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1.
一种由麦根腐平脐蠕孢(Bipolaris sorokiniana)引起的柳枝稷叶斑病 总被引：1，自引：0，他引：1
<正>柳枝稷(Panicum virgatum)属禾本科(Gramineae)黍属(Panicum)是多年生C4草本植物。该植物原产于北美,环境适应性极强,具有耐旱、耐盐碱、耐贫瘠等特点。它不仅是国际上公认的作为生物燃料的能源作物,还是一种优质牧草。截止2010年,柳枝稷在我国北方种植面积已达115.8 hm~2[1]。随着种植面积的不断扩大,柳枝稷病害问题越来越严重,病害造成柳枝稷生物量下 相似文献
2.
Induced Resistance as a Mechanism of Biological Control by Lysobacter enzymogenes Strain C3 总被引：1，自引：0，他引：1
ABSTRACT Induced resistance was found to be a mechanism for biological control of leaf spot, caused by Bipolaris sorokiniana, in tall fescue (Festuca arundinacea) using the bacterium Lysobacter enzymogenes strain C3. Resistance elicited by C3 suppressed germination of B. sorokiniana conidia on the phylloplane in addition to reducing the severity of leaf spot. The pathogen-inhibitory effect could be separated from antibiosis by using heat-inactivated cells of C3 that retained no antifungal activity. Application of live or heat-killed cells to tall fescue leaves resulted only in localized resistance confined to the treated leaf, whereas treatment of roots resulted in systemic resistance expressed in the foliage. The effects of foliar and root applications of C3 were long lasting, as evidenced by suppression of conidial germination and leaf spot development even when pathogen inoculation was delayed 15 days after bacterial treatment. When C3 population levels and germination of pathogen conidia was examined on leaf segments, germination percentage was reduced on all segments from C3-treated leaves compared with segments from non-treated leaves, but no dose-response relationship typical of antagonism was found. Induced resistance by C3 was not host or pathogen specific; foliar application of heat-killed C3 cells controlled B. sorokiniana on wheat and also was effective in reducing the severity of brown patch, caused by Rhizoctonia solani, on tall fescue. Treatments of tall fescue foliage or roots with C3 resulted in significantly elevated peroxidase activity compared with the control. 相似文献
3.
Z. Karolewski N. Evans † B. D. L. Fitt A. Baierl A. D. Todd S. J. Foster ‡ 《Plant pathology》2004,53(1):29-37
Despite differences in climate and in timing of light leaf spot epidemics between Poland and the UK, experiments provided no evidence that there are epidemiological differences between populations of Pyrenopeziza brassicae in the two countries. Ascospores of Polish or UK P. brassicae isolates germinated on water agar at temperatures from 8 to 24°C. After 12 h of incubation, percentages of ascospores that germinated were greatest at 16°C: 85% (Polish isolates) and 86% (UK isolates). The percentage germination reached 100% after 80 h of incubation at all temperatures tested. The rate of increase in germ tube length increased with increasing temperature from 8 to 20°C but decreased from 20 to 24°C, for both Polish and UK isolates. Percentage germination and germ tube lengths of UK P. brassicae ascospores were less affected by temperature than those of conidia. P. brassicae produced conidia on oilseed rape leaves inoculated with ascospores or conidia of Polish or UK isolates at 16°C with leaf wetness durations from 6 to 72 h, with most sporulation after 48 or 72 h wetness. Detection of both mating types of P. brassicae and production of mature apothecia on leaves inoculated with mixed Polish populations suggest that sexual reproduction does occur in Poland, as in the UK. 相似文献
4.
稻曲病菌分生孢子的生物学研究 总被引：47，自引：5，他引：47
本文对稻曲病菌分生孢子的一些生物学特性进行了研究,结果表明,基质养分对分生孢子萌发影响较大,纯水不利于孢子萌发,PSA最适于孢子萌发,葡萄糖则强烈抑制孢子萌发,马铃薯煮汁既可抵消葡萄糖的抑制作用,又可刺激孢子萌发。分生孢子在琼脂面上比在液滴中萌发率高。分生孢子萌发的适宜温度为22~31℃,以28℃最好。分生孢子萌发对pH值敏感,以pH 6~7最适宜。用振荡培养法获取分生孢子,培养10 d后,孢子的萌发力开始下降。分生孢子的存活对水的依赖性强,在水中保存8 d萌发力不变,在100% RH中8 d萌发力略有降低,而在25% RH中5 h萌发力即迅速下降。根据这些特性,作者对分生孢子在田间的动态作了一些推测。 相似文献
5.
