玉米是中国最主要的农作物之一,适宜种植区域广,生态类型复杂,各地发生的病害种类繁多。我国对玉米病害研究的历史不足百年,涉足该领域的专家较少,研究信息交流有限。病原鉴定是认识病害的起点,而病原名称承载着对病原生物特性、致病特性、遗传特性的重要信息。由于从事玉米病害研究的专业人员多注重病害发生规律的研究,忽视在病原分类学研究方面的进展,面对国内外刊物上同一玉米病害病原却有诸多名称的现象无法辨识其正误,导致在研究与交流中常常出现病原名称引用错误的问题。近年来,随着分子生物学技术和显微观察技术的快速发展与普及应用,一些困扰微生物分类学研究的技术瓶颈已经突破,对植物病原分类地位的重新认识方面获得显著进展。伴随着微生物分类学研究的进步,玉米病害中一些重要病原的分类地位改变,病原名称发生变化,这些改变不仅对于了解病原的遗传演化是重要的,同时对于深入研究病害发生与流行规律、有效交流病害研究信息也是非常重要的。
在近年玉米病害研究中,笔者发现6种重要病害（瘤黑粉病、丝黑穗病、红叶病、北方炭疽病、圆斑病、黑束病）的病原学名在中国及国际文献中存在多种名称混淆和错用的问题。因此,本文从这6种病害病原名称的历史变迁及当前所处正确分类地位的背景介绍着手,提出这6种玉米病害病原应该采用的正确学名和所对应的中文名称,以期逐渐规范我国玉米病害病原名称的引用。
1 玉米瘤黑粉病病原名称
1.1 玉米瘤黑粉病病原学名的历史变迁
1760年首次报道了玉米瘤黑粉病的致病菌。1768年,BECKMANN因病害症状与大型真菌马勃的形态相似,给予病菌以Lycoperdon zeae Beckmann（玉米马勃）名称。1805年,DE CANDOLLE经过鉴定,将病菌定名为Uredo segetum [var.] mays-zeae DC.,1815年提升为种Uredo maydis DC.（玉蜀黍夏孢锈菌）。1822年,SCHWEINTZII提出了名称Uredo zeae Schweintzii。1825年,LINK将病菌命名为Caeoma zeae Link（玉米裸孢锈菌）。1836年,UNGER首次确认致病菌为黑粉菌,将LINK的定名修订为Ustilago zeae (Link) Unger（玉米黑粉菌）[1]。1842年,CORDA根据国际植物命名法规（International Code of Botanical Nomenclature）的优先权原则,将玉米瘤黑粉病病菌学名确定为Ustilago maydis (DC.) Corda[2]。此名称被世界各国的研究者广泛采用并一直沿用至今[3],在2016年美国植物病理学会出版的“Compendium of Corn Diseases”（玉米病害概要-第4版）中,也采用U. maydis (DC.) Corda作为玉米瘤黑粉病病原的名称[4]。1.2 对Ustilago maydis分类地位的质疑
早在2002年,PIEPENBRING等根据U. maydis的核糖体大亚基（large subunit rDNA,LSU rDNA）序列特征,认为其应归入Sporisorium属,但该菌的内转录间隔区（internal transcribed spacer,ITS）的分子特征又不支持这种划分;同时发现在形态特征方面,U. maydis有与Sporisorium属相同的包被（peridia）和中轴（columellae）结构[5]。此后,STOLL等在利用ITS+LSU rDNA序列特征研究黑粉菌目中109个物种的遗传关系时发现,U. maydis并未聚到Ustilago属分支中,而是与另外3个黑粉菌共同表现出与Sporisorium属的遗传关系更近,且U. maydis在寄主组织中孢子团快速生长的特征使其又有别于Sporisorium种的致病特点,因此提出应开展进一步研究,然后可能需新建一个属予以这些种新的分类地位[6,7]。VáNKY等[8]在研究黑粉菌时也发现U. maydis在分子水平上与真正的Ustilago物种存在很大差别,推测具有不同的进化来源。1.3 Ustilago maydis分类地位的改变
近年来,采用分子生物学技术,已逐步揭示出Ustilago属是一个多源（polyphyletic）的属。通过U. maydis全基因组测序与基因研究,发现存在一些与其他真菌相异的在寄主组织中具有特定调控功能的基因[9],同时,U. maydis还具有不同于其他真菌的选择性剪切和反义转录的分子功能[10]以及在侵染玉米雌穗时,一些基因具有特异性组织表达的特点[11]。这些特异基因所调控的致病特征可能是造成U. maydis具有不同于Sporisorium属和Ustilago属中其他黑粉菌的寄主致病表型、能在植物组织上产生巨大瘤状体的原因所在。通过一系列的形态学、基因组、系统进化、与黑粉菌科（Ustilaginaceae）内不同分类种群共同衍生特征的多方位研究与比较,表明U. maydis在黑粉菌目中有独特的进化地位[12,13,14,15]。综合相关研究结果,MCTAGGART等在2016年撰文提出玉米瘤黑粉病致病菌的种名应恢复为1912年BREFELD建立Mycosarcoma属时作为该属模式种所采用的名称Mycosarcoma maydis (DC.) Brefeld[16],并给出了基于相关真菌ITS和LSU rDNA序列分析后M. maydis的系统发育地位[17]。
