scholarly journals Biocontrol of PGPR strain Bacillus amyloliquefaciens Ba168 against Phytophthora nicotianae on tobacco

2019 ◽  
Author(s):  
Dongsheng Guo ◽  
Chenhong Yuan ◽  
Yunyan Luo ◽  
YaHan Chen ◽  
Meihuan Lu ◽  
...  
Keyword(s):  
Crude Extract ◽  
Dry Weight ◽  
Plant Growth Promoting Rhizobacteria ◽  
Sem Analysis ◽  
Phytophthora Nicotianae ◽  
Black Shank ◽  
Biocontrol Efficacy ◽  
Plant Growth Promoting ◽  
Pgpr Strain

AbstractTobacco black shank (TBS) caused by Phytophthora nicotianae is destructive to almost all kinds of tobacco cultivars and is widespread in many tobacco-planted countries. Here, an isolated plant growth-promoting rhizobacteria (PGPR) strain Ba168 is promise in biocontrol of TBS. In vitro assays disclosed a strong P. nicotianae suppression activity and the field utilization potential (FUP) by characterized the crude extract of culture filtrates of Ba168. P. nicotianae’s growth was inhibited by the crude extract at minimum inhibitory concentration (MIC) of 5μl/mL. Extracellular conductivity, pH and the wet, dry weight of P. nicotianae’s mycelia, were significantly different after treated with different concentrations of the crude extract and the deformity and perforation of treated P. nicotianae’s hyphae can be observed in scanning electron microscope (SEM) analysis. Proteome characterizations of the crude extract were used as supplementary proofs that further evaluated FUP of Ba168. We then identified strain Ba168 as B. amyloliquefaciens by its genetic and phenotypic characteristics. Field assays comparatively evaluated TBS control efficacy of these PGPRs and agrochemicals. Pooling analysis of the results showed that the biocontrol efficacy of Ba168 preparation is only lower than Mixture of Propamocarb hydrochloride and Azoxystrobin (MPA) but better than other tested subjects. Although the existence of differences in biocontrol efficacy, PGPR preparations effectively reduced the disease index of tobacco.ImportanceThis work demonstrates the promising biocontrol potential of B. amyloliquefaciens Ba168 and highlights the positive roles of PGPR in suppression of this soil-borne disease.

scholarly journals Efecto de bacterias promotoras de crecimiento vegetal (PGPR) asociadas a Pennisetum clandestinum en el altiplano cundiboyacense

2013 ◽  
Vol 13 (2) ◽  
pp. 189 ◽  
Author(s):  
Paola Jimena Criollo ◽  
Melissa Obando ◽  
Leonardo Sánchez M. ◽  
Ruth Bonilla
Keyword(s):  
Dry Weight ◽  
Plant Growth Promoting Rhizobacteria ◽  
Pennisetum Clandestinum ◽  
Root Dry Weight ◽  
Indole Compounds ◽  
Plant Growth Promoting ◽  
Biological Nitrogen ◽  
Absolute Control

<p><em>Pennisetum clandestinum </em>(kikuyo) es una pastura común en  los sistemas silvopastoriles del altiplano cundiboyacense,  con altas propiedades nutritivas. Por tanto estudios que  permitan mejorar el proceso de producción en términos  económicos y ambientales reviste gran importancia.  En este estudio se evaluó el papel de la inoculación con  bacterias promotoras de crecimiento vegetal (PGPR)  sobre el crecimiento de pasto kikuyo. Las cepas 4K y 5B  fueron identificadas mediante amplificación y análisis  del 16S rADN, como <em>Stenotrophomona s</em>sp. y <em>Pseudomona  s</em>sp., respectivamente, caracterizadas por su eficiencia  <em>in vitro </em>en la fijación biológica de nitrógeno, producción  de compuestos indólicos y solubilización de fosfatos. Se  evaluaron las cepas en condiciones de invernadero en tres  tiempos de crecimiento de la planta (70, 100 y 130 días). Se  evidenció que la cepa 4K incrementó el peso seco radicular  de la planta en 50% a los 70 y 100 días, mientras que la  cepa 5B mostró un comportamiento similar en el peso seco  aéreo y radicular con aumentos de hasta el 50% a los 130  d. El efecto más importante se presentó después de 100 d  donde los tratamientos TQ, TB1 y TB2, superaron en más  del 80% al testigo absoluto en el peso fresco de la parte  aérea. Estos resultados demostraron que la inoculación  de PGPR representa una alternativa biotecnológica para  promover el crecimiento de <em>P. clandestinum</em>, con efectos  relevantes en producción de biomasa 100 días después de  la siembra (dds).  </p><p> </p><p><strong>Effect of plant growth-promoting rhizobacteria  (PGPR) associated to <em>Pennisetum clandestinum </em>in  the altiplano cundiboyacense  </strong></p><p><em>Pennisetum clandestinum </em>(kikuyo) is a common  pasture in the altiplano cundiboyacense silvopastoral  systems, which possesses high nutritional value.  Therefore, studies to improve the production process  in both economic and environmental terms are very  important. The role of inoculation with plant growthpromoting  bacteria was evaluated on the growth of  kikuyu grass. The 4K and 5B strains were identified,  through amplification and analysis of their 16S rDNA,  as members of the <em>Stenotrophomonas </em>and <em>Pseudomonas  </em>genera, respectively. They were characterized <em>in vitro </em>for  their efficiency of biological nitrogen fixation, production  of indole compounds, and phosphate solubilization. Four  treatments were evaluated under greenhouse conditions.  Furthermore, the biomass was evaluated at different  stages of the plant (70, 100 and 130 days). The 4K strain  demonstrated a root dry weight that increased by 50% at  70 and 100 days and the 5B strain showed a statistically  significant behavior for plant and root dry weight with  an increase of 50% at 130 days. The most important  effect was presented after 100 d where treatments, TQ,  TB1 and TB2, exceeded more 80% to absolute control  in the fresh weight of the air. These results showed that  inoculation with PGPR represents a biotechnological  alternative to promote growth of <em>P. clandestinum</em>, as we  observed relevant effects on biomass production 100  days after planting.  </p>

