黑龙江省一株红小豆锈病病原菌鉴定

【目的】为明确发生在黑龙江省大庆市红小豆田中的锈病病原物的分类地位。【方法】从大庆市采集红小豆锈病标样,采用单孢子堆分离法获得一株红小豆锈病菌纯培养物ZXL01。采用观测夏孢子芽孔数目、位置和冬孢子壁厚度等形态学特征结合ITS序列分析的方法,对其进行鉴定。【结果】ZXL01夏孢子发芽孔多为2个,位于孢子赤道部位较远之处,冬孢子壁厚度为2.9μm-3.3μm。在基于r DNA-ITS序列构建的系统发育树中,ZXL01菌株与两株豇豆单胞锈菌(Uromyces vignae)的参比菌株(Gen Bank登录号:AB115718和AB115731)在自举值99%相聚一群。用豇豆单胞锈菌的特异性引物UV-ITSF/R进行检测,ZXL01菌株可扩增出500 bp左右的特征片段。【结论】黑龙江省大庆市红小豆锈病病原菌ZXL01菌株为豇豆单胞锈菌,ZXL01菌株的Gen Bank登录号是KM461700。     

紫菀鞘锈菌的一个新寄主及其细胞学和超微结构特征

加拿大一枝黄花Solidago canadensis是一种外来入侵植物。由于它强大的竞争能力并缺乏自然天敌,这种植物在我国东部迅速扩展和蔓延,已引起严重生态问题。我们于2015年5月在浙江宁波地区第一次发现加拿大一枝黄花锈病。该病在叶片上产生黄斑,大量夏孢子堆和夏孢子覆盖植物叶片,引起叶片扭曲、叶疫和落叶。依据形态学特征和分子数据,引起加拿大一枝黄花锈病的病原菌被鉴定为紫菀鞘锈菌Coleosporium asterum。超微结构分析揭示,在一个孢子堆中冬孢子形成、萌发以及担子的产生是一个连续的过程,即在一个孢子堆中,既有冬孢子发育又有担子发育,而个体冬孢子间或担子间也具有不同的发育水平。研究结果为进一步探索病害侵染循环以及病原菌对寄主生长和传播的影响提供了科学数据。     

3种石斛多糖及其降血糖活性的比较研究

天然多糖安全、低毒,是潜在糖尿病治疗药物。为寻找活性高、含量高的植物多糖资源,本文从多糖得率、结构和降血糖活性三个方面,对云南地方药材大苞鞘石斛、铁皮石斛和金钗石斛进行比较。通过热水浸提、透析和层析得到多糖,然后用糖尿病小鼠模型测定降血糖活性。结果表明大苞鞘石斛的多糖得率高(14.1%,DW),且分子量较小,其单糖组成与铁皮石斛多糖相似;降血糖效果强于铁皮石斛和金钗石斛多糖。大苞鞘石斛可作优良的亲本,为降血糖的石斛多糖资源开发提供育种资源。     

中国鞘锈菌属一新记录种

在香港新界的鸡蛋花Plumeria rubra L.var.acutifolia Bailey植株叶片上发现锈病症状,病原菌经鉴定为鸡蛋花鞘锈菌Coleosporium plumierae Pat.,为中国首次报道。现根据香港的标本描述如下。鸡蛋花鞘锈菌图1,2Coleosporium plumierae Pat.,Bull.Soc.Mycol.France18:178,1902.Fi     

一种短循环型鞘锈菌新记录

<正> 中国的鞘锈菌(Coleosporium)已报47种,全部为转主寄生长循环型生活史,性孢子和春孢子产生在松属(Pinus)针叶上,引起各种松针锈病,冬孢子产生在单子叶植物和双子叶植物的13个科上,其中生在菊科植物上的种类最多(戴芳澜,1979)。鞘锈菌的生活史类型多种多样,除了上述的长循环型生活史以外,还有缺夏孢型生活史以及短循环型生活史(Cummins,1983)。作者于1989年7月14日在大兴安岭新林林业局碧州大青山的偃松(Pinus pumila Regel)上采     