Mycosarcoma属具有如下特征：寄主雌性花器组织过度膨大并产生孢子堆。孢子堆通常管状,纵向开裂后散出孢子球,有或无不育细胞。在茎、叶、花器（雄花和雌花）及根等所有器官中,孢子堆的量均较少。无中轴。孢子产生于逐渐消失的产孢菌丝,以Ustilago形式萌发。在植物表面或其他基质上形成酵母状腐生生长。
Mycosarcoma属的寄主：禾本科黍亚科（Panicoideae）植物。Mycosarcoma属的模式种：Mycosarcoma maydis (DC.) Bref. 1912（寄主Zea mays）。
自MCTAGGART等[17]提出玉米瘤黑粉病致病菌学名更改的建议后,已有****在研究报告中以新名称M. maydis取代了旧名称U. maydis[18,19,20]。美国Georgia大学Center for Invasive Species and Ecosystem Health网站、Iowa大学、有害生物综合治理图片网站（www.ipmimages.org）等也采用了该新名称。
1.4 Mycosarcoma maydis汉译名的建议
我国一直以U. maydis（玉蜀黍黑粉菌）作为玉米瘤黑粉病致病菌的学名。根据新的分类学研究结果,建议对玉米瘤黑粉病病原采用新的学名。由于“瘤黑粉菌属”的汉译名称已被用于黑粉菌科中的Melanopsichium属[21],因此根据Mycosarcoma的拉丁词义（myc-真菌的,sarco-肉质的）和引发的病害特征（组织极度增生）,建议汉译名称为“瘿黑粉菌属”,物种M. maydis的汉译名称建议采用“玉蜀黍瘿黑粉菌”。2 玉米丝黑穗病病原名称
2.1 玉米丝黑穗病病原名称的多次变更
玉米丝黑穗病在140多年前就有记载。1875年,KüHN对REIL在1868年采自埃及的高粱丝黑穗病进行了鉴定,以Ustilago reiliana Kühn（丝黑粉菌）命名了病原菌[22]。1876年,PASSERINI首次鉴定了引起玉米丝黑穗病的致病菌并定名为Ustilago reiliana forma zeae Pass.[23]。SACCARDO、DE TONI和NORTON分别在1876年、1888年和1896年建议将该菌划入Sorosporium属中。1900年,CLINTON将Ustilago reiliana修订为Cintractia reiliana (J. G. Kühn) Clinton（丝核黑粉菌）[24]。1902年,CLINTON通过对黑粉菌科的研究,依据显微镜下冬孢子颜色等特征,再次将病菌更名为Sphacelotheca reiliana (J. G. Kühn) Clinton（丝轴黑粉菌）[25]。1910年,MCALPINE研究了澳大利亚的植物黑粉菌,将玉米丝黑穗病病菌名称改为Sorosporium reilianum (J. G. Kühn) McAlpine（丝团黑粉菌）[26],但未被普遍接受。此后,名称Sphacelotheca reiliana被广泛采用。在美国植物病理学会第4版的Compendium of Corn Diseases（2016）中,也是采用的Sphacelotheca reiliana[4]。2.2 Sporisorium属的基本特征
Sporisorium（孢堆黑粉菌属）自1825年建立后被忽视了约150年,直到1978年,LANGDON等恢复了此属名称,并详细研究了Sphacelotheca和Sporisorium的特征。他们认为,蓼科和禾本科植物受黑粉菌侵染后,在病菌子实体中的中轴组织具有不同的来源：蓼科中病菌子实体中的中轴由病菌细胞相互黏连而成,但在禾本科中,中轴则由寄主组织构成。同样,在两类寄主中,病菌的包被和孢子团的发育也不相同。Sphacelotheca仅侵染蓼科植物,分类上属柄锈菌亚门（Pucciniomycotina）微球黑粉菌目（Microbotryales）,模式种为Sphacelotheca hydropiperis (Schumach.) de Bary;Sporisorium侵染禾本科植物,分类上属黑粉菌亚门（Ustilaginomycotina）黑粉菌目（Ustilaginales）,模式种为Sporisorium sorghi Ehrenb. ex Link[27]。根据这一观点,原属于Ustilago属的60多个种和Sorosporium属中的170多个种归入了Sporisorium属。2.3 玉米丝黑穗病病菌的正确学名
LANGDON等[27]在恢复Sporisorium属后,将玉米丝黑穗病病菌的名称确定为Sporisorium reilianum (J. G. Kühn) Langdon & Fullerton（丝孢堆黑粉菌）,Sphacelotheca reiliana (J. G. Kühn) Clinton为异名之一。由于玉米丝黑穗病和高粱丝黑穗病致病菌在寄主选择方面存在差异和不同的机理,因此将玉米丝黑穗病致病菌定为Sporisorium reilianum f. sp. zeae（丝孢堆黑粉菌玉米专化型）[28,29,30]。我国黑粉菌研究专家郭林在2000年出版的《中国真菌志第十二卷黑粉菌科》中详细描述了孢堆黑粉菌属（Sporisorium）和轴黑粉菌属（Sphacelotheca）的历史演变过程,并根据LANGDON等（1978）的分类观点,采用了孢堆黑粉菌属（Sporisorium）的名称,将玉米丝黑穗病致病菌确定为丝孢堆黑粉菌（Sporisorium reilianum）[21]。
