江苏麦类禾谷镰刀菌变异性的研究

1980～1981年选取代表江苏不同地区引致麦类赤霉病的禾谷镰刀菌野生型和培养型菌株17个,并人工移植1～3次后,观察培养性状的变化;同时分别接种感病小麦品种“矮秆早”,观察致病性的变化,以分析病菌的变异性。结果证明:江苏极大多数禾谷镰刀菌菌株的野生型经人工移植三次后,无论是培养性状和致病力都发生了改变。一般表现力生长速度减慢,产孢数量变少,产孢速度变慢,分生孢子变小,分生孢子分隔数减少,不易产生分生孢子或不产孢,不易形成子囊壳或不产生子囊壳而产生粘孢团,以及致病力减弱。但是,只有少数菌株的变异特别明显。以上结果说明禾谷镰刀菌菌株中存在有变异现象,但不同菌株并不一致,培养性状变异与致病力强弱变异间的关系也可能因菌株而异。至于禾谷镰刀菌在无性培养中发生变异的原因还有待进一步研究。     

大丽轮枝菌培养性状的变异

 对棉花,茄子、辣椒等植物上分离到的大丽轮枝菌(Verticillium dahliae kleb)的36个菌株进行了培养性状变异的研究。试验以分生孢子稀释培养的方法,检查单孢菌落的变异率.从野生型(A型)菌株分离到的92,947个单孢菌落,形成绒毛型(B型)菌落的变异率为5.85%,形成菌膜型(C型)菌落的变异率为0.07%。在绒毛型菌株的1,773个单孢菌落中,形成菌膜型菌落的变异率为0.19%。大丽轮枝菌野生型菌株培养性状的变异率,因试验菌株、单孢个体、营养条件、菌种保存温度和保存时间不同而异.绒毛型变异体的培养性状比较稳定.根据试验结果,探讨了菌种保存的方法.     

禾谷镰刀菌营养缺陷型的诱导与特性研究

 利用紫外线、γ射线和亚硝基胍处理禾谷镰刀菌菌株,经菌丝过滤法,获得4株稳定的营养缺陷型。其中1株为精氨酸缺陷型,1株为蛋氨酸缺陷型。比较禾谷镰刀菌营养缺陷型与野生型菌株的培养性状和致病力,表明营养缺陷型菌株生长速度慢,气生菌丝少,色泽淡,产孢能力下降,子囊壳形成能力丧失,致病力变弱。     

Fusarium graminearum sensu stricto和F.asiaticum在玉米秸秆和水稻秸秆上子囊壳形成的比较

为探究麦田前茬作物玉米秸秆和水稻秸秆上中国小麦赤霉病菌的两个优势种Fusarium graminearum sensu stricto (F.graminearum)和F.asiaticum子囊壳形成和发育成熟过程的差异,分别选择3株F.graminearum菌株(SE81,3-ADON型;LcA-2,15-ADON型;HX5-1,NIV型)和2株F.asiaticum菌株(M4A,3-ADON型;M31-2,NIV型),用其孢子悬浮液接种玉米秸秆和水稻秸秆,放置于花泥和地表两种环境条件下,比较接种不同菌株秸秆上子囊壳的形成和发育成熟情况及5个菌株对‘郑麦366’(高感小麦赤霉病品种)的致病力。结果表明：花泥环境下产生子囊壳的速度要快于地表,以玉米秸秆为载体子囊壳产生速度比水稻秸秆快且多数密度大,3个F.graminearum菌株(SE81、LcA-2和HX5-1)在同种秸秆相同环境下比2个F.asiaticum菌株(M4A和M31-2)产生子囊壳的速度快且子囊壳密度大。5个菌株在不同环境的不同秸秆上产生的子囊壳的成熟度均无规律,接种‘郑麦366’后其病情指数间有极显著差异(P<...     

