基于基因组的一株土壤固氮菌分离菌株鉴定及其促生作用

[目的] 为获得高效固氮菌株,充分研究利用土壤固氮菌资源。[方法] 选取固氮能力较高的紫色土发育水稻土,采用富集纯化法分离固氮微生物菌株。通过16S rRNA基因系统发育分析和全基因组相关指数比较对新分离菌株进行物种鉴定。采用乙炔还原法和¹⁵N₂示踪法定量测定新分离菌株的固氮能力,通过培养特性和接种效果初步研究固氮菌株的促生作用。[结果] 从紫色土发育水稻土中分离得到1株可在无氮培养基上快速生长的菌株P208。基于16S rRNA基因和基因组92个核心基因的系统发育分析结果表明,新分离菌株P208与Azotobacter chroococcum IAM 12666^T（=ATCC 9043^T）系统发育距离最近（16S rRNA基因相似度为99.79%）。菌株P208与A.chroococcum ATCC 9043^T的基因组平均核苷酸一致性（ANI）、平均氨基酸一致性（AAI）和数字DNA-DNA杂交值（dDDH）高于物种分类阈值（ANI>95%-96%,AAI>95%-96%,dDDH>70%）,最大唯一匹配指数（MUMi）低于物种分类阈值（<0.33）,得出新分离菌株P208为褐球固氮菌（A.chroococcum）。A.chroococcum P208固氮活性为模式菌株A.chroococcum ATCC 9043^T的2.61倍。除固氮能力外,A.chroococcum P208具有IAA生成、溶磷活性和铁载体生成等促进植物生长潜力的培养特性,室内培养条件下接种A.chroococcum P208能够促进水稻、小麦幼苗根系的生长。[结论] 从固氮能力较强的水稻土中分离纯化得到1株具有较强固氮、促生潜力的固氮菌,具有潜在的开发应用价值,可为研究利用生物固氮提供微生物资源。     

来源于中国南海的微生物新种乙醇速生杆菌(Celeribacter ethanolicus)多相分类研究

【目的】研究来源于南海海水的一株速生杆菌属菌株NH195^T 的多相分类。【方法】采用表型、基因型和化学分类方法,并综合系统发育关系结果,分析菌株NH195^T 的分类学地位。【结果】菌株NH195^T 是一株革兰氏阴性、好氧、杆状、无运动性细菌;能积累Poly-β-hydroxybutyrate (PHB);能在0.5%-10.0% (质量体积比) NaCl 浓度,pH 5.0-9.0 和20-40 ℃ 条件下生长,最适NaCl 生长浓度为1.0%-3.0%;氧化酶、触酶和脲酶反应结果阳性。菌株NH195^T 主要呼吸醌为Q-10,主要脂肪酸为C_18:1ω7c、C_18:1ω6c 和11 methyl C_18:1ω7c,主要极性脂为磷脂酰胆碱、磷脂酰甘油、双磷脂酰甘油、一个未知的氨基脂和两个未知脂。基因组G+C 含量为61.3 mol%。基于16S rRNA 基因的系统发育结果显示,菌株NH195^T 隶属于速生杆菌属;其与速生杆菌属标准菌株的16S rRNA 基因相似性范围为94.4%-97.7%。菌株NH195^T 与速生杆菌属标准菌株C. halophilus ZXM137^T 和C. indicus P73^T 的平均核苷酸一致性(ANI)分别为78.6%和78.0%;基于基因组数据计算所得的DNA 杂交同源率分别为26.1%和23.0%。【结论】基于表型和基因型结果,菌株NH195^T 代表了速生杆菌属一个新物种,命名为Celeribacter ethanolicus,标准菌株为NH195^T (CGMCC 1.15406^T=JCM 31095^T)。     

