Suppressive efficacy of volatile compounds produced byBacillus mycoideson damping-off pathogens of cabbage seedlings

2018 ◽  
Vol 156 (6) ◽  
pp. 795-809
Author(s):  
J.-S. Huang ◽  
Y.-H. Peng ◽  
K.-R. Chung ◽  
J.-W. Huang
Keyword(s):  
Radial Growth ◽  
Plant Pathogens ◽  
Biocontrol Agent ◽  
Antagonistic Activity ◽  
Yield Losses ◽  
Damping Off ◽  
Cultivation Medium ◽  
Dimethyl Disulphide ◽  
Volatile Organic ◽  
Potential Use

AbstractRhizoctonia solaniKühn andPythium aphanidermatumEdson cause cabbage seedling damping-off, resulting in severe yield losses. The current study demonstrates the production of toxic volatile organic compounds (VOCs) by two strains ofBacillus mycoidesand the evaluation of a potential use ofB.mycoidesas a biocontrol agent to control cabbage damping-off. Two VOCs, dimethyl disulphide and ammonia, were found to reduce radial growth, cause hyphal deformation and result in organelle degeneration in bothR. solaniandP. aphanidermatum. Pathogen hyphae, after being exposed to VOCs, showed poor rigidity, shrinkage, curling and swelling. The amount of VOCs produced byB. mycoidesand the antagonistic activity against plant pathogens varied, depending on the type of medium used to culture bacteria. Application ofB.mycoidescell suspensions to cultivation medium promotes growth of five different plant species tested. Experiments conducted in greenhouses revealed thatB. mycoidesdid not reduce damping-off incidence caused byR.solani. However,B. mycoidesreduced damping-off incidence induced byP. aphanidermatumby as much as 45% on cabbage seedlings. The results provide valuable information on the feasibility of utilizingB. mycoidesas a biocontrol agent in controlling cabbage damping-off.

scholarly journals Complete Genome Sequence of the Biocontrol Agent YeastRhodotorula kratochvilovaeStrain LS11

2018 ◽  
Vol 6 (10) ◽  
Author(s):  
Cecilia Miccoli ◽  
Davide Palmieri ◽  
Filippo De Curtis ◽  
Giuseppe Lima ◽  
Giuseppe Ianiri ◽  
...  
Keyword(s):  
Genome Sequence ◽  
Genome Assembly ◽  
Complete Genome Sequence ◽  
Genome Annotation ◽  
Complete Genome ◽  
Plant Pathogens ◽  
Biocontrol Agent ◽  
Antagonistic Activity ◽  
Protein Encoding ◽  
Encoding Genes

ABSTRACTRhodotorula kratochvilovaestrain LS11 is a biocontrol agent (BCA) selected for its antagonistic activity against several plant pathogens both in the field and postharvest. Genome assembly includes 62 contigs for a total of 22.56 Mbp and a G+C content of 66.6%. Genome annotation predicts 7,642 protein-encoding genes.

scholarly journals Bakteri Endofit Asal Berbagai Akar Tanaman sebagai Agens Pengendali Nematoda Puru Akar Meloidogyne incognita pada Tomat

2016 ◽  
Vol 12 (3) ◽  
pp. 75
Author(s):  
Pradana Pandu Ankardiansyah ◽  
Abdul Munif ◽  
Supramana Supramana
Keyword(s):  
Meloidogyne Incognita ◽  
Endophytic Bacteria ◽  
Seed Treatment ◽  
Biocontrol Agent ◽  
Biocontrol Agents ◽  
Yield Losses ◽  
Root Knot Nematode ◽  
Protease Enzyme ◽  
New Information ◽  
Potential Use

Infection caused by root knot nematode (RKN) Meloidogyne incognita may cause yield losses. Little is known regarding the effectiveness of endophytic bacterial group as biocontrol agents of RKN. This research was aimed to obtain endophytic bacteria group from 16 species of plants, which effectively controlled the RKN. Isolation of endophytic bacteria group was conducted using NA 20%, NA 50%, TSA 20%, TSA 50%, and King’s B medium. All of the bacteria groups giving negative result in hypersensitive and haemolytic tests, was further examined for their ability to produce protease, chitinase, and cyanide acid. The same endophytic bacteria groups were also tested for their potential to control juvenile 2 of M. incognita on tomatoes by seed treatment and soil drenching. Agronomical and pathological traits were observed 40 days after nematodes infestation. Eighty endophytic bacteria groups were successfully isolated and 17 of them were considered potential. Physiological test showed that 16 groups of endophytic bacteria can produce protease enzyme, 12 groups can produce chitinase enzyme, and 5 groups can produce cyanide acid. Specific endophytic bacteria group, i.e. TmtN5 from roots of tomato plant, is the most effective isolate for suppressing root damage and population of RKN. This group was effective as biocontrol agents of RKN because it produceds chitinase, protease, and cyanide acid. This research provided a new information regarding the potential use of endophytic bacteria group as a biocontrol agent of RKN.

