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。     

山东省烟草根际土壤真菌多样性研究

为了有助于研究烟草根际土壤真菌与根茎病害发生程度的相互关系,文中对采自山东省6个地区的122份烟草根际土壤样品进行了真菌的分离和培养,采用形态学方法进行鉴定,并分析了菌群的多样性组成。从山东烟草根际土壤中分离和鉴定出真菌22属79种,其中接合菌门4属6种,子囊菌门1属1种,无性型真菌17属72种。优势真菌种群为青霉属(Penicillium)、木霉属(Trichoderma)、镰孢菌属(Fusarium)和曲霉属(As-pergillus),所占分离真菌总菌数的比例分别为22.39%、13.62%、12.69%和9.88%。6个采样地区间真菌菌群的多样性水平存在差异,其中诸城地区的多样性指数(H′=2.066 6)、均匀度指数(J=0.689 8)和丰富度指数(R=3.730 1)均最高。     

野生越南槐组织特异性内生真菌组及体外抗病原菌功能

有益微生物组能帮助宿主植物防御病害。越南槐的根、茎和种子在野外环境下健康发芽生长,而栽培越南槐各组织极易感病。为了探明利用野生越南槐有益内生真菌组防治宿主病害的可能,该文在分离健康野生越南槐根、茎和种子内生真菌的基础上,并结合形态学和ITS序列特征鉴定内生真菌,通过系统发育树、α-多样性指数和β-多样性指数分别分析各内生真菌组的系统进化、多样性和相似性,通过琼脂块法和平板对峙法测试内生真菌组的体外抗病原菌功能。结果表明:(1)从越南槐根、茎和种子内生真菌组分别分离鉴定131株23个分类单元、108株23个分类单元、64株11个分类单元;(2)特有属多且所有种均为特有种显示根、茎和种子内生真菌组在属种进化上具有组织特异性;(3)根-茎/根-种子/茎-种子间极低的β-多样性显示根、茎和种子各内生真菌组间的物种相似性极低;(4)高的α-多样性显示越南槐根、茎和种子均有丰富多样的内生真菌组;(5)各内生真菌组三分之一以上的分类单元在体外均能拮抗供试病原菌,根茎内生真菌组显示了强广谱的体外抗病原细/真菌功能,种子内生真菌组显示了强广谱的体外抗病原真菌功能。该研究结果表明健康野生越南槐根、茎和种子内部均存在有益内生真菌组,其具有生物多样性、组织特异性以及强广谱的体外抗病原菌功能,在宿主各组织的抗病性方面可能发挥重要作用。这些结果将为进一步利用有益真菌组防治栽培越南槐各组织病害提供了材料和实验基础。     

贵州西南部艾纳香内生真菌多样性研究

本文以研究不同地点、时期和组织部位的艾纳香内生真菌类群多样性及分布为目标,从艾纳香Blumea balsamifera根、茎和叶中分离得到内生真菌152株,经形态分类学和分子生物学鉴定分别归属于11个属,其中Fusarium、Aspergillus、Trichoderma和Curvularia为艾纳香内生真菌的优势种群。结果表明,叶片内生真菌类群丰富度和类群多样性最高;罗甸、望谟、册亨和贞丰艾纳香内生真菌的分布比较集中,其中罗甸内生真菌类群多样性和类群丰富度最高;7月份在内生真菌类群多样性和类群丰富度上表现突出;而12月份分离获得的内生真菌菌株数量较多;不同地点、不同时期内生真菌分布相似程度较高,茎、根与叶的相似程度差别较大。     

南海局部海洋沉积物中真菌多样性及产酶活性

【目的】从11份南海海洋沉积物中分离耐盐真菌,并对其物种多样性及产酶活性进行研究。【方法】利用平板涂布法分离耐盐真菌,基于形态学和ITS序列的系统进化研究耐盐真菌多样性;利用6种筛选培养基对耐盐真菌进行产酶活性筛选。【结果】分离得到1689株耐盐真菌,共41个形态种。形态学和ITS序列分析表明,这些真菌归于15个属,其中曲霉属(Aspergillus)和青霉属(Penicillium)为优势菌群。对已测序的41株耐盐真菌的产酶活性研究表明,8株产纤维素酶,9株产淀粉酶,5株产复合酶,16株产蛋白酶,3株产脂肪酶,未发现产壳聚糖酶的菌株,其中Acrodontium sp.8m和Aspergillus sp.86b产复合酶的活性相对较高,而Penicillium sp.41m产蛋白酶的活性相对较高。【结论】南海局部海洋沉积物中耐盐真菌丰富,多数菌株具有产酶活性。     

玉米种子携带真菌的多样性研究

作者于2004年3月至2005年6月期间采集辽宁省广泛栽培的38个品种的玉米种子进行种子带菌分析。利用保湿培养检验法和分离培养检验法分别对种子表面粘附的真菌及内部寄藏真菌进行检验,通过纯化培养和形态鉴定,将几百个菌株鉴定到种。本文报道了从供试的玉米种子上分离得到的共16属的真菌,其中接合菌3属3种;子囊菌2属5种;有丝分裂孢子真菌11属18种,其中金黄色毛壳(Chaetromium aureumChivers)为中国新记录种。     

