低。该结果对于研究烟草黑胫病发生的微生态机制及其生物防治具有一定的理论指导意义。     

西藏昆诺阿藜种子可培养内生真菌多样性

探究西藏不同地区昆诺阿藜种子内生真菌的物种组成、多样性等群落结构特征,丰富昆诺阿藜种子相关微生物的可利用资源,对于微生物资源利用和昆诺阿藜病害的生物防控具有重要意义。本研究收集西藏不同海拔3个地区(日喀则、拉萨和林芝)的昆诺阿藜种子,利用传统分离方式进行了真菌的培养。从46份昆诺阿藜种子中共分离出947株真菌,经ITS序列分析结合形态观察鉴定为1门9目12科26属77种。所有的真菌都归类为子囊菌门Ascomycota,菌株数量相对丰度最高的3个属为链格孢属Alternaria (40.2%)、镰刀菌属Fusarium (17.4%)和茎点霉属Phoma (13.9%)。按照多样性指数,日喀则地区的昆诺阿藜内生可培养真菌的多样性明显高于拉萨和林芝两个地区。     

健康与患病刺梨植株可培养叶际真菌菌群差异比较

本研究比较了健康与患叶斑病刺梨植株叶际真菌群落特征差异,以期探索病原菌的潜在来源,为人工构建具拮抗功能群落和刺梨叶斑病的生物防控提供参考。通过可培养方法对不同健康状况的刺梨叶际真菌进行分离培养,结合形态学和分子系统学对菌株进行综合鉴定;利用FUNGuild平台对真菌进行功能注释;结合根际、根部真菌作拆分网络分析探索病原菌的潜在来源。本研究结果表明：1）刺梨叶际真菌具有丰富的多样性。从刺梨叶际8个样品中共分离到真菌266株,其隶属于3门、6纲、13目、30科、46属中的61个种。其中,健康植株叶际内生真菌（LHE）包括8属10种27株,附生真菌（LHS）包括33属37种77株。患病叶际内生真菌（LDE）分离到7属10种38株;附生真菌（LDS）分离到31属35种124株。2）不同样品的真菌优势属和特有类群有差异。不同健康状况下叶际附生真菌的优势属均为拟盘多毛孢属Pestalotiopsis,但二者的相对多度存在差异,LHS为11.49%,LDS为32.26%;内生真菌优势属二者均为链格孢属Alternaria,但相对多度各异,LHE为33.33%,LDE为63.16%。其中,LHE特有类群为盘长孢状刺盘孢 Colletotrichum gloeosporioides和果生刺盘孢Colletotrichum fructicola等8种;LDE特有类群为茄链格孢 Alternaria solani和Didymella sinensis 等8种;LHS特有类群是草酸青霉Penicillium oxalicum和Peniophora crassitunicata等21种;LDS特有类群是尖孢镰刀菌Fusarium oxysporum、赭绿青霉Penicillium ochrochloron和易脆毛霉Mucor fragilis等19种。3）不同样品叶际真菌功能不同。经FUNGuild解析表明,LHS、LHE和LDE的叶际真菌功能群主要以腐生型为主,LDS则主要以植物病原菌群为主。本研究结果初步揭示刺梨植株健康与患叶斑病叶际间真菌多样性、群落组成及营养功能群存在差异,植株健康状况与其真菌群落特征密切相关;叶斑病病原菌主要源于刺梨叶际的附生微生物群。     

刺槐内生真菌群落组成及其生态功能结构分析

基于高通量测序方法对贵州贵阳花溪刺槐内生真菌物种多样性进行分析,共获得有效序列43 942条,聚类后共获得81个可操作单元（OTUs）,分属4门13纲27目45科58属。其中,优势属为一分类地位未定属,其相对丰度为83.23%,次优势属为镰刀菌属 Fusarium（11.81%） 、拟船壳属 Gloniopsis（1.38%）和螺旋聚孢霉属 Clonostachys（0.72%）,相对丰度小于0.5%的属高达50个以上。Shannon-Wiener指数为0.6835,Simpson指数为0.7071。经FUNGuild软件平台解析显示,刺槐内生菌包含有如下生态功能群：植物病原菌、动物病原菌、内生真菌、真菌寄生菌、地衣真菌、粪生真菌、未定腐生菌和木腐菌等。     

