甘薯茎腐病症状及其病原鉴定

 甘薯茎腐病是危害甘薯的一种严重病害,甘薯茎、叶柄、叶片和块根均可被害。该病典型症状是茎基部发黑和变软腐烂,叶发黄,茎和块根维管束黑褐色,引起块根腐烂、有臭味。通过对甘薯茎腐病典型症状样本的采集、病原菌的分离和纯化以及致病性测定,明确该病害是一种细菌病害。通过对甘薯茎腐病菌的菌体形态和培养特性观察发现,病原菌是革兰氏阴性细菌,菌体短杆状,大小约为2.36 μm×0.4 μm, 周生鞭毛,可在烟草上激发过敏性反应(HR)。Biolog测定、脂肪酸分析、16S rDNA序列分析、MALDI-TOF质谱鉴定和8个看家基因(dnaX、rplB、fusA、gapA、gyrA、purA、recA和rpoS)的序列系统发育分析,发现该病原菌与达旦提狄克氏菌Dickeya dadantii高度一致。这些结果说明,浙江省发生的小番薯病害是甘薯茎腐病,病原为D. dadantii。     

西北地区马铃薯疮痂病病原菌鉴定及其生物学特性

为明确西北地区马铃薯疮痂病病原菌的种类和生物学特性,分别采用常规组织分离法和土壤混悬液分离法从宁夏、陕西和甘肃3个省区采集的29份疮痂病发病薯块和8份发病地块土壤中进行病原菌分离,并利用形态特征、生理生化特性和16S rDNA序列分析对病原菌进行鉴定。结果表明,从发病薯块和发病土壤中共分离到50株链霉菌Streptomyces spp.,通过回接法验证获得6株马铃薯疮痂病致病菌株。6株致病菌株的培养特性和形态特征差别较大;其中菌株G4-1、G9和SYN13不能以果糖和木糖为单一碳源,菌株SYNT3不能以棉子糖为单一碳源;除菌株NLG4-1外,其余5株菌株均能在络氨酸琼脂培养基上产生黑色素。经16S rDNA序列分析,菌株G4-1、G9与疮痂病链霉菌S. scabiei的相似率分别达99.47%和99.34%,菌株NLG4-1、SYNT3与S. enissocaesilis的相似率分别达97.90%和98.18%,菌株GBH2与加利利链霉菌S. galilaeus的相似率达99.93%,菌株SYN13与S. turgidiscabies的相似率达97.56%,表明西北地区马铃薯疮痂病病原菌至少存在4个种。     

甘肃省马铃薯镰刀菌干腐病优势病原的分离鉴定

 为明确甘肃马铃薯镰刀菌干腐病的优势病原,2006 年12 月~ 2007 年3 月由西至东从甘肃张掖、天祝、永登、临洮、渭源和西和等6 县市的马铃薯贮藏窖中采集表现有镰刀菌干腐病症状的马铃薯薯块,以组织分离法分离病原,单孢纯化镰刀菌(Fusarium spp. )菌株后,以形态学为基础,参照Nelson 镰刀菌分类系统进行鉴定。结果表明:6 个采样区共分离到293株镰刀菌菌株,其中以接骨木镰刀菌(F. sambucinum)和茄病镰刀菌(F. solani)出现频率高,是优势种。分析发现第一优势种随采样区而异,张掖、天祝和渭源采集的样品中茄病镰刀菌分离频率分别为42. 6% 、42. 1% 和32. 4% ,接骨木镰刀菌分离频率分别为14. 8% 、5. 3% 和26. 5% ,茄病镰刀菌为第一优势种;永登、临洮和西和采集的样品中接骨木镰刀菌分离频率分别为52郾1% 、50. 9% 和55. 2% ,茄病镰刀菌的分离频率分别为23. 3% 、32. 7% 和20. 7% ,接骨木镰刀菌为第一优势种。本文进一步对其在PDA、CLA 上的培养特征进行了观察和描述。按照柯赫氏法则用混合菌株接种法对大西洋(Atlantic)、夏波蒂(Shepody)以及一地方品种进行致病性测定,证实了优势菌种对块茎的致病性。利用EF鄄1琢基因引物(EF鄄1H 和EF鄄2T)对接骨木镰刀菌菌株GAUF鄄F12 进行基因组DNA 的PCR 扩增,将PCR 产物回收测序后在GenBank 上比对,菌株GAUF鄄F12 与GenBank 登记的接骨木镰刀菌5 个菌株的同源性均达99% ;用DNASTAR 分析软件将同源性较高的登记菌株的序列与GAUF鄄F12 菌株构建同源性树,结果表明:该菌株与以上5 个接骨木镰刀菌菌株均位于同源性树的同一分支,聚为一类,与形态学的鉴定结果一致。     