一株生防内生真菌的分离筛选、鉴定及抑菌特性

为获取优良植物病害生防菌,以交链孢菌Alternaria tenuis Ness和尖镰孢菌Fusarium oxysporum Schlecht为指示菌,采用平板对峙培养法、抑菌圈法和菌落直径法对健康龙柏鳞叶小枝中分离的4株优势内生真菌进行了筛选评价,并结合形态学观察及ITS序列分析对筛选出的生防内生真菌进行了鉴定。结果表明,对峙培养发现1菌株对交链孢菌和尖镰孢菌均具有较好的抑制作用,抑菌率分别为52.05%和48.65%,标记其为LB-1;LB-1菌株与指示菌对峙培养的菌落交界面处,2种指示菌的菌丝均出现了消解、断裂,而LB-1的菌丝则生长正常。未灭菌LB-1菌株发酵液对交链孢菌和尖镰孢菌产生的抑菌圈直径分别为14.1 mm和13.7 mm,抑菌率分别为47.89%和48.72%;灭菌LB-1菌株发酵液对交链孢菌和尖镰孢菌的抑菌圈直径分别为15.3 mm和15.0 mm,抑菌率分别为5.96%和33.90%,指示菌在生长过程中菌丝溶解现象明显。经鉴定,LB-1菌株为毛壳菌属Chaetomium中的近缘毛壳菌C.subaffine,是一种极具生防潜力的内生真菌,其抑菌特性可能通过溶菌作用实现。     

粤、桂、苏、皖四省稻瘟病菌有性态的研究

应用国际稻瘟病菌标准交配型菌株KA3和THl6对2000年从广东、广西、江苏和安徽4省采集的145个稻瘟病菌菌株的育性和交配型测定结果表明,广东、广西和安徽3省稻瘟病菌群体中存在着Matl.1和Matl.2两种交配型,江苏省的23个可交配菌株均为Matl.1。各省间稻瘟病菌群体的可交配率差异不大,总的可交配率为48.3%。有9个菌株与标准菌株交配产生了子囊孢子,可育率为6.2%。检测到2个两性菌株,不同地区稻瘟病菌群体雌雄性别的比例有显著性差异。用不同交配型的可育菌株进行互交,14个组合中只有1个组合产生子囊壳,但没有形成成熟的子囊孢子。     

苏云金素高产菌株的选育

用硫酸二乙酯(DES)处理苏云金杆菌CT-43菌株,得到了菌落形态、菌形和产生褐色素三种类型的突变株。光滑型(S-型)菌落自发突变的比例依亚种的不同而不同,CT-43菌株高达13.0％,苏云金亚种为10.6％,以色列亚种为3.9％,库斯塔克亚种不产生S-型菌落,S-型菌落依DES处理CT-43菌株芽孢时间的延长而增加,处理90分钟达49.0％。除个别S-型菌落外,均不产生苏云金素。诱变产褐色素菌落的频率为1.4％,它们都不产苏云金素。菌形变异株有仅芽孢,仅伴孢晶体,芽孢和伴孢晶体,营养体和芽孢,营养体和伴孢晶体,营养体、芽孢和伴孢晶体发生变异六种类型,它们产生苏云金素的水平各不相同。还获得了苏云金素产量比出发菌株明显提高的二个菌株。     

我国棉花黄萎病菌致病力分化及ISSR指纹分析

 来自我国12个省84个县（市）的棉花黄萎病菌,在PDA培养基上存在5种不同的培养类型,其中,产生微菌核较多的B型菌株为优势类群,占72.9%。长江流域的菌株培养性状变异最大,新疆棉区的变异最小。致病力测定结果和ISSR指纹图谱均将167个单孢菌株划分为强、弱、中3个致病力类型,供试菌株的ISSR指纹图谱与菌株的致病力存在明显的相关性。中等致病力类型菌株在我国占主导地位;强致病力类型的菌株主要分布在河北、河南、湖北等省;弱致病力类型菌株主要分布在新疆和江苏。     

棉花枯萎镰刀菌致病力变异的研究Ⅱ.生理Ⅱ、Ⅲ型菌系异核现象的研究

 本研究是对棉花枯萎镰刀菌生理Ⅱ、Ⅲ型菌系的四个菌株用切割菌丝尖端和单孢分离的方法研究它们的异核现象。试验结果表明:在田间它们能以异核体存在,并有三种核型组成,通过对Ⅲ型菌系的野生异核体菌株及原生质融合异核体菌株进行致病力测定,致病力发生了变异,证明异核现象是Ⅲ型菌系致病力变异的重要因素之一。     