Effect of the endophytic plant growth promoting Enterobacter ludwigii EB4B on tomato growth

2020 ◽  
Vol 13 (2) ◽  
pp. 54-65 ◽  
Author(s):  
M.E.A. Bendaha ◽  
H.A. Belaouni
Keyword(s):  
Root Length ◽  
Biocontrol Agent ◽  
Growth Promotion ◽  
Dry Weight ◽  
Antagonistic Activity ◽  
Rrna Gene ◽  
Plant Growth Promoting ◽  
Enterobacter Ludwigii ◽  
Tomato Growth

SummaryThis study aims to develop a biocontrol agent against Fusarium oxysporum f.sp. radicis-lycopersici (FORL) in tomato. For this, a set of 23 bacterial endophytic isolates has been screened for their ability to inhibit in vitro the growth of FORL using the dual plate assay. Three isolates with the most sound antagonistic activity to FORL have been qualitatively screened for siderophore production, phosphates solubilization and indolic acetic acid (IAA) synthesis as growth promotion traits. Antagonistic values of the three candidates against FORL were respectively: 51.51 % (EB4B), 51.18 % (EB22K) and 41.40 % (EB2A). Based on 16S rRNA gene sequence analysis, the isolates EB4B and EB22K were closely related to Enterobacter ludwigii EN-119, while the strain EB2A has been assigned to Leclercia adecarboxylata NBRC 102595. The promotion of tomato growth has been assessed in vitro using the strains EB2A, EB4B and EB22K in presence of the phytopathogen FORL. The treatments with the selected isolates increased significantly the root length and dry weight. Best results were observed in isolate EB4B in terms of growth promotion in the absence of FORL, improving 326.60 % of the root length and 142.70 % of plant dry weight if compared with untreated controls. In the presence of FORL, the strain EB4B improved both root length (180.81 %) and plant dry weight (202.15 %). These results encourage further characterization of the observed beneficial effect of Enterobacter sp. EB4B for a possible use as biofertilizer and biocontrol agent against FORL.

scholarly journals Activity of plant growth promoting rhizobacteria (PGPRs) in the biocontrol of tomato Fusarium wilt

2017 ◽  
Vol 53 (No. 2) ◽  
pp. 78-84 ◽  
Author(s):  
Boukerma Lamia ◽  
Benchabane Messaoud ◽  
Charif Ahmed ◽  
Khélif Lakhdar
Keyword(s):  
Fusarium Wilt ◽  
Plant Growth Promoting Rhizobacteria ◽  
Significant Inhibition ◽  
Systemic Resistance ◽  
In Situ Experiment ◽  
Fluorescent Pseudomonas ◽  
Split Root ◽  
Plant Growth Promoting ◽  
Severity Of The Disease

