喀麦隆芋艿根腐病病原菌鉴定

从采自喀麦隆没地区的芋艿病根及田土中分离菌株,分别从雅温得和巴马约分离到的腐霉菌株ＸＰＭＹ和ＸＰＭＭ１,根据其形态学及生理学特征鉴定为群结腐霉Ｐｙｔｈｉｕｍ ｍｙｒｉｏｔｙｌｕｍ,用上述腐菌株的注重动孢子县液或菌丝体片断悬液人工接种,表现叶黄黄化及根共型症状。肜经各结腐霉的立估丝Ｒｈｉｚｏｃｔｏｎｉａ ｓｏｌａｎｉ及茄镰孢Ｆｕｓａｒｉｕｍ ｓｏｌａｎｉ人工接种后均表现症状。研究结果表明：群结腐霉Ｐ     

蓖麻根腐病抗性鉴定及其SSR标记的初步建立

蓖麻根腐病是茄腐镰孢菌(Fusarium solani)引起的根部病害,严重影响蓖麻产量。抗源缺乏制约了抗病品种的选育。为寻找抗病种质、建立抗性分子标记,该研究对252份蓖麻材料的抗性进行了表型和分子标记鉴定。结果表明:(1)浓度为1×10⁶个·mL^-1的孢子悬浮液灌根是一种有效的接种方法; 以接种后枯萎天数为基础的5级评价法,可作为鉴定标准。(2)鉴定出130份抗病材料,其中高抗为105份。(3)野生材料中抗病材料比率(66%)远高于栽培材料(35%),建议将野生材料,尤其是中国华南野生材料的研究利用作为今后抗病育种的重要方向。(4)初步建立了8个与抗性关联的SSR标记。该研究结果提供了有效的根腐病抗性鉴定方法和评价标准,筛选出了一批育种迫切需要的抗病基因资源,初步建立了可用于辅助选择的SSR标记,为蓖麻抗根腐病育种奠定了重要基础。     

蓝莓腐霉根腐病的病原菌

在山东青岛新发现一种蓝莓根腐病害,症状最初出现在根部,病根腐烂坏死,根状茎维管束和皮层变黑,导致根数量减少,叶片变黄、变红,植株生长不良,严重时叶片全部脱落,植株死亡。通过组织分离法和菌丝段分离法获得纯化菌株HMQAU 180018,经柯赫氏法则验证,综合形态学特征及ITS区和cox I基因序列分析,菌株HMQAU 180018被鉴定为畸雌腐霉Pythium irregulare。这是国内首次描述畸雌腐霉引起蓝莓根腐病的报道。     

三江平原地区大豆根腐病病株上镰孢菌的分离鉴定

为了明确引起三江平原地区大豆根腐病的镰孢菌(Fusarium)种类及优势种群,对该地区大豆根腐病样本进行了采集。通过组织分离和形态学鉴定,共鉴定出6种镰孢菌,分别为木贼镰孢(F.equiseti)、尖孢镰孢(F.oxysporum)、芬芳镰孢(F.redolens)、半裸镰孢(F.semitectum)、腐皮镰孢(F.solani)和拟轮枝镰孢(F.verticillioides)。其中尖孢镰孢(F.oxysporum)的分离频率最高,达16.67%。对6种镰孢菌的形态学特征进行了描述。     

一株抗玉米纹枯病内生细菌的分离鉴定及其抗病促生作用

玉米纹枯病是玉米主要的真菌病害,从优良玉米品种川单13号中分离到一株对玉米纹枯病菌具有明显抑制作用并能够促进玉米生长的内生细菌.通过形态、生理生化特性分析以及16SrDNA序列同源性比较,鉴定该菌株为枯草芽孢杆菌.盆栽试验表明,菌株能够抑制玉米纹枯病的发生,抑菌率为 43.01%,促生试验表明,该菌能够显著促进玉米苗的生长,促生作用与植物生长刺激素(IAA)和效果相似,显示出良好的开发前景.     

