scholarly journals Antagonistic potential of Bacillus spp. isolates against bacterial pathogens of tomato and fungal pathogen of pepper

2018 ◽  
Vol 33 (1) ◽  
pp. 9-18 ◽  
Author(s):  
Svetlana Milijasevic-Marcic ◽  
Vesna Todorovic ◽  
Olja Stanojevic ◽  
Tanja Beric ◽  
Slavisa Stankovic ◽  
...  

In vitro antagonistic potential of eleven isolates of Bacillus spp. against two phytopathogenic bacteria and one fungus was tested in order to identify potential biocontrol agents in vegetable crops. The Bacillus spp. isolates demonstrated different levels of antagonistic effect against the tested pathogenic microorganisms. Data in the study proved Xanthomonas vesicatoria to be more sensitive to Bacillus spp. strains than Clavibacter michiganensis subsp. michiganensis. Ten B. subtilis strains induced growth inhibition of X. vesicatoria, while a strain of B. pumilus did not affect the growth of that bacterium. The largest inhibition zones against X. vesicatoria were induced by strains B-319, B-325 and B-358. The pathogenic strain C. michiganensis subsp. michiganensis was most inhibited by two B. subtilis strains (B-338 and B-348) with mean inhibition zone diameters of up to 20 mm. B. subtilis strain B-319 which was the best in inhibiting X. vesicatoria, showed the lowest inhibitory effect on C. michiganensis subsp. michiganensis. The largest growth inhibition percentage of Verticillium sp. (PGI approximately 70%) was induced by B. subtilis strains B-310 and B-322. The other B. subtilis strains showed PGI values ranging from 45% to 68%, while B. pumilus strain B-335 had the least antagonistic potential (PGI =34.43%) against the pathogen. This study identified at least one suitable biocontrol candidate, B. subtilis strain B-358, as effective in vitro against all three vegetable pathogens.

2019 ◽  
Vol 34 (2) ◽  
pp. 97-102
Author(s):  
Ivana Potocnik ◽  
Svetlana Milijasevic-Marcic ◽  
Olja Stanojevic ◽  
Tanja Beric ◽  
Slavisa Stankovic ◽  
...  

The study aimed to isolate potential biocontrol agents from mushroom substrate that could serve as an alternative to toxic chemicals commonly used for disease control in mushroom production. The antagonistic potential of ten native Bacillus subtilis strains against the causal agents of green mould disease of oyster mushroom, Trichoderma pleuroti and Trichoderma pleuroticola, was evaluated. The antagonistic potential of Bacillus spp. strains was quantified in vitro based on dual cultivation with the pathogen. Growth inhibition of T. pleuroti ranged from 54.44% to 62.22% and no significant differences in antagonistic activity were found between the tested B. subtilis strains. Inhibition of T. pleuroticola was slightly higher, ranging from 55.56% to 69.62% and B. subtilis strain B-358 induced the highest growth inhibition. This research confirmed mushroom substrate to be a good source of antagonistic microorganisms with potentials for use in biological control of green mould in oyster mushroom production.


Blood ◽  
1990 ◽  
Vol 76 (6) ◽  
pp. 1250-1255 ◽  
Author(s):  
S Whitehead ◽  
TE Peto

Abstract Deferoxamine (DF) has antimalarial activity that can be demonstrated in vitro and in vivo. This study is designed to examine the speed of onset and stage dependency of growth inhibition by DF and to determine whether its antimalarial activity is cytostatic or cytocidal. Growth inhibition was assessed by suppression of hypoxanthine incorporation and differences in morphologic appearance between treated and control parasites. Using synchronized in vitro cultures of Plasmodium falciparum, growth inhibition by DF was detected within a single parasite cycle. Ring and nonpigmented trophozoite stages were sensitive to the inhibitory effect of DF but cytostatic antimalarial activity was suggested by evidence of parasite recovery in later cycles. However, profound growth inhibition, with no evidence of subsequent recovery, occurred when pigmented trophozoites and early schizonts were exposed to DF. At this stage in parasite development, the activity of DF was cytocidal and furthermore, the critical period of exposure may be as short as 6 hours. These observations suggest that iron chelators may have a role in the treatment of clinical malaria.


