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。     

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%。     

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     

中国北方马铃薯黑痣病立枯丝核菌的融合群鉴定

从山东、甘肃、青海、内蒙古、河北和黑龙江6省采集马铃薯黑痣病标本300余份,分离获得251个立枯丝核菌Rhizoctonia solani菌株。融合群测定结果表明,这些菌株分别属于多核的丝核菌AG‐3、AG1‐IB、AG4‐HG‐Ⅰ、AG4‐HG‐Ⅱ、AG4‐HG‐Ⅲ、AG‐5和AG‐11融合群。其中AG‐3是优势致病群,占分离菌株总数的71.31%;其次是AG4‐HG‐Ⅰ,占15.14%;AG‐11融合群菌株是国内首次从罹病马铃薯植株上分离得到。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菌株的5.8S rDNA‐ITS区序列存在较大的差异,而相同融合群(亚群)不同菌株的序列具有较高一致性。     

云南省水稻纹枯病菌系研究

将来自云南省20多个县市的水稻纹枯病标样130多份,选代表性的标样分离得到54个菌株。按菌丝融合测定法,将54个菌株分为5个菌系：R.solani的AG－1 IA,AG-1 IC,AG-6GW以及以核丝核菌的AG－Bb,AG- ⅠⅡ。经致病性测定表明,该菌系对水稻、玉米、小麦的苗期及成株期的致病性有显著差异。其中AG－1ⅠA,AG－1 IC,AG－Ⅱ的致病力最,AG－6GW的最弱。对这些菌系的酯酶同工酶进行比较研究发现,不同菌系间均存在明显差异,而同菌系不同菌株间却具有一致性。由此说明,按菌丝融合与否区分丝核菌种群较之现行的其它分类法更能反映其遗传本质和亲缘关系,。     

山东省玉米纹枯菌融合群类型及遗传多样性

从山东省14个县市区采集的玉米纹枯病标本上分离获得103个玉米纹枯菌菌株。核荧光染色确定菌丝细胞核的数目,以及利用配对培养法确定不同菌株细胞是否融合。结果表明这些菌株分别属于多核丝核菌的AG-1-IA、AG-1-IB、AG-1-IC、AG-3、AG-4-HG-I、AG-5和WAG-Z融合群和双核丝核菌的AG-Ba融合群,其中AG-1-IA类型菌株数量占菌株总数的60.19%,为优势融合群。通过inter-simple sequence repeats（ISSR）标记技术进行菌株的遗传多样性分析,获得45个ISSR分子标记,其中91.1%的片段具有多态性,表明种群间存在丰富的遗传多样性。UPGMA聚类分析将103个菌株分成6个遗传聚类群,遗传聚类群的菌株组成说明遗传群组的划分与菌株的地理来源和菌株融合群类型均存在一定的相关性。     

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     

四川省东、南部稻区水稻纹枯病菌系研究

将来自川东、南稻区代表性的38个县(市)的水稻纹枯病标样296份,按不同的品种、海拔、土质、前作和症状归粪,选代表性的标样分离得到108个丝核菌菌株。按HCL—Giemsa染色程序和菌丝融合测定法,将108个菌株分为3个菌系：Rhizoctonia solani AG-1和AG-4,以及双核丝核菌的AG—Bb。其比例分别为97％、1％和2％。经致病性测定表明,该各菌系对水稻的致病性有显著差异：R. solani AG-1的大多数菌株最强,双核丝核菌AG—Bb最弱,R. solani AG一4居中。 对上述各菌系的培养性状、非特异性酯酶和过氧化物酶同工酶谱进行比较研究发现,不同菌系间在上述诸方面均存在明显差异,而同菌系不同菌株间却具一致性。由此说明,按菌丝融合与否区分丝核菌种群较之现行的其它分类法更能反映其遗传本质和亲缘关系。     

云南省水稻纹枯病菌系研究*

将来自云南省20多个县市的水稻纹枯病标样130多份,选代表性的标样分离得到54个菌株。按菌丝融合测定法, 将54个菌株分为5个菌系:R.solani的AG-1 IA ,AG-1 IC,AG-6GW 以及双核丝核菌的AG-Bb, AG-I II。经致病性测定表明,该菌系对水稻、玉米、小麦的苗期及成株期的致病性有显著差异。其中AG-1 IA, AG-1 IC, AG-I II 的致病力最强, AG-6GW的最弱。对这些菌系的酯酶同工酶进行比较研究发现,不同菌系间均存在明显差异, 而同菌系不同菌株间却具一致性。由此说明,按菌丝融合与否区分丝核菌种群较之现行的其它分类法更能反映其遗传本质和亲缘关系。     

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。     

草坪禾草丝核菌的核相研究

2003～2005年从上海市、浙江省、山东省、河南省和陕西省草坪褐斑病的97份病株标本中,分离得到了73个丝核菌分离物,其寄主包括多年生黑麦草Lolium perenne、高羊茅Festuca arundinacea、草地早熟禾Poa pratensis、匍匐翦股颍Agrostis palustris、结缕草Zoysia japonica和狗牙根Cynodon dactylon。用载玻片培养法和DAPI染色法对各分离物菌丝进行了染核观察。结果73个分离菌株可区分为单核丝核菌、双核丝核菌和多核丝核菌三大类,可能属于多个物种。单核丝核菌在中国为首次报道,同时也是其侵染草坪禾草的首次报道。     

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.     