近年来,国外真菌分类学家对黑粉菌科各属真菌在形态学、寄主病害特征和多基因联合序列分析等方面开展了研究,对相关属及所含种的分类现状进行了整理,重新确立了有关种的分类地位[6,7,12-15,31-32],其中也确认了玉米丝黑穗病病原Sporisorium reilianum (J.G. Kühn) Langdon & Fullerton的分类地位是正确的。
3 玉米红叶病病原名称
3.1 玉米红叶病致病病毒的多样性
玉米红叶病为蚜虫传播为主的病害,当大麦黄矮病毒（Barley yellow dwarf virus,BYDV）侵染一些禾本科植物后,引起叶片变红或黄化症状。1957年,ALLEN首次描述了玉米接种大麦黄矮病毒后的症状[33]。1965年,STONER研究了病毒传播到玉米的方式[34],但直到1974年才在英国埃克塞特地区发现自然发生的玉米红叶病并对病毒进行了分离与鉴定[35]。1974年后,英国（1975—1976）、美国（1976）、意大利（1978）和法国（1980）也相继发生由大麦黄矮病毒引起的玉米病毒病,并将法国的病毒株系鉴定为BYDV-PAV和BYDV-RPV[35,36,37,38,39,40]。中国在20世纪80年代初期在河南等地发生玉米红叶病[41],确诊是由小麦黄矮病致病病毒-大麦黄矮病毒所引起[42]。1993年,有研究认为在甘肃引起玉米红叶病的主要为大麦黄矮病毒GPV和RMV株系,GPV株系的传毒介体为禾谷缢管蚜（Rhopalosiphum padi）和麦二叉蚜（Schizaphis graminum）,而RMV株系的传毒介体为玉米蚜（Rhopalosiphum maidis）[43]。在其他国家,报道侵染玉米的大麦黄矮病毒也有多个株系,如PAV株系（美国、法国、伊朗、德国、土耳其、叙利亚、突尼斯、意大利、巴西、前南斯拉夫）、RPV株系（美国、法国、西班牙、匈牙利、伊朗）、MAV株系（前南斯拉夫、伊朗、匈牙利）、RMV株系（伊朗、匈牙利）[40,44-49]。3.2 玉米红叶病致病病毒分类地位的重新认识
大麦黄矮病毒是引起玉米红叶病的主要致病病毒。在与玉米红叶病相关的大麦黄矮病毒株系中,PAV株系经全基因组比较研究,仍属于黄症病毒属（Luteovirus）成员[50],PAV和MAV株系保留为大麦黄矮病毒的不同株系（BYDV-PAV,BYDV-MAV）;RPV株系已经转为马铃薯卷叶病毒属（Polerovirus）的禾谷黄矮病毒（Cereal yellow dwarf virus,CYDV）成员,为CYDV-RPV株系[51]。研究表明,中国的大麦黄矮病毒GPV株系在血清学、分子序列等特性方面不同于典型的大麦黄矮病毒PAV株系,外壳蛋白（coat protein,CP）序列更接近禾谷黄矮病毒（Cereal yellow dwarf virus,CYDV）[52];通过对GPV中国株系的测序,证明分离自小麦的BYDV-GPV株系在氨基酸水平与CYDV-RPV和CYDV-RPS株系相似性为79%和74%,外壳氨基酸序列与马铃薯卷叶病毒属（Polerovirus）中其他种的相似性低于80%,而种间全基因组水平的氨基酸相似性低于85%。根据以上特征,确定BYDV-GPV株系应该成为Polerovirus属的一个独立种,同时根据GPV株系在中国主要危害小麦的特点,建议定名为Wheat yellow dwarf virus-GPV（小麦黄矮病毒-GPV,WYDV-GPV）[53]。
2013年,美国****对分离自小麦的大麦黄矮病毒RMV株系进行了全基因组测序,证明该株系在分子特征上不属于黄症病毒属（Luteovirus）的大麦黄矮病毒（BYDV）,应归入马铃薯卷叶病毒属（Polerovirus）,但与该属中的禾谷黄矮病毒（CYDVs）和小麦黄矮病毒（WYDV）也有明显差异。根据该株系在美国主要侵染玉米的特点,定名为Maize yellow dwarf virus-RMV（玉米黄矮病毒-RMV,MYDV-RMV）[54]。
根据以上研究,在中国已知有两种病毒引起玉米红叶病：小麦黄矮病毒-GPV株系（Wheat yellow dwarf virus-GPV）和玉米黄矮病毒-RMV株系（Maize yellow dwarf virus-RMV）。国际上,该病害的致病病毒还有大麦黄矮病毒PAV株系（BYDV-PAV）和MAV株系（BYDV-MAV）,以及禾谷黄矮病毒-RPV株系（CYDV-RPV）。
4 玉米北方炭疽病病原名称
4.1 玉米北方炭疽病病原名称的变化
玉米北方炭疽病最早由成田武四等记载,1956年发生于日本,但在1959年的第一篇文章中,用“玉米褐斑病”一词对病害进行了描述,致病菌被命名为Kabatiella zeae Narita et Hiratsuka[55]。1973年,DINGLEY根据当时Kabatiella属中与K. zeae相似的一些种已被划入Aureobasidium的情况,将K. zeae更名为Aureobasidium zeae (Narita et Hiratsuka) Dingley[56]。1977年,HERMANIDES-HIJHOF将Kabatiella作为Aureobasidium的异名,但建议未被广泛接受[57]。4.2 分子特征揭示玉米北方炭疽病病原的正确分类地位
