scholarly journals Application of new bioformulations of Pseudomonas aureofaciens for biocontrol of cotton seedling damping-off

2014 ◽  
Vol 54 (4) ◽  
pp. 334-339 ◽  
Author(s):  
Samaneh Samavat ◽  
Asghar Heydari ◽  
Hamid Reza Zamanizadeh ◽  
Saeed Rezaee ◽  
Ali Alizadeh Aliabadi
Keyword(s):  
Biological Control ◽  
Rice Bran ◽  
Soybean Meal ◽  
Fungal Pathogens ◽  
Biocontrol Agent ◽  
Disease Incidence ◽  
Bacterial Suspension ◽  
Damping Off ◽  
Pseudomonas Aureofaciens ◽  
Phenazine Production

Abstract Pseudomonas aureofaciens (30-84) is a phenazine producing bacterium and reported as asuccessful biocontrol agent of some plant fungal pathogens. In the present study, the possibility of biological control of cotton damping-off caused by Rhizoctonia solani (AG-4) through phenazine production by the 30-84 strain, was investigated. In the search for the development of bioformulations of Pa (m) (PhzR–) and Pa (w) (PhzR+) strains of 30-84, four new carriers including soybean meal (SM), cottonseed meal (CM), rice bran (RB), and talc powder (TAL) were selected. The efficacy of bacterial formulations in reducing disease incidence was evaluated in four intervals (15, 30, 45, and 60 days after sowing), and compared with each bacterial suspension efficacy under green-house conditions. The results revealed that organic carriers were more effective than talc powder. It was also found that all the bioformulations were more efficient than each bacterial suspension. The most effective in reducing disease incidence was Pa (w) + RB. In contrast, Pa (m), Pa (m) + TAL, and Pa (m) + RB did not significantly suppress the disease in comparison with the infested control. Thus, phenazine production as a main biocontrol mechanism of P. aureofaciens (30-84) may be affected by the kind of carriers used for the bioformulation development.

scholarly journals Fusarium oxysporum (F221-B) as biocontrol agent against plant pathogenic fungi in vitro and in hydroponics

2017 ◽  
Vol 53 (No. 2) ◽  
pp. 85-95 ◽  
Author(s):  
Thongkamngam Titi ◽  
Jaenaksorn Tanimnun
Keyword(s):  
Fusarium Oxysporum ◽  
Fungal Pathogens ◽  
Biocontrol Agent ◽  
Disease Incidence ◽  
Pathogenic Fungi ◽  
Curvularia Lunata ◽  
Plant Growth Promoting ◽  
Healthy Control ◽  
Further Development

Efficacy of non-pathogenic Fusarium oxysporum (F221-B) was assessed as a possible biocontrol agent against fungal pathogens, namely Curvularia lunata (C11, C12), F. semitectum (F113), F. oxysporum f.sp. lactucae (F221-R, F442-G), Rhizoctonia solani (R11, R12), Rhizoctonia sp. (R111, R112, R113) in vitro, while F221-B showed a moderate ability to inhibit the mycelial growth of tested fungi about 36–56%. Then, F221-B was further evaluated for its ability of controlling lettuce root rot and wilt caused by F442-G in hydroponics. It was revealed that F221-B reduced disease incidence and severity about 60–80% compared to the inoculated control and significantly promoted the growth of 3 lettuce varieties. Interestingly, using only F221-B gave the significantly highest fresh weight (twice over the healthy control). Conclusively, this study provides an important suggestion for further development of F221-B since it showed the ability of biocontrol agent and plant growth promoting fungus.

Phaeotheca dimorphospora increases Trichoderma harzianum density in soil and suppresses red pine damping-off caused by Cylindrocladium scoparium

1995 ◽  
Vol 73 (5) ◽  
pp. 693-700 ◽  
Author(s):  
D. Yang ◽  
L. Bernier ◽  
M. Dessureault
Keyword(s):  
Biological Control ◽  
Trichoderma Harzianum ◽  
Plant Pathogens ◽  
Disease Incidence ◽  
Pinus Resinosa ◽  
Red Pine ◽  
Damping Off ◽  
Fungal Antagonist ◽  
Petri Dishes