棉花枯萎镰刀菌致病力变异的研究 Ⅱ.生理Ⅱ、Ⅲ型菌系异核现象的研究

本研究是对棉花枯萎镰刀菌生理Ⅱ、Ⅲ型菌系的四个菌株用切割菌丝尖端和单孢分离的方法研究它们的异核现象。试验结果表明:在田间它们能以异核体存在,并有三种核型组成,通过对Ⅲ型菌系的野生异核体菌株及原生质融合异核体菌株进行致病力测定,致病力发生了变异,证明异核现象是Ⅲ型菌系致病力变异的重要因素之一。     

假禾谷镰孢子囊壳的田间采集和子囊孢子后代室内杂交条件优化

假禾谷镰孢(Fusarium pseudograminearum,Fp)是我国黄淮麦区小麦茎基腐病(Fusarium crown rot of wheat)的优势病原菌,目前该病害呈不断蔓延和为害加重的趋势.本研究从五月中旬小麦灌浆期至玉米收获期,在河南开封和焦作田间调查采集小麦茎基腐病样,对13份小麦茎秆和小麦残茬上...     

Sexual Recombination in Gibberella zeae

ABSTRACT We developed a method for inducing sexual outcrosses in the homothallic Ascomycete fungus Gibberella zeae (anamorph: Fusarium graminearum). Strains were marked with different nitrate nonutilizing (nit) mutations, and vegetative compatibility groups served as additional markers in some crosses. Strains with complementary nit mutations were cocultured on carrot agar plates. Ascospores from individual perithecia were plated on a minimal medium (MM) containing nitrate as the sole nitrogen source. Crosses between different nit mutants segregated in expected ratios (3:1 nit(-):nit(+)) from heterozygous perithecia. Analysis of vegetative compatibility groups of progeny of two crosses indicated two and three vegetative incompatibility (vic) genes segregating, respectively. For rapid testing of sexual recombination between nit mutants, perithecia were inverted over MM to deposit actively discharged ascospores. Development of proto-trophic wild-type colonies was taken as evidence of sexual recombination. Strains of G. zeae group 2 from Japan, Nepal, and South Africa, and from Indiana, Kansas, and Ohio in the United States were sexually interfertile. Four group 1 strains were not interfertile among themselves or with seven group 2 strains. Attempts to cross G. zeae with representatives of F. acuminatum, F. avenaceum, F. culmorum, F. crookwellense, F. oxysporum, and three mating populations of G. fujikuroi were not successful.     

棉花黄萎病菌低致病力突变体的表型分析及致病相关基因克隆

 本研究通过对菌核型强致病力菌株Vd080产生的800个T-DNA插入突变体进行致病力测定,筛选得到31株致病力极显著降低的突变体,并对其进行了生物学性状分析。分子验证结果表明,这些低致病力突变体均为阳性,且有25株的T-DNA为单拷贝插入。与野生型菌株Vd080相比,这25株低致病力突变体菌落形态变异丰富,除了8株与野生型菌株形态一致的菌核型突变体外,还有3株黄色菌丝型,2株白色菌丝型和12株中间型突变体。此外,多数突变体的生长速率、产孢量和粗毒素产量都发生了显著变化,且各生理指标之间并无明显相关性。借助TAIL-PCR技术和VdLs.17的基因组数据库,进一步获得了这25株单拷贝插入低致病力突变体T-DNA的侧翼序列,并从Vd080中成功克隆得到了影响黄萎病菌致病力的相关基因。     

广西蔗区甘蔗白条病菌的鉴定与致病力分析

甘蔗白条病是一种检疫性病害,在我国多个蔗区均有报道,严重威胁我国甘蔗生产.本研究对采自广西蔗区不同品种(系)的病原菌进行分离、鉴定、保存,并选取其中40份白条黄单胞菌分离物进行遗传多样性分析与接种试验,评价其致病性.根据三磷酸腺苷结合盒转运蛋白等管家基因和Ⅳ型分泌系统virB基因的序列差异和进化树分析,将40个菌株分为...     