1996年,YORLOVA等通过RFLP技术、ITS序列比较技术研究了Kabatiella、Aureobasidium、Hormonema等相似属和种的分子特征,认为应将K. lini和K. caulivora重新归入A. pullulans种中,而K. zeae（菌株CBS767.71）在RFLP酶切模式、ITS序列上与A. pullulans种有明显的差异[58,59]。2011年,SEIFERT等根据形态学和分子生物学的研究结果指出,Kabatiella属是一个有别于Aureobasidium属的分类单元,再次将Kabatiella作为一个独立属予以保留[60]。此后,THAMBUGALA等通过系统的形态学与28S、18S和ITS的分子特征研究,确定了座囊菌目（Dothideales）中的32个属的分类地位,其中也将Kabatiella作为一个独立属而区别于Aureobasidium属[61]。WIJAYAWARDENE等对座囊菌纲各科的研究也表明,Kabatiella与Aureobasidium属均为短梗霉科（Aureobasidiaceae）的合格属[62]。笔者选择美国生物技术信息中心（The National Center for Biotechnology Information,NCBI）网站中Kabatiella的相关基因与Aureobasidium进行比较。结果表明,在ITS区段,Kabatiella不同种与Aureobasidium种的相似性为92%—100%,但K. zeae strain CBS 767.71与Aureobasidium株系的序列相似性仅为87%—96%;在EF1基因比较中,K. microsticta与A. melanogenum 相似性低于78%;在TUB基因比较中,K. microsticta与A. pullulans相似性小于96%;在RPB2基因比较中,K. microsticta与多数A. pullulans株系的相似性为99%;在ELO基因比较中,K. microsticta与Aureobasidium其他种相似性小于88%。
大量形态学和分子特征研究结果证明,在总体上,Kabatiella属的种与Aureobasidium属的种存在明显的分子进化差异,在分类学上Kabatiella应是一个独立的属。据此,玉米北方炭疽病病原的种名应采用Kabatiella zeae Narita et Hiratsuka,汉译名称为玉蜀黍球梗孢。
5 玉米圆斑病病原名称
5.1 玉米圆斑病病原名称的多次改变
玉米圆斑病最早描述于1941年ULLSTRUP发表的“Two physiologic races of Helminthosporium maydis in the corn belt”文章中,病害的发生地点为美国印第安纳州,并根据症状,认为该病害在1938和1939年就已经发生[63]。此后,该病逐渐在美国多地发生,由于一些自交系对此病害敏感,因此对制种生产有一定影响。1944年,ULLSTRUP将引起圆斑病的致病菌重新鉴定为Helminthosporium carbonum Ullstrup[64]。该病菌不仅引起玉米叶斑病,也能引起穗腐病和茎腐病。随着对Helminthosporium属研究的深入,H. carbonum被视为与1926年在美国伊利诺伊州发生的、由STOUT在1930年[65]定名的引起玉米茎部病害的致病菌H. zeicola G. L. Stout为相同的种。1959年,NELSON发现了H. carbonum的有性态,并根据无性态的种名将其命名为Cochliobolus carbonum R. R. Nelson[66]。由于早先建立的Helminthosporium属包括了一些分生孢子形态上相似的物种,而随着对分生孢子形态的细致研究、对产孢结构的认识以及有性态的发现,Helminthosporium属逐渐划分为Helminthosporium、Drechslera、Bipolaris和Exserohilum属,而玉米叶斑病病菌的名称也在此过程中发生了改变。1959年,SHOEMAKER建立Bipolaris属,玉米圆斑病致病菌H. zeicola划入Bipolaris属,名称改变为B. zeicola (G. L. Stout) Shoemaker[67];1966年,有****将B. zeicola转入Drechslera属中,名称随之改变为D. zeicola (G. L. Stout) Subram. & B. L. Jain[68];1984年,根据病菌有性态Cochliobolus carbonum的名称,其无性态名称又变更为D. carbonum (Ullstrup) Sivan.[69]。5.2 多性状分析确定玉米圆斑病病原的分类地位
2011和2012年,MANAMGODA等依据Cochliobolus有性态种下涉及的Bipolaris和Curvularia种的培养物采集地和其DNA序列信息、生活史、次生代谢物特征、菌株的生防功能、由部分菌株ITS、GPDH和EF1α基因序列构建的分子进化树等特征,将55个Cochliobolus种所对应的无性态进行了鉴定,确认了B. zeicola为C. carbonum的无性态[70,71]。2014年,MANAMGODA等通过形态学和多基因序列的鉴定,详细描述了Bipolaris属的47个种,证明玉米圆斑病致病菌B. zeicola是一个独立的物种[72]。由于Bipolaris属的有性态Cochliobolus在自然界中少见,2013年,根据国际真菌命名委员会的提议,经过真菌分类学家讨论和投票,已经被植物病理学家普遍采用的Bipolaris属名被保留[73]。根据这一结果,玉米圆斑病病原应采用B. zeicola (G. L. Stout) Shoemaker的无性态学名,汉译名称为玉米生平脐蠕孢,上述在历史上出现的其他种名均为异名,其对应的有性态为C. carbonum R. R. Nelson,汉译名称为炭色旋孢腔菌。