A fungal antagonist, Phaeotheca dimorphospora, was tested for its ability to control damping-off of red pine (Pinus resinosa) caused by Cylindrocladium scoparium. In vitro, the germination of seeds coated with P. dimorphospora microconidia was significantly increased by 10% compared with uncoated seeds. In experiments carried out in Petri dishes, addition of P. dimorphospora into soil significantly reduced the population of C. scoparium and disease incidence. In the greenhouse, application of P. dimorphospora into the top layer of soil reduced pre- and post-emergence damping-off by 79.5%. Under greenhouse conditions, P. dimorphospora stimulated the population of Trichoderma harzianum, a well-known antagonist of soil-borne plant pathogens. In soil treated with P. dimorphospora, the number of propagules of T. harzianum was 100–500 times higher than in the untreated control, whereas the population of C. scoparium decreased rapidly and was not detectable 1 month after sowing. Key words: Phaeotheca dimorphospora, Trichoderma harzianum, Cylindrocladium scoparium, damping-off, biological control, fungal antagonist, Pinus resinosa.

scholarly journals Identity and prevalence of wheat damping-off fungal pathogens in different fields of Basrah and Maysan provinces

2021 ◽  
Vol 45 (1) ◽  
Author(s):  
Mohammed Hamza Abass ◽  
Qusai Hattab Madhi ◽  
Abdulnabi Abdul Ameer Matrood
Keyword(s):  
Fusarium Solani ◽  
Seed Treatment ◽  
Fungal Pathogens ◽  
Laboratory Experiments ◽  
Disease Incidence ◽  
Macrophomina Phaseolina ◽  
Cereal Crops ◽  
Damping Off ◽  
Fungal Isolation ◽  
The World

Abstract Background Wheat is the most consumed cereal crops in the world infected by several pathogens and pests causing significant losses. The most threatening pathogens are fungi which cause serious diseases on roots, leaves and heads as one of the most threatening pathogens in specific wheat-growing countries. This study aimed to identify and evaluate the prevalence of damping-off fungal pathogens in different wheat fields at Basra and Maysan provinces. Results Disease incidence determination and fungal isolation were carried out from two sites at Basra province (Al-Qurna and Al-Madinah) and three sites at Maysan province (Al-Amarah, Kumit, Ali Al Sharqi and Ali Al Gharbi). Al-Qurna fields had the highest disease incidence (32%), while Ali-Alsharqi fields had the lowest one (11%). Fourteen fungal genera were identified. Rhizoctonia solani had the highest appearance (21.6) and frequency (20.20%) percentages followed by Fusarium solani (16.11,14.01) percentages and Macrophomina phaseolina (12.2,11.1) percentages. Seed treatment with R. solani (Rs1 isolate) showed significant decrease in germination (56.6%) compared to F. solani and M. phaseolina treatments. Seed treatment with R. solani (Rs1 isolate) showed significant decrease in germination (56.6%) compared to F. solani and M. phaseolina treatments. Conclusions These results revealed the prevalence of wheat damping-off disease in all examined fields at both Basra and Maysan province; the highest disease incidence was seen in Basra wheat fields (Al-Qurna fields); the identification of fungal pathogens showed that the most isolated fungus was R. solani followed by F. solani and M. phaseolina. Laboratory experiments showed the pathogenicity of isolated fungi which varied according to the isolate type.

scholarly journals A comparison between Pseudomonas aureofaciens (chlororaphis) and P. fluorescens in biological control of cotton seedling damping-off disease

2014 ◽  
Vol 54 (2) ◽  
pp. 115-121
Author(s):  
Samavat Samaneh ◽  
Asghar Heydari ◽  
Hamid Reza Zamanizadeh ◽  
Saeed Rezaee ◽  
Ali Alizadeh Aliabadi
Keyword(s):  
Biological Control ◽  
Greenhouse Experiment ◽  
Plant Diseases ◽  
Dual Culture ◽  
Damping Off ◽  
Wild Type ◽  
Cotton Seedling ◽  
Pseudomonas Aureofaciens ◽  
Volatile Metabolites ◽  
Bacterial Antagonists

