香榧根腐病病原菌鉴定

为明确香榧根腐病病原菌的种类,本研究采用常规组织分离法分离纯化病原菌,根据柯赫氏法则对病原菌进行致病性检测,通过形态学和分子生物学鉴定确定病原菌种类。对香榧病株进行常规组织分离,分离纯化得到12个菌株,经分子生物学鉴定将这12个菌株归为10类,分别用ZJ-1至ZJ-10表示;将ZJ-1至ZJ-10进行致病性检测,根据柯赫氏法则,证实ZJ-10是香榧根腐病的病原菌;结合菌株形态学特征和ITS rDNA序列,可将ZJ-10菌株鉴定为腐皮镰孢菌(Fusarium solani)。即香榧根腐病的病原菌是腐皮镰孢菌。     

甘肃高寒阴湿区豌豆根腐镰刀菌种群及致病性研究

甘肃省高寒阴湿区豌豆镰刀菌根腐病的病原有5种,即茄病镰刀菌[Fusarium solani(Mart.)Sacc]、茄病镰刀菌蓝色变种(Fusarium sola-ni var.coeruleum)、半裸镰刀菌(Fusarium semitec-tum)、单隔镰刀菌(Fusarium dimerum)、拟丝孢镰刀菌(Fusarium trichothecioides)。茄病镰刀菌致病性最强,拟丝孢镰刀菌和茄病镰刀菌蓝色变种次之,半裸镰刀菌和单隔镰刀菌的致病性较弱。其中半裸镰刀菌、单隔镰刀菌、拟丝孢镰刀菌是中国豌豆病原菌上的新纪录。     

亳州地区凤丹根腐病病原鉴定

为明确安徽亳州地区凤丹根腐病病原菌种类,观测了凤丹根腐病症状,通过对其病原菌分离纯化培养,依据病原菌形态特征、致病性、rDNA-ITS序列分析,鉴定病原菌种类。分离得到1种纯化菌株,其形态学特征与已报道的茄病镰刀菌(Fusarium solani)一致。在健康凤丹根部接种该分离培养的病原菌,引起的病害症状与田间症状相似。在Gen Bank进行同源性BLAST比较,该病原菌rDNA-ITS序列与4个已登录的茄病镰刀菌聚为一类,登录号为HQ176440.1、EU327190.1、HQ839783.1、JX524023.1。结果表明导致亳州栽培凤丹根腐病的病原菌为茄病镰刀菌。     

甜菜立枯病病原菌的分离和鉴定

旨在明确黑龙江大学呼兰校区甜菜立枯病的病原菌种类,为科学防治该病提供理论参考。以采自黑龙江大学呼兰校区的甜菜立枯病植株为试材,用形态学观察、致病性测定和分子生物学鉴定方法,依据柯赫氏法则,对病原菌进行分离和鉴定。结果表明,从发病甜菜幼苗根部上分离出的菌株L1,菌丝呈白色。大型分生孢子为镰刀型,有隔膜,小型分生孢子多为单细胞少数有隔膜。分子鉴定结果显示,该病原菌在基于ITS和tef1序列构建的系统发育树上与腐皮镰孢菌类群处同一分支。根据形态学和分子鉴定结果,确定引起黑龙江大学呼兰校区甜菜立枯病的病原菌为腐皮镰孢菌(Fusarium solani)。     

人参根腐病病原菌的鉴定与致病力检测

人参病害严重影响着人参产业的持续健康发展,为明确人参根部病害的发病情况及致病菌种类,本研究从中国农业科学院特产研究所左家资源圃的患病人参植株上共分离纯化获得8株致病菌株,在PDA培养基上观察病原菌菌落及分生孢子形态特征,采用rDNA-ITS序列分析方法鉴定了人参根腐病主要致病菌种类。结果表明,分离纯化的菌株中,6株为腐皮镰刀菌(Fusarium solani),rDNA-ITS序列与GenBank中的腐皮镰刀菌相似性达99%;2株为尖孢镰刀菌(Fusarium oxysporum),rDNA-ITS序列与GenBank中的尖孢镰刀菌相似性达99%。2种病原菌的致病性测定结果表明,腐皮镰刀菌的致病力要比尖孢镰刀菌的强一些。本研究结果对人参抗病育种和致病机理的研究具有一定的指导作用。     