6 玉米黑束病/头孢霉穗腐病病原名称
6.1 玉米黑束病病原两个名称的长期混乱应用
玉米黑束病在许多地区有发生,其致病菌在1839年由CORDA定名为Cephalosporium acremonium（顶头孢霉）[74]。该种名在此后的真菌研究中被使用,但由于不同研究者未采用该种的特定性形态标准,因而使得发表的C. acremonium已经不具有一个纯粹种的含义,而成为了一个庞杂的种,导致C. acremonium无法再作为一个种的标准进行应用[75]。同时,不同****在研究中对C. acremonium也几经更名,将其归于不同的属下,如Haplotrichum acremonium (Corda) Pound & Clem.、Hyalopus acremonium (Corda) M.A.J. Barbosa。通过对Cephalosporium类真菌的形态学研究,GAMS根据国际植物命名法规,提出了建立于1809年的Acremonium应是Cephalosporium（1839年建）的合格属名[76],将原归于Cephalosporium属下的种转入Acremonium属中,新命名或组合了一批种名,其中包括Acremonium strictum Gams,而C. acremonium作为该种的异名[75,77-78]。尽管A. strictum取代了C. acremonium,但两个名称仍长期在不同的研究报告中被采用,在“Compendium of Corn Diseases”（玉米病害概要-第4版）中,玉米黑束病和玉米头孢霉穗腐病的病原仍采用C. acremonium[4]。数十年来,由于许多研究者并未严格按照Acremonium属的定义进行细致研究,仅凭一些简单的形态特征命名物种[79],导致形成了一个包含有约150个种的庞杂Acremonium属,其有性态却对应多个子囊菌属,包括Emericellopsis、Hapsidospora、Nectria、Nectriella和Pronectria[80]。
6.2 分子特征研究解决玉米黑束病病原的分类地位
近20年来,利用分子技术对Acremonium属的特征开展了许多研究,以解决该属的多源性问题。依据18S RNA的特征,原Acremonium属中的5个类群（section）可以划分进子囊菌的4个目：肉座菌目（Hypocreales）、麦角菌目（Clavicipitales）、小囊菌目（Microascales）和粪壳菌目（Sordariales）[81],表明该属中不同种间存在明显的遗传差异;而用5.8S rDNA和ITS1-5.8S-ITS2序列并结合形态学特征的研究结果表明,Acremonium属内种间遗传变异大,即使是作为模式种A. alternatum的不同菌株,也在分子序列方面有明显不同[82];对A. strictum不同菌株的研究也表明,菌株间同样存在着很大的遗传变异[83]。SUMMERBELL等采用SSU和LSU rDNA序列信息对Acremonium属56个种和菌株进行研究的结果表明,Acremonium属的种可分别划入小丛壳目（Glomerellales）和肉座菌目（Hypocreales）,在后者中又可分为两大群;依据对200个Acremonium菌株的LSU rDNA序列信息,将Acremonium属菌株划入4个类群（clade）;将分子序列信息与形态学特征结合分析,重新确定了Acremonium属的概念及所含的种,而将大量的Acremonium属下的种划入恢复或新建的3个属（Gliomastix、Sarocladium、Trichothecium）中,3个属分别包含了原Acremonium属下的5个、8个和5个种,而A. strictum给予了新的种名Sarocladium strictum (W. Gams) Summerbell[84]。这一新的名称,正在逐渐被研究者接受[85,86,87,88]。6.3 玉米黑束病病原的特征及名称汉译
Sarocladium属的中文名称为帚枝杆孢属[89],因此,玉米黑束病病原菌新种名Sarocladium strictum (W. Gams) Summerbell的汉译名称为直帚枝杆孢;由该菌引起的穗腐病应该采用汉译名称“帚枝杆孢穗腐病”（Sarocladium ear rot）取代“头孢霉穗腐病”（Cephalosporium kernel rot）。Sarocladium属特征：从菌丝上或从分散或不断分枝的分生孢子梗上产生单个长形的瓶状产孢细胞,其上产生大量相互黏连的长形分生孢子[84]。Sarocladium strictum：菌落生长快,粉红或橘黄色,背面无色或粉红至橘黄色。分生孢子梗单生,偶尔分枝。产孢细胞瓶状,大小为（20—65）×（1.4—2.5）μm。分生孢子黏合在一起形成头状、柱状或椭圆体状,单个孢子无色,大小为（3.3—5.5）×（0.9—1.8）μm。
The authors have declared that no competing interests exist.
