共查询到20条相似文献，搜索用时 15 毫秒
1.
2.
ABSTRACT Fusarium spp. in maize can contaminate the grain with mycotoxins if environmental conditions are favorable for fungal growth. To quantify the relationship between growth of Fusarium spp. and environmental conditions, a mathematical model was developed to simulate growth of F. graminearum and F. verticillioides on maize ears following silk inoculation in field experiments from 1992 to 1995. Each species was inoculated separately and as a mixture of the two for 3 of the 4 years on one maize hybrid. Disease progress in ears was measured by a visual rating scale that was converted to percent visual infection. Measurements were made at regular time intervals after silks were inoculated 5 days after silk emergence. Differential equations were used to relate growth rates of Fusarium spp. in maize ears to hourly air temperature and relative humidity and to daily precipitation. Integration of these equations over time produced quantitative estimates of fungal growth. Model calculations compared well with measurements (R(2) = 0.931, standard error of estimate [SEE] = 2.11%) of percent visual disease infection of maize ears over 3 years. The model was tested against a second set of data (R(2) = 0.89, SEE = 5.9%) in which silks were inoculated at nine different times after first silk emergence for each of 2 years (1994 and 1995) with the two species of fungi on the same maize hybrid. At this time, a silk function was developed to account for changes in the susceptibility of silks to disease. F. graminearum responded to wet conditions more than F. verticillioides, and for the conditions of this experiment, grew much faster than F. verticillioides when inoculated separately. When they were inoculated together, F. graminearum growth rates were much lower, indicating some interference by F. verticillioides. During 1993, weather conditions before inoculation reduced the growth of both species in silks. 相似文献
3.
ABSTRACT Naturally occurring populations of Fusarium avenaceum, F. culmorum, F. graminearum, F. poae, and Microdochium nivale were studied in two field experiments from anthesis in June 2003 until harvest in crops of winter wheat, and subsequently during 10 months after harvest until June 2004 on their residues exposed on the soil surface under field conditions. The dynamics of the different pathogens were estimated by quantifying the amount of DNA present in wheat tissues using TaqMan-polymerase chain reaction. While colonization of grain by Fusarium spp. and M. nivale was low, high amounts of DNA of F. avenaceum, F. graminearum, and F. culmorum were found in ear residues, internodes, and nodes of the mature crop. Amounts of DNA of pathogens decreased significantly during the following 10 months in residues of internodes and nodes, but not in residues of stem bases. Knowledge on population dynamics of pathogens will help to develop preventive measures aimed at reduction of inoculum sources of head blight pathogens. 相似文献
4.
ABSTRACT The relative importance of several infection pathways (silks, stalks, and seed) leading to kernel infection of maize hybrids by Fusarium moniliforme was investigated in field experiments in 1993 and 1994. Systemic movement of specific fungal strains within plants was detected by using vegetative compatibility as a marker. Transmission of F. moniliforme from inoculated seed to stalks and developing kernels was detected in two of three field experiments; the seed-inoculated strain was detected in kernels on approximately 10% of ears. The percentage of kernels infected with the seed-inoculated strain ranged from 0 to 70%, with a mean of 0 to 2.5% (0 to 8.3% of F. moniliforme-infected kernels). Other pathways to kernel infection were more effective than seed transmission and systemic infection. F. moniliforme strains inoculated into the crowns and stalks of plants were found throughout the stalks and in up to 95% of the kernels in individual plants. Infection through the silks was clearly the most effective pathway to kernel infection. This was the only inoculation method that significantly increased overall incidence of F. moniliforme infection in kernels; the silk-inoculated strain infected up to 100% of the kernels in individual ears, with a treatment mean as high as 83.7% of kernels. When plants were silk-inoculated, the percentage of kernels infected by other F. moniliforme strains from the seed or stalk was reduced, apparently due to competition among strains. This study provides evidence that systemic development of F. moniliforme from maize seed and stalk infections can contribute to kernel infection, but silk infection is a more important pathway for this fungus to reach the kernels. 相似文献
5.
玉米穗腐病和茎基腐病镰孢菌间相关性的RAPD分析 总被引：2，自引：0，他引：2
利用随机扩增多态性DNA (RAPD)技术对玉米穗腐病和茎基腐病镰孢菌之间的相互关系进行了研究,证实了引起2种病害的串珠镰孢菌同源性很高,在遗传上具有较高的相似性,病菌不易受地域或环境和寄生部位选择作用的影响,同一类型的串珠镰孢菌可以是穗腐病和茎腐病的共同病原菌。禾谷镰孢菌间的遗传变异性很强,易受地域、环境和寄生部位选择作用的影响,出现明显的分化现象,穗腐病和茎基腐病可以由同一禾谷镰孢菌分化类型侵染所致,也可由不同分化类型侵染所致。 相似文献
6.
