丝核菌的分类系统：现状及存在问题

以重要植物病原菌为特征的丝核菌是一类在土壤中广泛分布的丝状真菌,通常不产孢,以菌丝或菌核的形式存在,多样性非常丰富。本文基于国内外最新研究进展,对依据菌丝体的细胞核数目、菌丝融合、有性生殖和系统进化等方面的基本特征展开的丝核菌分类体系及分类现状进行了综述。基于菌丝的细胞核数目,丝核菌被分为单核、双核和多核丝核菌三大类群。自然界中单核丝核菌数量极少,多核和双核丝核菌在全球分布广泛,占丝核菌的绝大多数。基于菌丝融合试验的结果,目前多核丝核菌被分为13个菌丝融合群,双核丝核菌被分为18个菌丝融合群。部分融合群内又根据一些稳定的特征分了亚群,但亚群的建立标准并不统一。目前的分子系统学研究结果基本支持丝核菌的菌丝融合群及亚群的分类。基于部分有性世代被发现的菌株的形态特征,多核和双核丝核菌分别被鉴定为亡革菌属和角担菌属。此外,目前已有分属重要植物病原菌和兰科菌根菌类群的至少9个融合群或亚群的17个菌株完成了基因组测序,比较基因组学和线粒体组学开始在丝核菌分类和进化研究中发挥作用。丝核菌分类系统特殊且复杂,作者在文末提出了目前丝核菌分类学研究面临的问题和今后研究的趋势,期待更多的学者参与到这个重要菌...     

中国北方棉花主产区立枯丝核菌的融合群鉴定

从山东、河北、河南三省采集棉花立枯病样品和土壤200余份,经分离获得198个丝核菌Rhizoctonia solani分离物。菌丝融合测定及5.8S rDNA-ITS区序列分析结果表明,这些分离物分别属于多核丝核菌的AG4-HG-I和AG4-HG-III融合群以及双核丝核菌的AG-A、AG-F、AG-Fb融合群。其中AG4-HG-I是优势融合类群,占分离物总数的88.38%,其次是AG4-HG-III,占10.10%,AG-A、AG-F、AG-Fb各仅有1株。其中双核丝核菌AG-A、AG-F和AG-Fb融     

新疆北疆棉田立枯丝核菌菌丝融合群及其营养亲和群研究

从新疆北疆棉区采集了典型的棉花立枯病病苗及棉田土标样686份,按常规分离方法分离得到399个分离物,从中鉴定出272个纯化的立枯丝核菌(Rhizotonia solaniKühn)菌株,经玻片吉姆萨氏染剂(Gimsa′sstain)染色程序观察细胞核数目,全部测试菌株均属于多核。用标准菌株,通过载玻片菌丝融合实验测定,将纯化的272个菌株划归为3个菌丝融合群:AG-2、AG-4和AG-5,分别占总菌株的6.24%、84.2%和1.1%。另有23个菌株不与任何标准菌株融合,占8.46%,说明新疆北疆棉田立枯丝核菌的优势菌系是多核丝核菌的AG-4融合群。通过从10种不同配方的培养基中筛选的效果好的麦芽蛋白胨(MPDA)配方培养基(Ⅱ)进行对峙培养,以建立标准菌株,将纯化获得的272个丝核菌菌株,划分为6个不同的营养亲和群,研究说明新疆北疆地区棉田立枯丝核菌各菌丝融合群内确有不同程度的分化。     

湖北省玉米纹枯病病原丝核菌的种类和致病性

从湖北省9个主要玉米产区采集玉米纹枯病标样,分离得到55个丝核菌菌株,融合群和致病性测定表明,这些分离菌分别属于AG1-IA、AG4、AG5、AGA、AGB(0)、AGE和WAG-Z等7个丝核菌融合群,其中AG1-IA是优势融合群,占分离菌株总数的61.82%,分布范围也最广。在致病性方面,除AGA不致病外,其它6群均致病,其中AG4致病力最强,AG1-IA次之,AG5最弱。研究同时表明,同一融合群内不同菌株致病性有差异,并且同一菌株对不同玉米自交系的致病力的强弱表现不完全一致。     