参考文献 原文顺序
文献年度倒序
文中引用次数倒序
被引期刊影响因子
| [1] | . |
| [2] | . |
| [3] | . |
| [4] | |
| [5] | . |
| [6] | . |
| [7] | . Combined analyses of ITS and LSU rDNA sequences were utilized to resolve the phylogenetic relationships of 98 members of the smut genera Lundquistia, Melanopsichium, Moesziomyces, Macalpinomyces, Sporisorium, and Ustilago (Basidiomycota: Ustilaginales). Minimum Evolution and Bayesian inference of phylogeny resolve three major groups of almost identical composition: Sporisorium, Ustilago, and a basal assemblage of both Ustilago and Sporisorium species. Macalpinomyces deserves generic rank regarding its type species M. eriachnes; all other Macalpinomyces species of our study clearly turn out to be part of Ustilago or Sporisorium. Lundquistia evidently belongs to Sporisorium. Moesziomyces, probably paraphyletic, stands basal to all other genera. Interestingly, Melanopsichium belongs to the Ustilago clade, being the only member of the ingroup not parasitizing on Poaceae. The patchy distribution of commonly used morphological characters along our phylograms points to their variability and dependence on the host's morphological traits instead of being valuable for resolving parasite phylogeny. The new combination: Sporisorium fascicularis comb. nov. (syn. Lundquistia fascicularis) is made. |
| [8] | . |
| [9] | . Ustilago maydis is a ubiquitous pathogen of maize and a well-established model organism for the study of plant09“microbe interactions. This basidiomycete fungus does not use aggressive virulence strategies to kill its host. U. maydis belongs to the group of biotrophic parasites (the smuts) that depend on living tissue for proliferation and development. Here we report the genome sequence for a member of this economically important group of biotrophic fungi. The 20.5-million-base U. maydis genome assembly contains 6,902 predicted protein-encoding genes and lacks pathogenicity signatures found in the genomes of aggressive pathogenic fungi, for example a battery of cell-wall-degrading enzymes. However, we detected unexpected genomic features responsible for the pathogenicity of this organism. Specifically, we found 12 clusters of genes encoding small secreted proteins with unknown function. A significant fraction of these genes exists in small gene families. Expression analysis showed that most of the genes contained in these clusters are regulated together and induced in infected tissue. Deletion of individual clusters altered the virulence of U. maydis in five cases, ranging from a complete lack of symptoms to hypervirulence. Despite years of research into the mechanism of pathogenicity in U. maydis, no 0900true0964 virulence factors had been previously identified. Thus, the discovery of the secreted protein gene clusters and the functional demonstration of their decisive role in the infection process illuminate previously unknown mechanisms of pathogenicity operating in biotrophic fungi. Genomic analysis is, similarly, likely to open up new avenues for the discovery of virulence determinants in other pathogens. |
| [10] | . |
| [11] | . |
| [12] | . |
| [13] | . |
| [14] | . |
| [15] | . |
| [16] | . |
| [17] | |
| [18] | . The enigmatic species Ustilago tillandsiae is the only known smut fungus associated with Bromeliaceae. Its generic position is evaluated by morphological, physiological, and molecular phylogenetic ana |
| [19] | . |
| [20] | . |
| [21] | |
| [22] | . |
| [23] | . |
| [24] | . |
| [25] | . |
| [26] | . |
| [27] | . The characteristics of S. hydropiperis are defined and the criteria for the gen. (valid for some smuts of polygonaceae) are established. Studies of the ontogeny and mature structure of sori of S. sorghi, and some other smuts of Poaceae currently included in S., have shown that these are markedly different from the type sp. Sporisorium, based on S. sorghi on sorghum, is available for certain smu... |
| [28] | . |
| [29] | . |
| [30] | . |
| [31] | . |
| [32] | . |
| [33] | . |
| [34] | . |
| [35] | . |
| [36] | . |
| [37] | . |
| [38] | . Si ringraziano sentitamente il Prof. F. Salamini (Istituto Sperimentale per la Cerealicoltura, Sezione di Bergamo) per averci messo a disposizione le parcelle sperimentali e i semi delle linee pure di mais; il Prof. E. Luisoni (Laboratorio di Fitovirologia Applicata, Torino) per averci fornito il siero contro SRSV. Maize plants growing in the district of Bergamo (Northern Italy) showed mosaic, yellow or red stripes and dwarfing. Samples taken from 8 plants with symptoms and from 2 healthy plants have been used for diagnostic tests made through mechanical inoculations, electron microscopy and serology. All the samples with symptoms resulted to be infected with MDMV; two of them resulted to contain also BYDV. |
| [39] | . |
| [40] | . |
| [41] | . . |
| [42] | . . |
