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21.
22.
拮抗菌对香蕉枯萎病菌的抑菌作用初步研究 总被引:25,自引:1,他引:25
从土壤中分离到一株对香蕉枯萎病菌(Fusarium oxysporum f.sp.cubense)具有抑制作用的拮抗细菌--假单胞杆菌(Pseudomonas sp.),并对其抑菌效果、热稳定性以及作用机理进行了初步研究.结果表明,拮抗细菌发酵液及其无菌滤液对香蕉枯萎病菌的生长及其分生孢子的萌发具有显著的抑制作用(P<0.05),并导致病菌菌丝和分生孢子芽管扭曲、膨大;拮抗细菌发酵液经121℃处理30min后,对病菌生长的抑制作用降低. 相似文献
23.
【目的】 针对生产中危害严重的3种蔬菜土传病原菌瓜果腐霉(Pythium aphanidermatum)、尖镰孢(Fusarium oxysporum)、大丽轮枝菌(Verticillium dahliae),建立三重PCR(triplex PCR)检测体系,为蔬菜土传真菌病害的早期诊断和鉴定提供技术与方法。【方法】 筛选3种病原菌特异性引物组合,通过设定不同的PCR退火温度、引物浓度、循环次数以及延伸时间,探索影响三重PCR扩增的因素,建立蔬菜土传病原菌三重PCR检测体系,并对体系灵敏度进行检测。为了验证建立体系的稳定性,选择2×Taq Master PCR Mix(北京博迈德生物技术有限公司)和TaKaRa Taq酶(大连宝生物工程有限公司)2个不同公司的试剂,分别利用C1000 Touch TM型(赛默飞世尔科技有限公司)与Aeris TM型(新加坡艺思高科技有限公司)热循环仪进行三重PCR反应,比较检测结果的可重复性。对田间采集的35份病害样本和149份土壤样本,分别进行三重PCR和病原菌分离检测,以确定所建立得三重PCR检测体系的适用性。 【结果】 三重PCR反应体系中引物对AsAPH2B/AsPyF、FOF1/FOR1、VActF/VActR可分别扩增出瓜果腐霉、尖镰孢、大丽轮枝菌长度为163、328和530 bp的特异性目的片段。反应体系(25 μL):0.12 μmol·L -1 AsAPH2B/AsPyF,0.16 μmol·L -1 FOF1/FOR1,0.24 μmol·L -1 VActF/VActR,2×Taq Master PCR Mix 12.5 μL,退火温度为60.8℃,35个循环。该体系对病原菌纯培养物的检测灵敏度为10 -1ng·μL -1,对土壤中大丽轮枝菌、尖镰孢和瓜果腐霉的检测灵敏度分别为10 5、10 6个孢子/g土壤和10 -2mg菌丝/g土壤。分别采用2×Taq Master PCR Mix和TaKaRa Taq酶,利用C1000 Touch TM型和Aeris TM型热循环仪进行三重PCR,扩增结果一致,说明三重PCR体系检测稳定性好。对田间采集的病害和土壤样本进行检测,25份病害样本和71份土壤样本中检测出带菌,三重PCR检测与病原菌分离培养结果一致。 【结论】 本研究建立的瓜果腐霉、尖镰孢、大丽轮枝菌三重PCR检测体系具有灵敏度高、稳定性和重复性好的特点,能够快速、准确地检测田间病株及其根围土壤中的瓜果腐霉、尖镰孢、大丽轮枝菌,为蔬菜土传病害的早期预防和流行监测提供了有效的技术手段。 相似文献
24.
Rhamnolipids, extracellular metabolites of Pseudomonas aeruginosa with surfactant properties, proved to be very effective in controlling the spread of brown root rot disease caused by Phytophthora cryptogea in the hydroponic forcing system of witloof chicory ( Cichorium intybus var. foliosum ). The biosurfactant was applied as the product PRO1, a formulation of 25% rhamnolipids in oil. Both an in vitro screening and in vivo experiments in a mini-hydroponic system demonstrated the ability of PRO1 to control brown root rot. A 25 µ g mL−1 rhamnolipids nutrient solution was enough to obtain good control of an artificial infection with a zoospore suspension of P. cryptogea . The biosurfactant PRO1 performed well in a semicommercial system under growers' conditions. A treatment of 25 µ g mL−1 rhamnolipids (100 µ g mL−1 PRO1) reduced the disease incidence significantly in two independent experiments. However, PRO1 was not effective when a mycelial suspension was used as inoculum. Rhamnolipids have good potential to limit the spread of P. cryptogea in the hydroponic forcing system of witloof chicory, and can be used as a preventive measure against brown root rot. 相似文献
25.