Abstract Due to the importance of the biological control of plant diseases, testing and introducing new biocontrol-active microorganisms is a major concern among plant pathologists. The causal agent of cotton seedling damping-off disease is Rhizoctonia solani. In this regard, we tried to investigate the antagonistic activities of Pseudomonas aureofaciens (chlororaphis) 30–84 (phenazine producing wild type and non-phenazine producing mutant) strains on R. solani, in comparison with some isolates of P. fluorescent under both in vitro (laboratory) and in vivo (greenhouse) conditions. In the laboratory experiment, the inhibitory effects of all the bacteria, on the growth of R. solani, were evaluated using the dual culture procedure. Results showed that five isolates of P. fluorescent along with both strains of P. aureofaciens significantly inhibited the growth of R. solani. Effective bacterial antagonists were then evaluated in a greenhouse experiment where cotton seeds were coated with their suspensions and were sown in pasteurised field-soil. The soil had been pre-inoculated with a virulent isolate of R. solani. The efficacy of the bacterial antagonists was evaluated by counting the number of surviving seedlings in different treatments, at 15 and 60 days after sowing, for determining pre- and post-emergence damping-off incidence. According to the results of the greenhouse experiment, at both intervals, two isolates of P. fluorescens along with both strains of P. aureofaciens caused significant increases in the number of healthy seedlings, in comparison with the untreated control, and a commonly used fungicide (carboxin-thiram). The efficacy of phenazine producing a wild type strain of P. aureofaciens was higher than its non-phenazine producing mutant, indicating that phenazine plays an important role in the antagonistic activity of P. aureofaciens. Effective bacterial antagonists were then studied for their antagonistic mechanisms. The results showed that all four bacteria employed different mechanisms. The bacteria produced siderophore, and volatile metabolites and non-volatile metabolites, in their antagonistic activities. The results of this study suggest that P. auerofaciens may be a new biocontrol agent for controlling cotton seedling mortality disease.

scholarly journals Antagonistic potential of lactobacillus plantarum against some postharvest pathogenic fungi

2019 ◽  
pp. 79-88
Author(s):  
Svetlana Zivkovic ◽  
Stefan Stosic ◽  
Danijela Ristic ◽  
Ivan Vucurovic ◽  
Milos Stevanovic
Keyword(s):  
Lactobacillus Plantarum ◽  
Fungal Pathogens ◽  
Disease Incidence ◽  
Pathogenic Fungi ◽  
In Vitro Assays ◽  
Colletotrichum Acutatum ◽  
Bacterial Suspension ◽  
Antagonistic Potential

Lactobacillus plantarum, one of the most widespread lactic acid bacte?ria, exert a strong antagonistic activity against many microorganisms. The present study was conducted to determine in vitro and in situ antagonistic potential of L. plantarum (DSM 20174) for control postharvest decay caused by phytopathogenic fungi: Aspergillus flavus, Colletotrichum acutatum, Colletotrichum gloeosporioides, and Fusarium avenaceum. The results obtained in in vitro assays showed that L. plantarum had a stronger inhibitory effect on spore germination than on mycelia growth of all tested fungi. After 3 days of incubation, the diameter of inhibition zones ranged from 11.67 mm for C. gloeosporioides to 14.67 mm for C. acutatum. The bacterial suspension of L. plantarum significantly inhibited conidial germination of all postharvest pathogens (89.62-97.61%). In situ assays showed that treatment with L. plantarum efficiently inhibited necrosis ranging from 42.54% for C. acutatum to 54.47% for A. flavus. The disease incidence in L. plantarum treated fruits was statistically significantly lower than in the positive control for all fungi tested (P<0.05). The presented data demonstrate the antagonistic potential of L. plantarum (DSM 20174) and indicate the possibility of using this bacterial strain as a biological agent to control postharvest fungal pathogens.

scholarly journals Characterization and Expression of β-1,3-Glucanase Genes in Jujube Fruit Induced by the Microbial Biocontrol Agent Cryptococcus laurentii

2007 ◽  
Vol 97 (3) ◽  
pp. 260-268 ◽  
Author(s):  
Shi P. Tian ◽  
Hong J. Yao ◽  
Xin Deng ◽  
Xiang B. Xu ◽  
Guo Z. Qin ◽  
...  
Keyword(s):  
Fungal Pathogens ◽  
Biocontrol Agent ◽  
Disease Incidence ◽  
Gene Activation ◽  
Polymerase Chain Reaction Analysis ◽  
Defense Responses ◽  
Cryptococcus Laurentii ◽  
Glucanase Activity ◽  
Jujube Fruit ◽  
Ziziphus Jujuba

