scholarly journals Cross Talk between 2,4-Diacetylphloroglucinol-Producing Biocontrol Pseudomonads on Wheat Roots

2004 ◽  
Vol 70 (4) ◽  
pp. 1990-1998 ◽  
Author(s):  
Monika Maurhofer ◽  
Eric Baehler ◽  
Regina Notz ◽  
Vicente Martinez ◽  
Christoph Keel
Keyword(s):  
Biocontrol Agent ◽  
Plant Diseases ◽  
Dual Culture ◽  
Antimicrobial Compound ◽  
Biosynthetic Genes ◽  
Wheat Roots ◽  
Wheat Seedlings ◽  
Root Diseases ◽  
Pathogen Inhibition

ABSTRACT The performance of Pseudomonas biocontrol agents may be improved by applying mixtures of strains which are complementary in their capacity to suppress plant diseases. Here, we have chosen the combination of Pseudomonas fluorescens CHA0 with another well-characterized biocontrol agent, P. fluorescens Q2-87, as a model to study how these strains affect each other's expression of a biocontrol trait. In both strains, production of the antimicrobial compound 2,4-diacetylphloroglucinol (DAPG) is a crucial factor contributing to the suppression of root diseases. DAPG acts as a signaling compound inducing the expression of its own biosynthetic genes. Experimental setups were developed to investigate whether, when combining strains CHA0 and Q2-87, DAPG excreted by one strain may influence expression of DAPG-biosynthetic genes in the other strain in vitro and on the roots of wheat. DAPG production was monitored by observing the expression of lacZ fused to the biosynthetic gene phlA of the respective strain. Dual-culture assays in which the two strains were grown in liquid medium physically separated by a membrane revealed that Q2-87 but not its DAPG-negative mutant Q2-87::Tn5-1 strongly induced phlA expression in a ΔphlA mutant of strain CHA0. In the same way, phlA expression in a Q2-87 background was induced by DAPG produced by CHA0. When coinoculated onto the roots of wheat seedlings grown under gnotobiotic conditions, strains Q2-87 and CHA0, but not their respective DAPG-negative mutants, were able to enhance phlA expression in each other. In summary, we have established that two nonrelated pseudomonads may stimulate each other in the expression of an antimicrobial compound important for biocontrol. This interpopulation communication occurs in the rhizosphere, i.e., at the site of pathogen inhibition, and is mediated by the antimicrobial compound itself acting as a signal exchanged between the two pseudomonads.

scholarly journals Transcriptional Profiling of Diffusible Lipopeptides and Fungal Virulence Genes During Bacillus amyloliquefaciens EZ1509-Mediated Suppression of Sclerotinia sclerotiorum

2020 ◽  
Vol 110 (2) ◽  
pp. 317-326 ◽  
Author(s):  
Ayaz Farzand ◽  
Anam Moosa ◽  
Muhammad Zubair ◽  
Abdur Rashid Khan ◽  
Muhammad Ayaz ◽  
...  
Keyword(s):  
Antifungal Activity ◽  
Oxalic Acid ◽  
Sclerotinia Sclerotiorum ◽  
Bacillus Amyloliquefaciens ◽  
Virulence Genes ◽  
Mass Spectrometry Analysis ◽  
Dual Culture ◽  
Biosynthetic Genes ◽  
In Vitro Interaction

Sclerotinia sclerotiorum is a devastating necrotrophic pathogen that infects multiple crops, and its control is an unremitting challenge. In this work, we attempted to gain insights into the pivotal role of lipopeptides (LPs) in the antifungal activity of Bacillus amyloliquefaciens EZ1509. In a comparative study involving five Bacillus strains, B. amyloliquefaciens EZ1509 harboring four LPs biosynthetic genes (viz. surfactin, iturin, fengycin, and bacilysin) exhibited promising antifungal activity against S. sclerotiorum in a dual-culture assay. Our data demonstrated a remarkable upsurge in LPs biosynthetic gene expression through quantitative reverse transcription PCR during in vitro interaction assay with S. sclerotiorum. Maximum upregulation in LPs biosynthetic genes was observed on the second and third days of in vitro interaction, with iturin and fengycin being the highly expressed genes. Subsequently, Matrix-assisted laser desorption/ionization-time of flight-mass spectrometry analysis confirmed the presence of LPs in the inhibition zone. Scanning electron microscope analysis showed disintegration, shrinkage, plasmolysis, and breakdown of fungal hyphae. During in planta evaluation, S. sclerotiorum previously challenged with EZ1509 showed significant suppression in pathogenicity on detached leaves of tobacco and rapeseed. The oxalic acid synthesis was also significantly reduced in S. sclerotiorum previously confronted with antagonistic bacterium. The expression of major virulence genes of S. sclerotiorum, including endopolygalacturonase-3, oxalic acid hydrolase, and endopolygalacturonase-6, was significantly downregulated during in vitro confrontation with EZ1509.