Viability and release of Neonectria ditissima ascospores on apple fruit in Brazil

During European canker monitoring in an apple experimental orchard, 14 mummified fruit (two and three trees with 10 and four positive records in 2018 and 2019, respectively) showed perithecia. Perithecium production on apple fruit, confirmation of pathogenicity of Neonectria ditissima isolated from mummified fruit, and ascospore release from fruit tissues has rarely been reported, and their role in the epidemiology of European canker has been largely overlooked. Thus, the objectives of our study were to (a) prove the presence of both conidia and ascospores of N. ditissima in mummified fruit in an experimental field, confirming pathogenesis in different apple cultivars, and (b) monitor production of the two types of inoculum in infected apple fruit over time. Canker incidence in this orchard was 47% of trees with symptoms in 2018 and 48% in 2019. Molecular and morphological tests confirmed that the fungus detected in the mummified apple fruit was N. ditissima. Apple fruit with sporodochia and perithecia washed immediately after collection from the orchard showed conidia but no ascospores of N. ditissima. However, after 4 days’ incubation, perithecia on mummified fruit showed many ascospore cirri. Koch's postulates were fulfilled on apple plants and mature fruit. Fruit inoculated with N. ditissima released spores for over a year under Brazilian field conditions. The release of both spore types peaked in May (Brazilian leaf fall) and October (spring); release of conidia also peaked in February (early harvest). These results support our hypothesis that fruit can serve as primary inoculum for European canker in Brazilian apple orchards.     

Coffee berry disease in Kenya. II. The role of Glomerella cingulata in the Colletotrichum population,colonizing the bark of Coffea arabica

On the maturing bark of cut branches ofCoffea arabica previously sprayed with copper fungicides perithecia ofGlomerella cingulata were easily found after two to ten days of incubation. Without fungicides the number of perithecia was decidedly lower. On prunings left on the ground under the coffee trees for 6 to 24 weeks the perithecia could also be found, but the numbers declined rapidly with time. Perithecia ofG. cingulata could forcibly discharge ascospores under laboratory conditions. Monospore cultures obtained by catching ascospores on agar, invariably belonged to threeColletotrichum types. It was rarely possible to isolate aColletotrichum able to infect green coffee berries. Growthrate, colour of the mycelium, number of conidia producedin vitro and infectivity on green coffee berries, however, differed substantially fromC. coffeanum, the cause of coffee berry disease. In Kenya no evidence has been obtained that ascospores from perithecia on bark could infect wounded or unwounded green coffee berries. Neither has any infection been obtained with ascospores from perithecia grownin vitro. Possible explanations for the difference with previous findings are offered. Based on the data presented in this paper, it is concluded thatG. cingulata is not likely to play a role in the epidemiology of the coffee berry disease in Kenya.     

温度、湿度和光照对苹果炭疽叶枯病菌(Glomerella cingulata)产孢的影响

苹果炭疽叶枯病(Glomerella cingulata)是我国苹果上新发现的一种病害,为了了解病原菌的产孢条件和产孢动态,为病害的预测预报与防控提供依据。本研究在人工控制条件下,测试了温度、湿度和光照对苹果炭疽叶枯病菌产生分生孢子和子囊孢子的影响。结果表明,苹果炭疽叶枯病新形成的病叶润湿后,在15℃~30℃下保湿培养2~6 d后可产生大量橘黄色的分生孢子堆,其中30℃下产孢量最大,产孢速度最快,仅需2 d时间。炭疽叶枯病菌在新形成的病叶上于15℃~30℃下培养20~30 d可形成子囊孢子,最适温度为25℃,子囊孢子的形成需要高湿环境或叶片润湿。炭疽叶枯病菌的单孢分离菌株于15℃~25℃下,在马铃薯葡萄糖琼脂培养基(PDA)上培养20~30 d也可形成子囊孢子,最适产孢温度25℃。紫外光、黑光和日光都能促进子囊孢子的形成。     