甘薯病毒病害SPVD抗性鉴定方法及产量损失估计

为了建立规范、有效的甘薯病毒病害（sweet potato virus disease,SPVD）抗性鉴定方法,于2011—2012连续两年,利用田间人工嫁接病毒接穗的方法对12个甘薯品种进行抗性鉴定和产量损失测定。结果显示,嫁接接种后,接穗成活率接近100%,12个品种都有不同程度发病,病情指数在51.0~95.2之间;感染SPVD的甘薯植株叶绿素含量降低、蔓长缩短;单株薯块产量损失范围在55.1%~97.8%之间。研究表明,供试的12个甘薯主栽品种感染SPVD后均可引起严重的产量损失,且田间人工嫁接病毒接穗是一个有效的SPVD抗性鉴定方法。     

三叶木通叶斑病病原菌鉴定

叶斑病是三叶木通生长过程中一种严重的病害.为明确引起叶斑病的病原,从三叶木通人工栽培基地叶斑病样本上分离病原菌,对病原菌进行致病性测定、显微形态与分子鉴定.结果表明,三叶木通叶斑病病原菌为链格孢属细极链格孢(Alternaria tenuissima).     

福建马铃薯S病毒的分子鉴定及发生情况

为明确福建省马铃薯S病毒(PVS)的发生与分布情况,对福建省马铃薯主要种植区的PVS进行了鉴定和普查.在利用电镜技术和传统生物学方法鉴定的基础上,克隆了PVS外壳蛋白(cp)基因,依据PVS外壳蛋白氨基酸序列建立了PVS不同分离物的系统进化树.研究表明,利用PVS 外壳蛋白氨基酸序列分析可准确鉴定PVS,同时可分析不同分离物间的分子差异.利用病毒特异性引物和DIG标记的PVS cp基因为探针,分别利用RT-PCR技术和核酸斑点杂交技术(NASH)对PVS进行了检测,并对检测技术进行了改进.调查结果表明,PVS在福建省广泛分布,发病率最高可达80%以上,当地农家自留种可能是田间PVS的主要来源.     

甘薯爪哇黑腐病的病原鉴定

甘薯爪哇黑腐病是甘薯贮藏期的一种真菌性病害,是全球热带和亚热带地区甘薯贮藏期的重要病害之一。2013年我们从广东湛江采集的甘薯中,发现病薯薯块由两端向中间变黑变硬,切开发病薯块,在伤口处会逐渐长出黑色或灰色的菌丝。发病薯块室内放置30d后表面龟裂,裂口处有大量的黑色粉末溢出,显微镜下观察发现大量褐色有隔膜孢子。经对病原菌进行分离,采用柯赫氏法则回接验证,依据病原菌的形态特征和rDNA-ITS及β-tubulin基因序列,确定该病害为甘薯爪哇黑腐病,病原菌为可可毛色二孢(Lasiodiplodia theobromae)。致病性测定发现该病具有较强致病性,对于贮藏期甘薯具有较大威胁。这是国内首次对该病进行的报道。     

Suppressive effects of N-triacontanol on symptoms of mulberry dwarf disease and on the causal phytoplasma

N-triacontanol (TRIA) was applied over a period of 1 year to dwarf mulberry plants ( Morus alba ) with symptoms caused by mulberry dwarf phytoplasma. The treated plants recovered, and symptoms of the disease did not reappear for at least 3 years. Over this period, light-microscope UV fluorescence tests using berberine sulphate failed to detect phytoplasmas in the phloem of young shoots from the treated plants.     

蚕豆和豌豆锈病病原菌的分子鉴定

为明确我国热带和亚热带地区蚕豆Vicia faba和豌豆Pisum sativum锈病的病原菌种类,通过致病性测定和ITS序列系统发育分析对来自我国云南省玉溪市的4份豌豆锈菌分离物及云南、广西、重庆和四川省(区、市)的5份蚕豆锈菌分离物进行系统鉴定。结果显示,分离自豌豆的锈菌WX1分离物对蚕豆和豌豆均具有高致病性,在侵染叶片上产生大量锈子器;分离自蚕豆的锈菌CX3分离物仅对蚕豆具有高致病性,能在叶片上产生大量夏孢子,而对豌豆的致病性相对较低,仅产生少量的夏孢子堆;分离物WX1和CX3对小扁豆和鹰嘴豆不具有致病性。基于ITS序列系统发育分析表明,所有不同寄主来源的蚕豆单胞锈菌分离物均聚类于一个系统发育组,但分离自蚕豆和豌豆的分离物分别聚类在不同的亚组。表明分离自云南省玉溪市豌豆上的蚕豆单胞锈菌Uromyces viciae-fabae应为豌豆专化型,定名为U. viciae-fabae ex P. sativaum,而来源于云南、广西、重庆和四川省(区、市)的蚕豆锈病病原菌为蚕豆专化型U. viciae-fabae ex V. faba。     