一株耐碱变形假单胞菌ZY-3的鉴定及其脱氮特性

【背景】目前缺少具有高效脱氮能力、较高生物安全性、能处理高碱含氮污水的好氧反硝化菌株,难以使用生物方法处理高碱性的工业、养殖废水。【目的】对前期于佛山市一水产养殖池塘底泥中分离得到的耐碱高效好氧反硝化细菌ZY-3进行研究,期望获得一株能用于不同酸碱环境脱氮的高效、安全的好氧反硝化细菌。【方法】通过形态学、生理生化试验及16S rRNA基因序列分析方法对菌株种属进行鉴定,采用抗生素试验及斑马鱼攻毒试验进行菌株的环境生物安全性评估,利用3种含不同氮素的含氮模拟废水进行脱氮能力的测定。【结果】确定ZY-3为假单胞菌属变形假单胞菌（Pseudomonas plecoglossicida）,其对多种临床常用抗生素敏感,对水生生物的毒性低,该菌株在高浓度含氮模拟废水中以28℃、180 r/min振荡培养时,其对数期出现在4—12 h,在12 h时NH₄⁺-N、NO₃^--N和NO₂^--N的去除率分别达到94.87%、81.44%和98.02%,其pH耐受范围为6.0—10.0。【结论】得到一株安全、高效、具有广泛pH适应范围的耐碱好氧反硝化细菌P. plecoglossicida ZY-3,其在有氧条件下对3种氮素（NH₄⁺-N、NO₃^–-N、NO₂^–-N）具有快速去除能力。     

猪链球菌4型疫苗用菌株的筛选

【背景】猪链球菌4型（Streptococcus suis serotype 4,SS4）分离率日益升高,对养殖业和公共卫生安全造成严重危害,目前尚无有效的SS4疫苗。【目的】筛选致病力强、抗原性好、遗传性状稳定的SS4疫苗菌种。【方法】以7株SS4分离株（代号为A1—A7）为受试菌株,通过累积法测定菌株半数致死量（LD₅₀）,ELISA测定免疫小鼠血清中IgG效价,攻毒保护试验测定免疫保护率,并采集小鼠脏器观察病理组织学变化。再连续传代培养受试菌株,分别对第10、20、30代菌株进行致病性和抗原性试验。【结果】A1—A7菌株对小鼠的LD₅₀分别为2.19×10⁸、1.76×10⁸、1.83×10⁸、1.01×10⁸、4.05×10⁸、1.19×10⁸和9.03×10⁷ CFU。二免7 d后,A1、A2、A3、A4、A6、A7免疫组IgG效价分别为1：1 600、1：1 600、1：3 200、1：6 400、1：3 200和1：6 400,免疫保护率分别为30%、30%、50%、70%、60%和80%,而且A4、A7免疫组小鼠组织病变较其余4组轻微。体外传至30代后,A4菌株的LD₅₀上升至3.81×10⁸ CFU,IgG效价下降至1：1 600,免疫保护率下降至40%,而A7菌株的LD₅₀上升至2.49×10⁸ CFU,IgG效价和免疫保护率稳定保持为1：6 400和80%,而且A7免疫组小鼠的组织病变较A4免疫组轻微。【结论】A7菌株（原始编号为HBgu18-4）具有强致病力和良好的抗原性,而且遗传性状均一、稳定,可作为SS4制苗候选菌株。     

大肠杆菌Zn2+敏感突变株构建及其功能验证

【背景】Zn²⁺在细胞解毒及许多生理过程中发挥着关键作用,Zn²⁺转运蛋白已逐渐引起人们的重视。在大肠杆菌中,zntA和zitB是2个外排Zn²⁺的关键基因。【目的】构建大肠杆菌Zn²⁺敏感突变株,并对其功能进行验证。【方法】以Escherichia coli DH5α为出发菌株,利用λ Red重组系统,通过携带卡那霉素抗性基因的同源重组片段敲除zntA基因。在单基因敲除菌株基础上,利用携带庆大霉素抗性基因的同源重组片段敲除zitB基因,获得一株敲除了zntA和zitB的双基因敲除菌株KZAB04。通过功能互补实验检测基因敲除菌株及对照菌株对不同浓度Zn²⁺的敏感程度。【结果】基因敲除菌株KZAB04比出发菌株E.coli DH5α具有更高的Zn²⁺敏感性。【结论】大肠杆菌Zn²⁺敏感突变株构建成功。该菌株的构建为zntA和zitB基因功能的研究提供了必要条件,同时也为其他Zn²⁺转运蛋白基因的功能鉴定与分析奠定了基础。     