| [43] | . 大麦黄矮病毒(BYDV)侵染玉米引起玉米红叶病,在个别品种上可产生细条症状。不同症状其潜育期不同,同一品种表现红叶症状潜育期平均20.9～25天,细条症状平均为13.4～18.6天。玉米红叶病最有效的传毒介体为粟缢管蚜、玉米蚜,其次为二叉蚜和长管蚜。侵染玉米的BYDV株系主要为二叉缢管蚜株系(GPV)、玉米蚜株系(RMV),不稳定的缢长蚜株系(PAV)亦可侵染。 . 大麦黄矮病毒(BYDV)侵染玉米引起玉米红叶病,在个别品种上可产生细条症状。不同症状其潜育期不同,同一品种表现红叶症状潜育期平均20.9～25天,细条症状平均为13.4～18.6天。玉米红叶病最有效的传毒介体为粟缢管蚜、玉米蚜,其次为二叉蚜和长管蚜。侵染玉米的BYDV株系主要为二叉缢管蚜株系(GPV)、玉米蚜株系(RMV),不稳定的缢长蚜株系(PAV)亦可侵染。 |
| [44] | . |
| [45] | . |
| [46] | . |
| [47] | . |
| [48] | . During 1998 and 1999, 40 samples of maize with long red-stripes and yellowing of leaf margins and 20 samples of Johnson grass (Sorghum halepense) with mosaic and in some cases red spots on the leaves were collected from Dasht-e-Naz in Sari. The samples were tested by ELISA using antisera to barley yellow dwarf (BYD) viruses. The results showed that most samples were infected with BYDV-RPV, BYDV... |
| [49] | . |
| [50] | . |
| [51] | |
| [52] | . Barley yellow dwarf viruses (BYDVs) are economically important viruses that infect cereal crops worldwide, including wheat grown in China. These viruses include several members of the Luteoviridae and are transmitted only by aphids. In this study, BYDV isolates and their aphid vectors were collected from different regions of China and assayed. BYDV isolates from China were generally transmitted by more than one aphid species except for BYDV-RMV and a few BYDV-PAV. Seven vector transmission phenotypes (VTPs) were identified involving five serotypes; BYDV-GAV, BYDV-GPV and BYDV-PAV were predominant in China. Aphid clones differing in virus transmission abilities were occasionally observed for three laboratory-maintained species although they generally showed similar virus transmission profiles. Degenerate primers similar to Lui and Lu4 were designed to amplify coat protein gene fragments from all in the virus collection. Serotypes could be distinguished after cleavage of the resulting PCR products with HinfL. Sequence variations among Chinese BYDVs were also deduced from differences among their restriction patterns. To clarify this, intact coat protein genes of a few isolates were amplified with serotype-specific primers, cloned and sequenced. Similarity and genetic distance analyses confirmed that the three major Chinese BYDVs possess coat protein genes distinct from those of BYDV from other countries. |
| [53] | . Abstract The complete nucleotide sequence of the ssRNA genome of a Chinese GPV isolate of barley yellow dwarf virus (BYDV) was determined. It comprised 5673 nucleotides, and the deduced genome organization resembled that of members of the genus Polerovirus. It was most closely related to cereal yellow dwarf virus-RPV (77% nt identity over the entire genome; coat protein amino acid identity 79%). The GPV isolate also differs in vector specificity from other BYDV strains. Biological properties, phylogenetic analyses and detailed sequence comparisons suggest that GPV should be considered a member of a new species within the genus, and the name Wheat yellow dwarf virus-GPV is proposed. |
| [54] | . |
| [55] | . . |
| [56] | . (Narita & Hiratsuka) nov. comb, is proposed. |
| [57] | . |
| [58] | . Taxonomic markers for differentiation of the anamorph genera Aureobasidium, Hormonema and Kabatiella were developed using PCR-ribotyping with the primers 5.8S-R and LR7 for amplification and the restriction enzymes Alul, DdeI, Hhal, MspI and RsaI for digestion. Aureobasidium and Hormonema are optimally differentiated with MspI; DdeI is particularly useful to distinguish aureobasidium, Kabatiella and Selenophoma . Relationships of the anamorph genera Aureobasidium, Hormoneng and Kabatiella with the teleomorph genera Pringsheimia and Dothiora are discussed. |
| [59] | . |
| [60] | . |
| [61] | . |
| [62] | . PLANT-PATHOGENIC FUNGI; SPORISORIUM-MACALPINOMYCES COMPLEX; DOTHIDEOMYCETES INCERTAE-SEDIS; SEQUENCE DATA; PHYLOGENETIC CLASSIFICATION; MOLECULAR CHARACTERIZATION; COLLETOTRICHUM-ACUTATUM; NATURAL CLASSIFICATION; MORPHOLOGICAL EVIDENCE; CAMELLIA-SINENSIS; Epitype; Generic types; Molecular data; Nomenclature; Systematics; Taxonomy; Typification |
| [63] | . |
| [64] | . |
| [65] | . English diagnoses (accompanied by brief notes) are given of sixteen species of fungi considered to be new to science, which were found on maize in Illinois in 1926 and 1927. Fourteen of these, namely, Ascochyta maydis, A. zeae, Coniothyrium zeae, Leptosphaeria maydis, L. variiseptata, L. zeae, Leptothyrium zeae, Mycosphaerella zeicola, Phyllosticta zeae, Physalospora zeae, Pleosphaerulina zeico... |
| [66] | . |
| [67] | . |
| [68] | . |
| [69] | . |
| [70] | . |
| [71] | . |
| [72] | . |
| [73] | . |
| [74] | . |
| [75] | . |
| [76] | . |
| [77] | . |
| [78] | . |
| [79] | . |
| [80] | . |