Blood ◽  
1999 ◽  
Vol 94 (10) ◽  
pp. 3551-3558 ◽  
Author(s):  
Maged S. Mahmoud ◽  
Ryuichi Fujii ◽  
Hideaki Ishikawa ◽  
Michio M. Kawano

In multiple myeloma (MM), the cell surface protein, CD19, is specifically lost while it continues to be expressed on normal plasma cells. To examine the biological significance of loss of CD19 in human myeloma, we have generated CD19 transfectants of a tumorigenic human myeloma cell line (KMS-5). The CD19 transfectants showed slower growth rate in vitro than that of control transfectants. They also showed a lower capability for colony formation as evaluated by anchorage-independent growth in soft agar assay. The CD19 transfectants also had reduced tumorigenicity in vivo when subcutaneously implanted into severe combined immunodeficiency (SCID)-human interleukin-6 (hIL-6) transgenic mice. The growth-inhibitory effect was CD19-specific and probably due to CD19 signaling because this effect was not observed in cells transfected with a truncated form of CD19 that lacks the cytoplasmic signaling domain. The in vitro growth-inhibitory effect was confirmed in a nontumorigenic human myeloma cell line (U-266). However, introduction of the CD19 gene into a human erythroleukemia cell line (K-562) also induced growth inhibition, suggesting that this effect is CD19-specific, but not restricted to myeloma cells. These data suggest that the specific and generalized loss of CD19 in human myeloma cells could be an important factor contributing to the proliferation of the malignant plasma cell clones in this disease.


2004 ◽  
Vol 4 (2) ◽  
pp. 83-88
Author(s):  
Efri Efri ◽  
Titik Nur Aeny

Effectivity of  Morinda citrifolia extract on in-vitro growth inhibition of Ralstonia sp.  Morinda citrifolia has been known as one of plants having numerous medicinal properties.  Extract of the fruits shows antibacterial activity against several bacteria including Pseudomonas aeruginosa.  The purpose of this study was to observe inhibitor effect of  M. citrifolia fruit extract, and to investigate the effect of different concentrations of  M. citrifolia fruit extract on in-vitro growth of  Ralstonia (Pseudomonas) sp., the causal agent of banana bacterial wilt disease in Lampung.  Inhibition effect of  M. citrifolia was determined by the presence of inhibition zone, and concentration effect was determined by the diameter of  inhibition zone . The study consisted of two experiments.  The treatments of the first experiment were three different kinds of fruit extract, namely the whole fruit, the seeds, and the fleshy parts, and the second one consisted of six different levels of extract concentrations.  The results showed that the whole fruit extract was the most effective as an in-vitro growth inhibitor, and the higher the concentration level the higher the growth inhibition zone formed.


2016 ◽  
Vol 12 (3) ◽  
pp. 96
Author(s):  
Susiana Purwantisari ◽  
Achmadi Priyatmojo ◽  
Retno Peni Sancayaningsih ◽  
Rina Sri Kasiamdari

Late blight disease on potato caused by a plant pathogenic fungus (Phytophthora infestans)  is the most important disease in Indonesia.  The use of antagonist fungi Trichoderma is an environmentally friendly technology to control the potato disease. The purpose of this study was to determine the ability of Trichoderma spp. to control P. infestans in vitro. Trichoderma spp. have been isolated from suppressive soil at central potato areas in district of Lembang, Bandung, West Java Province. To determine the inhibition ability of Trichoderma spp against P. infestans, a dual culture method was performed.  Variable observed was inhibition zone of Trichoderma spp. against P. infestans. The results showed that 9 isolates of Trichoderma were successfuly isolated from suppressive soil, i.e. T. viride (2 isolates), T. atroviride (1 isolate), T. harzianum (1 isolate) and T. aureoviride (5 isolates). All the Trichoderma isolates revealed growth inhibition abality against P. infestans and. The highest growth inhibition (68.6%) was observed by T. viride isolate ( Ti 9).


2021 ◽  
Vol 17 (2) ◽  
pp. 146-148
Author(s):  
Ashish Shrivastava

Studies were conducted to test the effect of oil cakes and organic manures on the growth of wilt pathogen under in vitro conditions. The extract of different oil cakes and organic manures were tested against F. oxysporum f. sp. ciceri by poisoned food techniques in vitro. Least growth of pathogen was recorded in extracts of Neem cake showing excellent inhibitory effect of 70.87 percent reduction over control. Next best in order of mustard cake (65.36 %), linseed (62.99%), groundnut (53.36%) and least by other. Among the organic manures tested, vermi compost and FYM showed maximum growth inhibition of 35.95 and 30.62 percent over control, respectively.