ABSTRACT Fusarium graminearum causes Fusarium head blight (FHB) in small grains worldwide. Although primarily a pathogen of cereals, it also can infect noncereal crops such as potato and sugar beet in the United States. We used a real-time polymerase chain reaction (PCR) method based on intergenic sequences specific to the trichodiene synthase gene (Tri5) from F. graminearum. TaqMan probe and primers were designed and used to estimate DNA content of the pathogen (FgDNA) in the susceptible wheat cv. Grandin after inoculation with the 21 isolates of F. graminearum collected from potato, sugar beet, and wheat. The presence of nine mycotoxins was analyzed in the inoculated wheat heads by gas chromatography and mass spectrometry. All isolates contained the Tri5 gene and were virulent to cv. Grandin. Isolates of F. graminearum differed significantly in virulence (expressed as disease severity), FgDNA content, and mycotoxin accumulation. Potato isolates showed greater variability in producing different mycotoxins than sugar beet and wheat isolates. Correlation analysis showed a significant (P < 0.001) positive relationship between FgDNA content and FHB severity or deoxynivalenol (DON) production. Moreover, a significant (P < 0.001) positive correlation between FHB severity and DON content was observed. Our findings revealed that F. graminearum causing potato dry rot and sugar beet decay could be potential sources of inoculum for FHB epidemics in wheat. Real-time PCR assay provides sensitive and accurate quantification of F. graminearum in wheat and can be useful for monitoring the colonization of wheat grains by F. graminearum in controlled environments, and evaluating wheat germplasms for resistance to FHB. 相似文献
7.
江苏省玉米茎腐病菌种类鉴定 总被引：8，自引：0，他引：8
作者于1992～1995年,从江苏省玉米主产区采集的玉米茎腐病标样中分离获得105个菌株,经鉴定,致病菌种类有肿囊腐霉(Pythium inflatum)、禾生腐霉(P.graminicola)、串珠镰孢浙江变种(Fusarium moniliforme var.zhejiangensis)、串珠镰孢中间变种(F.moniliforme var.intermedium)、串珠镰孢胶孢变种(F.moniliforme var.subglutinans)、禾谷镰孢(F.graminearum)、拟枝孢镰孢厚膜变种(F.sporotrichioides var.chlamydosporum)、尖孢镰孢芬芳变种(F.oxysporum var.redolens)、接骨木镰孢(F.sambucinum)、茄病镰孢(F.solani)、半裸镰孢(F.semitectum)等11个种或变种。其中串珠镰孢浙江变种出现频率最高,占44.8％,肿囊腐霉和禾生腐霉致病力最强,这两类菌是江苏玉米茎腐病主要病原。 相似文献
8.
The incidence of Fusarium spp. in stem bases of selected crops of winter wheat in the Midlands, UK 总被引：1，自引：1，他引：0
D. W. PARRY 《Plant pathology》1990,39(4):619-622
The incidence of pathogenic Fusarium and Microdochium species in stem bases of winter wheat was investigated in a total of nine crops in 3 years, i.e. 1987, 1988 and 1989. Four Fusarium species were isolated: F. nivale ( = Microdochium nivale ), F. avenaceum , F. culmorum and F. graminearum . The predominant species was F. nivale followed by F. avenaceum and F. culmorum . Isolations of F. graminearum were made only from shoots collected during August 1989. The highest incidence of F. nivale occurred during April 1989 in the cultivar Brock when the fungus was isolated from 65% of the shoots sampled. The highest incidence of F. avenaceum was 60% (August 1988, cv. Slejpner) and F. culmorum 37% (August 1989, cv. Mercia). A delay in the isolation of Fusarium spp. during 1987 was attributed to the low January temperatures, and an upsurge of F. culmorum and F. graminearum during 1989 to the warm dry summer. The incidence of F. nivale fluctuated during the 1988 and 1989 seasons, particularly during spring. The effects of fungicide spray programmes and the growth and development of the wheat crop are discussed as possible contributory factors to this. 相似文献
9.