云南金铁锁根腐病病原菌的分离及鉴定

金铁锁(Psammosilene tunicoides)是西南地区重要的民族民间药物、云南白药等中成药的主要原料药。为分离并鉴定云南金铁锁根腐病病原菌,该研究采用微生物纯培养方法,分离纯化金铁锁根腐病植株根部的病健交接处组织,获得金铁锁根腐病病原微生物。按照Koch''s法则验证分离得到的病原菌的致病性。结合形态学观察、真菌rDNA-ITS和TEF-1α序列分析以及系统发育树的构建鉴定获得的病原菌的种类。结果表明:(1)从金铁锁根腐病植株组织中分离纯化得到85株真菌,其中PSD-1、PSD-2、PSD-3菌株均能引起金铁锁的根腐病。(2)金铁锁健康植株接种PSD-1、PSD-2、PSD-3菌株后,产生与大田植株根腐病相似的症状,并且发病率分别为60%、61.7%、71.7%。(3)结合形态学观察及基因序列分析,鉴定该三株菌株均为尖孢镰刀菌(Fusarium oxysporum)。该文首次报道了尖孢镰刀菌是引起金铁锁根腐病的主要病原菌之一,为深入探究具有根腐病生物防治功能的内生菌群及其作用机制奠定了基础,也为后续金铁锁病害的防治工作提供了理论依据。     

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。     

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。     

中国小麦雪霉叶枯病菌种的鉴定

系统研究和鉴定了产自中国陕西、青海、宁夏、四川、贵州、西藏、湖北、新疆等8个省区的31个小麦雪霉叶枯病菌菌系和1个产自捷克的菌系。结果表明,各菌系的培养性状和形态特征、尤其是环痕状的产孢细胞和具淀粉质顶环的子囊等均符合 Gerlachia nivalis (Ces.Ex Sate．)W．Gares & E．Mdll．[有性态：Monographella nivalis (Schaffn·)E·Mfill·]的鉴别特征。小麦雪霉叶桔病菌对三唑酮等8种药物比镰刀菌敏感,各菌系人工接种小麦幼苗均引起相同症状,人工接种可侵染22属55种禾本科植物。确认了该菌与欧洲、北美发生的红色雪霉病病菌为同种。因此,将中国小麦雪霉叶枯病菌定名为雪腐格氏霉[Gerlaehia nivalis(Ces．Ex Saee．)W．Gams ＆ E. Miill.]。     

Root Rot and Wilt of Kangaroo Paw (Anigozanthos manglesii) Caused by Pythium myriotylum (Drechs.) in Israel

A root rot and wilt disease of Anigozanthos manglesii (Kangaroo Paw) grown in greenhouses in Israel, for exporting as cut flowers to Europe, was characterized. Pythium myriotylum (Drechs.) and Rhizoctonia solani (Kühn) were the prevalent pathogens in diseased plants collected from commercial greenhouses. Fusarium oxysporum, Fusarium spp. and Myrothecium sp. were also isolated, but P. myriotylum or R. solani were not detected in samples from symptomless plants in tissue cultures (Australian origin) or plants at different stages in the nursery; non‐pathogenic F. oxysporum and Fusarium spp. were detected in several samples. In pathogenicity tests carried out in pots, plant mortality occurred 7 days after inoculation with P. myriotylum. In a field experiment carried out in methyl bromide‐fumigated soil, the incidence of dead plants following inoculation with P. myriotylum alone was 22% 10 days after inoculation, increasing to 78% after an additional 25 days. The incidence of dead plants following inoculation with R. solani alone was only 5% and in plants inoculated simultaneously with both pathogens, disease incidence was 88% 35 days after inoculation. Mortality reached 90–100% in plants inoculated with P. myriotylum, either singly or combined with R. solani 60 days after inoculation, whereas in plants inoculated with R. solani it was 5%. The maximum mortality in plants inoculated with R. solani was 25%, 76 days after inoculation. These results clearly demonstrate that P. myriotylum was the dominant pathogen in the root rot and wilt of A. manglesii.     

海南非洲菊根腐病病原的分离与鉴定

从海南省五指山市非洲菊苗圃,儋州市兰花基地非洲菊苗圃的腐烂病根上采集分离到9个疫霉菌株,经鉴定属于隐地疫霉Phytophthoracryptogea。     

Biocontrol activity of salt tolerant Streptomyces isolates against phytopathogens causing root rot of sugar beet