线虫内寄生真菌明尼苏达被毛孢(Hirsutella minnesotensis)的营养研究 总被引：1，自引：0，他引：1
明尼苏达被毛孢(Hirsutella minnesotensis)是中国大豆胞囊线虫重要的内寄生菌,本研究采取固体和液体2种培养方法测定了6种天然培养基、20种碳源、19种氮源和9种维生素对其生长、产孢和孢子萌发的影响。结果表明:H. minnesotensis在酵母葡萄糖琼脂(Yeast dextrose agar,YDA)培养基上生长最快,在麦芽浸膏琼脂(Malt extract agar,MEA)培养基上产孢最好,胰化大豆琼脂(Tryptic soy agar,TSA)培养基既不适合生长,也不适合产孢。在碳氮源研究中,Melibiose在固体培养基上显著促进H. minnesotensis气生菌丝生长,Glycogen是液体培养和孢子萌发最好的碳源。H. minnesotensis在以Casein为氮源的培养基上气生菌丝最多,Peptone是H. minnesotensis液体培养最好的氮源,大多数的氮源可以促进H. minnesotensis孢子萌发,但L-Cystine抑制孢子萌发,且在固体培养中不能被H. minnesotensis利用。维生素对H. minnesotensis的生长、产孢和孢子萌发有一定的促进作用。 相似文献
6.
Lysobacter enzymogenes C3 is a bacterial biological control agent that exhibits antagonism against multiple fungal pathogens. Its antifungal activity was attributed in part to lytic enzymes. In this study, a heat-stable antifungal factor (HSAF), an antibiotic complex consisting of dihydromaltophilin and structurally related macrocyclic lactams, was found to be responsible for antagonism by C3 against fungi and oomycetes in culture. HSAF in purified form exhibited inhibitory activity against a wide range of fungal and oomycetes species in vitro, inhibiting spore germination, and disrupting hyphal polarity in sensitive fungi. When applied to tall fescue leaves as a partially-purified extract, HSAF at 25 mug/ml and higher inhibited germination of conidia of Bipolaris sorokiniana compared with the control. Although application of HSAF at 12.5 mug/ml did not reduce the incidence of conidial germination, it inhibited appressorium formation and suppressed Bipolaris leaf spot development. Two mutant strains of C3 (K19 and DeltaNRPS) that were disrupted in different domains in the hybrid polyketide synthase-nonribosomal peptide synthetase gene for HSAF biosynthesis and had lost the ability to produce HSAF were compared with the wild-type strain for biological control efficacy against Bipolaris leaf spot on tall fescue and Fusarium head blight, caused by Fusarium graminearum, on wheat. Both mutant strains exhibited decreased capacity to reduce the incidence and severity of Bipolaris leaf spot compared with C3. In contrast, the mutant strains were as efficacious as the wild-type strain in reducing the severity of Fusarium head blight. Thus, HSAF appears to be a mechanism for biological control by strain C3 against some, but not all, plant pathogenic fungi. 相似文献
7.
ABSTRACT Rhizoctonia solani anastomosis group (AG)-13 was collected from diseased roots of field grown cotton plants in Georgia in the United States. Isolates of AG-13 did not anastomose with tester isolates of AG-1 through AG-12. Mycelium of all isolates of AG-13 were light brown but darkened as cultures aged. All isolates produced aerial mycelium. Concentric rings were visible after 3 to 4 days of growth but disappeared as cultures aged and darkened. Individual sclerotia were up to 1.5 mm in diameter, similar in color to the mycelium, and generally embedded in the agar. Clumps of sclerotia up to 5 mm in diameter were produced on the agar surface. All attempts to induce basidiospore production were unsuccessful. The 5.8S region of the rDNA from isolates of AG-13 was identical in length and sequence to isolates of all other AGs of R. solani. Length and sequence of the internal transcribed spacer (ITS) regions of rDNA from isolates of AG-13 were unique among AGs of R. solani. Similarity between AG-13 and other AGs of R. solani ranged from 68 to 85% for ITS region 1 and 85 to 95% for ITS region 2. Selected isolates of AG-13 caused minor or no damage to barley, cauliflower, cotton, lettuce, potato, and radish in laboratory or greenhouse studies. 相似文献
8.