Cotyledons of resistant and susceptible cotton ( Gossypium hirsutum ) cultivars were inoculated artificially with four isolates of Xanthomonas campestris pv. malvacearum from Africa (H V1, HV3, H V7 and Sudan) and USA race 18. Each isolate was used as single inoculum and in combinations of mixed inoculum. Disease reactions were graded 15 days after inoculation on a scale of I (immunity) to 10 (fully susceptible). Inoculation with HVI alone produced the highest disease grade of all inoculum treatments. When HVI was included in a mixed inoculum, disease grades were greatly reduced compared to HVI alone. Disease grades were highest for the inoculum mixture of the most virulent isolates HVI and race 18, but were still reduced compared to those from HVI alone. The efficiency of selection when screening cotton germplasm for bacterial blight resistance may be reduced if the highly virulent HVI isolate is included in an inoculum mixture composed of non-virulent isolates. 相似文献
10.
本文分析了北京市与河北省小麦赤霉病菌群体遗传结构以及基础生物学特性。结果表明所有菌株均为禾谷镰刀菌(Fusarium graminearum),属于一个大的单一群体,群体内具有较高的遗传多样性。毒素化学型测定表明,北京与河北地区小麦真菌毒素污染的主要风险为DON与15ADON毒素。表型测定显示,与F.asiaticum群体相比,F.graminearum具有较高的产孢能力,而生长速率和产毒能力较低。该群体对主要杀菌剂多菌灵、戊唑醇和氰烯菌酯均无抗药性。 相似文献
11.
12.
I. Murillo L. Cavallarin B. San Segundo 《European journal of plant pathology / European Foundation for Plant Pathology》1998,104(3):301-311
The fungus Fusarium moniliforme infects a wide range of crops throughout the world. In maize (Zea mays L.) it causes seedling blight and root, stalk, and ear rots. A simple procedure that can be used to detect infection by F. moliliforme from infected plant tissues has been developed. A F. moniliforme genomic library was prepared and used to identify the recombinant clones containing fungal DNA sequences not hybridizing with the DNA of the host plant, maize. Based on the nucleotide sequence information obtained from the F. moniliforme pUCF2 genomic clone, specific oligonucleotides were designed and used as primers for in vitro DNA amplification by the polymerase chain reaction. An amplification product was obtained with F. moniliforme DNA preparations whereas no amplified DNA was detected with DNAs from other fungal pathogens, including various Fusarium species, or from the host plant. This PCR analysis was successfully employed to identify F. moniliforme directly from the mycelia that develop from naturally infected maize seeds, with no need to obtain pure fungal cultures for reliable diagnosis. The protocol can be used for the diagnosis of infected plants and soils in epidemiological studies of Fusarium diseases, for seed health testing, and for evaluation of susceptibility to colonization in commercial maize hybrids. 相似文献
13.
Liuyuan FU Jinpeng CHEN Shuan WANG Jia JIANG Zhiping CHE Yuee TIAN Genqiang CHEN Shengming LIU 《农药学学报》2021,23(4):694-702
由禾谷镰孢菌引起的赤霉病是小麦上的重要病害,可严重影响小麦的产量并降低小麦的品质。苯醚甲环唑属于三唑类杀菌剂,是甾醇脱甲基化抑制剂,具有较高的抑菌活性。采用菌丝生长速率法测定了于2016—2017采集自河南省的107株禾谷镰孢菌对苯醚甲环唑的敏感性。结果表明:苯醚甲环唑对禾谷镰孢菌菌丝的生长具有较强的抑制效果,其有效抑制中浓度(EC50)值范围为0.0128~0.6079 mg/L,符合正态分布,平均EC50值为(0.2239 ± 0.1192) mg/L。因此,这些敏感性数据可以作为河南省禾谷镰孢菌对苯醚甲环唑的敏感性基线。通过对苯醚甲环唑与其他7种杀菌剂氟环唑、多菌灵、氰烯菌酯、氟唑菌酰羟胺、戊唑醇、丙硫菌唑及叶菌唑对20株禾谷镰孢菌的log10 EC50值之间的Spearman’s rho (ρ) 相关性分析发现:苯醚甲环唑与叶菌唑之间具有较低水平的相关性,与其他供试杀菌剂之间无相关性。本研究可为监测河南省禾谷镰孢菌对苯醚甲环唑的抗药性发展和防控小麦赤霉病合理用药提供依据。 相似文献
14.
Disease assessment of pea lines with resistance to foot rot pathogens: protocols for in vitro selection 总被引：1，自引：1，他引：0
Cultural conditions were optimized so that disease reactions of plantlets and callus tissue from partially resistant and susceptible genotypes of Pisum sativum could be differentiated when inoculated with Fusarium solani f.sp. pisi. Disease was assessed using both semi-quantitative (disease score/fungal diameter) and quantitative methods (ergosterol assay).