G. Tuitert Y. Hofmeester 《European journal of plant pathology / European Foundation for Plant Pathology》1992,98(6):343-360
Using field plots where rhizomania had not previously been detected, different inoculum levels of beet necrotic yellow vein virus (BNYVV) were created by application of infested soil. A susceptible sugar beet cultivar (cv. Regina) was grown for two consecutive years (1988 and 1989), in the presence or absence of drip irrigation. In soil samples taken in spring 1989, the different initial inoculum levels of 1988 could be distinguished using a quantitative bioassay estimating most probable numbers (MPNs) of infective units per 100 g dry soil. The first sugar beet crop resulted in a tenthousandfold multiplication of inoculum of BNYVV (viruliferousPolymyxa betae). Mean MPNs of BNYVV ranged from 0.6 and 7 per 100 g soil for the lowest inoculum level to 630 and 1100 per 100 g for the highest level, in plots without and with irrigation, respectively. In spring 1990, MPNs had again increased. In both years, the initial inoculum level of 1988 had a significant linear effect on log-transformed MPNs of BNYVV determined. Log-transformed MPNs for 1990 and 1989 showed a positive linear correlation, despite a decreasing multiplication ratio at higher inoculum levels. Drip irrigation during one or two years enhanced the increase in MPN of BNYVV, which was reflected by the enhancement of multiplication ratios at all inoculum levels. The totalP. betae population was also higher after growing two irrigated crops than after growing two non-irrigated ones. 相似文献
26.
M. A-M. Mahir M. Fortass L. Bos 《European journal of plant pathology / European Foundation for Plant Pathology》1992,98(4):237-252
A virus, isolated from faba bean (Vicia faba) obtained from Algeria, was readily recognized as a tobravirus by its particle sizes and morphology. Pea (Pisum sativum) and French bean (Phaseolus vulgaris) characteristically reacted to the isolate like pea early-browning virus (PEBV), but faba bean,Antirrhinum majus, Nicotiana rustica, andN. tabacum reacted with line-pattern symptoms which were unusually brilliant on theNicotiana species. In electronmicroscope decoration tests, the isolate did not react with an antiserum to the Dutch type strain of PEBV, but with one to the broad bean yellow band (BBYB) serotype from Italy. It resembles this serotype in reaction on faba bean, but seems to differ appreciably onN. rustica, N. tabacum, andPetunia hybrida. It is described as a deviant isolate of the BBYB serotype of PEBV.All thirteen faba-bean genotypes tested were found to be susceptible to the Algerian isolate and two Dutch type strain isolates of the virus, and to react with erratic line-pattern symptoms to the Algerian isolate only. All ten genotypes of chickpea (Cicer arietinum) tested reacted hypersensitively, and four out of ten genotypes of lentil (Lens culinaris) were susceptible to the virus but reacted differentially to the three isolates. Seed transmission of PEBV, including the new isolate, in faba bean is confirmed (9% for the Algerian isolate, and over 45% for one of the Dutch type strain isolates), and seed transmission of the virus in a non-legume (N. rustica, 4%) is herewith first reported. This is the first report on the occurrence of the BBYB serotype of PEBV outside Italy, and of PEBV outside Morocco in North Africa. 相似文献
27.