scholarly journals Complete Genome Sequence of the Biocontrol Yeast Papiliotrema terrestris Strain LS28

2021 ◽  
Author(s):  
Davide Palmieri ◽  
Giuseppe Barone ◽  
Riccardo Aiese Cigliano ◽  
Filippo De Curtis ◽  
Giuseppe Lima ◽  
...  
Keyword(s):  
Genome Annotation ◽  
Plant Pathogens ◽  
Biocontrol Agent ◽  
Antagonistic Activity ◽  
Whole Genome ◽  
Genome Data ◽  
A Genome ◽  
Protein Encoding ◽  
Genetic Mechanisms ◽  
Encoding Genes

Abstract Papiliotrema terrestris strain LS28 is a biocontrol agent (BCA) selected for its antagonistic activity against several plant pathogens both in the field and postharvest. The availability of a genome sequencing sets the foundation for the identification of the genetic mechanisms of its antagonistic activity. The genome size is 21.29 Mbp with a G + C content of 58.65%, and genome annotation predicts 8,626 protein-encoding genes. Phylogenetic analysis based on whole genome data confirms that P. terrestris is a Tremellomycetes more closely related to P. flavescens than P. laurentii.

scholarly journals Aspergillus terreus obtained from mangrove exhibits antagonistic activities against Pythium aphanidermatum-induced damping-off of cucumber

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e7884 ◽  
Author(s):  
Hanaa Al-Shibli ◽  
Sergey Dobretsov ◽  
Abdulrahman Al-Nabhani ◽  
Sajeewa S.N. Maharachchikumbura ◽  
Velazhahan Rethinasamy ◽  
...  
Keyword(s):  
Aspergillus Terreus ◽  
Plant Pathogens ◽  
Dry Weight ◽  
Avicennia Marina ◽  
Pythium Aphanidermatum ◽  
Antagonistic Activity ◽  
Damping Off ◽  
Cucumber Seedlings ◽  
Percent Mortality

A study was conducted to investigate the potential of Aspergillus terreus obtained from Avicennia marina mangrove roots in inhibiting Pythium aphanidermatum and damping-off disease of cucumber. Aspergillus terreus exhibited in vitro inhibition of Pythium aphanidermatum growth. Electron microscope examination revealed that the antagonistic fungal isolate resulted in shrinking and groves in Pythium hypha. When Aspergillus terreus culture filtrate was added to Pythium aphanidermatum, it resulted in a significant increase (by 73%) in electrolyte leakage from Pythium hypha compared to the control, as well as significant reduction (by 71%) in oospore production. The Aspergillus terreus culture was also found to produce a cellulase enzyme, which is suggested to be involved in the antagonism against Pythium aphanidermatum. Adding Aspergillus terreus to soil infested with Pythium aphanidermatum significantly reduced percent mortality in cucumber seedlings by 70%. Aspergillus terreus, when applied alone on cucumber seedlings, did not show any suppressive effects on cucumber growth (length and fresh and dry weight). This appears to be the first report of isolation from mangrove of Aspergillus terreus with antagonistic activity against Pythium aphanidermatum-induced damping-off of cucumber. The study indicates that fungal isolates obtained from marine environments may serve as potential biocontrol agents against some plant pathogens.

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 Myco-Suppression Analysis of Soybean (Glycine max) Damping-Off Caused by Pythium aphanidermatum

Plants ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 788
Author(s):  
Shaban R. M. Sayed ◽  
Shaimaa A. M. Abdelmohsen ◽  
Hani M. A. Abdelzaher ◽  
Mohammed A. Elnaghy ◽  
Ashraf A. Mostafa ◽  
...  
Keyword(s):  
Glycine Max ◽  
Biocontrol Agent ◽  
Lateral Roots ◽  
Dry Weight ◽  
Pythium Aphanidermatum ◽  
Damping Off ◽  
Pythium Oligandrum ◽  
Rdna Its ◽  
Half Strength

The role of Pythium oligandrum as a biocontrol agent against Pythium aphanidermatum was investigated to avoid the harmful impacts of fungicides. Three isolates of P. oligandrum (MS15, MS19, and MS31) were assessed facing the plant pathogenic P. aphanidermatum the causal agent of Glycine max damping-off. The tested Pythium species were recognized according to their cultural and microscopic characterizations. The identification was confirmed through sequencing of rDNA-ITS regions including the 5.8 S rDNA. The biocontrol agent, P. oligandrum, isolates decreased the mycelial growth of the pathogenic P. aphanidermatum with 71.3%, 67.1%, and 68.7% through mycoparasitism on CMA plates. While the half-strength millipore sterilized filtrates of P. oligandrum isolates degrade the pathogenic mycelial linear growth by 34.1%, 32.5%, and 31.7%, and reduce the mycelial dry weight of the pathogenic P. aphanidermatum by 40.1%, 37.4%, and 36.8%, respectively. Scanning electron microscopy (SEM) of the most effective antagonistic P. oligandrum isolate (MS15) interaction showed coiling, haustorial parts of P. oligandrum to P. aphanidermatum hyphae. Furthermore, P. oligandrum isolates were proven to enhance the germination of Glycine max seedling to 93.3% in damping-off infection using agar pots and promote germination of up to 80% during soil pot assay. On the other hand, P. oligandrum isolates increase the shoot, root lengths, and the number of lateral roots.