After optimization of inoculum concentration and incubation period it was possible to differentiate the disease reactions of plantlets using disease scores and amount of ergosterol in the tissues.
Incubation period, temperature and the auxin added to the media were important in allowing differentiation of callus tissue cultures. These differences were visible by measurement of the diameter of fungal growth on the callus and the amount of ergosterol in the tissues, but not with disease scores.
The plantlet test was also applicable to the other foot rot pathogens Phoma medicaginis var. pinodella and Aphanomyces euteiches , allowing differentiation of the disease reactions of a partially resistant and susceptible genotype using disease scores. The ergosterol assay could be used to quantify infection caused by P. medicaginis var. pinodella , but this sterol was not detectable in mycelium of A. euteiches. In this fungus the presence of cholesterol was detected, which may be used to quantify infection. 相似文献
After optimization of inoculum concentration and incubation period it was possible to differentiate the disease reactions of plantlets using disease scores and amount of ergosterol in the tissues.
Incubation period, temperature and the auxin added to the media were important in allowing differentiation of callus tissue cultures. These differences were visible by measurement of the diameter of fungal growth on the callus and the amount of ergosterol in the tissues, but not with disease scores.
The plantlet test was also applicable to the other foot rot pathogens Phoma medicaginis var. pinodella and Aphanomyces euteiches , allowing differentiation of the disease reactions of a partially resistant and susceptible genotype using disease scores. The ergosterol assay could be used to quantify infection caused by P. medicaginis var. pinodella , but this sterol was not detectable in mycelium of A. euteiches. In this fungus the presence of cholesterol was detected, which may be used to quantify infection. 相似文献
15.
本文以玉米茎腐病人工接种所需的禾谷镰刀菌Fusarium graminearum和拟轮枝镰刀菌F.verticillioides为材料,比较了三角瓶、聚乙烯袋和牛皮纸袋内用谷物培养基制备接种体的差别。发现在牛皮纸袋内用孢子悬浮液接种玉米粒培养基可高效制备接种体。与三角瓶、聚乙烯袋相比,在牛皮纸袋中制备接种体表现生长点多、透气性好、菌丝生长快、污染率低、质量高、对存放环境要求不严的优点。这种方法可以为玉米茎腐病等相似土传病害的人工接种和病圃建造等提供高质量的接种体。 相似文献
16.
Mixtures of plant growth-promoting rhizobacteria enhance biological control of multiple cucumber pathogens 总被引：1，自引：0，他引：1
ABSTRACT Plant growth-promoting rhizobacteria (PGPR) strains INR7 (Bacillus pumilus), GB03 (Bacillus subtilis), and ME1 (Curtobacterium flaccumfaciens) were tested singly and in combinations for biological control against multiple cucumber pathogens. Investigations under greenhouse conditions were conducted with three cucumber pathogens-Colletotrichum orbiculare (causing anthracnose), Pseudomonas syringae pv. lachrymans (causing angular leaf spot), and Erwinia tracheiphila(causing cucurbit wilt disease)-inoculated singly and in all possible combinations. There was a general trend across all experiments toward greater suppression and enhanced consistency against multiple cucumber pathogens using strain mixtures. The same three PGPR strains were evaluated as seed treatments in two field trials over two seasons, and two strains, IN26 (Burkholderia gladioli) and INR7 also were tested as foliar sprays in one of the trials. In the field trials, the efficacy of induced systemic resistance activity was determined against introduced cucumber pathogens naturally spread within plots through placement of infected plants into the field to provide the pathogen inoculum. PGPR-mediated disease suppression was observed against angular leaf spot in 1996 and against a mixed infection of angular leaf spot and anthracnose in 1997. The three-way mixture of PGPR strains (INR7 plus ME1 plus GB03) as a seed treatment showed intensive plant growth promotion and disease reduction to a level statistically equivalent to the synthetic elicitor Actigard applied as a spray. 相似文献
17.