佛手山药线虫病害发生调查与病原鉴定

湖北省武穴市佛手山药是“农产品地理标志产品”, 近年佛手山药线虫病害严重, 为此在病源地采集山药土样进行了病害发生调查及病原鉴定?通过形态特征观察?形态特征测计值比较, 以及基于rDNA 28S D2/D3区序列构建短体线虫属线虫群体系统进化树并进行SCAR验证, 对引起佛手山药线虫病的病原线虫进行种类鉴定?结果表明:危害佛手山药的病原线虫的群体特征与咖啡短体线虫Pratylenchus coffeae相似?系统进化树显示:该病原群体与中国香港群体(HQ688677.1)聚类在一个分支上, 置信度达99%?因此, 将该群体线虫鉴定为咖啡短体线虫Pratylenchus coffeae?此外田间调查表明:线虫主要集中分布于10~20 cm深度的土层中, 线虫密度随土壤深度的增加而呈递减趋势, 且连作1年地较连作2年地的线虫数量少, 施用阿维菌素的地块较未施用的线虫数量少?上述结果表明, 在佛手山药生产中实行轮作和科学选择药剂防治, 避免连作, 可降低该线虫发生量?     

麻黄根腐病病原物的分离及鉴定

 2001年从宁夏麻黄基地采集麻黄根腐病病株样品10份,按照柯赫氏法则对其进行了病原物的分离、纯化、致病性测定及菌株鉴定。结果表明,发病部位分离物中主要优势菌群为镰孢属(Fusarium spp.)。分离物经致病性测定和复合接种试验发现,微胶镰孢Fusarium subglutinans致病性最强,接种后发病株率达60%以上,尖孢镰孢F. oxysporum、半裸镰孢F. semitectum、茄镰孢蓝色变种F. solani var. coeruleum和茄镰孢F. solani致病性弱,接种发病率为10%~20%,它们和微胶镰孢混合接种后的发病率均高于单独接种的发病率,其中微胶镰孢与含尖孢镰孢或半裸镰孢的组合接种发病率高于不含这2种镰孢的组合。病株上获得的其它分离物均无致病性。证实麻黄根腐病是以微胶镰孢为主要病原,并由尖孢镰孢、半裸镰孢和其它几种镰孢复合侵染导致的一种病害。     

灯盏花叶斑病病原物的分离及鉴定

首次报道了灯盏花主要栽培区发生的叶斑病的危害情况及其症状,经过病原物的分离鉴定、致病性试验,证明该病由Alternaria alternata侵染所致,灯盏花是该病菌的新记录寄主。     

Root-lesion nematodes of potato: Current status of diagnostics,pathogenicity and management

Root-lesion nematodes of the genus Pratylenchus are migratory endoparasites with worldwide economic impact on several important crops including potato, where certain species like P. penetrans, P. neglectus, and P. scribneri reduce the yield and quality of potato tubers. Morphological identification of Pratylenchus spp. is challenging, and recent advancements in molecular techniques provide robust and rapid diagnostics to differentiate species without the need of specialist skills. However, the fact that molecular diagnostics are not available for all Pratylenchus species means that there are limitations in worldwide application. In general, root-lesion nematodes are difficult to manage once introduced into agricultural land and damage can be related to pathogenicity and population densities. In addition, root-lesion nematodes interact with fungi such as Verticillium dahliae, resulting in disease complexes that enhance the damage inflicted on the potato crop. Management interventions are often focused on limiting nematode reproduction before planting crops and include the application of nematicides, and cultural practices such as crop rotation, cover crops, biofumigation, and biological control. Understanding the limitations of the available crop protection strategies is important and there are many gaps for further study. This review discusses the status of the diagnosis, distribution, pathogenicity, and management of the main species of root-lesion nematodes, reported to infect potatoes worldwide, and highlights areas for potential future research.     