灵芝UDP-葡萄糖4-差向异构酶酶学性质研究及其应用

【背景】灵芝多糖是灵芝的重要活性物质之一。UDP-葡萄糖4-差向异构酶（UDP-glucose 4-epimerase,UGE,EC 5.1.3.2）是灵芝多糖合成途径中糖供体生成的重要酶,其参与了UDP-葡萄糖与UDP-半乳糖的相互转化,与多糖中半乳糖残基含量密切相关。【目的】通过对来源于灵芝的UGE基因进行异源表达,丰富灵芝多糖糖供体合成途径重要酶的酶学特性信息,深入了解灵芝多糖代谢合成途径。【方法】以灵芝菌株（Ganoderma lingzhi） CGMCC 5.26的cDNA为模板,克隆得到UGE基因GL30389,并在Escherichia coli BL21（DE3）中诱导表达,产物纯化后进行酶学性质、酶动力学、底物专一性及转化率的研究。【结果】灵芝UGE的分子量为45 kDa。最适反应pH值为6.0,在pH 7.0—9.0范围内有较好的稳定性;最适反应温度为30℃,温度在40℃时稳定性最好。Fe²⁺和Mg²⁺对UGE有激活作用。以UDP-葡萄糖为底物时,K_m为0.824 mmol/L,V_max为769.230 μmol/（L·min）,k_cat为1.333 s^—1,k_cat/K_m为1.618 L/（mmol·s）。灵芝UGE对D-葡萄糖、半乳糖醛酸及N-乙酰葡萄糖胺有催化活性。通过优化pH、温度、底物与酶的配比、添加金属离子将转化率从16.0%提升至39.4%。【结论】灵芝UGE与植物来源的UGE酶学性质较为相似,其催化效率优于大部分细菌来源的UGE。本研究丰富了灵芝多糖糖供体合成途径重要酶的酶学特性信息,有利于深入了解灵芝多糖代谢合成途径。     

代谢工程强化脱氮副球菌DYTN-1去除氮素污染物

【目的】脱氮副球菌(Paracoccus denitrificans)是一种环境友好的α-变形菌纲菌株,在有氧条件下也可进行反硝化过程,具有较好的脱氮能力。本研究以脱氮副球菌DYTN-1为底盘细胞,筛选氮素诱导型启动子用于强化硝化和反硝化途径,进而达到代谢工程强化脱氮副球菌DYTN-1去除氮素污染物的目的。【方法】通过接合转移的方法分别将过表达amoA、amoB、hao和nirS基因的重组质粒导入脱氮副球菌DYTN-1细胞中。经过荧光定量检测和氮素定量检测对脱氮副球菌DYTN-1的基因元件和氮去除能力进行表征。【结果】从基因组中挖掘了6个受NO₂^‒、NO₃^‒和NH₄⁺诱导的启动子,诱导差异为2‒26倍;且过表达nirS的菌株用2 g/L KNO₃处理24 h后培养基中NO₃^‒的残余量为野生型菌株的67%。同时过表达hao和nirS基因的菌株在用1 g/L NH₄Cl和2 g/L KNO₃处理12 h后,其NO₃^‒的剩余量仅为野生型菌株的50%,且最终总氮的降解效率达79.5%,剩余总氮仅为野生型菌株的一半。【结论】上述研究表明,利用筛选获得的启动子工具在P. denitrificans DYTN-1中进行代谢工程改造强化氮素污染物的去除具有可行性。     

