一种简便易行的栗疫病菌单孢分离方法

介绍了一种分离栗疫病菌单分生孢子的简便易行的方法。此方法可以排除菌丝段的干扰,也适用于分生孢子器中产生微小分生孢子的其他真菌。     

烟草黑胫病菌拮抗细菌的筛选与鉴定

从烟草根际土壤分离到107个细菌分离物,通过室内平板对峙培养筛选,筛选到13株对烟草黑胫病菌有拮抗作用的菌株,其中,LZ-7菌株的室内平板抑菌效果最好,抑菌圈直径达27.82 mm。经盆栽试验,LZ-7、A3控病作用较好,防治效果分别达59.12%和55.84%。通过16 S rDNA序列测定与分析,LZ-7与Bacillus pumilus的同源性为99%,初步鉴定证明该菌株属于短小芽孢杆菌。     

七种杀菌剂对寄生疫霉菌的毒力测定试验

本试验对潺菜病叶进行了组织分离,经过纯化鉴定病原菌为寄生疫霉(Phytophthora parasitica Dastur)。试验使用了七种杀菌剂采用了含毒培养基生长速率法来测定对寄生疫霉的抑制效果,试验结果表明：药后48h,百菌清的EC₅₀值为13.60mg/L,毒力指数较大,对寄生疫霉菌抑制效果非常显著;恶霜锰锌和代森锰锌的EC₅₀值为16.99和28.62 mg/L,抑制效果较显著;甲霜锰锌、霜霉威和烯酰吗啉的EC₅₀值分别为为56.23mg/L、56.23mg/L和60.71mg/L,效果一般;二氯异氰的EC₅₀值为319.21mg/L,毒力效果较差;药后24h各药剂对寄生疫霉的抑制效果与药后48h抑制效果相似。     

韩国栗疫病抗病品种的遗传变异分析

为了分析韩国栗疫病的抗病品种和感病品种的遗传变异和抗病性的筛选,利用抗病性的快速检测法和RAPD(random amplified polymorphic DNA)方法对13个栗树品种进行了抗病性检测和RAPD标记分析。抗病性的快速检测选出了5个抗病品种、5个感病品种和3个中度抗病(或中度感病)品种,并且这一结果与该品种的田间表现相一致。利用筛选的12个随机引物,扩增了100个多态性RAPD片段,但未发现与抗病性或感病性相关的特异RAPD片段。聚类分析结果表明,12个品种大致分为抗病、感病和中度抗病(或中度感病)等3个大组,并与抗病性的快速检测结果基本一致。抗病品种“MANSEKI”表现出了相对于12个品种较远的亲缘关系。     

烟草黑胫病菌培养特性的研究

研究了云南烟草黑胫病菌在不同培养基、不同温度的生长情况及不同菌龄与不同诱导时间孢子囊的产生数量。结果表明,菌株在8种供试培养基中,以燕麦培养基和选择性培养基上菌落生长最好,其次为胡萝卜培养基,在番茄汁和马铃薯培养基上生长最差。同一菌株在不同培养基上产孢量不同、产生的孢子囊大小亦有所不同。05P226菌株在玉米培养基上产孢量最高;05P55菌株在燕麦培养基上产孢量最高,在番茄汁培养基上产生的孢子囊最大,而05P62菌株在燕麦培养基上产孢量最高,在烟叶汁培养基上产生的孢子囊最大。在30℃菌丝生长速率最高,其次为28℃,以35℃生长最差。供试3个菌株间生长差异显著,以05P226生长最好,05P55菌株次之,05P62生长最差。05P226、05P55菌株皆以培养14d、诱导72h产孢量最高,最适宜试验中产孢培养。     