scholarly journals Trichoderma species as Biocontrol Agent against Soil Borne Fungal Pathogens

2017 ◽  
Vol 5 (1) ◽  
pp. 39-45 ◽  
Author(s):  
Srijana Bastakoti ◽  
Shiva Belbase ◽  
Shrinkhala Manandhar ◽  
Charu Arjyal
Keyword(s):  
Rhizoctonia Solani ◽  
Fusarium Solani ◽  
Fungal Pathogens ◽  
Plant Pathogens ◽  
Biocontrol Agent ◽  
Sclerotium Rolfsii ◽  
Dual Culture ◽  
Trichoderma Species ◽  
Biocontrol Efficacy

Soil borne pathogenic fungi are of major concern in agriculture which significantly decreases the plant yield. Chemically controlled plant imposes environmental threats potentially dangerous to humans as well as other animals. Thus, application of biological methods in plant disease control is more effective alternative technique. This study was carried out to isolate Trichoderma species from soil sample and to assess its in vitro biocontrol efficacy against fungal pathogens viz. Sclerotium rolfsii, Sclerotionia sclerotiorum, Fusarium solani and Rhizoctonia solani. Biocontrol efficacy testing of isolates against different fungal pathogens was performed by dual culture technique.In this study, 5 different Trichoderma species were isolated from 26 various soil samples and were tested against four fungal soil-borne pathogens. Inhibition percentage of radial growth of Sclerotium rolfsii by three of the Trichoderma isolates was found to be 100%; about 62% and 68% of maximum inhibition was observed against Rhizoctonia solani and Fusarium solani respectively whereas Sclerotionia sclerotiorum was inhibited maximum up to 23%. This in vitro study revealed that although Trichoderma species plays an important role in controlling all type of soil borne fungal plant pathogens, however, isolates as biocontrol agent against Sclerotium rolfsii was found to be more efficient in comparison to other pathogens.Nepal Journal of Biotechnology. Dec. 2017 Vol. 5, No. 1: 39-49

scholarly journals Antagonism and modes of action of Chaetomium globosum species group, potential biocontrol agent of barley foliar diseases.

2016 ◽  
Vol 51 (4) ◽  
pp. 569-578 ◽  
Author(s):  
Paulina Moya ◽  
Debora Pedemonte ◽  
Susana Amengual ◽  
Mario E. E. Franco ◽  
Marina N. Sisterna
Keyword(s):  
Bipolaris Sorokiniana ◽  
Species Group ◽  
Plant Diseases ◽  
Chaetomium Globosum ◽  
Dual Culture ◽  
Foliar Diseases ◽  
Drechslera Teres ◽  
Potential Biocontrol Agent ◽  
Efficient Alternative

“Net blotch” (Drechslera teres) and “Bipolaris spot blotch” (Bipolaris sorokiniana) are foliar diseases of barley. Biological control is currently considered as an efficient alternative to chemical management of these plant diseases. The aim of the present study was to identify 2 isolates of Chaetomium (C2 and C5), endophytics on barley seedlings and to study the in vitro interactions with D. teres and B. sorokiniana, isolated from seeds of the same host. Cultural and morphologicalcharacterization of all microorganisms was done. In addition, molecular characterization of Chaetomiumspp. was conducted and dual culture tests were carried out to find, by microscopic observations, the effects of the antagonist on the morphology of the pathogens. The results confirm the identity of the pathogens and the isolates of Chaetomium spp. as Chaetomium globosum species group. Inhibition of B. sorokiniana and D. teres by C2 and C5 accounted for 30% and 31.2 %, and 40% and 36% respectively, compared with the control. The mechanisms of action against B. sorokiniana and D. teres were antibiosis and competition and mycoparasitism, respectively. Microscopic observation revealed deformed conidia in B. sorokiniana and plasmolisis, coiling and orange pigmentation in D. teres.