棉立枯丝核菌的dsRNA与致病力的研究

对我国北方棉立枯丝核菌(Rhizoctonia solani)的18个分离物进行了dsRNA的检测和致病力比较,可见：(1)dsRNA以高频度(16／18)存在于各分离中;(2)各分离物的dsRNA有明显不同的电泳图谱,有1—8个片段,分子量自0．94—4．8×106道尔顿;(3)同地区土壤中分离物常有相同的dsRNA片段;(4)以弱致病力分离物BALr-2的[r-32P]ATP末端标记dsRNA为探针与16个分离物dsRNA进行分子杂交,只有3个分离物有强的同源性,Northern转移杂交表明同源核苷酸在1．15×106的片段;(5)变性电泳示丝核菌的dsRNA泳动率有减慢现象,从而提出环状dsRNA的可能。     

中国东北地区玉米纹枯病菌的融合群鉴定

自东北三省采集玉米纹枯病标本300余份,分离获得286个丝核菌菌株。融合群测定及5.8S rDNA-ITS区序列分析结果表明,这些菌株分别属于多核丝核菌的AG1-IA、AG1-IB、AG1-IC、AG4-HG-I、AG4-HG-III、AG-5、WAG-Z群及双核丝核菌的AG-Ba群。其中AG1-IA是优势致病群,占分离菌株总数的38.46%,其次是WAG-Z和AG-5群,分别占26.92%及24.83%。AG4-HG-III群菌株是国内首次从罹病玉米植株上分离得到。自各融合群中选取代表性的菌株进行5.8     

江苏大麦纹枯病菌酯酶同工酶的测定

对立枯丝核菌(Rhizoctonia solani giihn)和禾谷丝核菌(R．E erealis Vande r Hoeven)的16个菌丝融合群或亚群的标准菌株及来自}工苏大麦纹枯病的9个菌丝融合群或亚群共68个菌株进行了聚丙烯酰胺凝胶电泳,测定酯酶同工酶。结果表明：1．立枯丝核菌主酶带数的变幅范围比禾谷丝核菌大;2．无论禾谷丝核菌,还是立枯丝核菌,各菌丝融合群或亚群之间的电泳图谱都有显著差异,但与各自对应的融合群或亚群的标准菌株的图谱则相似;3．44个大麦禾谷丝核菌CAG一1群菌株间的图谱也有差异,但都有一条共同的主酶带(E．);4．据主副酶带数目和位置,将禾谷丝核菌CAG一1群菌株再分为2个类型(1型和II型)和5个亚型(1a、Ib、Ic和Iia、Iib);酶谱类型与菌株的采集品种和致病性无关,但与采集地点似有一定的联系。     

湖北省玉米纹枯病病原丝核菌的种类和致病性*

从湖北省9个主要玉米产区采集玉米纹枯病标样,分离得到55个丝核菌菌株。融合群和致病性测定表明,这些分离菌分别属于AG1—IA、AG4、AG5、AGA、AGB(0)、AGE和WAG-Z等7个丝核菌融合群,其中AG1-IA是优势融合群,占分离菌株总数的61.82%,分布范围也最广。在致病性方面,除AGA不致病外,其它6群均致病,其中AG4致病力最强,AG1-IA次之,AG5最弱。研究同时表明,同一融合群内不同菌株致病性有差异,并且同一菌株对不同玉米自交系的致病力的强弱表现不完全一致。     

丝核菌的菌丝融合群及其遗传多样性研究的新进展

在介绍丝核菌按其菌丝细胞核相划分为单、双、多核丝核菌三大类,再行菌丝融合分类的基础上,较系统地评述了以生化和分子生物学等手段研究其遗传多样性和系统演化关系的最新进展。     

