新疆棉花细菌性烂铃病病原菌鉴定

 2006~2007年在棉花结铃盛期,从新疆奎屯和石河子等地的不同棉田中采集细菌性烂铃病样,分别从病部棉绒、种子和铃壳上分离纯化得到了20个细菌菌株;使用针刺法接种棉铃后,所有供试菌株均引起与田间自然发病相一致的症状;从中选取8个代表性菌株进行了形态特征、培养特性、生理生化反应的观察和测定,同时用细菌16S rDNA通用引物进行了PCR扩增和序列测定,登录GenBank比对后,将其鉴定为成团泛生菌(Pantoea agglomerans)。该病原菌在棉铃上的危害在国内尚属首次报道。     

稻米细菌性条斑点病病原菌鉴定

 从天津市水稻种植区的稻米病粒上分离和纯化,获得3种病原细菌,其中灰白色渐变浅黄色菌出现频率最高,占菌落的96.3%,为优势菌,另外2种分别占菌落的8.4%和1.9%;经过敏性反应、革兰氏染色、菌落形态、培养特性和生理生化反应等细菌学鉴定,伤口和喷雾接种致病性测定,前1种病粒率最高分别为62.4%和9.1%;后2种病粒率为0.8%和未发病。确定具有致病作用的病原细菌的优势菌为草生欧文氏菌[Pantoea agglomerans (E.herb icola (Lohnis) Dye)],其它为荧光假单孢菌(Pseudomonas fluorescens)和恶臭假单孢菌(Pseudomonas putida)。     

番茄细菌性髓部坏死病病原的鉴定

2015年,在广东省广州市番茄种植区发生番茄髓部坏死病,从番茄病样中分离到一种细菌。随机选取5株细菌进行致病性测定,结果显示,这5株细菌均可侵染番茄植株产生典型的髓部坏死症状,与田间病株的症状相同。5株细菌的16S rDNA序列间同源性为99.9%~100%,且与菊苣假单胞菌(Pseudomonas cichori)MAFF211996、TIs01和IP1-05菌株的16S rDNA序列同源性最高,为99%。利用菊苣假单胞菌hrcR基因的特异引物Hrp1a/Hrp2a进行PCR,从这5株细菌的DNA中均能扩增出大小约897 bp的特异片段;这些片段序列间同源性为99%~99.9%,且与P.cichori 83-1菌株hrcR基因的序列同源性为99.9%。这些结果表明,引起广东番茄髓部坏死病的病原为菊苣假单胞菌(P.cichorii)。生理生化试验显示,该病原菌与文献报道的菊苣假单胞菌的生理生化特征均相吻合,进一步证实引起广东番茄髓部坏死病的病原为菊苣假单胞菌。     

哈密瓜细菌性果斑病病原菌鉴定

 2000年在内蒙古和新疆的哈密瓜上发现一种新细菌病害-哈密瓜细菌性果斑病,从病叶和病果上分离到33个细菌菌株,接种哈密瓜、西瓜和甜瓜后,发病症状与自然发病症状完全一致,而且从接种病株上又重新分离到了此病原细菌,这33个细菌菌株经柯赫法则证明均为该病的致病菌。各菌株致病力无明显差异。经革兰氏染色反应、菌体形态、培养性状、生理生化反应、细胞化学成分分析(糖、蛋白质、氨基酸、脂肪酸、mol% G+C)、DNA-DNA杂交,确认该病原菌为燕麦食酸菌西瓜亚种(Acidovorax avenae subsp.citrulli Willems et al.1992)=类产碱假单胞菌西瓜亚种(Pseudomonas pseudoalcaligenes subsp.citrulli Schaad et al.1978)。该病菌除侵染哈密瓜外,人工接种尚能侵染多种葫芦科及番茄、茄子等作物。     

山东鱼台县发生番茄细菌性髓部坏死病

2001年在山东鱼台县大棚种植的番茄上首次发生番茄细菌性髓部坏死病，受害面积467hm^2，发病率达60％，造成植株枯死，个别大棚拔园，引起有关部门的重视。番茄细菌性髓部坏死病菌为皱纹假单胞菌，主要危害番茄和紫苜蓿。在南非、新西兰、丹麦、美国、法国、意大利、英国、日本、南斯拉夫、瑞     

