艾蒿提取物对13种植物病原菌物的抑制作用

研究了艾蒿乙醇提取物对13种植物病原菌物的抑制活性,并测定了提取物对4种植物病原菌物菌丝生长的毒力.结果表明,在50 mg.mL-1生药浓度下,艾蒿乙醇提取物对水稻纹枯病菌30 h和十字花科菌核病菌48 h的菌丝生长抑制率大于90%,对辣椒疫霉病菌、荔枝霜霉病菌、柑橘青霉病菌、红麻灰霉病菌48 h的菌丝生长抑制率在70%-86%之间,对香蕉枯萎病菌、棉花枯萎病菌、香蕉炭疽病菌、稻瘟病菌、红麻灰霉病菌等孢子的萌发抑制率在90%以上.显微观察说明,加药处理后,菌丝出现扭曲、膨大、液泡增多、分枝增加、分枝间隔缩短等异常变化.毒力测定表明,艾蒿乙醇提取物对水稻纹枯菌抑制作用较强,EC50仅为5.85 mg.mL-1.以上研究结果表明,艾蒿具有开发为新型植物源农药的潜力.

银杏酸对6种蔬菜病原菌物的抑制作用

室内测定了银杏酸对5种蔬菜病原菌物菌丝生长的活性,结果表明:在70mg/mL浓度下,银杏酸对茄子立枯病菌、茄子白绢病菌24h的菌丝生长抑制率分别为65.2%、65.3%,对甘蓝黑斑病菌、白菜炭疽病菌、黄瓜枯萎病菌48h的菌丝生长抑制率在63.6%～77.3%之间;加药后,稀薄菌丝沿培养基表面生长,气生菌丝少,有的菌丝变色;对黄瓜枯萎病菌、甘蓝黑斑病菌、苦瓜枯萎病菌、白菜炭疽病菌等孢子萌发抑制率均在86%以上,其中对黄瓜枯萎病菌的抑制率最好;显微观察说明:银杏酸处理后,菌丝细胞出现不规则膨大、凋亡、黄化、扭曲、液泡变多、节间缩短等异常现象;毒力测定显示:银杏酸对甘蓝黑斑病菌抑制作用较强,EC50为24.80mg/mL。

银杏酸微乳剂对几种蔬菜病原真菌的抑制作用

进行银杏酸微乳剂对蔬菜真菌的室内抑菌与室外防治试验,结果表明:银杏酸微乳剂5mg/kg对白菜炭疽病、黄瓜枯萎病、甘蓝黑斑病、茄子白绢病、茄子立枯病等5种病菌菌丝的抑菌率分别为96.7%、93.0%、100.0%、100.0%、100.0%;银杏酸微乳剂10 mg/mL以上对5种病原菌菌丝的抑菌率均达到100.0%。银杏酸微乳剂1 mg/mL对白菜炭疽病、甘蓝黑斑病、黄瓜枯萎病、茄子立枯病等4种蔬菜病害的田间防治效果分别为72.0%、77.9%、71.4%、73.4%,略低于50%多菌灵800倍液的防效。

植物病原菌抗药性群体的形成

植物病原菌抗药性群体的形成周明国（全国植保总站病虫抗药性监测培训中心，南京农业大学植保系，２１００９５）６０年代以来，内吸性杀菌剂的开发应用，在人类与自然界的斗争中发挥了重要作用，过去许多使人们束手无策的重要植物病害，得到了有效的化学防治。然而，随着...

碱木素焦油的抑菌活性及机理

测定了碱木素焦油对10个属16种植物病原菌物的抑制效果,研究了碱木素焦油对辣椒疫霉菌(Phytophthora capsici)的毒力和抑制机理.结果表明:碱木素焦油对供试病原菌物的菌丝生长均具有不同程度的抑制作用,抑制率为43.75%-100%;对P.capsici菌丝和孢子萌发的EC50分别为118和291μg·m L-1,优于甲霜灵;碱木素焦油对P.capsici有多个作用靶位点,能显著抑制P.capsici的有氧呼吸,使细胞膜受损,胞内蛋白、还原糖、电解质流失,使纤维素酶及多聚半乳糖醛酸酶活性降低.

