Role of chitinase and β-1,3-glucanase activities produced by a fluorescent pseudomonad and in vitro inhibition of Phytophthora capsici and Rhizoctonia solani

2007 ◽  
Vol 53 (2) ◽  
pp. 207-212 ◽  
Author(s):  
Naveen Kumar Arora ◽  
Min Jeong Kim ◽  
Sun Chul Kang ◽  
Dinesh Kumar Maheshwari

A study was conducted to investigate the possibility of involvement of chitinase and β-1,3-glucanase of an antagonistic fluorescent Pseudomonas in growth suppression of phytopathogenic fungi, Phytophthora capsici and Rhizoctonia solani . Fluorescent Pseudomonas isolates GRC3 and GRC4 were screened for their antifungal potential against phytopathogenic fungi by using dual culture technique both on solid and liquid media. The percent inhibition was calculated. Various parameters were monitored for optimization of enzyme activities by fluorescent Pseudomonas GRC3. The involvement of chitinases, β-1,3-glucanases, and antifungal metabolites of nonenzymatic nature was correlated with the inhibition of P. capsici and R. solani. The results provide evidence for antibiosis as a mechanism for antagonism. The study also confirms that multiple mechanisms are involved in suppressing phytopathogens as evidenced by the involvement of chitinase and β-1,3-glucanase in inhibition of R. solani but not P. capsici by isolate GRC3.

2016 ◽  
Vol 5 (1) ◽  
pp. 1
Author(s):  
Rita Noveriza ◽  
Tricita H. Quimio

Foot rot disease of black pepper caused by Phytophthora capsici had been reported in Batangas and Laguna, Philippines. The plant was recovered following the application of crop residue (organic substrate) and intercropping with other crops. This study was aimed to isolate, identify, and determine the soil mycoflora from the rhizosphere of black pepper grown on various cropping patterns in Batangas and Laguna. Antagonistic activity of mycoflora isolates was tested against P. capsici using dual culture technique. The result showed that 149 colonies of soil mycoflora isolated were belonging to 14 genera; three of them, i.e. Penicillium, Paecilomyces and Aspergillus, were the most dominant. All of the mycoflora isolates were able to inhibit the growth of the pathogen. Eighteen of them were the most promising antagonists, based on their inhibition growth of more than 60%. It is suggested that antagonistic mechanism of Mucor isolate (1001), Trichoderma (125, 170, 171, 179, 180, 181), Gliocladium (109), Cunninghamella (165, 168), Mortierella (177), and Aspergillus (106) was space competitor (competition for nutrient) since they rapidly overgrew the pathogen. Aspergillus (67, 79, 81, 83, 108, and 202) isolates inhibited the pathogen apparently by producing antibiotic, whereas Trichoderma (125, 170, 171, 179, 180, and 181) isolates were able to penetrate the hyphae of the pathogen. The organic matter percentage in the soil was significantly correlated with the number of antagonistic mycoflora in rhizosphere (R2 = 0.1094), but the cropping pattern was negatively correlated. This study suggests that organic matter increased antagonistic mycoflora in black pepper rhizosphere, which will reduce severity of the disease.


2018 ◽  
Vol 3 (02) ◽  
pp. 166-170
Author(s):  
Safdar Kaiser Hasmi ◽  
R. U. Khan

In-vitro effectiveness of various antagonistic fungi namely Aspergillus niger, A. flavus, Trichoderma koningii, T. atroviride, and T. harzianum were evaluated against Rhizoctonia solani by dual culture technique on potato dextrose agar. According to the observation recorded after 5 days, all the treatments were found to be superior over control (R. solani), but among all treatments A. niger was found to the most effective antagonist, with highest radial growth inhibition of the pathogen (77.01 percent), followed by A. flavus, T. harzianum and T. koningii i.e., 66.23, 64.42 and 62.20 percent. While as, T. atroviride was found to be the least effective one with minimum growth inhibition i.e., 42.21 percent. Whereas, at the same time control (R. solani) showed 100 percent radial growth and covered the whole Petri Plate within 5 days. All the bio-control agents were significantly effective to inhibit the sclerotia formation and development, except T. atroviride in which formation of sclerotia was recorded, while in all other treatments complete inhibition of sclerotia formation was recorded after 10 days of incubation.