| [81] | . Acremonium is generally considered to be a highly polyphyletic form genus containing distantly related fungi. Sectional divisions within Acremonium distinguish the clavicipitaceous grass endophytes of sect. Albolanosa from the generally saprobic species of sections Acremonium, Chaetomioides, Gliomastix, and Nectrioidea. In an effort to assess the possible number of lineages currently placed within Acremonium and to determine which groups of sexual ascomycetes are phylogenetically affiliated with Acremonium species, maximum parsimony and neighbor-joining analyses were performed using partial sequences of the nuclear small subunit ribosomal DNA (18S rDNA). Acremonium was shown to be a polyphyletic taxon with affiliations to at least three ascomycetous orders: 1) most of the examined species from the sections Acremonium, Gliomastix, and Nectrioidea showed a relationship to the Hypocreaceae even though many of these species have never been associated with any teleomorph; 2) the grass endophytes of sect. Albolanosa and other taxa from the Clavicipitaceae formed a monophyletic group derived from within the Hypocreales; 3) the thermophilic A. alabamense of sect. Chaetomioides was derived from within the Sordariales. Acremonium alternatum, the type species of the genus, was one of the species showing affiliation to the Hypocreaceae. In order to eliminate some of the heterogeneity within Acremonium while also emphasizing the unique biological, morphological, and ecological characteristics of the grass endophytes, we are proposing that the anamorphs of Epichlo毛 and closely related asexual grass endophytes be reclassified into the new form genus Neotyphodium. Phylogenetic and taxonomic considerations are also presented for other taxa. |
| [82] | . |
| [83] | . Abstract Primarily saprophytic in nature, fungi of the genus Acremonium are a well-documented cause of mycetoma and other focal diseases. More recently, a number of Acremonium spp. have been implicated in invasive infections in the setting of severe immunosuppression. During the course of routine microbiological studies involving a case of fatal mycosis in a nonmyeloablative hematopoietic stem cell transplant patient, we identified a greater-than-expected variation among strains previously identified as Acremonium strictum by clinical microbiologists. Using DNA sequence analysis of the ribosomal DNA intergenic transcribed spacer (ITS) regions and the D1-D2 variable domain of the 28S ribosomal DNA gene (28S), the case isolate and four other clinical isolates phenotypically identified as A. strictum were found to have 99% homology to the type strain at both loci. These results suggest that five out of the six clinical isolates belong to species other than A. strictum or that the A. strictum taxon is genetically diverse. Based upon these sequence data, the clinical isolates were placed into three genogroups. |
| [84] | . |
| [85] | . The circumscription of the genus Acremonium (Hypocreales) was recently reviewed on the basis of a DNA phylogenetic study. Several species were subsequently transferred to Sarocladium, but the relationships between both genera remained unresolved. Based on multilocus phylogenetic inferences combined with phenotypic data, we have revised the species concepts within Sarocladium and some genetically related species of Acremonium. As a result of these studies, six species are described as new, viz. S. bifurcatum, S. gamsii, S. hominis, S. pseudostrictum, S. subulatum and S. summerbellii. In addition, the new combinations S. implicatum and S. terricola are proposed for A. implicatum and A. terricola, respectively. Sarocladium attenuatum is confirmed as synonym of the type species of the genus, S. oryzae. An epitype and neotype are also introduced for S. oryzae and S. implicatum, respectively. Although Sarocladium species have traditionally been considered as important phytopathogens, the genus also contains opportunistic human pathogens. This study extends the spectrum of clinical species that could be diagnosed as causal agents of human infections. |
| [86] | . |
| [87] | . |
| [88] | . Fungi are ubiquitous occupiers of plant roots, yet the impact of host identity on fungal community composition is not well understood. Invasive plants may benefit from reduced pathogen impact when competing with native plants, but suffer if mutualists are unavailable. Root samples of the invasive dune grassAmmophila arenariaand the native dune grassLeymus molliswere collected from a Californian foredune. We utilised the Illumina MiSeq platform to sequence the ITS and LSU gene regions, with the SSU region used to target arbuscular mycorrhizal fungi (AMF). The two plant species largely share a fungal community, which is dominated by widespread generalists. Fungi detected on only one species were rare, accounting for a small proportion of the data. The SSU region recovered AMF from more samples and from more Glomeromycota lineages than ITS or LSU. A high degree of turnover among samples was observed, but there was no evidence for strong distance-decay. |
| [89] |