scholarly journals Cladobotryum mycophilum as Potential Biocontrol Agent

Agronomy ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 891
Author(s):  
Mila Santos ◽  
Fernando Diánez ◽  
Alejandro Moreno-Gavíra ◽  
Brenda Sánchez-Montesinos ◽  
Francisco J. Gea
Keyword(s):  
Biological Control ◽  
Fusarium Oxysporum ◽  
Biocontrol Agent ◽  
Biological Control Agent ◽  
Control Agent ◽  
Phytopathogenic Fungi ◽  
Antagonistic Activity ◽  
Dual Culture ◽  
Potential Biocontrol Agent

A study was conducted to explore the efficacy of potential biocontrol agent Cladobotryum mycophilum against different phytopathogenic fungi. The growth rates of 24 isolates of C. mycophilum were determined, and their antagonistic activity was analysed in vitro and in vivo against Botrytis cinerea, Fusarium oxysporum f. sp. radicis-lycopersici, Fusarium oxysporum f.sp. cucumerinum, Fusarium solani, Phytophthora parasitica, Phytophthora capsici, Pythium aphanidermatum and Mycosphaerella melonis. Most isolates grow rapidly, reaching the opposite end of the Petri dish within 72–96 h. Under dual-culture assays, C. mycophilum showed antagonistic activity in vitro against all phytopathogenic fungi tested, with mycelial growth inhibition ranging from 30 to 90% against all the different phytopathogens tested. Similarly, of all the selected isolates, CL60A, CL17A and CL18A significantly (p < 0.05) reduced the disease incidence and severity in the plant assays compared to the controls for the different pathosystems studied. Based on these results, we conclude that C. mycophilum can be considered as a potential biological control agent in agriculture. This is the first study of Cladobotryum mycophilum as a biological control agent for different diseases caused by highly relevant phytopathogens in horticulture.

scholarly journals In Vitro Study of Action Mode of Rhodotorula minuta Dmg 16 BEP as Biocontrol Agents on Alternaria solani

2020 ◽  
Vol 24 (1) ◽  
pp. 28
Author(s):  
Wawan Setiawan ◽  
Suryo Wiyono ◽  
Efi Toding Tondok ◽  
Atit Kanti ◽  
I Made Sudiana
Keyword(s):  
Skim Milk ◽  
In Vitro Study ◽  
Alternaria Solani ◽  
Plant Diseases ◽  
Yeast Cells ◽  
Dual Culture ◽  
Action Mode ◽  
Paper Disk ◽  
Rhodotorula Minuta

Rhodotorula sp. is widely known as a biocontrol agent and is reported effective in controlling several diseases on crops. Rhodotorula minuta Dmg 16 BEP is an antagonist yeast from Indonesia which was effective in controlling various plant diseases. The objective of this research was to study the in vitro mode of action of R. minuta Dmg 16 BEP against Alternaria solani. The antibiosis ability of R. minuta Dmg 16 BEP to A. solani might be based on the activity of volatile compounds and not from its metabolites products. The growth of A. solani in paper disk assay and dual culture tests were not inhibited nor inhibitory zones  developed, whereas the inverse petridish test showed the growth inhibition of A. solani. The results of the chitinolytic activity test on chitin agar and proteolytic on skim milk agar showed that no clear zone was formed. R. minuta has a strong hyperparasitic ability according to the slide culture test as the yeast cells surrounded A. solani hyphae and caused damage to some parts of hyphae.

scholarly journals In vitro evaluation of biocontrol agents and fungicides on wood decay fungiganoderma associated with mortality of tree legumes

2017 ◽  
Vol 6 (2) ◽  
pp. 31-35 ◽  
Author(s):  
M Bhadra ◽  
A Khair ◽  
MA Hossain ◽  
MM Sikder
Keyword(s):  
Growth Inhibition ◽  
Mycelial Growth ◽  
Biocontrol Agent ◽  
Wood Decay ◽  
Dual Culture ◽  
Trichoderma Spp ◽  
Decay Fungi ◽  
Trichoderma Species ◽  
Wood Decay Fungi