干旱沙地白刺根际Bacillus halotolerans DGL6对“青麦7号”的促生及防病效果

【背景】青海高原特殊生境孕育着特殊适生性的微生物资源。【目的】探究适生于高原生境的芽孢杆菌对高寒牧草的促生防病效应。【方法】以分离自青海海西州大格勒干旱沙地白刺(Nitraria tangutorum)根围的Bacillus halotolerans DGL6为研究材料,测定其对“青麦7号”的促生防病效应。分别以浸种、灌根的方法测定其对“青麦7号”种子萌发及幼苗生长的效应,并测定12d内幼苗生理指标的变化;测定菌株DGL6抑制“青麦7号”幼苗离体叶片感染病原真菌活性;以平板对峙法测定其对病原真菌的抑制率;以透明圈法检测其产抑菌相关水解酶活性。【结果】菌株DGL6对“青麦7号”种子萌发及幼苗生长具有显著的促生效果,种子萌发的芽长、根长及鲜重分别提高27.26%、23.03%和45.42%,12 d内幼苗的株高、根长、鲜重分别显著提高33.42%、107.85%和95.24%,叶绿素、可溶性糖及可溶性蛋白含量显著增加,丙二醛含量下降;喷施DGL6菌悬液可明显抑制小麦赤霉菌在“青麦7号”离体叶片上的生长;菌株DGL6对小麦赤霉菌(Fusarium graminearum)表现出显著拮抗活性(...     

Bacillus sp.ZJS3基因组测序及砷胁迫下相关基因表达分析

【背景】环境中高毒性As³⁺的微生物氧化在砷的生物地球化学循环中起重要作用,具有潜在的应用价值。【目的】Bacillus sp.ZJS3菌株是本实验室前期分离鉴定的一株As³⁺耐受菌株,而且对多种重金属具有耐受性,期望进一步明确该菌株在As³⁺胁迫下菌体形态变化及应对砷胁迫的遗传基础,为As³⁺耐受细菌的研究提供基础数据。【方法】使用单分子实时测序（single-molecule real-time sequencing,SMRT）及Illumina测序技术对Bacillus sp.ZJS3菌株进行全基因组测序,对其基因进行功能注释和生物信息学分析,并结合绝对定量PCR技术对砷抗性及砷代谢相关基因进行分析。【结果】Bacillus sp.ZJS3菌株基因组大小为5.82 Mb,GC含量为35.9%,包含染色体1个、质粒3个、CDS数量为5 981个、tRNA 104个、sRNA 136个、rRNA 42个、串联重复序列173个、基因岛13个、转运蛋白1 023个、跨膜蛋白1 717个和双组分调控基因160个。NR、Swiss-Prot、Pfam、COG、GO和KEGG数据库分别可注释Bacillus sp.ZJS3菌株基因组中97.66%、69.30%、78.52%、65.49%、67.65%和43.87%的基因。绝对定量PCR结果表明,arsC基因在砷处理条件下显著高于对照组,而arsB基因在砷处理条件下显著低于对照组。【结论】Bacillus sp.ZJS3菌株在As³⁺胁迫下可能导致细胞分裂无法正常进行,进而影响细胞形态。基因组中aqpZ、arsA、arsB、arsC等基因的存在表明该菌株具有As³⁺外排和还原As⁵⁺的能力,phoUpstBACS的存在表明菌株可以吸收As⁵⁺,但菌株受到外界环境As³⁺胁迫时arsB表达水平降低。     