广西地区葡萄黑痘病病原菌的分离与鉴定

采用常规组织分离法对广西南宁、河池两地的葡萄黑痘病菌进行分离、纯化,分别得到37和31株分离菌。经菌落形态观察及r DNA ITS序列分析,南宁37株分离菌为同一菌株,河池31株分离菌为同一菌株,以NN和HC分别代表两地菌株,对它们进行形态学、致病性鉴定及r DNA ITS区域序列分析。结果显示,两地菌株形态学与致病性存在较大差异,但都符合黑痘病菌生长形态。NN菌落为红棕色、近圆形,边缘光滑。菌落中心位置丘状凸起,表面有白色菌丝和透明粘稠的小液滴,周围边缘有较规则的褶皱。HC菌落呈浅橙色、近圆形,边缘光滑。菌落中心位置丘状凸起,表面有少量白色菌丝,无液滴,周围边缘有不规则褶皱隆起。人工接种葡萄后均能引起典型的黑痘病症状,NN致病性强于HC。使用r DNA ITS区域通用引物ITS1F/ITS4进行PCR扩增后,NN和HC分别得到1 124 bp和818 bp的片段。比对结果显示1 124 bp与Elsinoe ampelina(AY826763.1)序列覆盖率达92%,序列一致性达99%;818 bp与Elsinoe ampelina(AY826762.1)序列覆盖率达75%,序列一致性达99%。因此,NN和HC均是引起广西葡萄黑痘病的病原菌。     

核盘菌中dsRNA种类及其与致病力的关系

 对源于我国黑龙江省佳木斯市同一块茄子田的14个核盘菌(Sclerotinia sclerotiorum)菌株及其中1个菌株Ep-1PNA5的2个衍生菌株的致病力和菌丝中的双链RNA(dsRNA)进行了分析。在马铃薯琼脂培养基(PDA)上对5个弱致病型核盘菌菌株(Ep-1PD、Ep-1PI、Ep-1PL、Ep-1PM、Ep-1PN)异常性状(菌丝生长慢,且异常分枝)的传染特性进行了测定。结果表明:在离体油菜叶片上,16个供试核盘菌菌株中,7个属于强致病类型,7个属于弱致病类型,2个属于中等致病类型。从10个核盘菌菌株的菌丝中检测到dsRNA因子,并可分成3类dsRNA电泳谱型。第一类dsRNA谱型只含有7.4kb大小的dsRNA分子,3个强致病型核盘菌菌株属于这种谱型;第二类dsRNA谱型含有2种dsRNA分子,大小分别为6.4kb和7.4kb。6个弱致病型菌株属于这种谱型;第三类dsRNA谱型只含有6.4kb大小的dsRNA分子。1个弱致病类型菌株属于这种谱型。从另外6个核盘菌菌株的菌丝中没有检测到任何dsRNA因子,其中4个菌株属于强致病型菌株,2个菌株属于中等致病型。可见,6.4kb大小的dsRNA因子与核盘菌弱致病性状密切相关。5个弱致病型核盘菌菌株(Ep-1PD、Ep-1PI、Ep-1PL、Ep-1PM、Ep-1PN)的异常性状可以通过菌丝接触传染给一些强致病型核盘菌菌株,使其菌丝生长变慢及分枝异常。结果还表明:这些弱致病型核盘菌异常性状的传染具有菌株特异性。     

水稻稻瘟病菌有性世代形成条件的优化

 本研究通过改变燕麦片番茄培养基中的一些成分,包括番茄成熟度、pH值、钙的添加等,探讨了稻瘟病菌有性世代形成的适宜条件。结果表明:选用成熟番茄的榨汁作为培养基的主要组分之一,调节培养基pH值在5.5左右,并添加0.1% CaCO₃能显著提高子囊壳形成的数量、促进子囊和子囊孢子的发育、提高子囊孢子的成活率。在上述培养基上进行稻瘟病菌的有性杂交,并在子囊壳开始出现后7~18d内分离子囊孢子,其成活率可高达85.5%。