不同栽培方式的铁皮石斛根、茎中内生细菌多样性及其抑菌活性研究

【目的】分析树干仿生栽培和大棚种植的铁皮石斛根、茎中内生细菌的组成与分布,并挖掘潜在的微生物资源及功能。【方法】利用Illumina MiSeq高通量测序技术,对不同栽培方式铁皮石斛根、茎中免培养内生细菌丰富度及多样性进行比较分析;通过传统的内生菌分离法以及16S rRNA基因测序技术对可培养内生细菌进行分离鉴定;采用滤纸片法筛选拮抗石斛病原菌的内生菌株。【结果】高通量测序分析中内生细菌以Pseudomonas(30.52%)为主,其次是Mycobacterium(10.22%)以及Brachybacterium(8.32%),树干仿生栽培石斛内生细菌组成丰富度及多样性高于大棚种植,石斛根中内生细菌组成丰富度及多样性高于石斛茎。可培养内生细菌中Bacillus(18.37%)所占比例最高,其次是Curtobacterium (8.16%),同时筛选得到8株具有抑制石斛病原菌活性的菌株。【结论】铁皮石斛中蕴含着丰富的内生细菌资源,菌群组成和分布受其不同栽培方式和组织部位的影响。此外,筛选得到8株具有抑制病原菌活性的菌株,表明铁皮石斛内生细菌代谢产物具有抗菌活性。本试验对铁皮石斛内生细菌多...     

三裂叶豚草锈病发生和流行规律的研究

通过田间调查与定点系统观察,结合沈阳地区的气象条件,对三裂叶豚草锈病在沈阳地区的发生和流行规律进行了研究。结果表明：三裂叶豚草锈病属于喜高温、高湿型病害;该病于6月初在沈阳地区开始发病,可持续至9月,以7～8月发病最重。人工接种试验结果表明：在30℃和相对湿度96．9％条件下接种锈菌冬孢子,4d后三裂叶豚草即可发病;冷冻保藏（-20℃）可打破冬孢子休眠,在沈阳地区冬孢子是第二年锈病发生的初侵染菌源。苍耳柄锈菌三裂叶豚草专化型对三裂叶豚草表现出了显著的致病性、致死性及专一性,证明是防治三裂叶豚草的理想生防菌。     

海南火龙果细菌性腐烂病的病原鉴定及田间药剂筛选

细菌性腐烂病是近年在海南火龙果上普遍发生的一种病害。为有效防治该病害,阻止其进一步扩散和蔓延,本研究从临高县东英镇采集病样多份,经病原分离、形态和分子鉴定、致病性测定以及田间药效试验,对其进行了病原鉴定和田间药剂的筛选。结果表明:代表菌株Huo30能产生黄色素,使火龙果致病,与成团泛菌(Pantoea agglomerans)相似性100%,为火龙果细菌性腐烂病的病原菌。4种药剂中,53.8%氢氧化铜WG1000倍液和47%春雷·王酮WP600倍液处理的防效最好,分别为71.05%和69.93%,与另外两个处理的防效差异显著;72%农用链霉素SP5000倍液处理的防效一般,在供试浓度下防效为65.14%;而2%春雷霉素AS600倍液处理对该细菌病害的防效最差,仅为63.31%。本研究结果为海南火龙果的防治提供了重要的理论依据。     

3种石斛光合作用和叶绿素荧光特性的比较研究

以美花石斛、春石斛和铁皮石斛为材料,对它们的叶片进行光合作用、叶绿素含量和叶绿素荧光等参数的测定.结果表明:3种石斛的光饱和点都低于300 μmol·m-2·s-1,且美花石斛具有较高的净光合速率和较低的光饱和点,容易引起光抑制;美花石斛的羧化效率高于春石斛和铁皮石斛,其净光合速率随着CO2浓度的升高而迅速升高,并在CO2浓度达到500 μmol·m-2·s-1时达到最大值;美花石斛的非循环电子传递速率(ETR)、实际光化学反应量子效率(Yield)和光化学猝灭系数(qP)都明显高于铁皮石斛和春石斛,而春石斛具有较高的非光化学猝灭系数(qN),其光合机构的自我保护能力较强;美花石斛的叶绿素a、叶绿素b以及总叶绿素含量都较低.研究发现,3种石斛的光饱和点均比较低,具有石斛喜阴的生活习性,都表现出对密林和悬崖等独特生长环境的适应,并以美花石斛的这种特性更为突出.     