甘肃省张掖市玉米黑髓病病原的分离与鉴定

为明确引起甘肃省张掖市玉米黑髓病的病原菌种类,于2021年9月,在甘肃省张掖市采集具有典型病害症状标本,利用组织分离法进行分离纯化,并通过柯赫氏法则验证致病性;利用形态学特征和分子生物学方法进行鉴定。结果表明,于病样中共获得39株分离物,能引起与田间症状相一致的病原菌30株,表现症状为根茎腐烂型、根腐型和茎腐型3类。根据形态特征将30株病原物均鉴定为镰孢霉属真菌,结合分子生物学方法将30个致病镰孢霉菌分别鉴定为拟轮枝镰刀菌(Fusarium verticillioides)、尖孢镰刀菌(F.oxysporum)、层出镰刀菌(F.proliferatum)、茄病镰刀菌(F.solani)、变红镰刀菌(F.incarnatum)和柔毛镰刀菌(F.flocciferum),其分离频率依次为50.00%、20.00%、16.67%、6.67%、3.33%和3.33%,其中拟轮枝镰刀菌为张掖市玉米黑髓病的优势致病菌,首次报道柔毛镰刀菌可以侵染玉米。该研究结果为玉米黑髓病的诊断和防治提供了依据。     

渝产多花黄精根腐病病原菌的分离与鉴定

为了明确重庆地区多花黄精根腐病的病原菌,并进一步为该病害的防治提供理论依据。采集典型根腐病症状的多花黄精样品,通过切片和组织分离法对病原菌进行分离和纯化。按柯赫氏法则对其致病性测定,并对其中毒性最强的菌株L_1和L_6进行形态学、分子生物学鉴定。结果表明:分离的致病菌经形态学初步鉴定分别为尖孢镰刀菌(Fusarium oxysporum)和腐皮镰刀菌(F. solani);柯赫氏法则表明两种病原菌都能使多花黄精发病,发病症状与田间症状一致,且存在复合侵染现象;PCR技术扩增病菌rDNA-ITS基因,获得长度为600 bp、570 bp的DNA片段,菌株序列与尖孢镰刀菌和腐皮镰刀菌的序列同源性分别达到99%;ITS系统发育树上,L_1与尖孢镰刀菌和L_6与腐皮镰刀菌聚在同一分支上。结合形态特征、序列分析和系统进化分析,确定尖孢镰刀菌和腐皮镰刀菌是引起多花黄精根腐病的病原菌。本研究可为根腐病拮抗菌的筛选和多花黄精——根腐病互作机理研究提供帮助。     

四川茂县花椒根腐病病原菌的分离与鉴定

旨在明确引起阿坝藏族羌族自治州茂县花椒根腐病的病原菌种类,为科学有效防治该病提供理论参考。以采自茂县的花椒根腐病病根为材料,通过组织分离法、致病性测定、形态学观察与基于核糖体转录间隔区序列(ITS)和延长因子基因(tef1)的分子鉴定相结合进行病原菌的分离鉴定。结果表明,病原菌菌丝初为灰白色,后为兰褐色或紫红色。大型分生孢子为镰刀形,小型分生孢子呈肾形。分子鉴定结果显示,该病原菌在基于ITS和tef1序列构建的系统发育进化树上与腐皮镰孢菌类群处于同一分支。根据形态学和分子鉴定结果,将引起四川茂县花椒根腐病的病原菌鉴定为腐皮镰孢菌(Fusarium solani)。     

