Screening of plant extracts for organic management of downy mildew of sorghum

Antipathogenic potential of 38 plants was evaluated in the form of aqueous extracts against Peronoclerospora sorghi, causing downy mildew of sorghum. Conidial suspension and plant extracts were mixed individually and allowed to stand for 5 min and then used to inoculate the host by sprout-dip method. The sprouts thus inoculated were grown in pots, and the disease incidence was observed. Eight plant extracts (Cicer areatinum, Datura metel, Croton sparsiflorus, Parthenium hysterophorus, Nerium oleander, Chromolaena odorata, Duranta repens and Oxalis latifolia) at 20% concentration performed at par with chemical fungicide (Mancozeb 75%) by exhibiting total suppression of disease incidence to 0%, when compared with 64.1% of negative control. Organic management of air-borne inoculum of downy mildew of sorghum is feasible and preferable when compared with chemical control methods, considering human and environmental health concerns. The use of water extract keeps the technology simple so that it can be directly prepared and used by the farmers. Short-listing of eight most effective water extracts would help in self-reliance of farmers, reducing their dependence on commercial products.     

Seed treatment with aqueous extract of Viscum album induces resistance to pearl millet downy mildew pathogen

Abstract

Downy mildew (Sclerospora graminicola [Sacc.] Schroet.) is a serious agricultural problem for pearl millet (Pennisetum glaucum [L.] R. Br.) grain production under field conditions. Six medicinally important plant species Azadirachta indica, Argemone mexicana, Commiphora caudata, Mentha piperita, Emblica officinalis and Viscum album were evaluated for their efficacy against pearl millet downy mildew. Seeds of pearl millet were treated with different concentrations of aqueous extract of the plants to examine their efficacy in controlling downy mildew. Among the plant extracts tested, V. album treatment was found to be more effective in enhancing seed quality parameters and also in inducing resistance against downy mildew disease. Germination and seedling vigor was improved in seeds treated with V. album extracts over control. Seeds treated with 10% concentration of V. album showed maximum protection against downy mildew disease under greenhouse and field conditions. The downy mildew disease protection varied from 44–70% with different concentrations. Leaf extract of V. album did not inhibit sporulation and zoospore release from sporangia of Sclerospora graminicola, indicating that the disease-controlling effect was attributed to induced resistance. Seed treatment with V. album extract increased pearl millet grain yield considerably. In V. album, treated pearl millet seedlings increased activities of peroxidase, and phenylalanine ammonia-lyase enzyme was detected. FTIR analysis of V. album extracts showed the presence of amides and other aromatic compounds which are antimicrobial compounds involved in plant defense.     

A novel technique for greenhouse evaluation of plant extracts for management of downy mildew of sorghum

Antipathogenic potential of 16 plants was evaluated in the form of aqueous extracts against Peronosclerospora sorghi, causing downy mildew of sorghum. A novel method was developed in which conidial suspension and plant extracts were mixed individually and allowed to stand for 5?min and then used to inoculate the host by sprout-dip method. The sprouts thus inoculated were grown in pots, and disease incidence was observed. Three extracts (Parthenium hysterophorus, Duranta repens and Oxalis latifolia) suppressed the disease at par with chemical fungicide (Mancozeb 75%). In form of spray, D. repens extract with tween-20 adjuvant (1.9% disease) performed closest behind mancozeb (0% disease), while negative control showed 21% disease incidence. Organic management of airborne inoculum of downy mildew of sorghum is feasible and preferable as compared to the use of chemical fungicides, considering human and environmental health concerns. Use of water extract keeps the technology simple so that it can be directly prepared and used by farmers. Short listing of three most effective water extracts would help in self-reliance of farmers, reducing their dependence on commercial products.     

甜瓜抗霜霉病基因同源序列克隆与分析

采用RT—PCR扩增的方法,从高抗霜霉病甜瓜品种‘日本安农二号’中克隆到约3kb的cDNA片段（命名为MRGH-D,该基因是一个连续的通读编码框,编码1007个氨基酸。推测的蛋白质分子量为113．7kDa,等电点为7．88,蛋白质预测无跨膜区。根据推测的氨基酸序列,该基因属于TIR—NBS—LRR类抗病基因,具有TIR-NBS—LRR类抗病基因所有的保守结构域。核苷酸序列和氨基酸序列同源性分析结果显示,MRGH-J与甜瓜抗病基因的同源序列MRGHl2及抗霜霉病相关基因mp-19均具有高达99％的同源性,推测该基因可能在甜瓜抗霜霉病中起作用。     

荠菜，马齿苋生长阶段抗病性研究

研究以霜霉病菌为致病菌,分别感染2种常见野生蔬菜蔼菜,马齿见,马齿苋的染病植株与对照培养的健康植株生长状况差异不大,而荠 菜两者的生长状况有明显差异,其原因是马齿苋染病后多酚氧化酶,SOD,过氧化氢酶,苯丙氨酸解氨酶活性及木质素含量明显增加,膜脂过氧化水平相对较低,因而细胞结构保持相对稳定,抗病性较强。     

Dünnschichtchromatographische Bestimmung der Rückstände des Herbicids Leuna MECK im Boden

Abstract

Wetzel, TH. (Edit.): Symposium mit internationaler Beteiligung zur Schaderregerüberwachung in der industriemäßigen Getreideproduktion. 510 S., Teil I bis III, 134 Abb. Halle: 1975. Reviewed by G. Lutze.