烟草内生真菌多样性和种群结构

从云南“世界烟草品种园”10种烟草的根、茎、叶中分离得到199株内生真菌,根据rDNA-ITS系统发育分析鉴定为17属25种,其中格孢腔菌目Pleosporales内生真菌的种类和数量最多;茎点霉属Phoma、链格孢属Alternaria和镰孢菌属Fusarium为主要优势属,相对频率分别为25.1%、24.6%和11.6%,优势度Y值分别为0.251、0.172和0.104。烟草不同组织内生真菌的种群结构存在显著差异,分离自根的内生真菌的主要优势属为Fusarium和Phoma,Y值分别为0.235和0.123;分离自茎的内生真菌的主要优势属为Phoma和Alternaria,Y值分别为0.186和0.155;分离自叶片的内生真菌的主要优势属为Alternaria,Y值为0.286。Phoma从烟草根茎叶中均可分离得到,而Alternaria只分布在地上部茎叶中,Fusarium只分布在根茎中,表明这3个优势属真菌对根茎叶组织的专化性不同。     

艺术体操运动员局部体位及体操毯的真菌群落组成分析

艺术体操运动员的手掌、足部（包括足跟和足尖-鞋腔）、以及体操毯的真菌群落组成是否存在潜在的卫生安全隐患,目前国内尚未见研究报道。本研究对37位艺术体操运动员手掌、足跟、和足尖-鞋腔以及体操毯进行了运动场现场采样,通过高通量测序、宏基因组分析、FUNGuild平台功能注释等进行研究分析。研究结果表明,在艺术体操运动员脚尖鞋腔中存在较多人体潜在的病原真菌,其优势属为常见皮肤真菌,如迈氏酵母Meyerozyma、毛癣菌Trichophyton和谷氏酵母属Guehomyces等,同时也存在新兴病原真菌,如皮假黑粉菌Coniosporium epidermidis和萨氏曲霉Aspergillus sydowi等。在体操毯中常见的皮肤真菌类群虽未被发现,但一类新兴病原真菌链格孢属Alternaria的相对丰度竟达到了50.90%,它们都在一定程度上会引起公共卫生的安全问题。     

河南浓香型酒醅的真菌微生物菌群多样性及共变性

通过高通量测序研究河南三个不同酒厂的浓香型酒醅的真菌微生物菌群,逐次在门、纲、目、科和属5个水平上分析入窖酒醅和出窖酒醅的菌群多样性,探究酒醅发酵后菌群的共性变化规律。结果表明:出窖酒醅的真菌微生物多样性高于入窖酒醅的真菌微生物多样性,出窖酒醅的真菌主要有镰刀菌属Fusarium(相对丰度17%~32%),Plectosphaerella属(相对丰度10%~19%),链格孢属Alternaria(相对丰度2.5%~3.7%)等。入窖酒醅中真菌有酵母目的伊萨酵母属Issatchenkia(相对丰度27%~57%)或复膜孢酵母属Saccharomycopsis(相对丰度58.8%)等。浓香型酒醅发酵后子囊菌门Ascomycota的相对丰度稳定,担子菌门Basidiomycota的相对丰度增加。锤舌菌纲Leotiomycetes、银耳目Tremellales、镰刀菌属Fusarium、链格孢属Alternaria、Plectosphaerella属的相对丰度增加,而伊萨酵母属Issatchenkia、复膜孢酵母属Saccharomycopsis、发菌科Trichocomaceae的相对丰度降低。高通量测序研究揭示了河南浓香型酒醅的真菌菌群多样性以及发酵后真菌菌群的共性变化规律。     

构树可培养内生真菌的多样性初探

构树Broussonetia papyrifera为桑科重要的资源植物。为调查逆境构树内生真菌的多样性,我们对铅锌矿区构树根、茎、叶和果实各部位进行内生真菌分离鉴定,从中分离得到187株内生真菌,根据形态学与分子生物学方法鉴定为20属,其中链格孢属Alternaria（50.27%）、镰孢属Fusarium（11.76%）为优势属。不同培养基的内生真菌分离率结果表明,马铃薯葡萄糖琼脂培养基（PDA）分离出的菌株数最多,占总数的73.96%;构树不同部位的菌株分离数目显示,叶中分离出的菌株较多,占38.02%。在属的分类水平上,根、茎、叶、果实不同部位的真菌数量也存在明显差异。Shannon-Wiener多样性指数和Simpson多样性指数分析结果提示不同样地的构树内生真菌的多样性也存在差异。Chao1指数和ACE指数也提示构树内生真菌丰富度与样地和组织有关。     

豌豆茎基腐病病原菌分离鉴定及其对杀菌剂的敏感性测定

豌豆(Pisum sativum)是我国重要的豆类经济作物, 病害对豌豆生产造成重大经济损失。通过形态学观察、分子鉴定以及致病性测定, 最终确定引起豌豆茎基腐病的3种病原菌分别为尖孢镰刀菌(Fusarium oxysporum)、芸苔链格孢菌(Alternaria brassicae)和格氏镰刀菌(F. grosmichelii), 优势菌株为尖孢镰刀菌, 分离率为53.6%。室内毒力测定结果表明, 5种供试杀菌剂对3种病原菌的菌丝生长均有抑制作用, 其中咯菌腈和戊唑醇的抑菌效果最好。研究结果为豌豆茎基腐病的防治提供了科学依据。     