Pycnidia containing conidia characteristic of Phoma spp. and pseudothecia containing ascospores characteristic of Didymella applanata were isolated from edges of expanding stem lesions and dead stems of wilted cultivated hybrid arctic bramble plants ( Rubus arcticus nothossp. stellarcticus ) in Sweden in 1998 and 1999. The fungi were morphologically similar when grown on culture media, but some differences in growth rate were observed. They were also similar to the reference isolates of D. applanata (anamorph Phoma argillacea ). However, they were different from an isolate of Phoma sp. (HPP 38) isolated from cultivated arctic bramble ( R. arcticus ssp. arcticus ) in Finland in 1980, and from reference isolates of Phoma glomerata isolated from other hosts. Multivariate analysis of growth rate data and conidial dimensions measured in vitro indicated that the fungi isolated from hybrid arctic bramble in Sweden were not distinguishable from D. applanata , but were clearly distinct from P. glomerata and P. exigua. Furthermore, they had identical ITS1 and ITS2 sequences, and were placed in a phylogenetic clade very closely related to the clade that contained isolates of D. applanata isolated from raspberry ( Rubus idaeus ). In contrast, isolate HPP 38 from Finland was placed in a clade with P. exigua. These data indicate that the Swedish isolates infecting arctic bramble belong to a strain of D. applanata that differs from the isolate infecting raspberry only by two common nucleotide substitutions in ITS2. Fungi of the Phoma–Didymella complex on wild and cultivated arctic bramble (a total of 291 plants showing symptoms sampled from 37 sites) were detected by a PCR-based assay and found to be common in northern Sweden, but rare, albeit widely distributed, in Finland. 相似文献
9.
糖对稻曲病菌薄壁分生孢子萌发的影响 总被引：2，自引：0，他引：2
以琼脂平板为萌发基质,测定了10种糖化合物(木糖、果糖、山梨糖、核糖、甘露糖、葡萄糖、麦芽糖、半乳糖、乳糖和蔗糖)对稻曲病菌薄壁分生孢子萌发的影响。结果发现,在浓度为1%时,除蔗糖外,其余9种糖对孢子萌发均有不同程度的抑制作用,其中木糖、果糖、山梨糖和核糖的抑制作用强烈;孢子经木糖或果糖处理6h后,并未丧失活力;多种糖混合仍表现为抑制孢子萌发。当各种糖与起刺激作用的马铃薯煮汁分别混合时,表现出明显相反的两种效应,一是马铃薯汁的刺激作用可掩盖甘露糖、葡萄糖、麦芽糖、半乳糖、乳糖和蔗糖的抑制作用;二是木糖、果糖、山梨糖和核糖的抑制作用可掩盖马铃薯汁的刺激作用。表明外源糖化合物及某些生命活性物质可影响薄壁分生孢子萌发。 相似文献
10.
The pathogenicity of Alternaria spp. isolated from wheat leaves collected in regions where alternaria leaf blight has been reported was compared with that of IMI reference isolates of A. triticina and A. alternata using two durum and two bread wheat genotypes. To identify isolates putatively corresponding to A. triticina , morphological and DNA sequence analyses based on ribosomal DNA from the internal transcribed spacer (ITS) region (ITS1, 5·8S rRNA gene, ITS2) and toxicity bioassays of culture filtrate were combined. Glasshouse inoculations provided reliable information to assess the pathogenicity of A. triticina isolates on wheat. Alternaria leaf blight symptoms were produced by the A. triticina isolates only on durum wheat cv. Bansi, while A. alternata , A. tenuissima and A. arborescens isolates were found to be nonpathogenic on the wheat cultivars tested. Alternaria triticina isolates were distinguished from other Alternaria species by Simmons and Roberts' sporulation pattern 6 and two to three conidia per sporulation unit associated with primary conidia bearing long (> 7 µ m) apical secondary conidiophores. Phylogenetic analysis also proved effective at discriminating wheat-pathogenic A. triticina from other nonpathogenic Alternaria species. Alternaria triticina isolates yielded longer ITS sequences than A. alternata , A. tenuissima and A. arborescens isolates, leading to clear-cut differences as visualized with agarose gel electrophoresis. Additionally, only culture filtrates of A. triticina isolates caused nonspecific necrotic lesions on leaves of 3-week-old wheat plants. 相似文献
11.