O. V.: Pflanzenschutzmittel-Verzeichnis 1974/1975. 1. Aufl. 121 S. Berlin: VEB Dt. Landwirtschaftsverlag 1975. Reviewed by W. Tarnow.

Schumakov, E. M.; Gussev, G. W.; Fedorintschik, N. S. (Edit.): Biologi?eskie sredstva za??ita rastenij. 25000 Aufl. 408 S., 1. Band, 24 Abb. Moskau: Kolos 1974. Reviewed by Th. Wetzel.

Clifton, C. E. (Edit.): Annual Review of Microbiology. 771 S., 25. Band, zahlreiche Abb. Palo Alto: Annual Reviews Inc. 1971. Reviewed by K. Naumann.

Voronkevi?, I. V.: Vy?ivaemost' fitopatogennych Bakterij v Prirode. 268 S., 16 Abb., 41 Tab., Moskau 1974: Nauka. Reviewed by W. Ficke.

Bel'tjukova, K. I.; Koroleva, I. B.; Muras, V. A.: Bakterial'nye bolezni zernobobovych kultur. 339 S., 57 Abb., 49 Tab. Kiev 1974: Naukova Dumka. Reviewed by W. Ficke.

Pospelov, S. M.; Arsen'eva, M. V.; Grusdev, G. S.: Za??ita rastenij. 487 S. Leningrad 1973: Kolos. Reviewed by W. Ficke.

Noordam, D.: Identification of plant viruses. Methods and experiments. 1. Auflage, 218 S., 134 Abb. Wageningen 1973: Centre for agricultural publishing and documentation. Reviewed by D. Spaar.     

The efficacy of spraying programmes and treatment methods against downy mildew in two grapevine cultivars in Kosovo

The present study aimed to assess the efficacy of applied programmes and treatment methods against downy mildew (Plasmopara viticola). Two vine cultivars (Frankovka and Game) were tested in an experimental field (in Rahovec, Kosovo) for a two-year period (2010–2011). The fungicides used were Quadris (azoxystrobin), Antracol EP-70 (propineb), Dithan M-45 (mancozeb), Ridomil (metalaxyl), Curzate (cymoxanil), Bordeaux mixture (calcium hydroxide and copper sulphate) and Mikal (fosetyl-aluminium) applied three treatment methods. The evaluation of the disease severity was performed using the McKinney index. In both tested cultivars and in both treatment years (2010 and 2011), all of the programmes tested significantly reduced the severity of grape downy mildew compared to the control. The highest efficacy against grape downy mildew was achieved with the combined use of Ridomil and Dithan (programme 3); this treatment was more than 80% effective in both cultivars and in both years.     

黄瓜霜霉病抗性遗传分析

通过2个抗感杂交组合,采用多世代联合的分离分析方法研究了黄瓜霜霉病抗性的遗传机制.结果显示,2个组合的最适遗传模型分别是2对加性-显性-上位性主基因 加性-显性-上位性多基因模型和2对等加性主基因 加性-显性多基因模型.组合I最优模型的主基因遗传率是56.84%~87.16%,多基因遗传率是0~34.93%;2个主基因的加性效应均为-15.191,加性效应较强,显性效应较弱,它们之间的加性与加性和加性与显性上位性效应较强.组合Ⅱ最优模型的主基因和多基因遗传率分别为48.92%和42.11%;2个主基因的加性效应皆为-13.505,显性效性均为0,它们之间不存在互作效应.结果表明,黄瓜霜霉病抗性,以加性效应为主,主基因遗传力较高,但是微效多基因效应也占相当的比重,所以,在霜霉病抗性育种中,要重视主基因,同时兼顾多基因效应.     

Proteomic analysis of the compatible interaction between Vitis vinifera and Plasmopara viticola

We analyzed the proteome of grapevine (Vitis vinifera) leaves 24, 48 and 96 h post infection (hpi) with the downy mildew pathogen Plasmopara viticola. Total proteins were separated on 2-DE gels. By MS analysis, we identified 82 unique grapevine proteins differentially expressed after infection. Upregulated proteins were often included in the functional categories of general metabolism and stress response, while proteins related to photosynthesis and energy production were mostly downregulated. As expected, the activation of a defense reaction was observed more often at the late time point, consistent with the establishment of a compatible interaction. Most proteins involved in resistance were isoforms of different PR-10 pathogenesis-related proteins. Although > 50 differentially expressed protein isoforms were observed at 24 and 96 hpi, only 18 were detected at 48 hpi and no defense-related proteins were among this group. This profile suggests a transient breakdown in defense responses accompanying the onset of disease, further supported by gene expression analyses and by a western blot analysis of a PR-10 protein. Our data reveal the complex modulation of plant metabolism and defense responses during compatible interactions, and provide insight into the underlying molecular processes which may eventually yield novel strategies for pathogen control in the field.