进境澳大利亚豌豆细菌性萎蔫病病原菌的分离鉴定

 2008年3月自澳大利亚进口的豌豆种苗病变部位分离到致病性菌株,该菌株能引起豌豆茎部、卷须萎蔫腐烂,叶片褪绿等症状。针刺接种豌豆,发生的病变状态与自然发病的症状相同,且在接种发病植株中又分离到形态上一致的病原菌,得到了柯赫法则的验证。经形态特征、培养性状、生理生化及16S rDNA序列分析,鉴定其为桃色欧文氏菌(Erwinia persicina)。这是我国首次从进境豌豆中检出该病害。     

糜子细菌性条斑病病原菌鉴定及其对13种杀菌剂的敏感性

为有效防治糜子细菌性条斑病,采用平板划线分离法对2016年自黑龙江省齐齐哈尔市采集的罹细菌性条斑病的糜子植株进行病原菌分离与纯化,依据柯赫氏法则对其致病性进行测定;采用Biolog自动微生物鉴定系统、16S rDNA和16S-23S rDNA间隔区序列分析及病原菌的生理生化反应对病原菌进行鉴定;并测定该病原菌对13种常用杀菌剂的敏感性。结果显示,从糜子叶片和叶鞘病斑中共分离纯化获得10株培养性状一致的菌株,经柯赫氏法则验证均为细菌性条斑病病原菌。经Biolog鉴定,3株代表菌株与标准菌株燕麦噬酸菌Acidovorax avenae的相似值分别为0.716、0.705、0.723,序列分析显示,这3株代表菌株与燕麦噬酸菌燕麦亚种A. avenae subsp. avenae的一致性为99%以上;该病原菌的革兰氏染色反应及碳源利用等生理生化反应与对照菌株燕麦噬酸菌ICMP3183表现一致。因此,确定糜子细菌性条斑病病原菌为燕麦噬酸菌。糜子细菌性条斑病病原菌代表菌株MZ121101对80%乙蒜素乳油、30%乙蒜素乳油及0.3%四霉素水剂的敏感性较高,抑制中浓度EC50介于389.31～939.94μg/mL之间,这2种药剂可作为防治糜子细菌性条斑病的首选药剂。     

香料烟细菌性斑点病病原鉴定

 2004~2005年在云南保山香料烟上发现一种由细菌侵染引起的新病害,称为香料烟细菌斑点病。该病主要危害叶片,初为黑褐色水浸状圆形或多角形小斑点,以后病斑扩大、连片,形成不规则的较大坏死斑。从病叶上分离到了28株细菌菌株,菌株接种于香料烟上,发病症状与田间自然症状一致,并从回接病株上重新分离得到此病病原细菌。经过革兰氏染色反应、菌体形态、培养性状、LOPAT试验、生理生化特性分析和16S-23S rDNA序列分析,以及病原菌寄主范围测定,确定该病原菌为丁香假单胞菌烟草致病变种[Pseudomonas syringae pv. tabaci(Wolfet al.)Young et al.]。     

红掌细菌性疫病的病原菌初步鉴定

 在云南西双版纳的红掌上发现一种由细菌侵染引起的病害,从叶片的病组织上分离到具有致病性的杆状细菌,将分离的病原菌接种于健康的红掌上,表现出与田间一致的症状。感病初期在叶缘或叶脉间出现水渍状小点,后期病斑多呈棕褐色至黑色坏死,病健交界处多呈黄色。从接种发病的病斑与田间标样上分离的病原菌菌落形态完全相同。通过菌株的培养性状、常规生理生化特性及透射电镜下菌体形态观察结果,将病原菌初步鉴定为黄单胞菌属(Xanthomonas)。BIOLOG鉴定和致病性测定结果进一步鉴定病原菌为地毯草黄单胞菌花叶万年青致病变种Xanthomonas axonopodis pv. dieffenbachiae(Xad)(McCulloch & Pirone) Vauterin et al.     