玉米顶腐病鉴定

报道了玉米顶腐病发生的系统性症状特点及病原菌鉴定的结果。玉米顶腐病抽穗前主要表现叶缘缺刻、叶片枯死、扭曲卷裹、弯头、顶叶丛生;抽穗后表现为叶片基部腐烂,叶鞘、茎秆腐烂,植株畸形。叶缘缺刻和叶片撕裂是顶腐病区别于其他病害的鉴别性特征。引起玉米顶腐病的病原菌小分生孢子呈假头状着生,而不是串珠状着生,因此,将该病原菌鉴定为亚粘团镰孢霉[Fusarium subglutinans（Wr．＆Reink．）Nelson,Toussoun ＆ Marasas]。引起茎、叶部两种症状的亚粘团镰孢霉同源性很高,在遗传上具有较高的相似性,是同一病原。与串珠镰孢霉复合侵染可加重病害的发生,其发病率较单独接菌高11．1％。     

玉米顶腐病鉴定

报道了玉米顶腐病发生的系统性症状特点及病原菌鉴定的结果。玉米顶腐病抽穗前主要表?叶缘缺刻、叶片枯死、扭曲卷裹、弯头、顶叶丛生;抽穗后表?为叶片基部腐烂,叶鞘、茎秆腐烂,植株畸形。叶缘缺刻和叶片撕裂是顶腐病区别于其他病害的鉴别性特征。引起玉米顶腐病的病原菌小分生孢子呈假头状着生,而不是串珠状着生,因此,将该病原菌鉴定为亚粘团镰孢霉[Fusarium subglutinans(Wr.&;Reink.)Nelson,Toussoun&;Marasas]。引起茎、叶部两种症状的亚粘团镰孢霉同源性很高,在遗传上具有较高的相似性,是同一病原。与串珠镰孢霉复合侵染可加重病害的发生,其发病率较单独接菌高11.1%。     

马铃薯黑痣病病原菌分子鉴定及其生物学特性

随着马铃薯产业迅速发展,种植面积不断扩大,轮作倒茬年限逐渐缩短,诸多病害呈逐年加重的趋势,影响了马铃薯的产量和品质。黑痣病Rhizocto-nia solani是一种普遍且危害严重的土传病害。据调查,2009年内蒙古乌兰察布市马铃薯种植区黑痣病发病率为2.7%～52.3%,发病严重地块的植株死亡率高达90%。据Dj bali&Belhassen[1]报道,该病害能够造成马铃薯减产50%。马铃薯黑痣病菌侵害芽形成褐色斑并致芽坏死,地下茎和匍匐茎受侵表皮形成紫褐色溃疡斑,侵害薯块导致薯块畸形并在其表皮形成黑色颗粒状物。目前,国内关于马铃薯黑痣病的相关报道极少。本试验进行了马铃薯黑痣病病原菌鉴定和生物学特性研究。     

First application of PCR-Luminex system for molecular diagnosis of fungicide resistance and species identification of fungal pathogens

Fungicide resistance in plant pathogens is often caused by a single point mutation in a gene encoding fungicide target proteins. Such is the case for resistance to MBI-D (inhibitors of scytalone dehydratase in melanin biosynthesis) fungicides in rice blast fungus (Magnaporthe oryzae), which is caused by a mutation in the scytalone dehydratase gene that results in a replacement of valine with methionine at codon 75 of the fungicide target protein. PCR-Luminex, a novel system developed for high-throughput analysis of single nucleotide polymorphisms (SNPs) was successfully introduced to diagnose MBI-D resistance using specific oligonucleotide probes coupled with fluorescent beads. The PCR-Luminex system was further tested for its potential in identifying species causing Fusarium head blight on wheat. Four major pathogens, Fusarium graminearum (=F. asiaticum), F. culmorum, F. avenaceum, and Microdochium nivale, known to cause the disease, were tested, and the species were identified using the PCR-Luminex method. So far, this report is the first on the application of the DNA-based PCR-Luminex system in the area of crop protection and/or agricultural sciences.     

Identification of the pathotype of Synchytrium endobioticum,causal agent of potato wart disease,present in Georgia

Potato wart is one of the most important quarantine diseases of potato in the world. In Georgia, symptoms of wart were first seen in 2009–2013 during observations on potato in home gardens in Khulo district, although they may have been present since 2006. However, potato wart presence was only confirmed by PCR in 2013. Isolates pw13N and pw13 of Synchytrium endobioticum collected from the infested area of the village Didadjara, Khulo municipality were tested using laboratories in Georgia and the Netherlands in the framework of collaboration between scientists of Batumi State University and the National Plant Protection organization of the Netherlands. Additionally, pot tests were carried out in Georgia. Based on the results obtained, the pathotype found in Georgia is not known from Europe, and based on its reactions this pathotype resembles pathotype 38 (Nev?ehir) detected in (the non‐European part of) Turkey.