立枯丝核菌(Rhizoctonia solani)对日本结缕草(Zoysia japonica steud.)的侵染过程研究

【目的】了解立枯丝核菌(Rhizoctonia solani) AG1 IA对日本结缕草(Zoysia japonica steud.)的侵染过程及其引起的病害症状,为进一步从分子水平研究该菌的病理学侵染机制和草坪草抗病分子育种提供理论基础。【方法】通过根部接种法促使立枯丝核菌与日本结缕草无菌苗建立侵染关系,从而对其病叶率、病株率及病情指数进行统计分析,同时结合组织染色透明技术及植物组织石蜡切片对立枯丝核菌的侵染过程、感染方式进行研究。【结果】立枯丝核菌AG1 IA的侵染过程主要为：菌丝吸附在植物组织表面,并沿组织表面定向生长,形成侵染结构——侵染垫与组织建立密切的侵染关系。菌丝通过细胞间隙侵入植物组织内部,主要侵染植物皮层细胞及除木质部导管以外的整个维管束系统。结缕草的地上部分与地下部分组织对立枯丝核菌的侵染显现不同的寄主反应。【结论】立枯丝核菌的侵染过程主要包括吸附、定向生长、渗透、定殖4个部分;立枯丝核菌的侵染主要引起结缕草叶片病症;结缕草病变与菌丝直接侵染无直接联系,表明该菌具有复杂的侵染机制。     

Pathogenicity and symptom expressions of Rhizoctonia solani,R. oryzae and R. oryzae-sativae to some commercial cultivars of rice in Myanmar

Rhizoctonia complex of rice has been detected in rice growing areas of Myanmar. The primary objective of this study is to study the varietal response of rice to Rhizoctonia complex and to distinguish the symptom expression of rice responses to these pathogens. Myanmar rice cultivars namely Manawthukha, Shwethweyin, Sinthwelatt and Yezinlonthwe were used to inoculate with three isolates of each species of Rhizoctonia solani, Rhizoctonia oryzae and Rhizoctonia oryzae-sativae. The symptoms created by each species of Rhizoctonia were distinguished by the size and colour of the lesion. Variation in lesion length was observed among different isolate-rice cultivar combination. Shwethweyin variety is the most susceptible one to all the tested three species among the four tested varieties.     

Characterization and Pathogenicity of Rhizoctonia spp. from Onion in Amasya, Turkey

Forty‐two isolates of Rhizoctonia spp. were obtained from onion in Amasya, Turkey. Of these, 29% were Rhizoctonia solani (AG‐4), 69% were Waitea circinata var. zeae (Rhizoctonia zeae) and 2% were binucleate Rhizoctonia (AG‐B). Most of the isolates were recovered from rhizosphere soil. In pathogenicity tests on onion, R. solani AG‐4 caused the greatest disease severity, those of W. circinata var. zeae were moderately virulent but binucleate Rhizoctonia isolates were of low virulence. This is the first report of binucleate Rhizoctonia AG‐B and W. circinata var. zeae occurring on onion in Turkey.     

丝核菌菌丝融合群种类,寄生专化性及与温度的关系

丝核菌（Ｒｈｉｚｏｃｔｏｎｉａｓｐｐ．）是最重要的土传植物病原菌之一,分布世界各地。１９２１年Ｍａｔｓｕｍｏｔｏ用菌丝融合群（ＡｎａｓｔｏｍｏｓｉｓＧｒｏｕｐ,简称ＡＧ）的方法来划分多核立枯丝核菌（Ｒ．ｓｏｌａｎｉ）在生理上特异的菌株［６］,Ｐａｒ...     