麻疯树枝枯病病原鉴定及生物学特性测定

为了确定麻疯树枝枯病的病原及致病性,笔者通过形态和分子的方法鉴定出麻疯树枝枯病病原菌为Lasiodiplodia theobroma,查阅分析相关资料发现其是一种新病害,因此采用文字和插图方法对病害进行详细描述。结果表明,引起麻疯树枝枯病的病原为Lasiodiplodia theobroma,在此基础上完成病原菌生物学特性测定,发现病原菌是一种弱致病性真菌,在温度为28~30℃,pH值为6~7,培养基以葡萄糖、蔗糖、酵母粉为营养源的条件下利于病原菌营养生长;在温度为20~30℃,pH值为7,湿度在90%~100%,灭菌水的条件下病原菌孢子都能够正常萌发,其中光照刺激利于病原菌孢子的形成;测定还发现,病原菌对丙唑-多菌灵最敏感,而对苯醚甲环唑、链霉素、百菌清、乙蒜素、丙环唑、环胺类农药不敏感。病原菌生物学特性表明其非常适合干热河谷地理环境,能够在土壤和枯枝落叶中广泛存在。因此,预测病原菌在干热河谷环境中初侵染接种体数量大,一旦大量寄主受伤,雨水充足病害极易爆发成灾,建议防治病害一方面要消除寄主树势衰弱的诱因,减少病害发生侵染的机会,另一方面要科学合理地施用农药。     

进境水果重要真菌病害——星裂壳孢梨果腐病和苹果果腐病

星裂壳孢梨果腐病和苹果果腐病分别由Phacidiopycnis(缩写:Ph.)pyri和Ph.washingtonensis侵染所致,这两种真菌性病害在我国尚未有发生为害的报道,前者在欧洲和北美梨和苹果产区为害严重,而目前后者则仅在美国报道.本文介绍了以上两种病害的发生分布、寄主范围、病原菌及其形态特征、侵染特点及为害症状、病原菌培养性状、生物学特性、分离和鉴定方法、致病性测定及简要的防治方法;初步分析了病害的传播途径.自2008年4月起首次并连续3次从佛山澜石口岸截获的美国进境苹果中截获星裂壳孢苹果果腐病(Ph.washingtonensis),根据此疫情本文阐述了梨果腐病和苹果果腐病在我国口岸检疫的重要性.     

Overcoming chronic malnutrition in a future warming world: the key importance of mungbean and vegetable soybean

Stripe rust, caused by Puccinia striiformis, has been an important disease of wheat, barley, rye, triticale and certain graminaceous hosts for centuries. The significance of the disease on cultivated cereals has waxed and waned according to the vagaries of climate, inoculum levels and susceptible varieties. A progressive understanding of pathogen biology has revealed levels of specialisation between and within host groups, and these had varying impacts on the hosts concerned. The most economically important form is P. striiformis f. sp. tritici (Pst), the causal pathogen of stripe (yellow) rust of wheat, which is the major focus of this paper. The recent discovery of the perfect stage of Pst on Berberis spp. will encourage further work to uncover the potential importance of the sexual stage in pathogen biology in regions where Berberis spp. occur. A review of the evolution of pathotypes within Pst over the past 50 years reveals recurrent pandemics emanating from a combination of specific virulence in the pathogen population, wide scale cultivation of genetically similar varieties, and agronomic practices that led to high yield potential. When these factors operate in concert, regional stripe rust epidemics have proven to be dramatic, extensive and serious in terms of the magnitude of losses and the economic hardships endured. A review of these epidemics suggests that little progress has been made in containing the worst effects of epidemics. The current status of stripe rust was gauged from a survey of 25 pathologists and breeders directly associated with the disease. It was evident that Pst remains a significant threat in the majority of wheat growing regions of the world with potential to inflict regular regional crop losses ranging from 0.1 to 5%, with rare events giving losses of 5–25%. Regions with current vulnerability include the USA (particularly Pacific North West), East Asia (China north-west and south-west), South Asia (India, Pakistan, Nepal), Oceania (Australia, New Zealand), East Africa (Ethiopia, Kenya), the Arabian Peninsula (Yemen) and Western Europe (east England). The resources deployed to contain the worst effects of Pst will need to find a balance between training a new generation of breeders and pathologists in host-pathogen genetics, and an investment in infrastructure in IARCs and NARs.     