2016 ◽  
Vol 5 (1) ◽  
pp. 1
Author(s):  
Rita Noveriza ◽  
Tricita H. Quimio

Foot rot disease of black pepper caused by Phytophthora capsici had been reported in Batangas and Laguna, Philippines. The plant was recovered following the application of crop residue (organic substrate) and intercropping with other crops. This study was aimed to isolate, identify, and determine the soil mycoflora from the rhizosphere of black pepper grown on various cropping patterns in Batangas and Laguna. Antagonistic activity of mycoflora isolates was tested against P. capsici using dual culture technique. The result showed that 149 colonies of soil mycoflora isolated were belonging to 14 genera; three of them, i.e. Penicillium, Paecilomyces and Aspergillus, were the most dominant. All of the mycoflora isolates were able to inhibit the growth of the pathogen. Eighteen of them were the most promising antagonists, based on their inhibition growth of more than 60%. It is suggested that antagonistic mechanism of Mucor isolate (1001), Trichoderma (125, 170, 171, 179, 180, 181), Gliocladium (109), Cunninghamella (165, 168), Mortierella (177), and Aspergillus (106) was space competitor (competition for nutrient) since they rapidly overgrew the pathogen. Aspergillus (67, 79, 81, 83, 108, and 202) isolates inhibited the pathogen apparently by producing antibiotic, whereas Trichoderma (125, 170, 171, 179, 180, and 181) isolates were able to penetrate the hyphae of the pathogen. The organic matter percentage in the soil was significantly correlated with the number of antagonistic mycoflora in rhizosphere (R2 = 0.1094), but the cropping pattern was negatively correlated. This study suggests that organic matter increased antagonistic mycoflora in black pepper rhizosphere, which will reduce severity of the disease.


Author(s):  
Ma. Ángeles Valencia de Ita ◽  
Jiménez Huerta Fátima ◽  
Conrado Parraguirre Lezama ◽  
Alfredo Báez Simón ◽  
Gerardo Landeta Cortés ◽  
...  

Diversity of the different types of chilies in Mexico has been scarcely studied, and a large variety have been found to be, such as Manzano chili. Root rot caused by oomycete Phytophthora capsici is a severe disease that affects Manzano chili production in Mexico, detracted from its production and quality. The use of biological control agents such as Trichodermanative’s species, represents an efficient alternative to reduce losses and control the disease. For this reason, the objective of the present investigation was to evaluate the antagonistic effect in vitro and in vivo of four native strains of Trichoderma spp., on Phytophthora capsici in seedlings of Manzano chili from Puebla-Mexico was evaluated. Dual culture technique was used to determine the percentage of inhibition of radial growth (PICR) of the PC-A strain of P. capsici. Analysis of the percentage of germination was also carried out, as well as the incidence of root rot at 20 days after inoculation with the pathogen (dai) in the nursery. T. harzianum strain presented the highest PICR (42.86%) of antagonistic level in vitro and class I in the Bell scale, in addition, it obtained 88% germination in the nursery and 10% mortality at 20 dai, higher than the other native strains of Trichoderma. The bio-controlling effect of strains of Trichoderma spp., offers an effective alternative for root necrosis caused by P. capsici in the cultivation of Manzano chili in Puebla-Mexico.


2017 ◽  
Vol 7 (1) ◽  
pp. 10
Author(s):  
Tatsuya Ohike ◽  
Minori Maeda ◽  
Tetsuya Matsukawa ◽  
Masahiro Okanami ◽  
Shin’ichiro Kajiyama ◽  
...  

Rhizoctonia solani is fungal plant pathogen that infects many different host plants. Recently, biological control agents that are friendly to the environment and ecosystems have attracted much attention as an alternative to the use of chemical fungicide which have been used worldwide to control soil borne pathogens including R. solani. In this study, 53 strains of actinomycetes isolated from environmental soils, and antifungal activities of them were assessed by the dual culture assay. Strain KT showed strong inhibitory activities against 8 phytopathogenic fungi. A great suppressive effect on R. solani growth was observed in the inoculation test of plants using cucumber and chin-geng-sai. In addition, infection of Bipolaris oryzae also could be suppressed in the detached leaf assay using oats. As a result of genetic analysis, it was shown that KT was a species closely related to Streptomyces lavenduligriseus NRRL B-3173T. However, as far as we know, there is no report for biological control agents using S. lavenduligriseus. This study suggests that the strain KT may useful as biological control agents to suppress various crop diseases.