白刺几种主要病害的药剂防治试验

利用70%多菌灵、80%代森锰锌、1.5%多抗霉素、25%粉锈宁、80%乙蒜素四种药剂防治白刺白粉病、锈病和苗期立枯病,结果表明粉锈宁和多抗霉素对白刺白粉病的防效分别达到99.3%和99.4%;粉锈宁和乙蒜素对白刺锈病的防效分别达到97.6%和97.8%;乙蒜素和多抗霉素对白刺幼苗立枯病的防效分别达到96.3%和99.1%。     

Some problems of evaluating fungicides for use on coffee in Kenya

As part of a programme testing fungicides for control of coffee berry disease (CBD) promising materials were also tested in the field against leaf rust of coffee. In all, fourteen fungicides were tested, five of which have been recommended for control of CBD. Only Perenox (representative of 50% copper fungicides) and Du-Ter (not highly effective against CBD and no longer recommended) gave good control of rust; Difolatan gave some control but Benlate and Daconil were virtually ineffective.
Where only CBD is present there is generally a good relationship between disease control and yield, but in these experiments where leaf rust was also present, this relationship was seriously disturbed. The implications of this for testing fungicides for use on coffee in Kenya are discussed.     

Strobilurin + acibenzolar-S-methyl controls white rust without inducing leaf chlorosis in spinach

White rust (Albugo occidentalis) is a major foliar fungal disease of spinach (Spinacea oleracea) in Texas and the Southeastern USA. It causes leaf yellowing, decreasing product quality and marketability. There is a need for evaluating broad spectrum fungicides and new plant defence activators that have the potential to enhance leaf quality in spinach. Two of those fungicides are acibenzolar‐S‐methyl (ACIB) and strobilurin derivatives (STRO). ACIB appears to mimic natural systemic acquired resistance response in plants, while STRO inhibits mitochondrial respiration in fungi. We conducted three consecutive studies to a) determine the effects of ACIB rates and combinations with STRO and mefenoxam + copper hydroxide (MEFE‐Cu) for the control of white rust, and b) evaluate potential phytotoxicity expressed as leaf chlorosis. After two weekly applications in 1998, ACIB, STRO and ACIB + STRO significantly reduced the % of leaf area infected with white rust in the spinach cv. Cascade. In 1999, ACIB + STRO and ACIB + MEFE‐Cu had the best white rust efficacy, with ACIB equally effective when applied at reduced rates. After three applications in 2000, STRO, ACIB + STRO, and ACIB + MEFE‐Cu had significantly lower white rust values than the control, ACIB or MEFE‐Cu. The combination of ACIB + STRO did not cause leaf chlorosis in any year. Use of preventive applications of ACIB + STRO at 7–10 day intervals appear to be an effective strategy to improve leaf quality in spinach.     

Enhancement of Disease Control Efficacy of Chemical Fungicides Combined with Plant Resistance Inducer 2,3-Butanediol against Turfgrass Fungal Diseases

Turfgrass, the most widely grown ornamental crop, is severely affected by fungal pathogens including Sclerotinia homoeocarpa, Rhizoctonia solani, and Magnaporthe poae. At present, turfgrass fungal disease management predominantly relies on synthetic fungicide treatments. However, the extensive application of fungicides to the soil increases residual detection frequency, raising concerns for the environment and human health. The bacterial volatile compound, 2,3-butanediol (BDO), was found to induce plant resistance. In this study, we evaluated the disease control efficacy of a combination of stereoisomers of 2,3-BDO and commercial fungicides against turfgrass fungal diseases in both growth room and fields. In the growth room experiment, the combination of 0.9% 2R,3R-BDO (levo) soluble liquid (SL) formulation and 9% 2R,3S-BDO (meso) SL with half concentration of fungicides significantly increased the disease control efficacy against dollar spot and summer patch disease when compared to the half concentration of fungicide alone. In field experiments, the disease control efficiency of levo 0.9% and meso 9% SL, in combination with a fungicide, was confirmed against dollar spot and large patch disease. Additionally, the induction of defense-related genes involved in the salicylic acid and jasmonic acid/ethylene signaling pathways and reactive oxygen species detoxification-related genes under Clarireedia sp. infection was confirmed with levo 0.9% and meso 9% SL treatment in creeping bentgrass. Our findings suggest that 2,3-BDO isomer formulations can be combined with chemical fungicides as a new integrated tool to control Clarireedia sp. infection in turfgrass, thereby reducing the use of chemical fungicides.     

