Tulbaghia violacea L. I: In vitro antimicrobial properties towards plant pathogens

2006 ◽  
Vol 57 (5) ◽  
pp. 511 ◽  
Author(s):  
Leeto Nteso ◽  
Johan C. Pretorius
Keyword(s):  
Pseudomonas Syringae ◽  
Mycelial Growth ◽  
Xanthomonas Campestris ◽  
Pathogenic Bacteria ◽  
Plant Pathogens ◽  
Antimicrobial Properties ◽  
Diffusion Method ◽  
Mycosphaerella Pinodes ◽  
Soil Extracts

The antimicrobial properties of crude methanol extracts of above- and below-soil parts of Tulbaghia violacea were quantified by means of an agar diffusion method against 6 plant pathogenic bacteria and 7 fungi. The growth of 3 out of the 6 bacteria, Clavibacter michiganensis, Ralstonia solanacearum, and Xanthomonas campestris, was significantly inhibited by crude extracts of both below-soil and aerial parts of T. violacea, whereas the growth of Pseudomonas syringae, Erwinia carotovora, and Agrobacterium tumefaciens was unaffectedl. Compared with the standard fungicide, both the aerial and below-soil extracts of T. violacea significantly inhibited the mycelial growth of 6 of the 7 test fungi, Botrytis cinerea, Sclerotium rolfsii, Rhizoctonia solani, Mycosphaerella pinodes, Botryosphaeria dothidea, and P. ultimum, whereas only the below-soil extract inhibited the mycelial growth of Fusarium oxysporum significantly. The broad-spectrum antifungal activity shown by the crude T. violaceae extracts supplied a rationale for a further investigation into the in vivo activity of the extracts under glasshouse and field conditions.

Effects of Pesticides on the Reduction of Plant and Human Pathogenic Bacteria in Application Water

2013 ◽  
Vol 76 (4) ◽  
pp. 719-722 ◽  
Author(s):  
MICHAEL MAHOVIC ◽  
GANYU GU ◽  
STEVEN RIDEOUT
Keyword(s):  
Pseudomonas Syringae ◽  
Xanthomonas Campestris ◽  
Pathogenic Bacteria ◽  
Plant Pathogens ◽  
Erwinia Carotovora ◽  
Noticeable Effect ◽  
Tomato Production ◽  
Initial Application ◽  
Treated Plant

Overhead spray applications of in-field tomato treatments dissolved in aqueous solutions have specific pest targets (fungal, bacterial, insect, or other). Any organism present in the solution or on treated plant surfaces that is not a specific target of the application is unlikely inactivated and can instead be spread through the phyllosphere. In this laboratory study, commercially labeled pesticides (including Actigard 50WG, Bravo Weather Stik 6F, Cabrio 20EG, Kasumin, Kocide 3000 46WG, Oxidate 27L, Penncozeb 75DF, ProPhyt 54.5L, Stimplex 100L, Firewall, 22.4WP, and Tanos 50DF) in common use in commercial tomato production fields of the Eastern Shore of Virginia were investigated for activity against in vitro bacterial contamination of pesticide application waters. Pesticides of interest were tank mixed individually with one of the plant pathogens Ralstonia solanacearum, Xanthomonas campestris pv. vesicatoria, Pseudomonas syringae pv. tomato, Erwinia carotovora subsp. carotovora, or one of two serovars (Newport and Montevideo) of the human pathogen Salmonella enterica to assess reduction values during the average time between mixing and initial application. Observations suggested that while some treatments had a noticeable effect on population levels, only the oxidizer, peroxyacetic acid, showed significant and consistent levels of suppression against all bacteria investigated, at levels that could have practical implications.

scholarly journals In VitroActivity of Glucosinolates and Their Degradation Products against Brassica-Pathogenic Bacteria and Fungi

2014 ◽  
Vol 81 (1) ◽  
pp. 432-440 ◽  
Author(s):  
T. Sotelo ◽  
M. Lema ◽  
P. Soengas ◽  
M. E. Cartea ◽  
P. Velasco
Keyword(s):  
Pseudomonas Syringae ◽  
Xanthomonas Campestris ◽  
Pathogenic Bacteria ◽  
Degradation Products ◽  
Allyl Isothiocyanate ◽  
Leaf Extracts ◽  
Soil Pathogens ◽  
Content Type ◽  
Positive Effects