见血封喉内生真菌Rhizoctonia sp．J5化学成分研究

应用多种柱色谱技术,从见血封喉内生真菌Rhizoctonia sp.J5发酵液中分离纯化了7个化合物,根据理化性质和波谱数据分别鉴定为对羟基苯乙醇(1),对羟基苯甲醛(2),5-羟甲基-2-糠醛(3),甘草索(4),24-亚甲基-24(25)-二氢羊毛甾醇(5),(3α,5α,8α,22E,24R)-5,8-桥二氧麦角甾-6,22-二烯-3-醇(6),(3β,5α,8α,22E,24R)-5,8-桥二氧麦角甾-6,9(11),22-三烯-3-醇(7).以上化合物均为首次从见血封喉内生真菌中分离得到.抗菌活性测试结果表明化合物4具有抗金黄色葡萄球菌和耐甲氧西林金黄色葡萄球菌活性.     

Identification and Pathogenicity of Rhizoctonia spp. Causing Wirestem of Betula nigra in China

During July 2004, wirestem was frequently observed on the seedlings of Betula nigra at Dehong district in Yunnan Province, China. Isolates of Rhizoctonia spp. consistently obtained from their diseased leaves, roots and stems were identified as belonging to binucleate Rhizoctonia anastomosis groups (AG) AG‐P and AG‐R, and R. solani AG‐I IB and AG‐4 HG‐I, based on cultural characteristics, nuclear staining, anastomisis reaction and analysis of their ITS rDNA region. The percentage of recovery of AG‐P, AG‐1, AG‐R and AG‐4 was 48%, 39%, 8% and 3%, respectively. This is the first report of wirestem of red birch cause by binucleate Rhizoctonia AG‐P and AG‐R, and R. solani AG‐1 IB and AG‐4 HG‐I in China.     

Differentiation of Three Varieties of Rhizoctonia circinata; var. circinata, var. oryzae and var. zeae on the Basis of Cellular Fatty Acid Composition

Cellular fatty acid analysis was employed to differentiate three varieties of Rhizoctonia circinata ; var. circinata , var. oryzae and var. zeae . Eight fatty acids including myristic (14 : 0), pentadecanoic (15 : 0), palmitic (16 : 0), palmitoleic (16 : 1  cis 9), stearic (18 : 0), oleic (18 : 1  cis 9), linoleic (18 : 2  cis 9,12) and linolenic (18 : 3  cis 9,12) acids were present in isolates of all three varieties of R. circinata . Heptadecanoic acid (17 : 0) was detected in isolates of R. circinata var. zeae but not in isolates of R. circinata var. circinata or R. circinata var. oryzae . Palmitic, oleic and linoleic acids were the major fatty acids found, comprising 94–98% of the whole-cell fatty acid content. The remaining fatty acids were present in small amounts. Based on the composition (%) of fatty acids, isolates of R. circinata var. circinata , R. circinata var. oryzae and R. circinata var. zeae were clearly differentiated into three groups as shown by principal component and cluster analyses. This finding agrees well with the grouping of R. circinata into three varieties based on differences in colony morphology of the vegetative state. In principal component and cluster analysis, isolates of R. circinata var. circinata from Japan and Alaska were indistinguishable.     

Effect of the herbicides trifluralin,dinitramine and fluometuron on rhizoctonia disease in cotton

Summary The effect of three different concentrations (half, equal and twice of the recommended dose) of three herbicides (trifluralin, dinitramine and fluometuron) usually used to control cotton weeds on the development of Rhizoctonia disease in cotton was studied. Trifluralin and dinitramine at the lower concentrations increased pre- and/or post-emergence damping off. Both herbicides at these concentrations increased the saprophytic activity of the fungus, while they did not affect the susceptibility of the cotton plants. Fluometuron at the highest concentration used was highly phytotoxic and increased the post-emergence damping off. This chemical at the recommended dose caused a drastic reduction in the pre- and post-emergence damping off caused byR. solani. Fluometuron at this concentration decreased both the susceptibility of the host plants and the saprophytic activity of the fungus.     

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。     

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.