ABSTRACT The soybean cyst nematode, Heterodera glycines, and the fungus that causes sudden death syndrome (SDS) of soybean, Fusarium solani f. sp. glycines, frequently co-infest soybean (Glycine max) fields. The interactions between H. glycines and F. solani f. sp. glycines were investigated in factorial greenhouse experiments with different inoculum levels of both organisms on a soybean cultivar susceptible to both pathogens. Measured responses included root and shoot dry weights, H. glycines reproduction, area under the SDS disease progress curve, and fungal colonization of roots. Both H. glycines and F. solani f. sp. glycines reduced the growth of soybeans. Reproduction of H. glycines was suppressed by high inoculum levels but not by low levels of F. solani f. sp. glycines. The infection of soybean roots by H. glycines did not affect root colonization by the fungus, as determined by real-time polymerase chain reaction. Although both pathogens reduced the growth of soybeans, H. glycines did not increase SDS foliar symptoms, and statistical interactions between the two pathogens were seldom significant. 相似文献
18.
ABSTRACT Fusarium oxysporum f. sp. radicis-lycopersici, the causal agent of Fusarium crown and root rot of tomato, and F. oxysporum f. sp. basilici, the causal agent of Fusarium wilt in basil, are soilborne pathogens capable of producing conspicuous masses of macroconidia along the stem. The role of the airborne propagules in the epidemics of the disease in tomato plants was studied. In the field, airborne propagules of F. oxysporum f. sp. radicis-lycopersici were trapped with a selective medium and their prevalence was determined. Plants grown in both covered and uncovered pots, detached from the field soil, and exposed to natural aerial inoculum developed typical symptoms (82 to 87% diseased plants). The distribution of inoculum in the growth medium in the pots also indicated the occurrence of foliage infection. In greenhouse, foliage and root inoculations were carried out with both tomato and basil and their respective pathogens. Temperature and duration of high relative humidity affected rate of colonization of tomato, but not of basil, by the respective pathogens. Disease incidence in foliage-inoculated plants reached 75 to 100%. In these plants, downward movement of the pathogens from the foliage to the crown and roots was observed. Wounding enhanced pathogen invasion and establishment in the foliage-inoculated plants. The sporulation of the two pathogens on stems, aerial dissemination, and foliage infection raise the need for foliage protection in addition to soil disinfestation, in the framework of an integrated disease management program. 相似文献
19.
利用禾谷镰刀菌Fusarium graminearum和稻瘟病菌Magnaporthe grisea基因组测序结果,对这两种植物病原真菌基因组中的微卫星(SSR)序列进行了系统地分析和比较.结果表明,在禾谷镰刀菌基因组中,共发现4679个SSR序列,总长度为96.2kb,占基因组全长的0.27%.平均7.7kb碱基中有一个大于15 bp的SSR序列.在稻瘟病菌基因组中共发现16398个SSR系列,其总长度达到330kb,约占整个基因全长的0.85%,平均2.36kb碱基中就分布有1个SSR序列.在禾谷镰刀菌基因组中,数量最多的是五碱基重复序列,其次是六碱基重复序列;稻瘟病菌基因组中数量最多的是单碱基重复序列,其次为三碱基重复序列和五碱基重复序列.两基因组中数量最少的都是二碱基重复序列.尽管这两种植物病原真菌都属子囊菌,基因组大小也十分接近,但无论是在SSR的总体数量上,还是在各类SSR的分布上,两种植物病原真菌都存在十分显著的差别. 相似文献
20.
Experiments were conducted under controlled environment conditions to study the relationship between environmental conditions, development of fusarium head blight (FHB) and mycotoxin production. A single isolate from each of four Fusarium species ( F. avenaceum , F. culmorum , F. graminearum and F. poae ) was used to inoculate wheat ears separately. Combinations of two or three isolates were also used to inoculate ears simultaneously. Inoculated ears were subjected to various combinations of duration of wetness (6–48 h) and temperature (10–30°C). For all inoculations, both incidence of spikelets with FHB symptoms and concentration of mycotoxins generally increased with increasing length of wetness period and temperature. There were significant positive correlations among disease incidence, fungal biomass (quantified as total amount of fungal DNA) and mycotoxins. Mycotoxin production was also greatly enhanced by high temperatures (≥ 20°C) during initial infection periods. In single-isolate inoculations, F. poae was the least aggressive. There was no evidence to support synergetic interactions between fungal isolates in causing visual symptoms; rather the results suggest, in most cases, the presence of competitive interactions. Furthermore, the competition led to large reductions in fungal biomass compared to single-isolate inoculations, often > 90% reduction for the weaker isolate(s). In contrast, mycotoxin productivity increased dramatically in the co-inoculations, by as much as 1000 times, suggesting that competition resulted in greater production of trichothecene mycotoxins. The F. graminearum isolate was most competitive and isolates of the other three species were similar in their competitiveness. 相似文献