An experiment was conducted to isolate a number of biocontrol agent- Trichoderma spp. from infected spawn packets of oyster mushroom at National Mushroom Development and Extension Centre, Savar, Dhaka, Bangladesh. These bio-control agents were used as antagonist against four wild wood decay fungi of Ganoderma, viz., G. lucidum-1, G. lucidum-2, G. lucidum-3, G. applanatum and two cultivated G. lucidum-4, G.lucidum-6 under in vitro condition. An in vitro trial of Trichoderma spp. against Ganoderma were performed by dual culture, by treating with volatile, non-volatile and naturally untreated metabolites of bio-control agents. In dual culture, all the Trichoderma species showed 70- 100% mycelia inhibition of G. lucidum-1 and G. lucidum-2, 55.6-100% inhibition of G. lucidum-3, 20-66.7% of G. applanatum, 100% of G. lucidum-5, 75-100% of G. lucidum-6. Effects of heat killed extracts of Trichoderma spp. on growth of G. lucidum-2 (wild) and G. lucidum-6 (cultivated) were also evaluated. Fungicides Bavistin and Dithane M-45 were also used to investigate the mycelial growth inhibition of Ganoderma spp.Int. J. Agril. Res. Innov. & Tech. 6 (2): 31-35, December, 2016

scholarly journals Screening for Antagonistic Tropical Fungi against Selected Maize and Bean Pathogens

2016 ◽  
Vol 5 (2) ◽  
pp. 73-80
Author(s):  
Khadija N. Hassan ◽  
Josphat C. Matasyoh ◽  
Marc Stadler
Keyword(s):  
Mycelial Growth ◽  
Pythium Ultimum ◽  
Colletotrichum Lindemuthianum ◽  
Plant Diseases ◽  
Biocontrol Agents ◽  
Dual Culture ◽  
Tropical Fungi ◽  
Phaseolus Vulgaris L ◽  
Inhibition Zones

Phytopathogens are known to be the leading cause of important plant diseases which result in significant losses in agricultural crops. The need to maintain the level of yield both quantitatively and qualitatively is vital in order to curb the losses. So far there has been a positive advance recognized in research to the use of tropical fungi as biocontrol agents. The objective of this study was to screen for antagonistic tropical fungi against selected phytopathogens of maize (Zea mays L.) and beans (Phaseolus vulgaris L.) namely Fusarium graminearum, Fusarium moniliforme, Pythium ultimum, and Colletotrichum lindemuthianum in vitro. A total of 87 tropical fungi isolates were collected from Kakamega tropical rainforest, Kenya. Dual culture experiment was carried out to screen the tropical fungi against the selected phytopathogens. The bioassay was performed in a completely randomised design in triplicate and the inhibition zones recorded after every week for three weeks. Differential biocontrol ability among nine tropical fungi was noticed against F. moniliforme with the percentage inhibition increasing over time. Fusarium solani was the most active antagonist with an inhibition of 64% while Phaeomarasmius sp. had the lowest activity of 19.1% against F. moniliforme. Epicoccum sp. inhibited the mycelial growth of P. ultimum by 38% and also inhibited C. lindemuthianum by 58%. None of the fungal antagonists inhibited the mycelial growth of F. graminearum. The outcome of this study indicates that tropical fungi can be used as biocontrol agents and can be further explored and developed into effective fungicides for management of phytopathogens.

scholarly journals The fungal endophyte Epicoccum dendrobii as a potential biocontrol agent against Colletotrichum gloeosporioides

2020 ◽  
Author(s):  
Jin-Yue Bian ◽  
Yu-Lan Fang ◽  
Qing Song ◽  
Mei-Ling Sun ◽  
Ji-Yun Yang ◽  
...  
Keyword(s):  
Colletotrichum Gloeosporioides ◽  
Biocontrol Agent ◽  
Phylogenetic Analyses ◽  
Fungal Endophytes ◽  
Fungal Endophyte ◽  
Chinese Fir ◽  
Dual Culture ◽  
Potential Biocontrol Agent ◽  
Fungal Phytopathogen