ABSTRACTGlucosinolates (GSLs) are secondary metabolites found inBrassicavegetables that confer on them resistance against pests and diseases. Both GSLs and glucosinolate hydrolysis products (GHPs) have shown positive effects in reducing soil pathogens. Information about theirin vitrobiocide effects is scarce, but previous studies have shown sinigrin GSLs and their associated allyl isothiocyanate (AITC) to be soil biocides. The objective of this work was to evaluate the biocide effects of 17 GSLs and GHPs and of leaf methanolic extracts of different GSL-enrichedBrassicacrops on suppressingin vitrogrowth of two bacterial (Xanthomonas campestrispv. campestris andPseudomonas syringaepv. maculicola) and two fungal (AlternariabrassicaeandSclerotiniascletoriorum)Brassicapathogens. GSLs, GHPs, and methanolic leaf extracts inhibited the development of the pathogens tested compared to the control, and the effect was dose dependent. Furthermore, the biocide effects of the different compounds studied were dependent on the species and race of the pathogen. These results indicate that GSLs and their GHPs, as well as extracts of differentBrassicaspecies, have potential to inhibit pathogen growth and offer new opportunities to study the use ofBrassicacrops in biofumigation for the control of multiple diseases.

scholarly journals Study of Antimicrobial, Antioxidant and Cytotoxicity Properties of Selected Plant Extracts for Food Preservative Applications

2021 ◽  
pp. 95-111
Author(s):  
Tania Islam ◽  
Md Nazrul Islam ◽  
Wahidu Zzaman ◽  
Md Morsaline Billah
Keyword(s):  
Pathogenic Bacteria ◽  
Radical Scavenging Activity ◽  
Radical Scavenging ◽  
Antimicrobial Properties ◽  
In Vivo Studies ◽  
Diffusion Method ◽  
Plant Materials ◽  
Food Preservative

An attempt has been made to evaluate antimicrobial, antioxidant and cytotoxicity properties of extracts from onion (Allium cepa L.), garlic (Allium sativum), leaves of guava (Psidium guajava), papaya (Carica papaya), tea (Camellia sinensis), baen (Avicennia alba) and keora (Sonneratia apetala), respectively to apply as natural preservatives for tomatoes. The air-dried plant materials of the respective plant species were subjected to ethanol-methanol extraction, concentrated and stored at 4 °C before use. The extracts were dissolved in 95% ethanol for analysis of antioxidant and antimicrobial properties. Of the extracts tested, tea extracts showed the highest zone of inhibition against several pathogenic bacteria (E. coli 35.0±3.2 mm; P. aeruginosa 29.3±2.6 mm; S. typhi 28.4±2.1 mm and S. pyogenes 27.7±3.7 mm) using the disc diffusion method. In regard to DPPH free radical scavenging assay, keora and guava extracts showed the highest percentage of radical scavenging activity with the values of 89.64± 0.18 and 89.39± 0.88, respectively, which were in agreement with higher total antioxidant capacity (TAC) of these extracts obtained by the phosphomolybdenum method. Brine shrimp lethality bioassay for cytotoxicity assessment showed LC50 of 132.54 ± 18.99 µg/mL for the leaf extract of keora which was found to be most toxic among all studied extracts. The initial results indicated that the extracts could be used for food preservative applications based on the antimicrobial, antioxidant and cytotoxicity properties of the tested extracts. However, efficacy, stability and safety issues need to be addressed with both in vitro and in vivo studies.

scholarly journals Apis andreniformis associated Actinomycetes show antimicrobial activity against black rot pathogen (Xanthomonas campestris pv. campestris)

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e12097
Author(s):  
Yaowanoot Promnuan ◽  
Saran Promsai ◽  
Wasu Pathom-aree ◽  
Sujinan Meelai
Keyword(s):  
Antimicrobial Activity ◽  
16S Rrna ◽  
16S Rrna Gene ◽  
Honey Bee ◽  
Pseudomonas Syringae ◽  
Xanthomonas Campestris ◽  
Pathogenic Bacteria ◽  
Rrna Gene ◽  
Apis Andreniformis