The potential of Pseudomonas fluorescens PF15 and Pseudomonas putida PP27 to protect tomato plants against Fusarium wilt under greenhouse conditions was evaluated. In vitro antagonism showed a significant inhibition of the pathogen growth (47%) revealed by PF15. However, PP27 presented a 10% rate of the mycelium inhibition. An in situ experiment was conducted with split-root design for induced systemic resistance (ISR) and without split-root design to measure both ISR and antagonistic activities. Fluorescent Pseudomonas revealed a delay in the onset of symptoms and slower kinetics of disease progression compared to the pathogen control. McKinney’s index, which measures the severity of the disease, was reduced by 37–72%, and the levels of infection (incidence) by 7–36%.

scholarly journals Perlakuan Rizobakteri Pemacu Pertumbuhan Tanaman (RPPT) dengan Beberapa Tingkat Kerapatan Inokulum Rizobakteri Terhadap Viabilitas dan Vigor Benih Cabai Merah Kadaluarsa (Capsicum annuum L.)

2020 ◽  
Vol 4 (1) ◽  
pp. 229-238
Author(s):  
Dayang Rahmanita Simanjuntak ◽  
Halimursyadah Halimursyadah ◽  
Syamsuddin Syamsuddin
Keyword(s):  
Plant Growth ◽  
Capsicum Annuum ◽  
Seed Treatment ◽  
Dry Weight ◽  
Plant Growth Promoting Rhizobacteria ◽  
Seed Vigor ◽  
Inoculum Density ◽  
Plant Growth Promoting ◽  
Actinobacillus Suis ◽  
Growth Promoting

Abstrak. Biological seed treatment merupakan salah satu perlakuan benih menggunakan mikroorganisme seperti rizobakteri pemacu pertumbuhan tanaman (RPPT). Penelitian ini bertujuan untuk mengetahui jenis rizobakteri dan kerapatan inokulum yang dapat meningkatkan viabilitas dan vigor benih cabai kadaluarsa. Penelitian ini menggunakan Rancangan Acak Lengkap (RAL) pola faktorial dengan 2 faktor dan 3 ulangan. Faktor pertama adalah jenis rizobakteri (R) terdiri atas lima taraf yaitu R1: Necercia sp; R2:Bacillus polymixa; R3: Actinobacillus suis; R4: Azotobacter sp; R5: Pseudomonas capacia. Faktor kedua adalah kerapatan inokulum rizobakteri terdiri dari tiga taraf yaitu K1: 107 cfu/ml; K2: 108 cfu/ml; K3: 109 cfu/ml. Hasil penelitian ini menunjukkan bahwa perlakuan benih menggunakan rizobakteri jenis Necercia sp dengan kerapatan inokulum 108 cfu/ml nyata meningkatkan vigor benih pada tolok ukur  indeks vigor yaitu 40% dan Pseudomonas capacia dengan kerapatan inokulum 109 cfu/ml juga merupakan kombinasi perlakuan terbaik dalam meningkatkan berat kering kecambah normal yaitu 69,33 mg.Treatment Of Plant Growth Promoting Rhizobacteria (PGPR)With Multiple Levels of Rhizobacteria Inoculum Density On Viability and Vigor Of Expired Red Chilli Seeds (Capsicum annuum L.Abstract. Biological seed treatment is one of the seed treatment using microorganisms such as plant growth-promoting rhizobacteria (PGPR). This study aims to determine the type of rhizobacteria and inoculum density that can increase the viability and vigor of expired chili seeds. This research uses Completely Randomized Design (CRD) factorial pattern with 2 factors and 3 replications. The first factor is the type of rhizobacteria (R) consists of five levels, namely R1: Necercia sp; R2: Bacillus polymixa; R3: Actinobacillus suis; R4: Azotobacter sp; R5: Pseudomonas capacia. The second factor is the density of rhizobacteria inoculum consisting of three levels namely K1: 107 cfu/ml; K2: 108 cfu/ml; K3: 109 cfu/ml. The results of this study showed that the seed treatment using the Necercia sp-type rizobacteria with 108 cfu/ml inoculum density significantly increased the seed vigor on the vigor index benchmark of 40% and Pseudomonas capacia with 109cfu/ml inoculum density was also the best treatment combination in increasing dry weight normal sprout is 69,33 mg. 

scholarly journals In vitro evaluation of fungal antagonists of Phytophthora nicotianae

2017 ◽  
Vol 38 (SI 2 - 6th Conf EFPP 2002) ◽  
pp. 634-637
Author(s):  
R. Nicoletti ◽  
F. Raimo ◽  
E. Cozzolino
Keyword(s):  
Mycelial Growth ◽  
Central Italy ◽  
Phytophthora Nicotianae ◽  
Aspergillus Sydowii ◽  
Black Shank ◽  
Culture Filtrates ◽  
Dual Cultures ◽  
Penicillium Brevicompactum ◽  
Fusarium Chlamydosporum