Prevalence and control of wheat (Triticum aestivum L.) seed borne fungi in farmer-saved seeds

High incidence of diseases associated with the use of seeds saved from previous harvests as desire of maintaining local varieties with special attributes is of increased concern in wheat industry worldwide. Prevalent of seed-borne fungi in farmer-saved seeds and seed dressing fungicides to prevent infection from seeds to seedlings was studied in Northern Tanzania. One hundred and thirty five untreated farmer-saved seed lots were collected randomly from farmers. Alternaria alternata, Bipolaris sorokiniana, Drechslera tritici, Fusarium graminearum, Fusarium moniliforme, Aspergillus flavus, Cladosporium sphaerospermum, Epicoccum purpurascens, Pyricularia oryzae and Penicillium corylophilum were fungi isolated in farmer-saved seeds. Mean seed infection was 29% causing average grain yield loss of 1.2 mt/ha^?1. Seed dressing with Metalaxy plus (Methyl carboxaitide), Mancozeb (Manganase-zinc salt) and Baytan (Chlorophenoxy ethanol) increased seed germination by 14, 13 and 17%, respectively, and grain yield by 28, 20 and 18%, respectively. Farmer-saved seeds were heavily infected by fungi with low grain yield performance.     

Alternaria alternata prevalence in cereal grains and soybean seeds from Entre Ríos, Argentina

A mycological survey was carried out at Entre Ríos province, Argentina, on sorghum grain, maize, rice, soybean seeds and on freshly harvested and stored wheat. The isolation frequencies and relative densities of species belonging to genera Alternaria, Aspergillus, Fusarium, Penicillium and other fungi were calculated. Alternaria alternata was the major fungal species isolated from sorghum, rice, soybean seeds and on freshly harvested wheat, and a low incidence of Fusarium species was observed on the same substrates. In maize the major fungal species isolated was Fusarium verticillioides. The high incidence levels of A. alternata observed,suggest that it may be necessary to determine, among other mycotoxins, if Alternaria toxins occur in these commodities.     

半夏内生真菌的初步研究

从健康无病害的半夏(Pinellia ternate)根、茎、叶和花组织中分离获得内生真菌共计61株,对其进行形态学鉴定后,针对不产孢的菌株,测定了ITSrDNA序列以进行分子鉴定。分离到的内生真菌分别来自11个属,以半知菌为主要群落,其中Hyphomycetes,Zygomycetes和Coelomycetes的比例分别为62.2%,18.1%和8.2%;镰刀菌属(Fusarium spp.)是半夏植物中分离率最高(6%)的属,其余主要优势属为Alternaria,Mucor,Epicoccum,Mortierella和Plectosphaerella。研究表明:从半夏球茎组织中分离到的内生真菌数量多于其他组织。     

Fungi isolated from tobacco leaves and brown-spot lesions before and after flue-curing

Discs of tissue excised from ripe nonflue-cured and flue-cured tobacco leaves, harvested on six dates and cultured on three selective media, yielded 21 and 24 genera of fungi, respectively. Of 5,094 fungi isolated from 3,240 pieces of nonfluecured leaf tissue, 89.5% comprised five genera, Alternaria, Cladosporium, Epicoccum, Trichoderma, and Nigrospora. Of 2,494 fungi isolated from 3,240 pieces of flue-cured leaf tissue, 70.9% were Alternaria, Cladosporium Epicoccum, Aspergillus, and Nigrospora. Flue-cured and nonflue-cured brown-spot lesions harvested at two locations yielded 12 and 14 genera of fungi, respectively. Alternaria, Penicillium, Phoma, and Stemphyllium comprised 91.5% of the 2,245 fungi isolated from noncured and 87.1% of the 1,118 fungi isolated from the cured lesions. The number and kinds of fungi obtained from diseased and healthy tissue were reduced but not eliminated by flue-curing.     

The endophytic fungi from wheat (<Emphasis Type="Italic">Triticum aestivum</Emphasis> L.)