This study aimed to investigate cultivable actinomycetes associated with rare honey bee species in Thailand and their antagonistic activity against plant pathogenic bacteria. Actinomycetes were selectively isolated from the black dwarf honey bee (Apis andreniformis). A total of 64 actinomycete isolates were obtained with Streptomyces as the predominant genus (84.4%) followed by Micromonospora (7.8%), Nonomuraea (4.7%) and Actinomadura (3.1%). All isolates were screened for antimicrobial activity against Xanthomonas campestris pv. campestris, Pectobacterium carotovorum and Pseudomonas syringae pv. sesame. Three isolates inhibited the growth of X. campestris pv. campestris during in vitro screening. The crude extracts of two isolates (ASC3-2 and ASC5-7P) had a minimum inhibitory concentration (MIC) of 128 mg L−1against X. campestris pv. campestris. For isolate ACZ2-27, its crude extract showed stronger inhibitory effect with a lower MIC value of 64 mg L−1 against X. campestris pv. campestris. These three active isolates were identified as members of the genus Streptomyces based on their 16S rRNA gene sequences. Phylogenetic analysis based on the maximum likelihood algorithm showed that isolate ACZ2-27, ASC3-2 and ASC5-7P were closely related to Streptomyces misionensis NBRC 13063T (99.71%), Streptomyces cacaoi subsp. cacaoi NBRC 12748T (100%) and Streptomyces puniceus NBRC 12811T (100%), respectively. In addition, representative isolates from non-Streptomyces groups were identified by 16S rRNA gene sequence analysis. High similarities were found with members of the genera Actinomadura, Micromonospora and Nonomuraea. Our study provides evidence of actinomycetes associated with the black dwarf honey bee including members of rare genera. Antimicrobial potential of these insect associated Streptomyces was also demonstrated especially the antibacterial activity against phytopathogenic bacteria.

scholarly journals Antimicrobial Activity of two Semisynthetic Triterpene Derivatives from Euphorbia Officinarum Latex Against Fungal and Bacterial Phytopathogens

2017 ◽  
Vol 12 (3) ◽  
pp. 1934578X1701200 ◽  
Author(s):  
Amal Smaili ◽  
Noureddine Mazoir ◽  
Lalla Aicha Rifai ◽  
Tayeb Koussa ◽  
Kacem Makroum ◽  
...  
Keyword(s):  
Pseudomonas Syringae ◽  
Mycelial Growth ◽  
Erwinia Amylovora ◽  
Antimicrobial Effect ◽  
Penicillium Expansum ◽  
Diffusion Method ◽  
Disc Diffusion ◽  
Disc Diffusion Method ◽  
Verticillium Dahlia

This study evaluated the in vitro antimicrobial effect of 3β-acetoxy-norlup-20-one (1) and 3-chloro-4α,14α-dimethyl-5α-cholest-8-ene (2), triterpene derivatives from Euphorbia officinarum latex against fungal and bacterial phytopathogens. Results showed that although mycelial growth of several strains of Verticillium dahlia, and Fusarium oxysporum fsp. melonis and Penicillium expansum was affected only moderately, the two compounds were able to reduce highly conidia formation and germination, suggesting that they act as fungistatic compounds. Their antibacterial activity was tested against Pseudomonas syringae pv. syringae (Pss), P. syringae pv. tabacci (Pst), Erwinia amylovora (Ea) and Agrobacterium tumefaciens (At) using disc diffusion method. Results showed that compound 2 was more effective in inhibiting the growth of Pss, Pst and Ea than compound 1.

scholarly journals Antimicrobial Properties of Catha edulis (Miraa) against Select Bacterial and Fungal Pathogens, an in-vitro Experimental Study

2021 ◽  
Author(s):  
Dennis Kithinji ◽  
Susan Maina ◽  
Stanley Ndwigah ◽  
Hannington Mugo ◽  
Julius Oyugi
Keyword(s):  
Clinical Isolate ◽  
Antimicrobial Susceptibility ◽  
Pathogenic Bacteria ◽  
Antimicrobial Properties ◽  
Diffusion Method ◽  
Therapeutic Effects ◽  
Catha Edulis ◽  
Methanolic Extracts ◽  
Zones Of Inhibition

Abstract Background: The increasing risk of emergence of antimicrobial resistance can be addressed by discovering alternatives to antibiotics such as plant-based botanicals. In the present study, the antimicrobial properties of aqueous and methanolic extracts of Catha edulis (Miraa) were tested on select pathogenic bacteria and fungi.Methods: Antimicrobial susceptibility tests were conducted in-vitro using the agar well diffusion method. The aqueous and methanolic extracts were dissolved in water to form 1000 mg/ml, 100 mg/ml, and 10 mg/ml doses. The antimicrobial susceptibility testing was done in appropriate culture media and conditions. Diameters of zones of inhibition were obtained, their means calculated, and t-tests applied to test significance of differences between means. Results: The aqueous Miraa extracts at all three concentrations significantly inhibited the growth of all bacterial pathogens except E. coli but did not have an effect on C. albicans. The largest zones of inhibition for the aqueous extracts were observed at 1000 mg/ml against S. pneumoniae (28.41 mm), S. pyogenes ATCC 19615 (24.27 mm), MRSA (21.86 mm), and S. aureus clinical isolate (20.38 mm). Similarly, the largest zones of inhibition for the methanolic extracts were at 1000 mg/ml against S. pneumoniae clinical isolate (26.75 mm), S. pyogenes ATCC 19615 (25.38 mm), S. aureus clinical isolate (19.71 mm), and MRSA ATCC 43300 (16.38 mm).Conclusions: Crude Miraa extracts have significant antimicrobial effects in vitro against the tested microorganisms. Further studies on Miraa extracts to identify the active phytochemicals and investigate their therapeutic effects in-vivo in animal models are indicated.