豚草锈菌对三裂叶豚草叶片生理生化特性的影响

【背景】自20世纪50年代三裂叶豚草传入我国以来,迅速蔓延,已给我国农业生产、生态环境、人民健康造成巨大威胁。近年来发现的豚草锈菌对三裂叶豚草有一定的致病性,具备生物防治潜力。【方法】本文利用植物生理学技术研究了豚草锈菌对三裂叶豚草叶片生理生化特性的影响。【结果】锈菌侵染后,三裂叶豚草叶片的相对电导率随病级的增高和侵染时间的延长而上升,说明锈菌破坏了豚草叶片的细胞膜,导致其电解质外渗。同时,发病初期叶片内的丙二醛(MDA)与超氧自由基(O2.-)含量逐渐上升;当发病程度为3级时,O2.-含量达到最高;4级时,MDA含量达到最高。此外,锈菌侵染后,三裂叶豚草叶片抗坏血酸(AsA)含量持续上升,而脯氨酸(Pro)含量在发病后期下降,说明在三裂叶豚草与锈菌互作时,AsA含量虽然增加,但抗性并不明显,而Pro可能具有更为重要的作用。【结论与意义】豚草锈菌的侵入干扰了三裂叶豚草的生理生化反应,这将为深入研究豚草锈菌的致病机理、发挥其生物防治潜力奠定基础。     

Antifungal activity against plant pathogenic fungi of chaetoviridins isolated from Chaetomium globosum

The Chaetomium globosum strain F0142, which was isolated from barnyard grass, showed potent disease control efficacy against rice blast (Magnaporthe grisea) and wheat leaf rust (Puccinia recondita). Two antifungal substances were purified from broth from this organism and identified as chaetoviridins A and B. Chaetoviridin A exhibited higher antifungal activity than chaetoviridin B against plant pathogenic fungi both in vitro and in vivo. Treatment with chaetoviridin A at 62.5 microg/mL suppressed the development of rice blast and wheat leaf rust by over 80%. The molecule also exhibited moderate control of tomato late blight, resulting in 50% control following the application of 125 microg/mL chaetoviridin A.     

水肥处理对黄瓜土壤养分、酶及微生物多样性的影响

以津优1号黄瓜为试材,设3个土壤相对含水量水平（50%～60%、70%～80%、90%～100%）和2个肥料追施量（600 kg N·hm^-2和420 kg P₂O₅·hm^-2,420 kg N·hm^-2和294 kg P₂O₅·hm^-2）处理,研究了不同水肥供应对日光温室黄瓜土壤养分、酶活性及微生物多样性的影响.结果表明：土壤中NH₄⁺-N含量随施肥量的增加而提高,随土壤相对含水量的增加而降低;水肥供给的增加有利于提高土壤中速效磷含量和蔗糖酶活性;肥料增加使土壤中蛋白酶活性降低,而水分降低使土壤中脲酶活性提高.土壤中微生物多样性与土壤中养分含量无显著相关性,与土壤脲酶活性呈显著正相关,与蔗糖酶活性呈显著负相关.土壤相对含水量70%～80%、氮肥追施量600 kg N·hm^-2和420 kg P₂O₅·hm^-2处理的土壤养分含量、蔗糖酶、磷酸酶和脲酶活性较高,且土壤中微生物多样性和均匀度显著高于其他处理,土壤生产潜力最优.     

Antifungal activities of Bacillus thuringiensis isolates on barley and cucumber powdery mildews

Fourteen Bacillus thuringiensis isolates having both insecticidal activity and in vitro antifungal activity were selected and tested for in vivo antifungal activity against tomato late blight, wheat leaf rust, tomato gray mold, and barley powdery mildew in growth chambers. All the isolates represented more than 70% disease control efficacy against at least one of four plant diseases. Specifically, 12 isolates exhibited strong control activity against barley powdery mildew. Under glasshouse conditions, four (50-02, 52-08, 52-16, and 52- 18) of the isolates also displayed potent control efficacy against cucumber powdery mildew. To our knowledge, this is the first report of B. thuringiensis isolates that have disease control efficacy against powdery mildew of barley and cucumber as well as insecticidal activity.     