Metabolites ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 37
Author(s):  
Krishni Fernando ◽  
Priyanka Reddy ◽  
Kathryn M. Guthridge ◽  
German C. Spangenberg ◽  
Simone J. Rochfort

Epichloë endophytes, fungal endosymbionts of Pooidae grasses, are commonly utilized in forage and turf industries because they produce beneficial metabolites that enhance resistance against environmental stressors such as insect feeding and disease caused by phytopathogen infection. In pastoral agriculture, phytopathogenic diseases impact both pasture quality and animal production. Recently, bioactive endophyte strains have been reported to secrete compounds that significantly inhibit the growth of phytopathogenic fungi in vitro. A screen of previously described Epichloë-produced antifeedant and toxic alkaloids determined that the antifungal bioactivity observed is not due to the production of these known metabolites, and so there is a need for methods to identify new bioactive metabolites. The process described here is applicable more generally for the identification of antifungals in new endophytes. This study aims to characterize the fungicidal potential of novel, ‘animal friendly’ Epichloë endophyte strains NEA12 and NEA23 that exhibit strong antifungal activity using an in vitro assay. Bioassay-guided fractionation, followed by metabolite analysis, identified 61 metabolites that, either singly or in combination, are responsible for the observed bioactivity. Analysis of the perennial ryegrass-endophyte symbiota confirmed that NEA12 and NEA23 produce the prospective antifungal metabolites in symbiotic association and thus are candidates for compounds that promote disease resistance in planta. The “known unknown” suite of antifungal metabolites identified in this study are potential biomarkers for the selection of strains that enhance pasture and turf production through better disease control.


2021 ◽  
Vol 2021 ◽  
pp. 1-6
Author(s):  
E. K. Wanjiku ◽  
J. W. Waceke ◽  
J. N. Mbaka

Demand for organic avocado fruits, together with stringent food safety standards in the global market, has made producers to use alternative, safe, and consumer-friendly strategies of controlling the postharvest fungal disease of avocado fruits. This study assessed the in vitro efficacy of Trichoderma spp. (T. atroviride, T. virens, T. asperellum, and T. harzianum) against isolated avocado stem-end rot (SER) fungal pathogens (Lasiodiplodia theobromae, Neofusicoccum parvum, Nectria pseudotrichia, and Fusarium solani) using a dual culture technique. The Trichoderma spp. were also evaluated singly on postharvest “Hass” avocado fruits. Spore suspension at 5 × 104 conidial/ml of the Trichoderma spp. was applied on the avocado fruits at three time points, twenty-four hours before the fungal pathogen (preinoculation), at the same time as the fungal pathogen (concurrent inoculation), and 24 hours after the fungal pathogen (postinoculation). In the in vitro study, T. atroviride showed the highest mycelial growth inhibition against N. parvum (48%), N. pseudotrichia (55%), and F. solani (32.95%), while T. harzianum had the highest mycelial growth inhibition against L. theobromae. Trichoderma asperellum was the least effective in inhibiting the mycelial growth of all the pathogens. Similarly, T. virens showed the highest mycelial growth inhibition against N. pseudotrichia at 45% inhibition. On postharvest “Hass” fruits, T. atroviride showed the highest efficacy against N. parvum, N. pseudotrichia, and F. solani in all the applications. Trichoderma virens and T. harzianum were most effective against all the pathogens during postinoculation, while Lasiodiplodia theobromae was best controlled by T. virens, T. harzianum, and T. asperellum during postinoculation. Both T. atroviride and T. harzianum present a potential alternative to synthetic fungicides against postharvest diseases of avocado fruits, and further tests under field conditions to be done to validate their efficacy. The possibility of using Trichoderma spp. in the management of SER on avocado fruits at a commercial level should also be explored.


2021 ◽  
Vol 12 (5) ◽  
pp. 339-347
Author(s):  
S. Ameer Basha ◽  
◽  
V. Ramya ◽  
A. Sajeli Begum ◽  
G. Raghavendra ◽  
...  