向日葵细菌性茎腐病的研究Ⅰ.症状及病原菌鉴定

 本文首次报道了向日葵细菌性茎腐病在我国的发生。对分离到的20个菌株经形态学特性、培养性状、生理生化和血清学反应测定,确定引起我国东北地区向日葵细菌性茎腐病的病原细菌有三种,即Erwinia carotovora subsp.carotovora Dye,E.carotovora subsp.atroseptica Dye和Pseudomonas caryophylli (Burkholder) Starr and Burkholder。     

香蕉叶鞘腐败病病原鉴定

 香蕉叶鞘腐败病为近年来发生在广东、广西、海南等地蕉园的一种新病害。经病原菌分离及柯赫氏法则检测,证明引起该病的病原菌为一种细菌,根据致病性、寄主范围测定、菌体形态、培养特性、生理生化反应及16S rDNA序列分析将该病原细菌初步鉴定为成团泛菌(Pantoea agglomerans)。成团泛菌危害香蕉,引起叶鞘腐败病在国内尚属首次报道。     

广东省冬枣叶枯病病原菌的分离与鉴定

2018年2月,广东省清远市冬枣种植区发生了一种叶枯病,发病率约为17％,严重影响植株生长.为明确引起广东省清远市冬枣叶枯病的病原,采用常规病组织分离法获得2株菌株,通过致病性、生理生化特征和分子生物学对2株菌株进行鉴定.致病性测定结果显示,该细菌可侵染引起冬枣叶片产生枯死症状,与田间病株的症状相同.生理生化测定结果显...     

山东省生姜细菌性黄叶斑病病原鉴定

Ginger (Zingiber officinale Roscoe) is an important economic crop in China. Bacterial leaf spot disease is the major limiting factor for the ginger crop production in Shandong. In recent years, a bacterial leaf spot disease was observed on ginger in Laiwu and Anqiu, that became a major limiting factor in ginger production. Yellowish bacterial colonies that were obtained after incubation at 28°C for 2 days from infected leaves were purified by streaking on nutrient agar. The purified isolates were initially identified as Pantoea ananatis by the phenotypic and biochemical characterization. Further molecular identification based on the 16S rDNA sequence analysis and multilocus sequence analysis with the gyrB, rpoB, and atpD sequences confirmed that the isolates were P. ananatis. To our knowledge, this is the first report of bacterial leaf spot of ginger caused by P. ananatis in Shandong. Our study will provide basic references for disease management of this pathogen.     

西葫芦弯孢叶枯病病原菌Curvularia spicifera的鉴定

In June 2021, a new disease with necrotic symptoms affecting the leaves of Cucurbita pepo was observed in Yan'an city, Shaanxi province, China. Disease samples were collected and fifteen isolates (cucup1-cucup15) were obtained by tissue isolation and single spore purification methods. According to the morphological features and analysis of rDNA internal transcribed spacer (ITS) and RNA polymerase II second largest subunit (RPB2) sequences, the fungal isolates were identified as Curvularia spicifera, a new pathogen on C. pepo. The pathogenicity assay confirmed that C. spicifera was the pathogen causing this disease. This is the first record of leaf necrotic disease caused by C. spicifera in China.     

A new Fusarium lineage within the Gibberella fujikuroi species complex is the main causal agent of mango malformation disease in Brazil

Mango malformation is a serious disease in tropical and subtropical areas of the world and has been attributed to various Fusarium spp., including F. mangiferae , F. proliferatum , F. sacchari , F. sterilihyphosum and F. subglutinans . Isolates of Fusarium associated with mango malformation from Brazil, Egypt, India, South Africa and the United States were evaluated through amplified fragment length polymorphisms (AFLPs) and partial DNA sequences of the genes encoding β-tubulin ( tub2 ) and translation elongation factor 1-α ( tef1 ). These techniques were used to delimit species and to estimate the genetic and phylogenetic relatedness of the isolates. In the AFLP analysis, most of the Brazilian isolates formed a unique cluster. Additionally, one small cluster was formed by isolates of F. sterilihyphosum from Brazil and South Africa, and another by isolates of F. mangiferae from Egypt, India, South Africa and the United States. In the phylogenetic analysis, most of the Brazilian isolates represented a new phylogenetic lineage in the Gibberella fujikuroi species complex, where they formed a sister clade to F. sterilihyphosum. Representatives of both clades were pathogenic to mango (cv. Tommy Atkins) and Koch's postulates were completed for isolates belonging to the new lineage and to F. sterilihyphosum . Thus, most of the mango malformation disease in Brazil is due to a distinct phylogenetic lineage of Fusarium , and to a lesser extent by F. sterilihyphosum. The new phylogenetic lineage identified in this study, together with F. mangiferae and F. sterilihyphosum , are the only known taxa of Fusarium proven to be capable of causing mango malformation.     