Antibiotic Resistance in Plant-Pathogenic Bacteria

2018 ◽  
Vol 56 (1) ◽  
pp. 161-180 ◽  
Author(s):  
George W. Sundin ◽  
Nian Wang
Keyword(s):  
Antibiotic Resistance ◽  
Pseudomonas Syringae ◽  
Xanthomonas Campestris ◽  
Pathogenic Bacteria ◽  
Plant Pathogens ◽  
Management Strategies ◽  
Resistance Management ◽  
Plant Diseases ◽  
Plant Pathogenic Bacteria ◽  
Continued Use

Antibiotics have been used for the management of relatively few bacterial plant diseases and are largely restricted to high-value fruit crops because of the expense involved. Antibiotic resistance in plant-pathogenic bacteria has become a problem in pathosystems where these antibiotics have been used for many years. Where the genetic basis for resistance has been examined, antibiotic resistance in plant pathogens has most often evolved through the acquisition of a resistance determinant via horizontal gene transfer. For example, the strAB streptomycin-resistance genes occur in Erwinia amylovora, Pseudomonas syringae, and Xanthomonas campestris, and these genes have presumably been acquired from nonpathogenic epiphytic bacteria colocated on plant hosts under antibiotic selection. We currently lack knowledge of the effect of the microbiome of commensal organisms on the potential of plant pathogens to evolve antibiotic resistance. Such knowledge is critical to the development of robust resistance management strategies to ensure the safe and effective continued use of antibiotics in the management of critically important diseases.

scholarly journals Phytochemical screening and antimicrobial assay of some Nepalese medicinal plants

1970 ◽  
Vol 9 (9) ◽  
pp. 90-92 ◽  
Author(s):  
Bijaya Laxmi Maharjan ◽  
Smritri Mainali ◽  
Bikash Baral
Keyword(s):  
Medicinal Plants ◽  
Plant Extracts ◽  
Pathogenic Bacteria ◽  
Antimicrobial Properties ◽  
Phytopathogenic Fungi ◽  
Diffusion Method ◽  
Phytochemical Analysis ◽  
Acinetobacter Species ◽  
Antimicrobial Assay

Medicinal plants constitute several bioactive compounds that are antimicrobial. Due to the extensive need of the new antimicrobial compounds of plant origin the study was conducted. The present paper deals with the qualitative phytochemical analysis and antimicrobial assay of methanolic extracts of four medicinal plants namely Butea monosperma (seed), Cissampelos pareira (root), Myrica esculenta (bark) and Selinum tenuifolium (root). The standard phytochemical test of the extracts revealed the presence of polyphenols, glycosides and coumarins in all the plant extracts. For the in-vitro antimicrobial assay, agar well diffusion method was employed against human pathogenic bacteria (11) and phytopathogenic fungi (5). The extracts of C. pareira, M. esculenta were effective against all the tested bacteria and fungi which indicated their broad spectrum antimicrobial potential. The extract of B. monosperma was effective against B. subtilis, S. typhi, Acinetobacter species, F. oxysporum, F. moniliformie, E. turticum and S. roulfsii. But the extract of S. tenuifolium was ineffective against all the tested bacteria but was effective against all the fungal strains revealing it to have more antifungal potential. The antimicrobial properties of these plant extracts may be due to the presence of various secondary metabolites. The results provided evidence that the studied plants might indeed be employed in the management of microbial infections. Key words: Plant extract; Phytochemicals; Antibacterial; Antifungal DOI: http://dx.doi.org/10.3126/sw.v9i9.5526 SW 2011; 9(9): 90-92

scholarly journals Evaluation of Proposed Amended Names of Several Pseudomonads and Xanthomonads and Recommendations