洱源西湖底质中捕食线虫真菌多样性研究

捕食线虫真菌是环境中线虫密度的主要控制因子之一, 目前对水生捕食线虫真菌多样性的相关研究还较少。我们对大理州洱源县西湖不同样点底质中捕食线虫真菌多样性进行了调查, 并对底质中捕食线虫真菌多样性与线虫密度的相关性进行比较分析。结果共从78 份底质中分离到135 株捕食线虫真菌菌株, 初步鉴定有3 属23 种捕食线虫真菌, 待定种3 种。捕食线虫真菌总检出率为85.90%, 其中Arthrobotrys oligospora 和Arthrobotrys conoides 的物种优势度Y 值分别为0.091 和0.023, 检出率分别为31.35%和12.71 %, 为优势种。在所分离到的捕食线虫真菌中, 产黏性菌网的种类占86.44%。表明西湖底质中存在丰富的捕食线虫真菌资源, 产黏性菌网的捕食线虫真菌为优势种群。捕食线虫真菌多样性与线虫密度呈负相关关系(r=–0.957, P<0.01), 负相关性极显著, 即捕食线虫真菌种群对线虫密度具有良好的控制作用。     

不同培养基对兰科药用植物手参原球茎共生真菌的分离效果

兰科植物手参Gymnadenia conopsea作为国家二级重点保护野生植物具有重要的药用价值。目前手参还未实现人工栽培,但其种子的真菌共生萌发已获成功。为明确除促萌发真菌外,还有哪些土著真菌参与了手参种子的萌发过程,本研究在自然条件下采用促萌发真菌伴播手参种子,获得了种子萌发形成的原球茎,进而对比了6种常见的培养基PDA (马铃薯葡萄糖琼脂培养基)、MMN (改良Melin-Norkrans培养基)、FIM (真菌分离培养基)、MEA (麦芽浸膏琼脂培养基)、CAM (胡萝卜葡萄糖琼脂培养基)和CMA (玉米粉琼脂培养基)对手参原球茎共生真菌分离效果的影响。共从6种培养基上分离获得了75个菌株,其中MMN、CAM、PDA、FIM、MEA、CMA培养基依次分离得到20株、16株、15株、11株、8株、5株菌。此外,真菌的多样性分析结果表明,MMN培养基的Chao 1、Shannon-Wiener和Simpson多样性指数最高,CAM和PDA培养基次之,CMA培养基最低。综上所述,真菌分离效果最好的是MMN培养基,其次是CAM和PDA培养基,而FIM和MEA培养基对真菌的分离效果影响不大,CMA培养基的分离效果最差。本研究结果可为其他兰科植物原球茎共生真菌的分离提供借鉴,所获得的菌株也有望进一步应用于功能菌剂的研发。     

黄土高原区苜蓿与小麦轮作系统根部入侵真菌研究

以甘肃庆阳黄土高原地区草田轮作系统中苜蓿(Medzfago sativn)和小麦(Triticum aestivum)为研究材料,分别于2002年两种作物的拔节期(分枝期)、开花期、成熟期和幼苗期(第3茬分枝期)取样,分离、鉴定了根部入侵真菌,测定了分离所得根部入侵真菌对其寄主作物及另一种轮作作物的致病力。结果表明：在试验区内共分离到27种根部入侵真菌,包括自小麦根系分离到26种,苜蓿侧根分离到23种,其中22种为苜蓿和小麦共同的根部入侵真菌。两种作物根部入侵真菌区系中优势种明显不同,苜蓿根部最主要的5种入侵真菌按分离率的高低依次为尖镰孢(Fusarium oxysporum)17．0％、大孢肉座菌(Selinia sp．)15．4％、茎点霉(Phoma medicaginis)9．5％、腐皮镰孢(Fusarium solani)6．7％及柱孢(Cylindrocarpon destructans)6．6％;而小麦根部5种最主要的入侵真菌按分离率的高低依次为黑团孢(Periconia sp.)15．0％、丝葚霉(Papulaspora sp．)12．1％、多主枝孢(Cladosporium herbarum)5．4％、丝核菌(Rhizoctonia sp．)4．0％及尖镰孢3．9％;总的真菌分离率亦是苜蓿高于小麦。苜蓿与小麦的根段带菌率均有随生长季的延长而增高的特征。在试验条件下,参试的苜蓿、小麦根部入侵真菌对苜蓿和小麦均有一定的致病力,但对苜蓿种子和幼苗的致病力强于对小麦种子和幼苗的致病力。在轮作体系中,小麦田轮作苜蓿应注意防治根部入侵真菌的危害。     

北柴胡种子内生菌群落结构与多样性

为研究北柴胡种子内生菌的群落结构与多样性.采用Illumina Miseq高通量测序技术,分别对山西(BC_1)、黑龙江(BC_2)、河北(BC_3)和内蒙古(BC_4)的四个产地(4份)北柴胡种子的16S RNA V3-V4区和ITS1区扩增片段进行测序,并对内生细菌和内生真菌群落结构和多样性进行分析.结果表明,BC...     

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.     

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％),Plect...     

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.