芝麻细菌性青枯病病原菌及其生化变种鉴定

芝麻细菌性青枯病是我国南方芝麻生产上的重要病害。调查研究表明,芝麻青枯病除前人报道的萎蔫、顶梢常有溃疡裂缝等典型症状外,还有植株畸形、茎秆表皮泡状突起、溃疡裂缝延伸至茎秆中下部、折断茎秆可见菌脓形成的透明细丝等症状。分离获得的病原菌菌株经菌体形态、菌落形态、培养性状、致病性、烟草过敏性反应及16S rRNA基因和16S～23S rRNA基因间区ITS序列测定,证实了芝麻青枯病是由青枯菌Ralstonia solanacearum引起。江西省15个县(市)的22个代表性菌株的生化变种鉴定显示,20株菌属于生化变种Ⅲ,占90.91%,2株属于生化变种Ⅳ,占9.09%。说明生化变种Ⅲ菌群是诱发芝麻青枯病流行的优势种群。     

一种玉米新型细菌性褐腐病的病原鉴定

本研究从河北省武邑、献县、阜城和永年采集感病玉米植株。病株症状为叶梢枯死卷曲,叶脉产生黄色病斑,茎秆处黄褐色干腐。从发病植株中分离得到了10株疑似病原细菌菌株,经过回接验证和16SrDNA和gyrB基因的序列分析,结果表明,引起该病害的病原物为菠萝泛菌(Pantoea ananatis)和分散泛菌(Pantoea dispersa)。这是国内首次报道菠萝泛菌和分散泛菌引起玉米细菌性病害。     

玉米线虫矮化病病原鉴定

为明确东华北春玉米区暴发的一种危害严重、引起玉米植株矮化的新病害病原,从病区采集大量病株及其根际土壤,采用室内人工接种的方法对分离频率最高的3种镰孢菌,即亚粘团镰孢菌Fusarium subglutinans、拟轮枝镰孢菌F.verticillioides和层出镰孢菌F.proliferatum及线虫(群体)进行致病性测定。结果表明:有线虫(群体)的处理能够引起该病害典型症状,即植株矮化,叶片上有沿叶脉方向的黄色或白色失绿条纹,茎基部组织从内向外呈纵向或横向开裂,推断该病的发生和线虫有关。将回接发病植株病土中分离的矮化线虫属Tylenchorhynchus sp.、短体线虫属Pratylenchus sp.、发垫刃线虫属Trichotylenchus sp.、拟盘旋线虫属Pararotylenchus sp.、小环线虫属Criconemella sp.、垫刃线虫属Tylenchus sp.、丝尾垫刃线虫属Filenchus sp.、螺旋线虫属Helicotylenchus sp.和真滑刃线虫属Aphelenchus sp.进行分属后再回接,只有发垫刃属线虫的处理出现与田间发病症状一致的植株。综合形态特征、致病力和分子序列分析结果,确定该病病原为长岭发垫刃线虫T.changlingensis,并将该病害称为玉米线虫矮化病(maize nematode stunt disease)。     

壳聚糖对芒果离体叶片渗透胁迫的缓解效应

研究不同浓度壳聚糖溶液对芒果(Mangiferaindica)离体叶片在20%聚乙二醇(PEG-6000)渗透胁迫条件下生理生化的影响,结果表明,渗透胁迫下,壳聚糖可减缓叶片中水分的丧失以及叶绿素含量的下降,并能提高过氧化物酶活性和增加脯氨酸含量。因此,壳聚糖可有效缓解渗透胁迫对植物的损伤,提高植物的抗旱性。