M. P. McQuilken J. M. Whipps 《European journal of plant pathology / European Foundation for Plant Pathology》1995,101(1):101-110
Coniothyrium minitans grew on all ten solid-substrates (barley, barley-rye-sunflower, bran-vermiculite, bran-sand, maizemed-perlite, millet, oats, peat-bran, rice and wheat) tested, producing high numbers of germinable pycnidiospores (1.9–9.3×108 g–1 air dry inocula). All solid substrate inocula survived better in the laboratory at 5 and 15 °C than at 30 °C for at least 64 weeks.In pot bioassays carried out in the glasshouse and field, soil incorporations of each inoculum almost completely inhibited carpogenic germination ofS. sclerotiorum. In the field bioassay, no sclerotia were recovered after 38 weeks fromC. minitans-treated pots compared to 56% from control pots. In the glasshouse bioassay, 9–30% of sclerotia were recovered after 20 weeks fromC. minitans-treated pots, but 88–100% of these were infected by the antagonist. The antagonist also spread to infect sclerotia in control pots.In larger scale glasshouse trials, single preplanting soil-incorporations of five inocula (barley-ryesunflower, maizemeal-perlite, peat-bran, rice and wheat) controlled Sclerotinia disease in a sequence of lettuce crops, with only small differences between the types of inocula tested. At harvest,C. minitans reduced sclerotial populations on the soil surface and over 74% of sclerotia recovered fromC. minitans-treated plots were infected by the antagonist.C. minitans survived in soil in all solid-substrate inocula-treated plots for at least 39 weeks at levels of 104–105 colony forming units cm–3 soil and spread to infect over 36% of sclerotia recovered from control plots. 相似文献
28.
P. Oyarzun M. Gerlagh A. E. Hoogland 《European journal of plant pathology / European Foundation for Plant Pathology》1993,99(1):35-44
The relation between the frequency of legume crops in a rotation and the root rot severity in pea was examined in a field survey. Additionally, greenhouse experiments were performed with soil samples from legume rotation trials or from farmers' fields. The frequency of pea crops in current rotations proved to be much less than the recommended value of one in six years. The correlation between pea root rot and the number of years that pea or other legumes were not grown on the field under consideration (called crop interval) was weak. Root rot severity correlated better with the frequency of peas or legumes in general over a period of 18 years, but the frequency still explained only a minor fraction of the variation in disease index. Some experimental data pointed to the occurrence of a highly specific pathogen microflora with continuous cropping of only one legume species, but this phenomenon probably does not occur in farmers' fields. In field samples, root disease index for pea correlated well with that for field bean. The survival of resting structures of pathogens such asAphanomyces euteiches probably explains why the frequency of legume cropping has a higher impact than crop interval on root disease incidence. Pea-free periods and legume frequencies have a poor predictive value for crop management purposes. 相似文献
29.
30.
Ariena H. C. van Bruggen Alexander M. Semenov Anne D. van Diepeningen Oscar J. de Vos Wim J. Blok 《European journal of plant pathology / European Foundation for Plant Pathology》2006,115(1):105-122
A healthy soil is often defined as a stable soil system with high levels of biological diversity and activity, internal nutrient
cycling, and resilience to disturbance. This implies that microbial fluctuations after a disturbance would dampen more quickly
in a healthy than in a chronically damaged and biologically impoverished soil. Soil could be disturbed by various processes,
for example addition of a nutrient source, tillage, or drying-rewetting. As a result of any disturbance, the numbers of heterotrophic
bacteria and of individual species start to oscillate, both in time and space. The oscillations appear as moving waves along
the path of a moving nutrient source such as a root tip. The phase and period for different trophic groups and species of
bacteria may be shifted indicating that succession occurs. DGGE, Biolog and FAME analysis of subsequent populations in oscillation
have confirmed that there is a cyclic succession in microbial communities. Microbial diversity oscillates in opposite direction
from oscillations in microbial populations. In a healthy soil, the amplitudes of these oscillations will be small, but the
background levels of microbial diversity and activity are high, so that soil-borne diseases will face more competitors and
antagonists. However, soil-borne pathogens and antagonists alike will fluctuate in time and space as a result of growing plant
roots and other disturbances, and the periods and phases of the oscillations may vary. As a consequence, biological control
by members of a single trophic group or species may never be complete, as pathogens will encounter varying populations of
the biocontrol agent on the root surface. A mixture of different trophic groups may provide more complete biological control
because peaks of different trophic groups occur at subsequent locations along a root. Alternatively, regular addition of soil
organic matter may increase background levels of microbial activity, increase nutrient cycling, lower the concentrations of
easily available nutrient sources, increase microbial diversity, and enhance natural disease suppression. 相似文献