Author(s):  
Meral Yılmaz ◽  
Ömür Baysal ◽  
Ragıp Soner Silme

The study aimed to evaluate the efficacy of a seed film coating with Origanum vulgare Linnaeus essential oil (EO) against Clavibacter michiganensis subsp. michiganensis (Cmm) on tomatoes. Tomato seeds (cv. Rio Grande) coated with different doses of EO derived from O. vulgare were inoculated with Cmm (1.8 × 10<sup>8</sup> CFU/mL). O. vulgare's EO showed a remarkable inhibition effect on the Cmm growth. The EO effect against Cmm was determined based on the parameters, such as the inhibition zone and bacterial population in a seed. The GC-MS analysis of EO showed that carvacrol is the major component (at 74.05%), which may inhibit the bacterial growth. Later, we have expanded our studies to determine the inhibitory effect of the EO's mode of action on the pathogenic bacteria with a molecular docking analysis based on the molecular protein-ligand interaction. The results showed that carvacrol has a strong interaction with the bacterial expansin protein (PDB 4JJO) of Cmm and the qPCR analyses confirmed the effect of the O. vulgare treatment against Cmm. This original approach has the prominent potential to prevent seed transmission of Cmm for seed quality in the world, suggesting a method for paving the way for Cmm disease management.


2021 ◽  
Vol 21 (no 1) ◽  
Author(s):  
K. Vignesh ◽  
K. Rajamohan ◽  
P. Balabaskar ◽  
R. Anandan

Tomato (Solanum lycopersicum L.) is one of the most important, commercial and widely grown vegetable crop in the world. Tomato plays a critical role in nutritional food requirements, income and employment opportunities for the people. However, its production is threatened by the Fusarium wilt caused by Fusarium oxysporum f.sp. lycopersici and production losses between 30%to40%. In the present investigation an attempt has been made to study the in vitro efficacy of Pseudomonas fluorescens against Fusarium oxysporum f.sp. lycopersici. The antagonistic effect of Pseudomonas fluorescens were observed by the Dual culture technique and Agarwell method under the in vitro conditions.Among the ten isolates of Pseudomonas fluorescens, isolate Pf5 found to show the maximum percent inhibition over control (58.75%) and least mycelial growth (37.12mm) in dual culture technique against Fusarium oxysporum f.sp. lycopersici. In Agar well method isolate Pf5 proved out the maximum inhibition zone (17.47mm)against Fusarium oxysporumf.sp. lycopersici and percent inhibition over control (80.97%) at 30% concentration level.


2020 ◽  
Vol 8 (11) ◽  
pp. 1683
Author(s):  
Gilles Stouvenakers ◽  
Sébastien Massart ◽  
Pierre Depireux ◽  
M. Haïssam Jijakli

Aquaponic systems are an integrated way to produce fish and plants together with mutual benefits. Fish provide nutrients to plants on the one side, and plant nutrients uptake allow water reuse for fish on the other side. In this kind of system, the use of phytosanitary treatments to control plant pathogens is sensitive because of the risk of toxicity for fish present in the same water loop, especially coupled aquaponics. Among plant pathogens, Pythium aphanidermatum is a most problematic microorganism due to the Oomycete’s capacity to produce mobile form of dispersion (zoospores) in the recirculated water. Therefore, this study aimed at elucidating the potential antagonistic capacity of aquaponic water against P. aphanidermatum diseases. It was shown that aquaponic water presented an inhibitory effect on P. aphanidermatum mycelial growth in in vitro conditions. The same result was observed when lettuce plants growing in aquaponic water were inoculated by the same plant pathogen. Aquaponic lettuce was then compared to lettuce grown in hydroponic water or complemented aquaponic water (aquaponic water plus mineral nutrients). The disease was suppressed in the presence of aquaponic water, contrary to lettuce grown in hydroponic water or complemented aquaponic water. Root microbiota were analyzed by 16S rDNA and ITS Illumina sequencing to determine the cause of this aquaponic suppressive action. It was determined that the diversity and the composition of the root microbiota were significantly correlated with the suppressive effect of aquaponic water. Several taxa identified by metabarcoding were suspected to be involved in this effect. Moreover, few of these microorganisms, at the genus level, are known to have an antagonistic effect against P. aphanidermatum. These innovative results indicate that aquaponic water could be an interesting and novel source of antagonistic agents adapted to control P. aphanidermatum diseases in soilless culture.


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