In order to study the species composition of endophytes from wheat healthy plants in Buenos Aires Province (Argentina) and to determine their infection frequencies from leaves, stems, glumes and grains, wheat plants were collected from five cultivars at five growth stages from crop emergence to harvest. A total of 1,750 plant segments (leaves, stems, glumes and grains) were processed from the five wheat cultivars at five growth stages, and 722 isolates of endophytic fungi recovered were identified as 30 fungal genera. Alternaria alternata, Cladosporium herbarum, Epicoccum nigrum, Cryptococcus sp., Rhodotorula rubra, Penicillium sp. and Fusarium graminearum were the fungi that showed the highest colonization frequency (CF%) in all the tissues and organs analysed. The number of taxa isolated was greater in the leaves than those in the other organs analysed.     

Czapek-Dox agar containing iprodione and dicloran as a selective medium for the isolation of Fusarium species

A new selective medium for Fusarium species has been developed using Czapek-Dox agar (CZ) containing the fungicides iprodione (3 mg/1) and dicloran (2 mg/1). This new medium (CZID) is selective against numerous species of Alternaria, Epicoccum, Penicillium and mucoraceous fungi. CZID was compared with CZ using samples of barley, malt, sorghum, bean and pea. Fusarium species produced large and easily recognizable colonies on CZID while isolates of Alternaria, Epicoccum and Rhizopus were significantly restricted on CZID compared with their growth on CZ. The use of CZID thus facilitates the isolation and subculturing of Fusarium species.     

Detection of fungal infectous agent of wheat grains in store-pits of Markazi province, Iran

Wheat is an economic and important crop that provides approximately 20% of food calorie in the world. It is first crop in Iran and cultivated in the most areas of this country. Store-pit fungi make undesirable changes in quality and appearance of wheat grains. Even, some fungi produce different mycotoxins which are toxic to human and livestock's that use wheat grains as source of food. In this study, several samples were randomly collected from each of five store-pits located in different areas of Markazi Province including: Arak, Mahallat, Khomein, Saveh and Sarband. Grains were treated on PDA, and blotter, agar and washing test also used for isolating and detection of fungi. At least 100 grains per each sample were randomly used for each test and treatment. The fungi that determined in this study were Cochliobolus australiensis, Cladosporium herbarum, Epicoccum sp., Tilletia leavis, Aspergillus flavus, A. niger, A. fumigatus, Alternaria alternata, Alternaria sp., Penicillium italicum, P. digitatum, Fusarium sp., Rhizopus sp., Ustilago tritici, Scytalidium sp. Among these fungi the most isolates were belonged to Cladosporium, Alternaria, Rhizopus and Fusarium. Cladosporium herbarum was the most common in different sampling areas. Tilletia laevis and Ustilago tritici were just recovered in washing test. This study revealed that different fungi are associated with wheat grains in store-pits in Markazi Province. Some of them like Aspergillus flavus normally produce aflatoxin, a very toxic and carcinogenic mycotoxin that is harmful for human.     

Mouse Toxicity of Fungi of Tobacco

A bioassay for fungal toxins based on the intraperitoneal injection of test materials into mice was used to screen 976 cultures isolated from tobacco and grown in a high-protein baby cereal and also to determine whether samples of tobacco damaged by fungi are more toxic than samples of apparently sound tobacco. Of 236 fungal isolates from noncured tobacco, 79% were lethal when homogenized cultures of these isolates were tested. Forty-nine per cent of 740 fungi isolated from cured tobacco were lethal. Of the genera from which 30 or more isolates were tested, Epicoccum, Alternaria, and Penicillium had the highest percentage of toxic isolates from non-cured tobacco, whereas Epicoccum, Aspergillus, and Alternaria had the highest percentage from cured tobacco. Samples of tobacco naturally infected with brown spot, caused by Alternaria tenuis, did not have a significantly different LD(50) value after 48 hr than comparable disease-free samples. However, animals which died from doses near the LD(50) dose of tobacco infected with Alternaria generally died in 24 to 48 hr with signs associated with a depressant rather than a stimulant, such as nicotine, which caused death in 15 to 30 min. These signs were duplicated by injecting homogenized pure cultures of Alternaria. These studies, although inconclusive with regard to the effects of fungal contaminants on the quality or usability of tobacco, have developed evidence that suggests the advisability of a study on smoke or smoke condensates from moldy and nonmoldy tobacco.     

Infection rates of perennial ryegrass seeds (Lolium perenne L.) with different fungi

Authors made investigations to map occurrence of different fungal pathogens on seeds of varieties from different grass species. This work presents data on three cultivars of perennial ryegrass (Lolium perenne L.). When seeds were germinated, eight genuses of fungi were identified belonging to the Deuteromycota. Alternaria was the most frequently occurred genus. Drechslera, Bipolaris, Cladosporium, Stemphylium, and Epicoccum spp. has also been found in the seed samples. Two genus of fungal pathogens (Embellisia and Septonema) were identified which were not mentioned in Hungary so far.