贝莱斯芽孢杆菌BG-2对厚皮甜瓜贮藏品质及防御酶活性的影响

【背景】厚皮甜瓜白霉病主要由尖孢镰刀菌引起,严重影响厚皮甜瓜品质,从而造成经济损失。【目的】研究贝莱斯芽孢杆菌BG-2对尖孢镰刀菌的抑制作用,以及对采后厚皮甜瓜贮藏品质的影响。【方法】以贝莱斯芽孢杆菌为供试菌株,研究其对2种不同贮藏温度（25℃和4℃）下厚皮甜瓜果实腐烂率、失重率、果肉硬度、可滴定酸、可溶性固形物含量和维生素C含量的影响,同时测定过氧化氢酶（catalase,CAT）、过氧化物酶（peroxidase,POD）和超氧化物歧化酶（superoxide dismutase,SOD）防御酶活性,进而探究Bacillus velezensis BG-2对尖孢镰刀菌的抑制作用及对厚皮甜瓜贮藏品质的影响。【结果】贝莱斯芽孢杆菌BG-2菌悬液能有效抑制尖孢镰刀菌的生长,菌悬液浓度为1×10⁷ CFU/mL时抑菌圈直径为（20.45±0.39） mm,抑菌效价为144.48 mm/mL;同时,B. velezensis BG-2能有效减缓果肉硬度、维生素C含量、可溶性固形物含量和可滴定酸的下降,抑制果实失重和腐烂,能较好地保持果实的品质,抑制防御酶活性的下降。【结论】B. velezensis BG-2能显著抑制尖孢镰刀菌的生长,延缓厚皮甜瓜的后熟,维持采后甜瓜果实较高的品质和防御酶活性,对甜瓜腐烂有较好的防治效果。     

Foreign exploration for Scirtothrips perseae Nakahara (Thysanoptera: Thripidae) and associated natural enemies on avocado (Persea americana Miller)

Scirtothrips perseae Nakahara was discovered attacking avocados in California, USA, in 1996. Host plant surveys in California indicated that S. perseae has a highly restricted host range with larvae being found only on avocados, while adults were collected from 11 different plant species. As part of a management program for this pest, a “classical” biological control program was initiated and foreign exploration was conducted to delineate the home range of S. perseae, to survey for associated natural enemies and inventory other species of phytophagous thrips on avocados grown in Mexico, Guatemala, Costa Rica, the Dominican Republic, Trinidad, and Brazil. Foreign exploration efforts indicate that S. perseae occurs on avocados grown at high altitudes (>1500 m) from Uruapan in Mexico south to areas around Guatemala City in Guatemala. In Costa Rica, S. perseae is replaced by an undescribed congener as the dominant phytophagous thrips on avocados grown at high altitudes (>1300 m). No species of Scirtothrips were found on avocados in the Dominican Republic, Trinidad, or Brazil. In total, 2136 phytophagous thrips were collected and identified, representing over 47 identified species from at least 19 genera. The significance of these species records is discussed. Of collected material 4% were potential thrips biological control agents. Natural enemies were dominated by six genera of predatory thrips (Aeolothrips, Aleurodothrips, Franklinothrips, Leptothrips, Scolothrips, and Karnyothrips). One genus each of parasitoid (Ceranisus) and predatory mite (Balaustium) were found. Based on the results of our sampling techniques, prospects for the importation of thrips natural enemies for use in a “classical” biological control program in California against S. perseae are not promising.     

Molecular phylogeny of Phebalium (Rutaceae: Boronieae) and related genera based on the nrDNA regions ITS 1+2

Parsimony analyses of the internal transcribed spacer regions of nuclear ribosomal DNA (ITS 1 & ITS 2) for 38 taxa sampled from the Phebalium group (Rutaceae: Boronieae) and two outgroups confirm that, with the exception of Phebalium sensu stricto and Rhadinothamnus, six of the currently recognised genera within the group are monophyletic. The data indicate that Phebaliums. str. is paraphyletic with respect to Microcybe, and Rhadinothamnus is paraphyletic with respect to Chorilaena. Rhadinothamnus and Chorilaena together are the sister group to Nematolepis. Drummondita, included as an outgroup taxon, clustered within the ingroup as sister to Muiriantha and related to Asterolasia.The phylogeny suggests that the evolution of major clades within a number of these genera (e.g. Phebalium) relates to vicariance events between eastern and south-western Australia. Leionema is an eastern genus, with the most basal taxon being the morphologically distinct Leionema ellipticum from northern Queensland. Leionema also includes one species from New Zealand, but this species (as with some others) proved difficult to sequence and its phylogenetic position remains unknown. Taxonomic changes at the generic level are recommended.The authors wish to thank Paul G.Wilson, PERTH, for advice and discussion, and Paul Forster, BRI, for collecting and providing material of Leionema ellipticum. The project was supported by a Melbourne University Postgraduate Award (to BM), the Australian Biological Resources Study (ABRS), Australian Systematic Botany Society and Wolf Den (Australia) Investments.     