Biological control of fungi causing root rot on sugar beet by native Streptomyces isolates (C and S2) was evaluated in this study. The dry weight and colony forming unit (CFU) of S2 and C increased when 300 mM NaCl was added to medium. The in vitro antagonism assays showed that both isolates had inhibitory effect against Rhizoctonia solani AG-2, Fusarium solani and Phytophthora drechsleri. In dual culture, Streptomyces isolate C inhibited mycelial growth of R. solani, F. solani and P. drechsleri 45%, 53% and 26%, respectively. NaCl treatment of medium increased biocontrol activity of soluble and volatile compounds of isolate C and S2. After salt treatment, growth inhibition of R. solani, F. solani and P. drechsleri by isolate C increased up to 59%, 70% and 79%, respectively. To elucidate the mode of antagonism, protease, chitinase, beta glucanase, cellulase, lipase and α-amylase activity and siderophore and salicylic acid (SA) production were evaluated. Both isolates showed protease, chitinase and α-amylase activity. Also, biosynthesis of siderophore was detectable for both isolates. Production of siderophore and activity of protease and α-amylase increased after adding salt for both isolates. In contrast, chitinase activity decreased significantly. Production of SA, beta glucanase and lipase by isolate S2 and biosynthesis of cellulase by isolate C were observed in presence and absence of NaCl. Soil treatment with Streptomyces isolate C inhibited root rot of sugar beet caused by P. drechsleri, R. solani and F. solani. Results of this study showed that these two Streptomyces isolates had potential to be utilized as biocontrol agent against fungal diseases especially in saline soils.     

In vitro antifungal activity of chitinolytic enzymes produced by bio-agents against root rot pathogenic fungi

A study was carried out using simple laboratory techniques to examine the influence of the antagonistic isolates of Trichoderma harzianum, T. viride, Bacillius subtilis and Pseudomons flourescence and their culture filtrates on selected soil-borne root rot pathogens Rhizoctonia solani and Fusarium solani. Testing procedures were standardised using two different methods. The experiments were based on the principle of dual culture and agar diffusion techniques. The experiment involved the recording of the percentage of reduction in growth and inhibition zones formed by various filtrates of antagonistic culture growth. The results showed that the antagonists tested had the ability to reduce the linear growth of fungal pathogens. Also, the cultures filtrates of antagonists had antifungal activities by forming inhibition zones. Culture filtrates have shown a strong clear inhibition zone which increases in diameter as the incubation period of antagonists increases. This observation was related to the increase in the activity of chitinolytic enzymes as secondary metabolic compounds produced in growth media by prolonging the period of incubation. The study has proved that such enzymes can be effectively used for suppression of soil-borne pathogens and that it can evolve as a potential biocide.     

青海豌豆根腐病病原菌种类及致病性的研究

豌豆极腐病是青海东部干旱地区豌豆生产上的一种新病害,近年来危害逐年加重,致使豌豆产量遭受严重损失。根据分离鉴定和致病性测定结果,青海豌豆根腐病病原真菌是由茄镰刀菌、尖孢镰刀菌、豌豆丝囊霉、根串珠霉、立枯丝核菌、腐霉、链孢粘帚霉等复合反染所引起的。经回接试验：镰刀菌和豌豆丝囊霉对豌豆具有较强的致病力;腐霉及其他病原菌则有加强腐烂作用。     

广东省烟草花叶病病原病毒的鉴定

烟草花叶病是广东省产烟区的主要病害之一。我们在南雄等八个县进行调查,1983年至1984年的一般发病率为2～20％。根据血清学反应、病毒粒体形态、鉴别寄主反应及寄主范围、媒介昆虫种类、物理性质、交互保护反应等各项检验结果,鉴定广东省烟草花叶病病原是:三个黄瓜花叶病毒可能株系(普通株系CMV-C,烟草坏死株系CMV-TN,烟草黄色坏死株系(CMV-TYN),烟草花叶病毒(TMV),马铃薯病毒Y(PVY),烟草脉带花叶病毒(TVBMV)和烟草褪绿斑驳病毒(TCMV)(暂定)。     

腐霉属的一个新种和二个新记录

本文报告作者1982—1983年在北京和广东一些地区土壤中用已知方法(余永年,1975)分离到的几种腐霉,其中1个新种(Pythium borealis sp.nov.)、2个国内未报道的种(P.oligandrum和P.myriotylum)和1个已知种的变异株(P.ultimum variant)。文中对以上各菌进行了形态学描述。     

箭舌豌豆根瘤中根瘤菌的形态变化观察

箭舌豌豆(Vicia sativa)是一种抗性强、适应性广、产量高、营养丰富的优质饲料和绿肥作物,能大最结瘤固氮,有效提高土地肥力,因此全国各地广为种植。人们对箭舌豌豆的栽培技术、生长条件、遗传规律和有毒成份已有不少研究,但至今国内外对该种根瘤中根