![11.[31 36]integration of bioagent and bioproduct for the management of root-k...](https://cdn.slidesharecdn.com/ss_thumbnails/11-31-36integrationofbioagentandbioproductforthemanagementofroot-knotnematode-copy-120512235657-phpapp01-thumbnail.jpg?width=560&fit=bounds)
![11.[31 36]integration of bioagent and bioproduct for the management of root-k...](https://cdn.slidesharecdn.com/ss_thumbnails/11-31-36integrationofbioagentandbioproductforthemanagementofroot-knotnematode-120512235700-phpapp01-thumbnail.jpg?width=560&fit=bounds)
![Arefins paper [308651]](https://cdn.slidesharecdn.com/ss_thumbnails/90e557c3-ab19-4004-8e51-4516abfb59d4-160819202727-thumbnail.jpg?width=560&fit=bounds)
Presentation1.pptx
- 1. Identification and antifungal activity of pNPP against Peronophythora litchi; the causal agent of downy blight disease of litchi (Litchi chinensis Sonn.) Uttam Kumar, Srikanti Kumari1, Nirmala Dhar, Arindam Pathak, Aditya kumar, Swastika karki, Rishi raj Alpine Institute of Management and Technology, Dehradun, 248006 Uttarakhand 1Ranchi University, Ranchi Introduction Litchi (Litchi chinensis Sonn.) is one of the most important crop belongs to the family Sapindaceae (Jiang et al., 2003, Sivakumar et al., 2007, Kumar et al., 2008). It is indigenous to Southern China (Jiang et al., 2003). Litchi is an evergreen, tropical and subtropical (Jiang et al.,2003, Sivakumar et al., 2007, Kumar et al., 2008) fruit tree which bears a whitish translucent fruit called aril surrounding a single glossy brown seed (Jiang et al., 2003) and is enclosed inside a pinkish-red rough inedible skin or pericarp which turns brown and dries out after harvest. Litchi cultivation is specific to climatic requirement and henceforth, major litchi producing countries in the world include China, India, Vietnam, Thailand, South Africa, Australia, USA etc. (Singh and Kaur, 2009). India ranks second in litchi production while the first place is bagged by China. In India, litchi is cultivated in Bihar, West Bengal, Assam Jharkhand, Punjab, Chattisgarh, Orrisa, Uttarakhand and Tripura. Methodology Sample Collection and Isolation Disease affected litchi fruit materials (Fig. 1) were collected from five different places of Dehradun (Nanda Ki Chawki, Premnagar, Forest Research Institute, Rajpur Road and Clement Town). Affected parts from the fruit pericarp were firstly collected and cultured in Petri plates containing potato dextrose agar (PDA) and on test tubes containing potato dextrose broth and incubated at 280 C for five days. Remaining samples were thoroughly washed, dried under the dark condition and grounded to a fine powder in liquid nitrogen, by using a mortar and pestle. The powder (plant extract) obtained from each sample was stored separately and carefully at 20 °C. The powder obtained from each sample was also separately spread on petri plates containing PDA and on test tubes containing potato dextrose broth and incubated at 28 °C for five days. Conidia of the fungus, Peronophythora litchi was isolated from 4-5 days old culture grown on PDA media at 28 °C in the dark, was examined under the microscope after staining with Cotton Blue dye. Screening of antifungal activity The control of pNPP on spore germination of Peronophythora litchi was screened on PDA by petri plate assay. Five different concentrations of pNPP (0.5. 1.0, 1.5, 2.0 and 2.5 mg/ml) were evaluated for antifungal activity by Agar Well Diffusion method with a sterile cork borer of size 6.0 mm. The cultures of 48 hours grown on PDA were used for inoculation of fungal strain on PDA plates. An aliquot (0.02 ml) of inoculums was introduced to melted PDA and poured into a petri dish by pour plate technique. After solidification, wells were made on agar plate by using cork borer for diffusion method. In agar well 0.05 ml of pNPP was introduced. Incubation period of 24 - 48hours at 28°C was maintained for observation of antifungal activity of extract. The antifungal activity was evaluated by measuring zones of inhibition of fungal growth surrounding the extracts. The complete antifungal analysis was carried out under the strict aseptic conditions. The zones of inhibition were measured with antibiotic zone scale in mm. and the experiment was carried out in triplicates. Fig. 1 Colonization of isolates LC-1 and LC-2 on Potato Dextrose agar Fig.2. Germinating oospore of Peronophythora litchi (A and B Fig. 3 Antifungal activity pNPP against Peronophythora litchi pNP P mg/ ml Fungal isolates LC1 LC2 LC3 LC4 LC5 5mg/ ml 10.1 10.4 6.2 6.0 Nil 10m g/ml 12.0 10.5 5.1 9.0 Nil 15m g/ml 10.9 12.1 5.3 9.1 1.4 20m g/ml 15.9 12.2 6.5 10.1 1.1 25m g/ml 16.4 13.1 10.0 11.0 10.4 Results inhibition was displayed by L Peronophythora litchi, the causal organism of litchi downy blight, is a transitional species between Phytophthora and Peronospora The branched, determinate sporangiophores of this fungus resemble those of Peronospora; however, the mode of zoospore release from sporangia, morphology of sex organs and ability to grow on artificial media are characteristic of Phytophphora Fungus showed colonization on petri plates in the period of 5 days (Fig. 1). This ability to grow on artificial media resembles that of Phytophthora. Germinating oospores of Peronophythora litchi stained with cotton blue dye examined under the microscope resembled that of Peronospora or Phytophthora. The germ tube with many sporangia (Fig. 2) on the tip emerged from the antheridium, while that with many sporangia emerged. All sporangium were connected with the tube. Thus, the study confirmed the presence of fungus Peronophythora litchi on litchi fruit causing downy blight disease of litchi in Dehradun which limits the production of litchi and its post harvest self-life. Antifungal activity pNPP against Peronophythora litchi Gershon et. al., reported, 18 nitrophenols (2- and 4- nitrophenols, 4-, 5> and 6-halo-2- nitrophenols, 3- halo-4-nitrophenols) were tested for antifungal activity against six fungi (A. niger, A. oryzae, M. verrucaria, T. viride, M. cirinelloides, and T. mentagrophytes) in Sabouraud dextrose broth. Only a small number of halo-nitro and halo-phenols were tested for antifungal activity. It was recorded that 4- Fluoro- and 5-fluoro-2- nitrophenols inhibited some plant pathogenic fungi, among which were Fusarium sp. and Curvularia sp. (Shirley et. al.,). In the present study, we have chosen the p-nitrophenol as inhibiting substrata for In-Vitro control of the Peronophythora litchii. All the five different concentrations (0.5mg/ml, 1.0mg/ml, 1.5mg/ml, 2.0mg/ml and 2.5mg/ml) of p-nitrophenol were active against Peronophythora litchii (Fig. 3). Maximum zone of inhibition was showed by LC1 (16.4 mm in diameter), while minimum C 5 (Table 1).