中国柑橘菌物病原名录

我国是世界上最大的柑橘生产国,柑橘产业在我国农业生产中占有重要地位。菌物病害是制约我国柑橘产业效益的重要因素。在过去一百余年里,我国植物病理学家和菌物学家描述和记载了大量柑橘上的病原菌物。然而随着分子系统学在菌物分类鉴定中的广泛应用,以及菌物命名法规的变化,一些菌物的分类地位和拉丁学名发生了较大的变化。为了方便使用者了解这些变化,方便柑橘菌物病害相关知识的交流,本文汇总了我国已经描述的柑橘菌物病害的病原种类,其中病原真菌103种,病原卵菌12种,此外还列出我国禁止入境病原菌5种,并依据最新分类系统和菌物命名法规对相关病原菌物的拉丁学名、中文名称以及病害中文和英文名称等进行了整理和修订。该项工作有利于我国柑橘产业相关工作者对柑橘病原菌物名称的检索和规范使用,促进学术交流和科学知识的普及。

Fungal genus Hypocrea/Trichoderma:from barcodes to biodiversity

Hypocrea/Trichoderma is a genus of soil-borne or wood-decaying fungi containing members important to mankind as producers of industrial enzymes and biocontrol agents against plant pathogens, but also as opportunistic pathogens of immuno- compromised humans and animals, while others can cause damage to cultivated mushroom. With the recent advent of a reliable, BarCode-aided identification system for all known taxa of Trichoderma and Hypocrea, it became now possible to study some of the biological fundamentals of the diversity in this fungal genus in more detail. In this article, we will therefore review recent progress in (1) the understanding of the geographic distribution of individual taxa; (2) mechanisms of speciation leading to development of mushroom diseases and facultative human mycoses; and (3) the possible correlation of specific traits of secondary metabolism and molecular phylogeny.

Advance of entomopathogenic nematodes

This paper summarized the history and present condition of studying and utilizing entomopathogenic nematodes at home and abroad, expounded its taxonomy, life cycle and the mechanism with symbiotic bacteria killing host insect. Taxonomy, mycelial form, pathogenic function and anti-bacteria function of symbiotic bacteria were introduced. Production and utilization of entomopathogenic nematodes, the characteristic genetic improvement by use of biological engineering technology, as well as the existing problem and applying foreground were also discussed.

Initial Screening of 10 Plant Essential Oils in Vitro Antibacterial Activity Against Blueberry Pathogens

In order to develop natural antistaling agent for blueberries preservation,the antibacterial activities of 10 kinds of plant essential oils were analyzed by oxford-cup test and tube dilution method,and their inhibitory abilities to two kinds of representative Gram bacteria which are Escherichia coli and Staphylococcus aureus,and three kinds of harmful fungi in blueberries,involving Alternaria alternata,Penicillium digitatum and Botrytis cinerea,were tested.The results showed that 7 kinds of essential oils can inhibit the three fungi,among which cinnamon oil,clove oil,anise oil and thyme oil have strong fungi static efficacy.Cinnamon oil and thyme oil can effectively inhibit the Gram-positive bacterium(Staphylococcus aureus);cinnamon oil and masson pine oil are strongly inhibitory to Gram-negative bacterium(E.coli).Cinnamon oil has broad-spectrum ability to inhibit fungi,Gram-negative and positive bacteria,with a minimum inhibitory concentration(MIC)ranging from 0.0391 to 0.1560 L/mL.With strong inhibition effects on fungi,cinnamon oil can be used as a compound base oil and mixed with other essential oils to retain the freshness of blueberries,thus achieving better antibacterial and anti-corrosion effects.