New species and new combinations in Peruvian Orchidaceae

seventeen new species and combinations are proposed in the generaChondrorhyncha, Cischweinfia, Cochlioda, Eloyella, Encyclia, Kefersteinia, Koellensteinia, Macroclinium, Rodriguezia, Solenidiopsis, andStenia. All new species are illustrated. A key is provided for 2-flowered species ofMacroclinium, PeruvianSigmatostalix, and PeruvianStenia. Solenidium (Solenidiopsis) peruvianum Schltr. is lectotypified.     

Phylogeny of cardinalfishes (Teleostei: Gobiiformes: Apogonidae) and the evolution of visceral bioluminescence

The cardinalfishes (Apogonidae) are a diverse clade of small, mostly reef-dwelling fishes, for which a variety of morphological data have not yielded a consistent phylogeny. We use DNA sequence to hypothesize phylogenetic relationships within Apogonidae and among apogonids and other acanthomorph families, to examine patterns of evolution including the distribution of a visceral bioluminescence system. In conformance with previous studies, Apogonidae is placed in a clade with Pempheridae, Kurtidae, Leiognathidae, and Gobioidei. The apogonid genus Pseudamia is recovered outside the remainder of the family, not as sister to the superficially similar genus Gymnapogon. Species sampled from the Caribbean and Western Atlantic (Phaeoptyx, Astrapogon, and some Apogon species) form a clade, as do the larger-bodied Glossamia and Cheilodipterus. Incidence of visceral bioluminescence is found scattered throughout the phylogeny, independently for each group in which it is present. Examination of the fine structure of the visceral bioluminescence system through histology shows that light organs exhibit a range of morphologies, with some composed of complex masses of tubules (Siphamia, Pempheris, Parapriacanthus) and others lacking tubules but containing chambers formed by folds of the visceral epithelium (Acropoma, Archamia, Jaydia, and Rhabdamia). Light organs in Siphamia, Acropoma, Pempheris and Parapriacanthus are distinct from but connected to the gut; those in Archamia, Jaydia, and Rhabdamia are simply portions of the intestinal tract, and are little differentiated from the surrounding tissues. The presence or absence of symbiotic luminescent bacteria does not correlate with light organ structure; the tubular light organs of Siphamia and chambered tubes of Acropoma house bacteria, those in Pempheridae and the other Apogonidae do not.     

Biological control of three floating water weeds,<Emphasis Type="Italic">Eichhornia crassipes,Pistia stratiotes</Emphasis>, and <Emphasis Type="Italic">Salviniamolesta</Emphasis> in the Republic of Congo

Since 1999, four specific weevils (Coleoptera, Curculionidae) were released in the Republic of Congo against three exotic floating water weeds: Neochetina eichhorniae Warner and N. bruchi Hustache against water hyacinth, Neohydronomus affinis Hustache against water lettuce, and Cyrtobagous salviniae Calder and Sands against water fern. Recoveries of exotic weevils were made from all 24 release sites except one, and all four species have established and spread (up to 800 km for water hyacinth weevils). Within a few years of releases, control of water fern and water lettuce was such that fishing and navigation could be resumed, while reductions of water hyacinth populations were only beginning.     