甜椒根腐病防治药剂效果比较

甜椒根腐病(Phytophthora capsici)是一种毁灭性病害,在很多国家和地区都有危害。甜椒根腐病发生迅速,发病前的药剂预防和发病后的及时补救都离不开高效低毒的杀菌剂。本试验利用我国现有的防治蔬菜病害的新杀菌剂对甜椒根腐病的防治效果进行了筛选,结果表明:25%吡唑醚菌酯乳油、30%壬菌铜水乳剂、3%中生菌素可湿性粉剂等对菌丝生长表现出很好的抑制作用。25%吡唑醚菌酯乳油、25%烯酰吗啉可湿性粉剂等药剂防效均在75%以上。     

栗疫病菌菌株的毒性联合与毒性分离现象的初步研究

 对来自3个中国板栗居群的共18个栗疫病菌株进行单株及混合菌株的毒力评价,结果表明各单株毒力差异显著,混合菌株存在毒性联合与毒性分离现象。同一种群的组合中有64.4%为毒性联合,不同种群的组合其毒性分离率高达88%,同一种群组合的毒性联合强度比不同种群组合的毒性联合强度大,而不同种群组合的毒性分离强度比同一种群组合的毒性分离强度大。大多数组合的毒性联合或毒性分离的性状表达稳定。     

Long-term storage and survival structure of three species of <Emphasis Type="Italic">Phytophthora </Emphasis>in water

 Cultures of Phytophthora cinnamomi, P. parasitica, and P. palmivora remained viable in water at room temperature for periods ranging from 6 to 23 years. The colonies that developed from the stored cultures were thin-walled and spherical, ranging from 19.2 to 30.0 μm in diameter. The survival structures are thought to be small chlamydospores produced in the absence of adequate nutrition and aeration. Received: October 7, 2002 / Accepted: January 8, 2003 Acknowledgment I thank Dr. Michael L. Parsons for assistance in preparing the photograph.     

栗疫病菌的培养性状、毒力与dsRNA的关系

 根据菌落的培养性状将中国东部12个省(市)的429个栗疫病菌(Cryphonectria parasitica)菌株划分为5种培养类型。其中Ⅰ型为桔黄色菌落的野生型正常菌株,占总菌株数的89.3%;Ⅱ~Ⅳ型为培养性状不正常菌株,共有46株,菌落有黄褐色、白色和深褐色等类型。供试菌株间存在明显的毒力分化,可分为强中弱三种类型。培养性状正常的菌株毒力普遍较强,极少菌株检测到dsRNA;培养性状不正常的菌株毒力一般较低,在菌落白色的菌株中都检测到dsRNA。在所测试的70个菌株中含dsRNA的菌株有38个,其中32个属于弱毒力类型,其他6个属中毒力类型;分布于除河南、湖南和广东以外的其他9个省(市)。     

Lesion size induced by Chrysoporthe fungal pathogens varies between Eucalyptus species and geographic locations in Zambia

Chrysoporthe canker disease is one of the serious threats facing planted Eucalyptus in southern Africa. In order to manage this disease, planting of less susceptible species of Eucalyptus has been promoted in many countries but it is not clear which species are less susceptible for Zambian environments. The purpose of this study was to test the response of different Eucalyptus species to Chrysoporthe fungal pathogens under field conditions to identify the least susceptible species to the disease. Two-year-old Eucalyptus trees (E. grandis, E. camaldulensis, E. cloeziana and E. tereticornis) growing in low- and high-rainfall locations were inoculated separately with three Chrysoporthe fungal species (C. austroafricana, C. syzygiicola and C. zambiensis) and the induced lesion size was measured six months after inoculation. Analysis of variance revealed that lesion size differed significantly between Eucalyptus species (F_3,948 = 1 978.8, p < 0.001). Lesion size on Eucalyptus species increased in the order E. camaldulensis < E. teriticornis < E. cloeziana < E. grandis. On average, trees growing in the higher-rainfall site produced significantly larger lesions than trees growing in the low-rainfall site (F_1,948 = 565, p < 0.001), suggesting that location influences disease severity. Smaller lesions on E. camaldulensis indicate lower susceptibility to Chrysoporthe canker disease, providing an opportunity to use this species in the selection and breeding for resistant Eucalyptus genotypes for plantation development in high disease-risk sites in Zambia.