Study on the Biology and Epidemiology of Uncinula necator---The Causal Agent of Grape Powdery Mildew Disease

This study was carried out during 2007-2009 in the vineyards of Ardebil province of lran to study the biology and the epidemiology of Uncinula necator--the causal agent of grape powdery mildew disease. The study concentrated on the survival and the initiation of primary inoculum of the fungal causal agent. Results of histopathological experiments indicated that U. necator survived as mycelium in the dormant buds of the grapes during winter season. Results of study on the effect of environmental factors on fungus biology showed that the pathogenic activity of the fungus began when the temperature was between 16-19 ℃ with a relative humidity more than 50%. It was also found that optimum temperature and relative humidity for the sporulation of U.necator was 20-25 ~C and 50%-100% respectively. According to the results, fungal conidia were trapped during formation of 5-6 true leaves and first disease symptoms were observed on the clusters on late June after fruit formation. Fungal cleistothecia were observed abundantly at the end of season on the leaves, petioles and twigs but they were not able to survive during winter. Formation of ascospores on young leaves was proved but their role as the primary inoculum was not supported by the results of this study. Results of this study and the new findings on the biology and epidemiology of U.necator may be of national and international interests for the management of powdery mildew disease which is one of the most destructive diseases around the world including Iran.

Pathogenicity of Vibrios in Fish: an Overview

Bacteria of the genus Vibrio are ubiquitously distributed in the marine environment. Due to the rapid expansion of intensive mariculture and the consequent deterioration of culture conditions, more and more Vibrio spp. have been recognized as pathogenic agents in outbreaks of vibriosis, a serious epizootic disease affecting most wild and farmed fish species worldwide, which has become the most important limiting factor for the development of intensive mariculture industry. Attempts have been made to understand the pathogenicity of vibrios in host fish with the ultimate aim of elucidating the best means for disease control. After an extensive literature survey of the recent advances in the field of fish vibriosis, the pathological changes, virulence factors and associated potential pathogenic mechanisms, transmission routes and related environmental factors involved in outbreak of vibriosis, as well as the controlling strategies are reviewed in the present paper.

Antibacterial Activity of Extracts from Zostera marina Against Pathogens of Apostichopus japonicus Skin Ulceration Disease

The purpose of this study was to investigate the antibacterial activity of extracts from Zostera marina against the pathogens of Apostichopus japonicus skin ulceration disease.When 95% ethanol (v/v) solvent was used to extract Zostera marina at 50℃,aqueous extract (ZA) showed obvious bacteriostatic effects on the tested bacterial strains (inhibition halo diameters between 8.23 mm and 13.62 mm),whereas the ethyl acetate extract (ZE) was almost inactive.The minimal inhibitory concentration (MIC) of ZA against four pathogens were homogeneous at 12.8 g L-1.ZA components were analyzed by thin layer chromatography (TLC) assay and six fractions were obtained.In another study,the six fractions showed inhibitory effects against the tested bacteria while their functions seemed to counteract the ZA activity.

Recent Achievements in the Bio-control of Orobanche Infesting Important Crops in the Mediterranean Basin

Orobanche spp. （broomrapes） are holoparasitic plants distributed predominantly in the Northern Hemisphere parasitizing the roots of a range of plant species mainly in wild ecosystems. Orobanche species cause severe yield reduction of many important crops. There are only very few herbicides which are able to selectively control broomrapes and different approaches have been put forward to develop natural product based pesticides to control Orobanche. Several phytopathogenic fungi were evaluated for their use as potential mycoherbicide and for ability to produce toxic metabolites which could be applied as herbicides. Using the alternative approach ＂suicidal germination＂, interesting results were obtained by testing two microbial metabolites （fusicoccins and ophiobolin A） especially with Orobanche species whose germination is not induced by the synthetic strigolactone GR24. From pea root exudates, peagol and peagoldione, close related to strigolactones, and three polyphenols, named peapolyphenols A-C, together with already well known polyphenol and a chalcone, were isolated. They showed a selective stimulation of Orobanche seed germination with the last two and peapolyphenol A showing a specific stimulatory activity on O. foetida. This review describes the most recent results achieved on Orobanche bio-control, mainly focusing on those regarding O. ramosa, O. crenata and O. foetida.