Two β-1,3-glucanase genes were cloned from jujube (Ziziphus jujuba Mill) fruit and designated Glu-1 and Glu-2 (GenBank accession numbers DQ012940 and DQ093571), respectively. The expression of Glu-1 and Glu-2 in jujube fruit in response to wounding and microbial biocontrol agent was evaluated by semi-quantitative reverse-transcription polymerase chain reaction analysis. Wounding and treatment with Cryptococcus laurentii stimulated an increase in β-1,3-glucanase (EC 3.2.1.39) activity in jujube fruit. Analysis of gene expression proved that Glu-1 was highly induced both by wounding and C. laurentii, whereas Glu-2 was broadly not responsive to the yeast. The expression of Glu-1 was noticeably enhanced with increased concentrations of C. laurentii, suggesting that Glu-1 may play a role in defense responses to fungal pathogens. The results hold true at the levels of gene activation and enzyme accumulation in jujube fruit treated by both stimuli, resulting in a significant decrease in disease incidence and lesion diameter, thus providing evidence that changes in β-1,3-glucanase activity are related to expression of the genes. Taken together, these findings suggest the possible use of β-1,3-glucanase activity as a biochemical marker for screening jujube fruit against fungal pathogens, and also provide a mechanistic framework for the functions of β-1,3-glucanase in defense responses.

scholarly journals The Potential of Rhizoctonia-Like Fungi for the Biological Protection of Cereals against Fungal Pathogens

Plants ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 349
Author(s):  
Dominik Bleša ◽  
Pavel Matušinský ◽  
Romana Sedmíková ◽  
Milan Baláž
Keyword(s):  
Biological Control ◽  
Fungal Pathogens ◽  
Plant Pathogens ◽  
Higher Plants ◽  
Fusarium Culmorum ◽  
Suppressive Effect ◽  
Plant Production ◽  
Shoot Biomass ◽  
Organic Substrates

The use of biological control is becoming a common practice in plant production. One overlooked group of organisms potentially suitable for biological control are Rhizoctonia-like (Rh-like) fungi. Some of them are capable of forming endophytic associations with a large group of higher plants as well as mycorrhizal symbioses. Various benefits of endophytic associations were proved, including amelioration of devastating effects of pathogens such as Fusarium culmorum. The advantage of Rh-like endophytes over strictly biotrophic mycorrhizal organisms is the possibility of their cultivation on organic substrates, which makes their use more suitable for production. We focused on abilities of five Rh-like fungi isolated from orchid mycorrhizas, endophytic fungi Serendipita indica, Microdochium bolleyi and pathogenic Ceratobasidium cereale to inhibit the growth of pathogenic F. culmorum or Pyrenophora teres in vitro. We also analysed their suppressive effect on wheat infection by F. culmorum in a growth chamber, as well as an effect on barley under field conditions. Some of the Rh-like fungi affected the growth of plant pathogens in vitro, then the interaction with plants was tested. Beneficial effect was especially noted in the pot experiments, where wheat plants were negatively influenced by F. culmorum. Inoculation with S. indica caused higher dry shoot biomass in comparison to plants treated with fungicide. Prospective for future work are the effects of these endophytes on plant signalling pathways, factors affecting the level of colonization and surviving of infectious particles.

scholarly journals Biological and Host Range Characteristics of Lysathia flavipes (Coleoptera: Chrysomelidae), a Candidate Biological Control Agent of Invasive Ludwigia spp. (Onagraceae) in the USA

Insects ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 471
Author(s):  
Angelica M. Reddy ◽  
Paul D. Pratt ◽  
Brenda J. Grewell ◽  
Nathan E. Harms ◽  
Ximena Cibils-Stewart ◽  
...  
Keyword(s):  
Biological Control ◽  
Host Range ◽  
Plant Species ◽  
Biocontrol Agent ◽  
Biological Control Agent ◽  
Control Agent ◽  
Native Plant ◽  
Native Plant Species ◽  
The Usa ◽  
Physical And Chemical

Exotic water primroses (Ludwigia spp.) are aggressive invaders in aquatic ecosystems worldwide. To date, management of exotic Ludwigia spp. has been limited to physical and chemical control methods. Biological control provides an alternative approach for the management of invasive Ludwigia spp. but little is known regarding the natural enemies of these exotic plants. Herein the biology and host range of Lysathia flavipes (Boheman), a herbivorous beetle associated with Ludwigia spp. in Argentina and Uruguay, was studied to determine its suitability as a biocontrol agent for multiple closely related target weeds in the USA. The beetle matures from egg to adult in 19.9 ± 1.4 days at 25 °C; females lived 86.3 ± 35.6 days and laid 1510.6 ± 543.4 eggs over their lifespans. No-choice development and oviposition tests were conducted using four Ludwigia species and seven native plant species. Lysathia flavipes showed little discrimination between plant species: larvae aggressively fed and completed development, and the resulting females (F1 generation) oviposited viable eggs on most plant species regardless of origin. These results indicate that L. flavipes is not sufficiently host-specific for further consideration as a biocontrol agent of exotic Ludwigia spp. in the USA and further testing is not warranted.

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.

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