Taxonomic status of the species of the green algal genusNeochloris

Komárek has recently reviewed the various species assigned to the green algal genusNeochloris Starr (Chlorococcales, Chlorococcaceae) and removed those with uninucleate vegetative cells to a new genus,Ettlia. Watanabe & Floyd, unaware ofKomárek's work, also reviewed the species ofNeochloris and distributed them among three genera—Neochloris, Chlorococcopsis gen. nov., andParietochloris gen. nov.—on the basis of details of the covering of the zoospore and the arrangement of the basal bodies of the flagellar apparatus. This paper reconciles these two treatments and makes additional recommendations at the ranks of genus, family, order, and class.     

A molecular phylogeny of Hebeloma species from Europe

In order to widen the scope of existing phylogenies of the ectomycorrhizal agaric genus Hebeloma a total of 53 new rDNA ITS sequences from that genus was generated, augmented by sequences retrieved from GenBank, and analysed using Bayesian, strict consensus and neighbour joining methods. The lignicolous Hebelomina neerlandica, Gymnopilus penetrans, and two species of Galerina served as outgroup taxa. Anamika indica, as well as representatives of the genera Hymenogaster and Naucoria, were included to test the monophyly of Hebeloma, which is confirmed by the results. Hebeloma, Naucoria, Hymenogaster and Anamika indica cluster in a strongly supported monophyletic hebelomatoid clade. All trees largely reflect the current infrageneric classification within Hebeloma, and divide the genus into mostly well-supported monophyletic groups surrounding H. crustuliniforme, H. velutipes, H. sacchariolens, H. sinapizans, and H. radicosum, with H. sarcophyllum being shown at an independent position; however this is not well supported. The section Indusiata divides with strong support into three groups, the position of the pleurocystidiate Hebeloma cistophilum suggests the possible existence of a third subsection within sect. Indusiata. Subsection Sacchariolentia is raised to the rank of section.     

Phylogenetic investigations of Sordariaceae based on multiple gene sequences and morphology

The family Sordariaceae incorporates a number of fungi that are excellent model organisms for various biological, biochemical, ecological, genetic and evolutionary studies. To determine the evolutionary relationships within this group and their respective phylogenetic placements, multiple-gene sequences (partial nuclear 28S ribosomal DNA, nuclear ITS ribosomal DNA and partial nuclear β-tubulin) were analysed using maximum parsimony and Bayesian analyses. Analyses of different gene datasets were performed individually and then combined to generate phylogenies. We report that Sordariaceae, with the exclusion Apodus and Diplogelasinospora, is a monophyletic group. Apodus and Diplogelasinospora are related to Lasiosphaeriaceae. Multiple gene analyses suggest that the spore sheath is not a phylogenetically significant character to segregate Asordaria from Sordaria. Smooth-spored Sordaria species (including so-called Asordaria species) constitute a natural group. Asordaria is therefore congeneric with Sordaria. Anixiella species nested among Gelasinospora species, providing further evidence that non-ostiolate ascomata have evolved from ostiolate ascomata on several independent occasions. This study agrees with previous studies that show heterothallic Neurospora species to be monophyletic, but that homothallic ones may have a multiple origins. Although Gelasinospora and Neurospora are closely related and not resolved as monophyletic groups, there is insufficient evidence to place currently accepted Gelasinospora and Neurospora species into the same genus.     

Die GattungKarschia — Bindeglied zwischen bitunicaten Ascomyceten und lecanoralen Flechtenpilzen?

The genusKarschia, in the earlier sense, including saprophytes and parasites on lichens, has been thought to be a non-lichenized parallel genus of the lichen genusBuellia. Modern workers included it on the one hand inBuellia, on the other hand combined it with bitunicate ascomycetes. It is now proved thatKarschia is heterogeneous and contains but superficially similar members both of the genusBuellia of theLecanorales and of typical or masked bitunicateAscomycetes. Therefore, it can not be regarded as a link betweenLecanorales andDothideales. The type species ofKarschia belongs to theDothideales.