Effect of Some Biopreparations on Health Status of Strawberry （Fragaria ananassa Duch.）

The study aimed at comparing the effect of selected biopreparations （Boni protect forte, beta-chikol, Trianum P） and fungicide treatment Switch 62.5 WG （cyprodinil ＋ fludioxonil） on the health status of strawberry grown in the fruiting field at the strawberry farm in Jasionka, Lublin region. The experiment was conducted for three years （2012-2014）. Results showed that the application of all biopreparations and fungicide significantly reduced the number of diseased plants and the disease index. The effect of three biological products was similar. The mycological analysis of plants showed that among the fungi potentially pathogenic to strawberry, Fusarium spp., Cylindrocarpon spp., Botrytis cinerea and Alternaria were predominated. The fewest colonies of pathogenic fungi were isolated from plants treated with Trianum P.

Diversity of Bacteria Isolated from Crustacea Larvae and Their Rearing Water

The bacteria in the genus Vibrio are heterothrophic, which exist in the larval rearing water of Crustacea and often show diverse pathogenicities to marine animals. In order to assess the bacterial diversity associated with Crustacean seed production, 32 strains were isolated from black tiger shrimp (Penaeus monodon) and mangrove crab (Scylla paramamosain) larvae and their rearing-water and characterized using biochemical and molecular approaches. Two or more genotypically different species were identified. The vibriosis of black tiger shrimp was caused by V. harveyi, V. alginolyticus and Vibrio spp. predominantly, while that of crab by V. harveyi and V. alginolyticus only.

Utilization of Fungi for the Biological Control of Insect Pests and Ganoderma Disease in the Indonesian Oil Palm Industry

Biological control is usually the first choice of control and prevention method for integrated pest management （IPM） strategies and has now been widely implemented by Indonesian oil palm plantations. Entomopathogenic fungus, i.e., Metarhizium anisopliae, Cordyceps militaris and Beauveria bassiana have been demonstrated to control renowned pests of oil palm. Metarhizium has been used to control Oryctes larvae and the mortality has ranged from 91.67% to 100% in laboratory and 7.4% to 88.75% in the field. Metarhizium has been applied in combination with a termite baiting system （TBS） to control termites in the field for preventive and curative action as well. In many oil palm plantations in Indonesia, Cordyceps has been used to reduce the field moth population ofSetothosea asigna. Application of Cordyceps within the oil palm circle was able to infect S. asigna pupae up to 80%. Meanwhile, Beauveria in an effervescent formulation was demonstrated to have better efficacy on Darna trima larvae. A significant finding on the biological control of basal stem rot disease （Ganoderma） was the isolation of Trichoderma sp. and Gliocladium sp.. The efficacy was conducted with promising result and techniques on the application of Triehoderma have been developed, i.e., hole-in-hole system, surgery and a mounding method. However, as the roots developed, Trichoderma was no longer able to protect the palm from Ganoderma. In spite of that, the use of Trichoderma still prolonged the life ofoil palms by up to 2-3 years. Another fungi belonging to vesicular arbuscular mychorrhiza （VAM） has been developed to control Ganoderma. The efficacy in the nursery showed promising results and the Ganoderma incidence remained low compared to the untreated control. Large scale field trials are ongoing. Challenges on the implementation of biological control in oil palm plantations are because of application and availability of biopesticides/natural enemies. Therefore, advances in research on the formulation of biological control agents are still needed.

Screening of Fnngos Antagonists against Six Main Disease Pathogens in Crops

28 soil samples were collected from the rhizosphere of 16 plant species in six different districts in Hunan. As a result of isolation and purification, 122 fungus strains were obtained of which the antagonistic activity was tested against six fungus pathogens in tomato, cotton, cucumber, chilli, rice and rape, and 17 strains were found antagonistic to one or more pathogenic fungi.