The population genetics of plant pathogens and breeding strategies for durable resistance

The durability of disease resistance is affected by the evolutionary potential of the pathogen population. Pathogens with a high evolutionary potential are more likely to overcome genetic resistance than pathogens with a low evolutionary potential. We will propose a set of guidelines to predict the evolutionary potential of pathogen populations based on analysis of their genetic structure. Under our model of pathogen evolution, the two most important parameters to consider are reproduction/mating system and gene/genotype flow. Pathogens that pose the greatest risk of breaking down resistance genes are those that possess a mixed reproduction system, with at least one sexual cycle per growing season and asexual reproduction during the epidemic phase, and a high potential for gene flow. The lowest risk pathogens are those with strict asexual reproduction and low potential for gene flow. We will present examples of high- and low-risk pathogens. Knowledge of the population genetic structure of the pathogen may offer insight into the best breeding strategy for durable resistance. We will present broad guidelines suggesting a rational method for breeding durable resistance according to the population genetics of the pathogen. This revised version was published online in August 2006 with corrections to the Cover Date.     

四川省无花果疫霉病病原鉴定

为明确四川省无花果爆发的疫霉病病原菌种类,对四川省无花果种植区的无花果疫霉病的发生进行调查,并采集发病果实。采用组织分离法对无花果疫霉病的病原菌进行分离培养,并通过形态与分子鉴定相结合对该病原菌进行鉴定。结果表明,病原菌菌丝为白色;卵孢子球形;孢子囊椭圆形或卵形,顶端有乳突。分子生物学鉴定结果显示：四川省无花果疫霉病病原菌与棕榈疫霉(Phytophthora palmivora)序列同源性高达99%。根据形态学和分子鉴定,将四川省无花果疫霉病病原菌鉴定为棕榈疫霉(Phytophthora palmivora)。     

Methods for detecting the cassava bacterial blight pathogen: A practical approach for managing the disease

Cassava bacterial blight (CBB), caused by Xanthomonas axonopodis pv. manihotis (Xam), is a particularly destructive disease in South America and Africa. The movement of infected asymptomatic stems is a major means of pathogen dispersal as well as infected seeds. The success of a cassava-seed certification program depends on the availability of reliable tests to detect the pathogen in vegetative planting materials and true seeds. We report here the different methods that permitted to detect the pathogen in cassava tissues. A polymerase chain reaction (PCR) test was developed for this pathogen. The PCR assay worked well for pathogen detection in extracts from leaf and stem lesions and the minimum number of cells that could be detected ranged from 3 × 10² to 10⁴ CFU per ml. Nested-PCR worked well for Xam detection from naturally infected seeds. This technique was specific, sensitive, and rapid for detecting Xam in cassava true seeds. The highest detection level found was 1–2 viable cells per reaction. A dot-blot assay was developed by evaluating a 898 bp DNA fragment unique to Xam strains as a diagnostic DNA probe. The probe detected Xam strains in crude extracts of leaf and stem lesions, cassava fruits and sexual seeds that were naturally infected. Overall sensitivity of the dot-blot method was about10³CFU per reaction. The dot-blot hybridization technique can be easily used for culture indexing. A monoclonal antibody (MAb) was also used for an enzyme-linked immunosorbent assay (ELISA) and tested with various infected tissues. Overall sensitivity of the method was about10³CFU per reaction. This revised version was published online in July 2006 with corrections to the Cover Date.     

北京萝卜萎蔫病病原鉴定及病原生长影响因子

2009年北京郊区发生一种萝卜(Raphanus sativus L.)新病害,其主要症状表现是叶子黄化萎蔫,生长受阻。针对该病的发生,作者采集典型发病植株进行病原菌的分离纯化,用传统的形态学方法和rDNA-ITS序列分析方法进行病原鉴定,并进一步对病原菌生长影响因子进行研究,以便为该病的进一步深入研究、抗病种质资源的筛选和抗病品种的选育打下基础。研究认为该病由大丽轮枝菌(Verticillium dahliae)侵染引起。该病原菌生长适宜温度为20~25℃,适宜pH为6~8,该病原菌能够很好地利用多种氮源和碳源,氮源以硫酸铵最为适宜,碳源则已可溶性淀粉最适宜。这是首次报道由大丽轮枝菌侵染引起的萝卜黄萎病在中国的发生。     