Anthracnose caused by Colletotrichum gloeosporioides is one of most serious fungal diseases on Chinese fir (Cunninghamia lanceolata). Eight fungal endophytes were isolated from a young heathy branch of Chinese fir and screened against the pathogen in vitro. One isolate, designated as SMEL1 and subsequently identified as Epicoccum dendrobii based on morphological and phylogenetic analyses, suppressed mycelial growth of C. gloeosporioides on dual culture plates. Additionally, the metabolites of E. dendrobii significantly decreased the biomass of C. gloeosporioides. E. dendrobii was able to enter the internal tissues of the host plant via stomatal cells. The metabolites of E. dendrobii significantly inhibited conidial germination and appressorium formation, which at least partly explained why the endophyte significantly inhibited lesion development caused by C. gloeosporioides on various host plants. We further confirmed that some components with antifungal activity could be extracted from E. dendrobii using ethyl acetate as an organic solvent. To our knowledge, this is the first report of E. dendrobii as a potential biocontrol agent against a fungal phytopathogen.

scholarly journals In vitro potential of Paenibacillus alvei DZ-3 as a biocontrol agent against several phytopathogenic fungi

Biologija ◽  
2018 ◽  
Vol 64 (1) ◽  
Author(s):  
Natalija Atanasova-Pancevska ◽  
Dzoko Kungulovski
Keyword(s):  
Biocontrol Agent ◽  
Phytopathogenic Fungi ◽  
Diffusion Method ◽  
Rrna Gene ◽  
Dual Culture ◽  
Promising Alternative ◽  
Antagonistic Microorganisms ◽  
Paenibacillus Alvei ◽  
Fungal Phytopathogens

Fungal phytopathogens cause significant losses in many economically important crops and vegetables. One way to control these devastating pathogens is using higher doses of fungicides that not only increase the cost of production but also cause significant damage to the environment. Consequently, there is an increasing demand from consumers and officials to reduce the use of chemical pesticides. In this context, biological control through the use of natural antagonistic microorganisms has emerged as a promising alternative. The goal of this paper is to evaluate environmentally-friendly treatment for in vitro control of some fungal phytopathogens. In the present study, the bacterial strain DZ-3, which shows strong antifungal activity, was isolated from the samples of rotten apple compost from the composting plant in Resen, Macedonia, and identified as Paenibacillus alvei according to morphological and taxonomic characteristics and 16S rRNA gene sequence analysis. As test microorganisms, we used Botrytis cinerea FNSFCC 23, Fusarium oxysporum FNS- FCC 103, Plasmopara viticola FNS- FCC 65, Alternaria alternata FNS- FCC 624, but also Aspergilus ochraceus FNS- FCC 46, Aspergilus niger FNS- FCC 142, and Penicillium commune FNS- FCC 864. The effect of Paenibacillus alvei DZ-3 on growth of the tested fungi was evaluated by the dual culture technique and disc diffusion method. Clear inhibition zones were observed in all test microorganisms. The above-described results indicate that Paenibacillus alvei DZ-3 may have the potential as a biocontrol agent to control various phytopathogenic fungi.

An Attempt at Biological Control of Blossom Blight of Rose Caused by Botrytis cinerea Using some Local Trichoderma spp. Strains

2020 ◽  
Vol 55 (1) ◽  
pp. 27-34
Author(s):  
G. Zadehdabagh ◽  
K. Karimi ◽  
M. Rezabaigi ◽  
F. Ajamgard
Keyword(s):  
Botrytis Cinerea ◽  
Mycelial Growth ◽  
Limiting Factor ◽  
Dual Culture ◽  
Trichoderma Spp ◽  
Khuzestan Province ◽  
Inhibitory Potential ◽  
Cut Rose

The northern of Khuzestan province in Iran is mainly considered as one of the major areas of miniature rose production. Blossom blight caused by Botrytis cinerea has recently become a serious limiting factor in rose production in pre and post-harvest. In current study, an attempt was made to evaluate the inhibitory potential of some local Trichoderma spp. strains against B. cinerea under in vitro and in vivo conditions. The in vitro results showed that all Trichoderma spp. strains were significantly able to reduce the mycelial growth of the pathogen in dual culture, volatile and non-volatile compounds tests compared with control, with superiority of T. atroviride Tsafi than others. Under in vivo condition, the selected strain of T. atroviride Tsafi had much better performance than T. harzianum IRAN 523C in reduction of disease severity compared with the untreated control. Overall, the findings of this study showed that the application of Trichoderma-based biocontrol agents such as T. atroviride Tsafi can be effective to protect cut rose flowers against blossom blight.

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