Effects of 60Co-γ Ray Radicidation on Instant Tea

Effects of 60Co-γ ray radicidation on instant tea were studied through contaminant microbe assay,absorbed dose measurement and analysis of principal components of instant tea.The minimum effective dose of 4.0kGy and maximum tolerance dose of 8.0KGy were proposed.

Proteomic study of three component interactions: plant, pathogens and antagonistic fungi

The molecular factors involved in the three-way interaction between plant, pathogenic fungi and antagonistic/biocontrol fungi, such as Trichoderma, are still poorly understood, even if they represent a matter of interest for improving crop management and developing new strategies for plant diseases control. The aim of this work is to investigate the components involved in this interaction and, for this purpose, a proteomic approach was used. 2-D maps of the protein extracts from the single components in various interactions between plants (potato, bean, tobacco or tomato), pathogens (Botrytis cinerea, Rhizoctonia solani or Pythium ultimum) and biocontrol fungi (Trichoderma atroviride strain P1 or Trichoderma harzianum strain T22) were obtained. The proteome of each partner was collected separately and extracted by acetone precipitation in presence of trichloroacetic acid and a reducing agent (DTT). The extracted proteins were separated by isoelectrofocusing (IEF), using IPG (Immobilized pH gradient) strips, followed by SDS-PAGE. In order to improve resolution the separations were performed both on wide than narrow pH range and on different gel lengths. Differential spots were noted in the proteome of the three-way interaction when compared to each single component. These were further characterized by mass spectrometry and in silico analysis with the aim of identifying and cloning the relative genes. During the in vitro interaction of T. harzianum strain T22 with tomato and the culture filtrate or cell walls of pathogens, the spot number was higher than in the presence of pathogen biomass. In terms of Trichoderma differential proteins displayed on 2D gels, the most important changes were obtained in the presence of P. ultimum . During the in vivo interaction with tomato, the antagonist proteome changed much more in presence of soilborne fungi R. solani and P. ultimum than with the foliar fungus B. cinerea, both in terms of total and increased or novel spots. In silico analysis of some of those spots revealed homology with intracellular enzymes (GTPases, hydrolases) and with stress-related proteins (heat shock proteins HSP70, bacteriocin cloacin). Specific proteins in the plant proteome, i.e. pathogenesis-related proteins, have been identified during the in vivo interaction of bean with R. solani and T. atroviride strain P1. This is in agreement with the demonstrated ability of these beneficial fungi to induce plant systemic disease resistance by activating expression of defence-related genes. Proteins extracted from T. atrovride strain P1 which were analysed by mass spectrometry, revealed some interesting homologies with a fungal hydrophobin of Pleurotus ostreatus and an ABC transporter of Ralstonia metallidurans. These could represent molecular factors involved in the antagonistic mechanisms of Trichoderma and play a role in the three-way interaction with the plant and other microbes.

Use of Cladophora glomerata Extract against Multidrug Resistant Bacterial Pathogens

The antibacterial effect of the crude methanol extracts and purified fractions of Ctadophora glomerata （Linnaeus） Kutzing （Cladophoraceae） against multidrug resistant human pathogen were investigated. The test bacterial strains were Staphylococcus aureus, Pseudomonas aeruginosa, Streptococcus faecalis, Escherichia coli and S. typhimurium. Ethanol extract （0.5 mg/mL） of Cladophora glomerata inhibited growth of all the test organisms. Primary detection of active compounds showed that maeroalgae （Cladophora glomerata） containing flavonoids, alkaloids, phenols and tannins. Gas Chromatography-Mass Spectrometry was used to know the compounds which responsible of antibacterial activity and they were g-Pentadecanone that was found to be a major compound （42.67%） followed by 8-Octadecanone （22.43%） and Salicylic acid （20.04%） in addition to 10-hexadecaden （8.01%）. These findings suggest the possibility of using the Cladophora glomerata as a novel source of natural antimicrobial agents in pharmaceutical industries.