A study was made to evaluate the efficacy of Pseudomonas fluorescens strains, fungicides and non-conventional chemicals against Botryotinia ricini, causing grey mold disease in castor, under in vitro conditions. Among the 40 strains isolated from rhizosphere soil samples of different crops across the State of Telangana, India, only eight strains inhibited the growth of B. ricini under dual culture technique, of which strains Pf 21 (90.56%), Pf 23 (88.89%), Pf 34 (86.11%) and Pf 36 (84.17%) were the most effective. Among the seven chemicals (four fungicides and three non-conventional chemicals) tested for their efficacy, carbendazim followed by propiconazole had significant antagonistic effect against B. ricini. Exposure of healthy castor capsules to B. ricini and P. fluorescens for different time periods revealed that strains Pf 34 and Pf 36 were effective in completely inhibiting the growth of B. ricini and hence these two strains have been identified as effective biocontrol agents, on par with carbendazim, which offer scope for sustainable and integrated disease management of grey mold disease in castor.


Agronomy ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1398
Author(s):  
Vishal Gupta ◽  
Krishna Kumar ◽  
Kausar Fatima ◽  
Vijay Kumar Razdan ◽  
Bhagwati Charan Sharma ◽  
...  

Saffron (Crocus sativus L.) is considered as one of the most expensive spices. Fusarium corm rot of saffron, caused by Fusarium oxysporum, is known to cause severe yield losses worldwide. In the present study, efficacy of biocontrol agents (Trichoderma asperellum, Pseudomonas fluorescens, Pseudomonas aeruginosa, Pseudomonas putida, Bacillus stratosphericus, Bacillus pumilus, and Bacillus subtilis) along with a chemical fungicide, carbendazim, was evaluated for managing the corm rot of saffron. Under in vitro conditions, using dual culture and poison food techniques on potato dextrose agar, T. asperellum and carbendazim significantly reduced the mycelial growth of the pathogen F. oxysporum, with the inhibition of 62.76 and 60.27%, respectively, compared with control. Under field conditions, dipping of saffron corms in carbendazim and T. asperellum exhibited maximum reduction of 82.77 and 77.84%, respectively, in the disease incidence, during the first year of experiment. However, during the second year, maximum reduction in the incidence of corm rot (68.63%) was recorded with the T. asperellum. Moreover, the population density of F. oxysporum was also significantly reduced by 60 and 80.19% while using T. asperellum after 75 and 260 days of sowing of saffron corms, compared to its population before planting of corms. In case of growth promotion traits, such as sprouting and flowering, biocontrol treatments reduced the number of days (average) of sprouting and flower emergence after sowing, compared to control.


1988 ◽  
Vol 34 (11) ◽  
pp. 1203-1208 ◽  
Author(s):  
M. F. Van Outryve ◽  
F. Gosselé ◽  
K. Kersters ◽  
J. Swings

The bacterial composition of the chicory rhizosphere (Cichorium intybus L. var. foliosum Hegi) was examined at four different growth stages in the field and also after 1 month storage of the roots. Based on protein fingerprints (SDS – polyacrylamide gel electrophoresis of total cell proteins) 233 isolates were grouped into 117 different groups. Forty percent of the isolates belonged to one of three groups: CH001, CH002, or CH213. Fingerprint type CH001 and CH002 were comprised of fluorescent pseudomonads. Fingerprint type CH213 was identified as Alcaligenes paradoxus. Fingerprint type CH213 strains, normally isolated early in the growing season, were inhibited in vitro by fingerprint type CH001 strains which appeared later in the growing season. Gram-negative isolates were predominant among the remaining fingerprint types: Pseudomonas paucimobilis, Xanthomonas maltophilia, Agrobacterium radiobacter, and Flavobacterium spp. A few Gram-positive isolates were found at the beginning of the growing season, i.e., Bacillus spp. and Streptomyces spp. The production of antifungal compounds was restricted to the 11 isolates among which were fluorescent Pseudomonas and Bacillus spp. Twenty-four fluorescent pseudomonad isolates from the rhizosphere were pathogenic on chicory leaves.


Sign in / Sign up

Export Citation Format

Share Document