scholarly journals Effectiveness of Bacillus subtilis, B. pumilus, Pseudomonas fluorescens on Meloidogyne incognita infecting cowpea

2019 ◽  
Vol 37 (1) ◽  
pp. 35-43 ◽  
Author(s):  
W. M. A. El-Nagdi ◽  
Plants ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 1145
Author(s):  
Ahmed Noureldeen ◽  
Mohd Asif ◽  
Taruba Ansari ◽  
Faryad Khan ◽  
Mohammad Shariq ◽  
...  

This study was conducted on tomato (Solanum lycopersicum cv. K-21) to investigate the bioprotective nature of Pseudomonas fluorescens and its interactive effects with Meloidogyne incognita in terms of growth biomarkers, changes in biochemical attributes and modulation in antioxidant enzymes of the tomato plant. In this study, we grew tomato plants with M. incognita and P. fluorescens in separate pots, simultaneously and sequentially (15 days prior or post) after 15 days of seed sowing. The sequential inoculation of Mi15→Pf maximally increased the root-knot index and decreased the nematode population. It was also noted that inoculation suppressed the plant growth biomarkers in comparison to control. However, maximum suppression in nematode reproduction and increment in growth and physiological attributes were observed when P. fluorescens was applied 15 days prior to the nematode (Pf15→Mi) as compared to control. All the treatments showed an increase in antioxidant enzymes. Expression of phenol content and defensive enzymes such as peroxidase (POX) and superoxide dismutase (SOD) increased, in contrast to a significant reduction in malondialdehyde (MDA) and hydrogen peroxide (H2O2) contents when compared with the untreated inoculated plants. However, the highest levels of POX and SOD, and a lowest of phenol, MDA and H2O2 were displayed in the treatment Pf15→Mi, followed by Mi+Pf and Mi15→Pf.


2020 ◽  
Vol 16 (1) ◽  
pp. 37-48
Author(s):  
Ratna Sari Dewi ◽  
Giyanto Giyanto ◽  
Meity Suradji Sinaga ◽  
Dadang Dadang ◽  
Bambang Nuryanto

Saat ini teknologi pengendalian hayati penyakit utama padi terus berkembang. Dalam pengembangan teknologi pengendalian hayati, mekanisme penghambatan patogen dalam perkembangan penyakit pada suatu populasi tumbuhan dalam area tertentu menjadi hal yang penting. Penelitian bertujuan mendapatkan bakteri agens hayati potensial dalam pengendalian penyakit penting padi di antaranya yang disebabkan Pyricularia oryzae, Xanthomnas oryzae pv. oryzae, Rhizoctonia solani, Burkholderia glumae, dan Drechlera oryzae, berdasarkan mekanisme antagonisme, kemampuan menginduksi ketahanan dan mendukung kebugaran tanaman, serta kompatibilitas antaragens hayati. Ralstonia pickettii TT47, Pseudomonas fluorescens P12, Chromobacterium sp. T51118, Bacillus subtilis 451 dan 154, serta Streptomyces sp. T51105 dibuktikan memiliki mekanisme antibiosis dengan menghasilkan metabolit sekunder dan senyawa volatil. Berdasarkan uji produksi enzim kitinolitik Chromobacterium sp. dan Streptomyces sp. memiliki mekanisme lisis. Aktivitas antibiotik R. pickettii dan P. fluorescens tergolong kuat terhadap P. oryzae dengan penekanan secara berurutan sebesar 79.68% dan 77.59% pada uji biakan ganda. Penekanan pertumbuhan miselium P. oryzae dan R. solani pada uji volatil mencapai 100% oleh Chromobacterium sp. Semua agens hayati umumnya mampu menginduksi ketahanan dan mendukung kebugaran tanaman. Uji kompatibilitas menunjukan R. pickettii, P. fluorescens, dan Chromobacterium sp. bersifat kompatibel. Dari hasil penelitian diperoleh tiga bakteri agens hayati dengan kategori unggul, yaitu P. fluorescens P12, R. pickettii TT47, dan Chromobacterium sp. T51118. Ketiganya mampu menekan pertumbuhan patogen, menginduksi ketahanan dan mendukung kebugaran tanaman, memiliki patogen sasaran yang lebih beragam, serta bersifat kompatibel.