A simple test based on the germination of conidia of Botrytis on agar media augmented with various fungicides has been developed. Average concentrations causing a 50% reduction of germ-tube growth (EC50) of highly sensitive isolates were determined on 1% malt extract agar (thiophanate-methyl 0.090 ppm; iprodione 0.566 ppm; fludioxonil 0.026 ppm; fenhexamid 0.144 ppm), 1% malt extract agar with 100 ppm salicyl hydroxamic acid (QoI fungicides, viz. trifloxystrobin 0.009 ppm; pyraclostrobin 0.013 ppm; azoxystrobin 0.087 ppm), 0.5% yeast extract agar (boscalid 0.069 ppm) and 0.5% sucrose agar (cyprodinil 0.053 ppm). In order to detect different levels of resistance against these various fungicides, two discriminatory concentrations were identified for each compound. A routine assay method was developed in which drops of a conidial suspension harvested directly from diseased plant material or sporulating cultures were incubated on each of 20 different agar media. Because of a very short time-span of 24–48 h between sample collection and evaluation of results, field-specific information on the occurrence, frequency and types of resistance of Botrytis against common botryticides in soft-fruit production may be generated prior to the main fungicide spray season at blossom time.
相似文献12.
Experiments were conducted to determine the effects of temperature, relative humidity (RH) and duration of wetness period on in vitro germination of conidia and infection of detached pear leaves by Venturia nashicola , the causal agent of pear scab. Conidia germinated only in near-saturation humidity (RH > 97%). The final percentage germination (24 h after inoculation) at 100% RH without free water was less than half that in free water. Conidia germinated over the range of temperatures tested (5–30°C); the optimum temperature for germination was ≈21°C. Changes in percentage germination of conidia over time were fitted by logistic models at each individual temperature. Polynomial models satisfactorily described the relationships between two (rate and time to 50% of maximum germination) of the three logistic model parameters and temperature. The minimum length of the wetness period for successful infection of detached pear leaves by conidia was observed at several temperatures. The shortest length of wetness period required for infection was 7 h at 22°C. Two polynomial models fitted well the relationship between the minimum wetness duration required for infection, and temperature. 相似文献
13.
玉米灰斑病菌生物学特性研究 总被引：35，自引：0，他引：35
玉米灰斑病菌(Cercospora zeae-maydis Tehon and Doniels)适合分离的培养基有花生叶斑病尾孢菌培养基、PDA、V8汁、V8汁+蔗糖20 g和Richard培养基。适宜菌丝生长的pH 4~12,最适宜的pH 6~8,适宜温度为20~25℃。病菌对葡萄糖、麦芽糖、乳糖和对酵母膏、硝酸钾、牛肉膏的利用好于其它碳源或氮源。分生孢子萌发的温度为20~30℃,pH范围广,RH ≥ 81%以上分生孢子萌发,随湿度增加萌发率增高。营养对孢子萌发无影响。 相似文献
14.
烟草赤星病菌菌种保存及致病性研究 总被引：2，自引：0，他引：2
在烟草赤星病抗性鉴定和生防菌剂筛选工作中,常因菌种在室内连续多代移植培养导致菌株的致病力衰弱,而影响测定结果的准确性和一致性。对此,本研究尝试将赤星病菌种经Richards培养液制备成菌层,置于4℃低温环境条件下长期保存,连续5年测定其培养性状和致病力,与连续转代培养方法保存的菌种进行比较,结果表明在连续5年的试验过程中,Richards法保存的菌种在培养性状和致病性上没有发生衰退,该菌种保存方法制作简单、经济、可靠,适用于烟草品种抗赤星病鉴定和生防菌剂的筛选工作。 相似文献
15.
对杨树角斑病菌进行分离和鉴定,并研究不同培养条件对其培养特性的影响,以获得病原菌的纯培养并筛选出最佳培养条件,为杨树角斑病防治提供理论参考。分别采用组织和单孢分离法分离病原菌,根据子实体形态和病菌rDNA ITS序列对其进行鉴定。观察不同培养基、温度、光照、pH对病原菌生长的影响。结果表明,自然条件下,用杨树角斑病菌的分生孢子分离较病组织分离易成功。根据病菌的形态特征和rDNA ITS序列分析,将病菌鉴定为柳假尾孢[Pseudocercospora salicina(Ell.&Ev.)Deighton]。培养基、温度、光照、pH等因素影响病菌在培养基上的生长。燕麦培养基、pH6～7、25℃、黑暗条件是适合的培养条件。 相似文献
16.
烟草赤星病拮抗细菌的筛选及其控病作用 总被引：12，自引：0，他引：12
从烟草叶片上分离到236株非病原细菌,通过平板对峙培养,筛选出对不同致病力的烟草赤星病菌Alternaria alternata(Fr.)Keissl均有拮抗作用的菌株:Ata28、Ata81、Ata124和Ata160.室内测定其对赤星病菌抑菌带的宽度达6.1～10.5mm;室内离体叶片悬滴法测定,提前喷施拮抗菌其防治效果为53.9%～73.0%;接赤星病菌后喷施的防治效果为44.0%～60.0%;在温室中进行盆栽防病试验,防治效果为52.3%～75.8%.无菌滤液试验表明,拮抗菌Ata28无菌滤液在一定浓度范围内均能有效地抑制菌丝生长,减少孢子萌发,且浓度越高,抑制能力越强. 相似文献
17.