马占相思心腐病发生初期的病原鉴定

为了明确马占相思心腐病发生初期的病原菌种类,为病害的早期诊断和防治提供依据,笔者从广东省龙眼洞国营林场外表无症状的6年生马占相思树上采集病样36份,分离出3种担子菌,通过田间枝条接种、室内木块接种测定其致病性。结果显示,3种担子菌在6年生马占相思树1年生健康枝条上接种20天,枝条髓心变褐深度分别为5.0、2.4、7.0 cm;室内25℃下接种61天,木块腐朽质量损失分别为25.88%、31.48%、21.02%。对3种担子菌进行PCR扩增,测定核糖体DNA（rDNA）内转录间隔区（ITS）的序列,将测序结果在GenBank中进行同源性比对分析,结合形态特征,确定3种病原菌分别为Phanerochaete avellanea、Peniophora aurantiaca、Phlebia brevispora。得出结论：Phanerochaete avellanea、Peniophora aurantiaca和Phlebia brevispora具有侵染枝条和使木块腐朽的能力,是马占相思心腐病发生初期的病原菌。     

一种引起火龙果茎病害的病原菌鉴定

对贵州省西南地区火龙果种植园发生的一种茎病害进行发病率调查,并对其病原菌进行鉴定。结果表明：该茎病害的发病率为10%~20%,病原菌显微结构观察和分子鉴定结果表明其为黑附球菌(Epicoccum nigrum)。本研究是该病原菌对火龙果危害的初次报道。     

百香果茎基腐病菌分离鉴定与药剂筛选研究

为研究百香果产业中多发病害茎基腐病的病原菌鉴定与防治问题,在广东省百香果主产区采集茎基腐病病株,结合形态学观察与分子测序方法鉴定分离病原菌菌株,并对其进行致病性检测,同时检测系列杀菌药剂对病菌生长及其致病性的影响。结果表明,通过形态特征观察、分子生物学鉴定,从百香果茎基腐病病株中分离获得的8个菌株鉴定为腐皮镰刀菌(Fusarium solani)。离体和活体致病力测试结果显示,致病力较高的菌株为FP6、FP7、FP2,其次为FP1、FP3、FP8、FP4,最低为FP5。不同药剂处理对病菌的生长及致病力均产生影响,其中30%苯甲嘧菌酯处理的抑制效果为最佳。研究结果可为后续百香果茎基腐病病理学、百香果抗病育种等研究提供基础。     

Adaptation of wheat rusts to the wheat cultivars in former Czechoslovakia

Summary In former Czechoslovakia virulence of rusts attacking wheat was studied since the sixties. Since the same time genes for resistance in the registered cultivars were identified. The role of Berberis and Thalictrum as alternate hosts for stem rust and leaf rust, respectively, was investigated as well. Determined changes of virulence in rust populations could only partially be ascribed to changes of resistance genes in the grown cultivars. Unnecessary genes for virulence had no negative effect on the fitness of the pathogen. All tested samples of aeciospores from barberries attacked rye, not wheat. None of Thalictrum species occurring in the Czech and Slovak Republics was found to host wheat leaf rust. However, the sexual stage of wheat stem rust and wheat leaf rust could be induced on Berberis vulgaris and Thalictrum speciosissimum, respectively. General epidemiological conclusions are drawn from the results and experience of the last 35 years.     

小麦白粉病经济阈值和预报模型的研究

采用相关分析和逐步回归分析方法,建立了小麦白粉病的中短期(60～90天)预报模型,经15年次实际调查数据检验,拟合率达99％以上。采用协方差分析求得了不同病情指数与小麦产量损失关系的直线回归方程,据此方程求出不同产量水平下防治经济阈值,经大面积示范,验证其切实可行。