scholarly journals Application of Bio-Friendly Formulations of Chitinase-Producing Streptomyces cellulosae Actino 48 for Controlling Peanut Soil-Borne Diseases Caused by Sclerotium rolfsii

2021 ◽  
Vol 7 (3) ◽  
pp. 167
Author(s):  
Gaber Abo-Zaid ◽  
Ahmed Abdelkhalek ◽  
Saleh Matar ◽  
Mai Darwish ◽  
Muhammad Abdel-Gayed
Keyword(s):  
Open Field ◽  
Biocontrol Agent ◽  
Sclerotium Rolfsii ◽  
Dry Weight ◽  
Culture Broth ◽  
Field Conditions ◽  
Damping Off ◽  
Mycelium Growth ◽  
Particle Size Analyzer ◽  
Cell Pellet

Of ten actinobacterial isolates, Streptomyces cellulosae Actino 48 exhibited the strongest suppression of Sclerotium rolfsii mycelium growth and the highest chitinase enzyme production (49.2 U L−1 min−1). The interaction between Actino 48 and S. rolfsii was studied by scanning electron microscope (SEM), which revealed many abnormalities, malformations, and injuries of the hypha, with large loss of S. rolfsii mycelia density and mass. Three talc-based formulations with culture broth, cell-free supernatant, and cell pellet suspension of chitinase-producing Actino 48 were characterized using SEM, Fourier transform infrared spectroscopy (FTIR), and a particle size analyzer. All formulations were evaluated as biocontrol agents for reducing damping-off, root rot, and pods rot diseases of peanut caused by S. rolfsii under greenhouse and open-field conditions. The talc-based culture broth formulation was the most effective soil treatment, which decreased the percentage of peanut diseases under greenhouse and open-field conditions during two successive seasons. The culture broth formulation showed the highest increase in the dry weight of peanut shoots, root systems, and yielded pods. The transcriptional levels of three defense-related genes (PR-1, PR-3, and POD) were elevated in the culture broth formulation treatment compared with other formulations. Subsequently, the bio-friendly talc-based culture broth formulation of chitinase-producing Actino 48 could potentially be used as a biocontrol agent for controlling peanut soil-borne diseases caused by S. rolfsii.

scholarly journals Streptomyces roseolus, A Promising Biocontrol Agent Against Aspergillus flavus, the Main Aflatoxin B1 Producer

Toxins ◽  
2018 ◽  
Vol 10 (11) ◽  
pp. 442 ◽  
Author(s):  
Isaura Caceres ◽  
Selma Snini ◽  
Olivier Puel ◽  
Florence Mathieu
Keyword(s):  
Aspergillus Flavus ◽  
Aflatoxin B1 ◽  
Biocontrol Agent ◽  
Cyclopiazonic Acid ◽  
Over Expression ◽  
Expression Of Genes ◽  
B1 Gene ◽  
Genes Encoding ◽  
Molecular Mechanism Of Action ◽  
Potential Use

Crop contamination by aflatoxin B1 is a current problem in tropical and subtropical regions. In the future, this contamination risk may be expanded to European countries due to climate change. The development of alternative strategies to prevent mycotoxin contamination that further contribute to the substitution of phytopharmaceutical products are thus needed. For this, a promising method resides in the use of biocontrol agents. Several actinobacteria strains have demonstrated to effectively reduce the aflatoxin B1 concentration. Nevertheless, the molecular mechanism of action by which these biological agents reduce the mycotoxin concentration has not been determined. The aim of the present study was to test the potential use of Streptomyces roseolus as a biocontrol agent against aflatoxin B1 contamination. Co-cultures with Aspergillus flavus were conducted, and the molecular fungal response was investigated through analyzing the q-PCR expression of 65 genes encoding relevant fungal functions. Moreover, kojic and cyclopiazonic acid concentrations, as well as morphological fungal changes were also analyzed. The results demonstrated that reduced concentrations of aflatoxin B1 and kojic acid were respectively correlated with the down-regulation of the aflatoxin B1 gene cluster and kojR gene expression. Moreover, a fungal hypersporulated phenotype and a general over-expression of genes involved in fungal development were observed in the co-culture condition.

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