Resistance inducers applied alone or in association with fungicide for the management of leaf rust and brown eye spot of coffee under field conditions

The use of resistance inducers is a promising development in the management of plant diseases, owing to their ability to control a broad spectrum of pathogens and improve the efficacy of fungicides. This study evaluates different sources of phosphonates (potassium, manganese, copper), a formulation prepared from the by‐products of the coffee industry (Greenforce CuCa), as well as the effects of their application, alone or in association with fungicide, in the management of two important coffee fungal diseases in Brazil: leaf rust and brown eye spot, caused by Hemileia vastatrix and Cercospora coffeicola, respectively. The effect of these products on defoliation, productivity and chemical composition of coffee beans (content of trigonelline, chlorogenic acid, caffeine and total soluble solids) was evaluated. Among all the alternative products tested individually, potassium phosphonate (P₂O₅—33.6% + K₂O—29%) stood out, particularly for rust control, which was similar to the results of fungicide treatments. Treatments with fungicide, Greenforce CuCa and cuprous oxide, individually, caused less plant defoliation. Regarding the chemical composition of the coffee beans, the manganese phosphonate treatment showed the highest values for trigonelline, chlorogenic acid, caffeine and total soluble solid content. The results of this study show that resistance inducers can be useful in disease management, may come to eventually replace traditional fungicides and can also contribute to the beverage quality.     

Effectiveness of acibenzolar-S-methyl, fungicides and antibiotics for the control of brown eye spot, bacterial blight, brown leaf spot and coffee rust in coffee

This study was carried out to evaluate the potential of acibenzolar‐S‐methyl (ASM), combined or not combined with fungicides and antibiotics for the control of brown eye spot (Cercospora coffeicola) and bacterial blight (Pseudomonas syringae pv. garcae) in coffee seedlings, and ASM combined with conventional fungicide application schedules for the control of coffee rust (Hemileia vastatrix) and brown leaf spot (Phoma costarricencis) under field conditions in two coffee crops in the State of São Paulo, Brazil. ASM protected coffee seedlings against C. coffeicola when applied at the rates of 2.5 and 5 g of active ingredient per hectolitre of water (g a.i. hL^?1), providing 34–55% of disease control, and against bacterial blight, when applied at the rates of 2.5, 10 and 20 g a.i. hL^?1, with 38–57% of disease control. Tebuconazole (100 g a.i. hL^?1) and azoxystrobin (10 g a.i. hL^?1) showed the best results for brown eye spot control. Oxytetracycline + streptomycin, kasugamycin hydrochloride, oxytetracycline + metallic copper, copper oxychloride and mancozeb + copper oxychloride also controlled bacterial blight in levels similar to those shown by ASM. In the field experiments, all fungicide application schedules tested, cyproconazole (December, February, April), epoxiconazole (December, March), tetraconazole (December, February, April), cyproconazole (December, February) and azoxystrobin (January, March) were effective for coffee rust control and provided partial control of brown leaf spot. The results also showed that for all experiments, there was no synergistic effect of the combination of ASM with azoxystrobin, cyproconazole or cupric fungicides.     

Potential for integrated biological and chemical control of damping-off disease caused by Pythium ultimum in tomato

Pythium ultimum (Trow) is one of the main causes of damping-off disease in many parts of the world. Control of the disease depends mainly on application of chemical fungicides. However, soil treatments with fungicides are not always feasible due to economical and ecological reasons. Soil-borne, non-pathogenic bacteria of the genus Pseudomonas fluorescens with the ability to antagonise fungal phytopathogens, represent a realistic alternative to chemical fungicides and show great promise with respect to protect plant roots from fungal-induced diseases. In an attempt to find an integrated control system of damping-off disease in tomato, fungicides including azoxystrobin, metalaxyl-M and pyraclostrobin were applied alone and in combination with P. fluorescens isolate CW2. The fungicides were tested in in vitro for their antagonistic potential against P. ultimum and for compatibility with CW2. It was found that the fungicides were fungitoxic to P. ultimum, but did not inhibit the growth of the P. fluorescens. The efficacy of the fungicides alone and in combination with CW2 was also tested in greenhouse experiments against damping-off disease on tomato. Two concentrations (5 and 10?μg?ml^?1) were applied. Damping-off incidence of tomato seedlings in Humosoil^?:sand mixture infested with P. ultimum was reduced following seed treatment with the fungicides. However, the degree of control obtained varied significantly depending on the fungicide used. Combined seed treatment with P. fluorescens and the fungicides resulted in a significant improvement in disease control and improved plant growth as indicated by shoot and root dry weights. Metalaxyl-M treatment applied alone or in combination with P. fluorescens, significantly protected tomato seedlings against damping-off. Strobilurin fungicides stimulated plant growth compared to metalaxyl-M. Combined treatment of tomato seeds with strobilurin fungicides and CW2 showed a moderate to good disease control and an increase in shoot and root dry weights.