The mode of action of soluble silicon against strawberry powdery mildew (Sphaerotheca aphanis var. aphanis) was investigated in four experiments. First, silicon-treated leaves from plants grown with silicate (Si+) and control leaves
were excised, inoculated with conidia, and subsequent germination and formation of appressoria in a petri dish was assessed
after 24 h. The germination rate was 49.7% on Si+ leaves, and was 67.2% on control leaves (t-test, P < 0.01). Second, we soaked cellulose membranes in various solvents and then placed the membranes on 4% water agar, dusted
the membranes with conidia, and examined after 12 h. No difference was apparent between any treatment and the control (distilled
water). Third, strawberries growing hydroponically with additional silicon in the medium were inoculated with conidia, and
leaves were observed with a scanning electron microscope 1–2 days after inoculation. Germ tubes and secondary hyphae were
shorter and had fewer branches on Si+ leaves than on the control. Moreover, penetration appeared to be inhibited. Fourth,
the cuticle was separated from leaves from plants grown as in the third experiment, placed on water agar, and dusted with
conidia. Germination of conidia, observed with a light microscope, on Si+ leaves was suppressed markedly to 40%–60% of that
of the control. These results suggested that soluble silicon induced physiological changes in the cuticle layer after absorption
by the plant. In addition, soluble silicate reduced germination of conidia, formation of appressoria, and possibly the penetration
of powdery mildew. 相似文献
18.
新病害—山核桃果实黑斑病病原菌的鉴定 总被引：1，自引：0，他引：1
2007年以来,浙江临安、淳安、桐庐和安徽部分地区山核桃主产区出现了一种果实新病害——山核桃果实黑斑病,该病严重影响山核桃果实的产量和品质。本研究从采集的病果中分离得到了一种真菌,离体幼果接种的症状与田间相似。病原菌在PDA培养基上形成白色轮纹状菌落,分生孢子长梭形,直或弯曲,(22.6～29.9)μm×(6.1～9.0)μm,5个细胞,中间3个有色孢(上部2个为黑褐色、下部1个为淡橄榄色),孢子顶生2～3根附属丝、多为3根。根据该病原菌的培养和形态特征及其ITS序列,将其鉴定为小孢拟盘多毛孢(Pestalotiopsis microspora)。 相似文献
19.
ABSTRACT Avirulent isolates of Pyricularia oryzae and isolates of Bipolaris sorokiniana, a nonrice pathogen, were used to suppress rice blast caused by P. oryzae. In greenhouse experiments, both fungi substantially reduced leaf blast when applied 24 h or more before the pathogen. B. sorokiniana, but not avirulent isolates of P. oryzae, systemically reduced disease in leaf 5 when applied to whole plants at the four-leaf stage. In field experiments, both fungi were able to reduce neck blast significantly. No increase in grain yield was obtained by using avirulent isolates of P. oryzae, whereas five sprays with B. sorokiniana from seedling to heading stages increased the grain yield in two of three experiments conducted at two locations in Nepal. The significant increase in yield was observed under high inoculum pressure of P. oryzae. Induced resistance is suggested to be involved in the suppression of disease. 相似文献
20.
氰烯菌酯(2-氰基-3-氨基-3-苯基丙烯酸乙酯,JS399-19) 是一种对禾谷镰孢菌Fusarium graminearum具有专化活性的新型杀菌剂。离体条件下,采用菌丝生长速率法测定了该药剂对禾谷镰孢菌抗性菌株和敏感菌株的生长抑制活性;同时采用孢子萌发法测定了其对禾谷镰孢菌分生孢子萌发的影响。结果表明,氰烯菌酯能够强烈地抑制禾谷镰孢菌敏感菌株菌丝的生长,EC50值分布在0.092~0.141 μg/mL之间;并可降低敏感菌株分生孢子的萌发速率,以及影响其萌发的方式,使芽管从分生孢子基部和中间细胞萌发的比率增加;同时氰烯菌酯使敏感菌株分生孢子膨大、畸形,并使其芽管肿胀、扭曲,明显抑制其芽管的伸长生长;但对抗性菌株的抑制作用和致畸作用不明显。 相似文献