2000 ◽  
Vol 90 (3) ◽  
pp. 208-213 ◽  
Author(s):  
N. W. Schaad ◽  
A. K. Vidaver ◽  
G. H. Lacy ◽  
K. Rudolph ◽  
J. B. Jones
Keyword(s):  
Pseudomonas Syringae ◽  
Xanthomonas Campestris ◽  
Pathogenic Bacteria ◽  
Plant Pathogens ◽  
Genetic Data ◽  
Published Data ◽  
Type B ◽  
American Phytopathological Society ◽  
Code Of Nomenclature ◽  
International Code Of Nomenclature

In 1980, over 90% of all plant-pathogenic pseudomonads and xanthomonads were lumped into Pseudomonas syringae and Xanthomonas campestris, respectively, as pathovars. The term “pathovar” was created to preserve the name of plant pathogens, but has no official standing in nomenclature. Proposals to elevate and rename several pathovars of the genera Pseudomonas and Xanthomonas to the rank of species has caused great confusion in the literature. We believe the following changes have merit and expect to adopt them for publication in a future American Phytopathological Society Laboratory Guide for Identification of Plant Pathogenic Bacteria. Upon review of published data and the Rules of The International Code of Nomenclature of Bacteria, we make the following recommendations. We reject the proposal to change the name of P. syringae pvs. phaseolicola and glycinea to P. savastanoi pvs. phaseolicola and glycinea, respectively, because both pathogens are easily differentiated phenotypically from pv. savastanoi and convincing genetic data to support such a change are lacking. We accept the elevation of P. syringae pv. savastanoi to the rank of species. We accept the reinstatement of X. oryzae to the rank of species with the inclusion of X. oryzicola as a pathovar of X. oryzae and we accept the species X. populi. We agree with the elevation of the pvs. cassavae, cucurbitae, hyacinthi, pisi, and translucens to the rank of species but not pvs. melonis, theicola, and vesicatoria type B. We recommend that all type A X. vesicatoria be retained as X. campestris pv. vesicatoria and all type B X. vesicatoria be named X. exitiosa. We reject the newly proposed epithets arboricola, bromi, codiaei (poinsettiicola type B), hortorum, sacchari, and vasicola and the transfer of many pathovars of X. campestris to X. axonopodis. The proposed pathovars of X. axonopodis should be retained as pathovars of X. campestris.

scholarly journals Inhibition of Fungal and Bacterial Plant Pathogens In Vitro and In Planta with Ultrashort Cationic Lipopeptides

2007 ◽  
Vol 73 (20) ◽  
pp. 6629-6636 ◽  
Author(s):  
Arik Makovitzki ◽  
Ada Viterbo ◽  
Yariv Brotman ◽  
Ilan Chet ◽  
Yechiel Shai
Keyword(s):  
Pseudomonas Syringae ◽  
Pathogenic Bacteria ◽  
Plant Pathogens ◽  
Antimicrobial Agents ◽  
Plant Protection ◽  
Microscopic Analysis ◽  
Plant Diseases ◽  
In Planta ◽  
Global Food Security

ABSTRACT Plant diseases constitute an emerging threat to global food security. Many of the currently available antimicrobial agents for agriculture are highly toxic and nonbiodegradable and cause extended environmental pollution. Moreover, an increasing number of phytopathogens develop resistance to them. Recently, we have reported on a new family of ultrashort antimicrobial lipopeptides which are composed of only four amino acids linked to fatty acids (A. Makovitzki, D. Avrahami, and Y. Shai, Proc. Natl. Acad. Sci. USA 103:15997-16002, 2006). Here, we investigated the activities in vitro and in planta and the modes of action of these short lipopeptides against plant-pathogenic bacteria and fungi. They act rapidly, at low micromolar concentrations, on the membranes of the microorganisms via a lytic mechanism. In vitro microscopic analysis revealed wide-scale damage to the microorganism's membrane, in addition to inhibition of pathogen growth. In planta potent antifungal activity was demonstrated on cucumber fruits and leaves infected with the pathogen Botrytis cinerea as well as on corn leaves infected with Cochliobolus heterostrophus. Similarly, treatment with the lipopeptides of Arabidopsis leaves infected with the bacterial leaf pathogen Pseudomonas syringae efficiently and rapidly reduced the number of bacteria. Importantly, in contrast to what occurred with many native lipopeptides, no toxicity was observed on the plant tissues. These data suggest that the ultrashort lipopeptides could serve as native-like antimicrobial agents economically feasible for use in plant protection.

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