Author(s):  
Umeh Odera Richard ◽  
E. I. Chukwura ◽  
Ibo Eziafakaego Mercy

A fish pond with recommended water quality will produce healthy fishes. Fish ponds with poor water quality will cause fish mortality and outbreak of diseases to fish consumers. Physicochemical analysis was done using standard analytical methods, the total bacterial count was determined by dilution and membrane filtration techniques. Parasitological analysis was done using the centrifugation method. A total of fifteen well waters were sampled during wet season. Results showed that the temperature ranged from 27°C to 29°C, pH, 6.21 to 8.15; dissolved oxygen, 4.28 mg/l to 5.78 mg/l, electrical conductivity, 166.36 µs/cm to 394.00 µs/cm; total dissolved solids, 41 mg/l to 121 mg/l; total suspended solids, 1.00 mg/l to 19.40 mg/l; total solids, 42.00 mg/l to 140.4 mg/l; turbidity values, 7.01 NTU to 10.36 NTU; nitrate, 3.10 mg/l to 28.00 mg/l; total alkalinity, 36 mg/l to 91 mg/l; phosphate, 1.26 mg/l to 13.11 mg/l; sulphate, 0.39 mg/l to 4.37 mg/l; total chloride, 7.08 mg/l to 14.19 mg/l; carbonates, 1.33 mg/l to 2.35 mg/l; bicarbonates, 34.59 mg/l to 89.38 mg/l; total hardness, 25.31 mg/l to 53.04 mg/l; calcium hardness, 23.94 mg/l to 51.96 mg/l; magnesium hardness, 1.08 mg/l to 4.20 mg/l; total acidity, 2 mg/l to 22 mg/l; potassium, 0.04 mg/l to 2.23 mg/l; cadmium, 0.00 mg/l to 0.04 mg/l; lead, 0.01 mg/l - 0.16 mg/l; chromium, 0.00 mg/l - 0.03 mg/l; mercury was not detected, copper, 0.00 mg/l - 0.04 mg/l; arsenic, 0.00 mg/l - 0.02 mg/l; zinc, 0.00 mg/l to 0.02 mg/l; iron, 0.01 mg/l - 1.19 mg/l. The total bacterial counts ranged from 3.60-4.12 log cfu/ml; total coliforms, 14-46 cfu/100ml, Vibrio cholerae, 0-11 cfu/100ml; Vibrio parahaemolyticus, 0-15 cfu/100ml; faecal coliform, 1-9 cfu/100 ml; Acinetobacter calcoaceticus, 0-8 cfu/100 ml; Bacillus subtilis, 0-9 cfu/ml; Staphylococcus aureus, 0-5 cfu/ml; Pseudomonas aeruginosa, 0-12 cfu/100 ml; Pseudomonas fluorescens, 0-12 cfu/100 ml and Clostridium perfringens were not detected in any of the samples. Twelve bacterial species namely Klebsiella pneumoniae, Acinetobacter calcoaceticus, Escherichia coli, Staphylococcus aureus, Vibrio cholerae, Pseudomonas fluorescens, Pseudomonas aeruginosa, Proteus mirabilis, Vibrio parahaemolyticus, Bacillus subtilis, Shigella flexineri and Salmonella typhi were isolated and identified using standard analytical and molecular procedures. Parasites identified were Ichthyobodo species, Diplostomum species, Myxobolus species, Chilodonella species, Bothriocephalus species, Ambiphrya species and Leech species. Salmonella typhi had the highest frequency of isolation (20.63%) while Acinetobacter calcoaceticus and Staphylococcus aureus had the lowest frequency of isolation (2.83%). Ichthyobodo species had the highest frequency of isolation (21.43%) while Leech species had the lowest frequency of isolation (5.71%). Some of the physicochemical, bacteriological and parasitological parameters had values above World Health Organization admissible limits and therefore proper sanitary practices and water treatments must be employed to prevent epidemic among fish consumers.


2016 ◽  
Vol 23 (3) ◽  
pp. 244
Author(s):  
Hanudin Hanudin ◽  
Abdjad Asih Nawangsih ◽  
Budi Marwoto ◽  
Boedi Tjahjono

<p>Penyakit busuk lunak (PBL) yang disebabkan oleh Pectobacterium carotovorum subsp. carotovorum atau Pseudomonas viridiflava merupakan kendala utama dalam budidaya anggrek. Serangan patogen tersebut sangat merugikan petani, mengingat biaya investasi produksi anggrek tergolong tinggi. Oleh karena itu patogen tersebut harus dikendalikan menggunakan metode pengendalian yang ramah lingkungan, yaitu dengan mengaplikasikan biobakterisida berbahan aktif rizobakteri, seperti Bacillus subtilis dan Pseudomonas fluorescens. Tujuan penelitian ini ialah (1) mendapatkan komposisi bahan aktif dan bahan pembawa biobakterisida yang efektif mengendalikan penyakit busuk lunak pada anggrek Phalaenopsis, (2) mengetahui perubahan reaksi kimia formula biobakterisida dan pertumbuhan populasi bahan aktif (rizobakteri B. subtilis dan P. fluorescens) pada kondisi sebelum dan setelah difermentasikan, dan (3) mengetahui kompatibilitas antara B. subtilis, P. fluorescens, dan bahan pembawa biobakterisida. Percobaan dilaksanakan mulai Bulan Mei sampai dengan Desember 2009 di Laboratorium Bakteriologi Departemen Proteksi Tanaman, Institut Pertanian Bogor, dan Laboratorium Bakteriologi serta Rumah Kaca, Balai Penelitian Tanaman Hias, di Segunung, Cianjur, Jawa Barat. Ruang lingkup penelitian meliputi pembuatan propagul rizobakteri sebagai bahan aktif biobakterisida, pembuatan formula biobakterisida, uji viabilitas bahan aktif, dan uji kemangkusan biobakterisida pada tanaman anggrek di rumah kaca. Hasil penelitian menunjukkan bahwa (1) perlakuan gabungan antara B. subtilis B12 dan P. fluorescens Pf10 yang difermentasikan dalam media ekstrak kotoran cacing (kascing) dan molase, merupakan perlakuan yang konsisten dapat menekan PBL pada anggrek Phalaenopsis dengan persentase penekanan sebesar 80%, (2) reaksi kimia formula biopestisida pada kondisi sebelum dan setelah fermentasi diindikasikan dengan perubahan pH basal medium yang sebelum fermentasi menunjukkan pH 3,75 dan berubah menjadi pH 3,50 setelah difermentasikan. Pertumbuhan populasi mikrob antagonis setelah fermentasi meningkat secara signifikan bila dibandingkan pada kondisi sebelum difermentasikan, dan (3) isolat bahan aktif (B. subtilis dan P. fluorescens) bersifat kompatibel dengan bahan pembawanya (ekstrak kascing dan molase).</p>


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