As tobacco black shank epidemics caused by Phytophthora nicotianae occurred in central Italy in the late 1990s, fungal antagonists of the pathogen were searched in the rhizosphere of tobacco plants. Isolates of Aspergillus sydowii, Fusarium chlamydosporum, Gliocladium roseum, Penicillium brevicompactum, P. chrysogenum, Scopulariopsis candida and Trichoderma harzianum were recovered. Antagonism of these isolates toward P. nicotianae was evaluated in vitro: even if no hyphal interactions were observed in dual cultures, aberration in mycelial growth and morphology of sporangia occurred in most cases. Unlike those of T. harzianum, concentrated culture filtrates of A. sydowii, F. chlamydosporum, G. roseum, P. brevicompactum, P. chrysogenum, inhibited growth of all P. nicotianae isolates tested, while culture filtrates of S. candida caused aberrant mycelial growth.

scholarly journals Sensitivity of Phytophthora nicotianae From Tobacco to Fluopicolide, Mandipropamid, and Oxathiapiprolin

Plant Disease ◽  
2016 ◽  
Vol 100 (10) ◽  
pp. 2119-2125 ◽  
Author(s):  
Tianli Qu ◽  
Yuanyuan Shao ◽  
Alexander S. Csinos ◽  
Pingsheng Ji
Keyword(s):  
Mycelial Growth ◽  
Agar Medium ◽  
Phytophthora Nicotianae ◽  
Limited Information ◽  
Growth Reduction ◽  
Pathogen Population ◽  
Baseline Sensitivity ◽  
Resistance Development ◽  
Black Shank

Black shank incited by Phytophthora nicotianae is a devastating disease in the production of tobacco. Fungicides have been commonly used for managing the disease; however, there is only a narrow pool of effective fungicides. A few new fungicides became available in recent years, including fluopicolide, mandipropamid, and oxathiapiprolin, which reduced diseases incited by oomycetes under field conditions. Limited information is available regarding sensitivity of P. nicotianae isolates to these new fungicides. Research was conducted to determine effects of the three new fungicides on P. nicotianae isolates from tobacco in Georgia. Studies with 106 isolates indicated that they did not grow when agar medium was amended with the fungicides at the rate of 1 μg/ml. Twenty isolates were used for in vitro studies to determine sensitivity to the fungicides. Fluopicolide, mandipropamid, and oxathiapiprolin inhibited mycelial growth of the isolates with mean EC50 values (effective concentrations that provide 50% growth reduction) of 0.09, 0.04, and 0.001 μg/ml, respectively. EC50 values of fluopicolide, mandipropamid, and oxathiapiprolin for inhibiting sporangial formation were 0.15, 0.03, and 0.0002 μg/ml, respectively. EC50 values for suppressing zoospore germination averaged 0.16, 0.04, and 0.002 μg/ml for fluopicolide, mandipropamid, and oxathiapiprolin, respectively. Results from the study indicated that P. nicotianae isolates from tobacco in Georgia were sensitive to the fungicides, with lower EC50 for oxathiapiprolin than for fluopicolide and mandipropamid. The information on effectiveness and baseline sensitivity of fungicides on P. nicotianae will facilitate monitoring of resistance development in the pathogen population.

Field evaluation of asparagus crowns and germinating seeds inoculated with plant growth-promoting rhizobacteria

2009 ◽  
Vol 89 (6) ◽  
pp. 1133-1138
Author(s):  
S M Liddycoat ◽  
D J Wolyn
Keyword(s):  
Water Stress ◽  
Plant Growth ◽  
Field Evaluation ◽  
Dry Weight ◽  
Plant Growth Promoting Rhizobacteria ◽  
Asparagus Officinalis ◽  
Shoot Height ◽  
Plant Growth Promoting ◽  
Growth Promoting ◽  
Germinating Seeds

Plant growth-promoting rhizobacteria (PGPR) have the ability to enhance growth and establishment by reducing stress ethylene, or providing exogenous indol-3-acetic acid (IAA), nitrogen, iron, or phosphorus. In previous greenhouse studies, PGPR inoculation of asparagus seeds or seedlings enhanced growth under optimal and water stress conditions. Experiments were conducted in this study to determine if PGPR could provide benefits to transplanted crowns and germinating seeds in the field. Plant growth-promoting rhizobacteria did not positively affect shoot height, count, or diameter of inoculated crowns, or percent germination and seedling dry weight of inoculated seeds. The limitations of using PGPR in the field and potential for future success are discussed.Key words: Asparagus officinalis, Pseudomonas , water stress, drought, irrigation

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