Morphological,pathological and molecular characterisation of rice sheath blight disease causal organism Rhizoctonia solani AG-1 IA in Egypt

Rice sheath blight disease caused by Rhizoctonia solani is considered a distractive soil-borne disease of rice production worldwide. The study aimed to determine the causal organism of sheath blight symptoms in Egyptian rice fields. Sheath blight symptoms were first observed in a small area during 2013, 2014 and 2016 seasons, later in a wide area of rice fields in 2016 to 2018 seasons. Pathogen identification was carried out based on morphological traits and internal transcribed spacer sequencing. Thirty-six isolates were identified as R. solani fungus. The isolates exhibited a wide range of variability in their morphological traits and virulence patterns. Five isolates were sequenced and aligned with Chinese isolates with 75–100% identity. This is the first report of R. solani AG-1 IA that associated with rice sheath blight in Egypt. Initiate a breeding program for disease resistance and integrated disease management procedures are important to keep the disease under control.     

黄淮海地区夏玉米纹枯病菌的融合群鉴定

从黄淮海地区采集玉米纹枯病标样250余份,分离得到176个丝核菌菌株。融合群测定及5.8SrDNA-ITS区序列分析结果表明,这些菌株分别属于多核丝核菌的AG1-IA、AG1-IB、AG4-HG-I、AG-5、WAG-Z融合群及双核丝核菌的AG-A、AG-Ba融合群。其中AG1-IA是优势融合群,占分离菌株总数的64.20%,其次是AG-Ba,占12.50%,再依次分别是WAG-Z(10.23%)、AGI-IB(5.11%)、AG-4-HG-I(3.98%)、AG-5(2.27%)和AG-A(1.70%)。其中AG-Ba融合群是国内首次在玉米上分离得到。从各融合群中选取代表性的菌株进行5.8S rDNA-ITS区序列分析结果表明,隶属不同融合群或亚群的菌株其5.8S rDNA-ITS区序列存在较大的差异,而相同融合群(或亚群)不同菌株之间其序列的一致性可高达97%-100%。     

Variations in culture morphology and pathogenicity among protoplast-regenerated strains of Rhizoctonia solani

Abstract Protoplast-regenerated cultures derived from mycelia of cereal-infecting field isolates of Rhizoctonia solani exhibited major variations in cultural morphology and in pathogenicity. Each field isplate yielded three of four distinct morphological types of protoplast cultures. The presence of the new morphological phenotypes was attributed to the selection of homokaryons arising from protoplasts with single nuclei. Highly pathogenic field isolates produced protoplast cultures with higher virulence than those from weakly virulent pathogenic isolates, and homokaryotic strains were generally less pathogenic than the parental field isolate.     

棉立枯丝核菌(Rhizoctonia solani)中的一个dsDNA病毒

自从1962年Hollings在栽培蘑菇(Agaricus bisporus)中发现第一例真菌病毒以来,迄今已在100多种真菌中发现了病毒,多数含双链RNA基因组。1972年Bozarth报道在R.solani中发现病毒,但未报道该病毒的理化性质。1975年Finlker在R.solani的一个强致病力菌株中分离到双链RNA病毒,它含3个组分dsRNA。     

Identification and pathogenicity of Rhizoctonia species isolated from bean and soybean plants in Samsun,Turkey

A total of 434 isolates of Rhizoctonia belonging to 10 anastomosis groups were obtained from the roots and rhizosphere soils of bean and soybean plants grown in Samsun, Turkey. AG-4 was found to be the most common group on bean and soybean plants and AG-5, AG-6, binucleate AG-A, AG-B and R. zeae were other groups isolated from the both plant species. AG-1, AG-7 and AG-K from bean and AG-E from soybean were other groups obtained in the study. The pathogenicity tests on bean and soybean seedlings showed that the highest disease severities were caused by AG-4 isolates, whereas AG-1 and AG-6 isolates were moderately pathogenic. Binucleate Rhizoctonia AG-B isolates were also moderately pathogenic, while other binucleate Rhizoctonia were found to be weakly pathogenic. Rhizoctonia zeae isolates caused moderate disease symptoms on bean, but soybean plants were slightly affected by this group of isolates. This is the first reported observation of R. solani AG-6 and AG-7 and binucleate Rhizoctonia AG-B on bean, and R. solani AG-5 and AG-6 and binucleate Rhizoctonia AG-A, AG-B and AG-E on soybean, in Turkey.