scholarly journals Azadirachta indica Reduces Black Sigatoka in East African Highland Banana by Direct Antimicrobial Effects against Mycosphaerella fijiensis without Inducing Resistance

2017 ◽  
Vol 9 (4) ◽  
pp. 61 ◽  
Author(s):  
Alfred Kumakech ◽  
Hans. J. L. Jørgensen ◽  
David B. Collinge ◽  
Richard Edema ◽  
Patrick Okori

Black Sigatoka is a major disease of East African highland cooking bananas in Uganda. Aqueous extracts of Azadirachta indica, Cinnamomum zeylanicum and Capsicum annuum have shown the potential to reduce Black Sigatoka in banana plantlets. The mechanisms by which plant extracts confer protection against plant pathogens has previously been reported to involve activation of defence and direct antimicrobial activity. In the current study, both antimicrobial activities of selected extracts were studied as well as expression of three defence-related genes using quantitative real-time PCR. Gene expression was compared in susceptible (cv. Musakala, genomic group AAA-EA) and resistant (cv. Kayinja, genomic group ABB) banana cultivars. Additionally, Musakala treated with A indica extract at 1 day before inoculation (DBI) was tested for induction of defence-related genes at 0, 10 and 20 days after inoculation (DAI). Pathogenesis-related genes (PR-1 and PR-3) and non-expressor of PR-genes (NPR1B) were up-regulated in the resistant cultivar. The genes analysed responded at late time points to M. fijiensis inoculation in both extract-treated and control plants in the susceptible cv. Musakala. On the other hand, A. indica and C. annuum completely inhibited mycelial growth of M. fijiensis at 30% (w/v). These findings suggest that the effect of plant extracts on Black Sigatoka is strongly associated with the direct antimicrobial effects.

2020 ◽  
Vol 9 (1) ◽  
pp. 43-49
Author(s):  
Timothy I. Olabiyi ◽  
Samuel O. Akinrinola ◽  
Olajumoke E. Ayanda

Three different plant extracts (Khaya ivorensis, Azadirachta indica and Daniella oleifera) and two Trichoderma species (T. harzianum and T. atroviride), singly and in combination, were assessed on nematode population changes and also in the control of plant parasitic nematodes on tomato under field condition during 2018 and 2019 planting seasons. During each trial, plant parasitic nematodes encountered in the field were Meloidogyne, Pratylenchus, Xiphinema and Helicotylenchus species. The experiment was a randomized complete block design with 4 x 3 factorial scheme and five replications. Factor A being plant extracts (Khaya ivorensis, Azadirachta indica, Daniella oleifera) and control, and factor B being bio-control agents (Trichoderma harzianum, T. atroviride) and control, resulting in 12 treatments. Significant reductions were observed on the population of the plant parasitic nematodes at all treatment levels with neem plant extract, in combination with either T. harzianum or T. atroviride resulted in the greatest significant decrease. Applications of different plant extracts and Trichoderma species, singly and in combination, enhanced the growth and yield of tomato infected with parasitic nematodes.


Antibiotics ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 289
Author(s):  
Qiuping Wang ◽  
Cheng Zhang ◽  
Youhua Long ◽  
Xiaomao Wu ◽  
Yue Su ◽  
...  

Tetramycin, a novel polyene agriculture antibiotic, has excellent antimicrobial activity against many plant pathogens. In this study, the antimicrobial activities of tetramycin and conventional antibiotics on eight common pathogens and their field control efficacies against four serious diseases in kiwifruit were investigated. The results show that 0.3% tetramycin aqueous solutions (AS) exhibited the superior antibacterial and antifungal activity against Pseudomonas syringae pv. actinidiae, Pseudomonas fulva, Agrobacterium tumefaciens, Botryosphaeriadothidea, Phomopsis sp., Alternaria tenuissima, Armillariella mellea and Phytophthora cactorum of kiwifruit pathogens with EC50 values of 1.21, 1.24, 0.72, 0.14, 0.09, 0.16, 0.06 and 0.17 mg kg−1, respectively. These EC50 values of tetramycin were much higher than those of conventional kasugamycin, zhongshengmycin or polyoxin. Meanwhile, 0.3% tetramycin AS possessed the good field control efficacies for canker, soft rot, blossom blight and brown spot disease of kiwifruit with 74.45, 83.55, 84.74 and 89.62%. Moreover, 0.3% tetramycin AS application notably increased fruit resistance substances contents, activated fruit superoxide dismutase and polyphenoloxidase activities, as well as remarkably enhanced fruit growth, improved fruit quality and storability. This study highlights that tetramycin can be used as a preferred alternative to conventional antibiotics in kiwifruit production.


Nanomaterials ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 1146 ◽  
Author(s):  
Md. Arshad Ali ◽  
Temoor Ahmed ◽  
Wenge Wu ◽  
Afsana Hossain ◽  
Rahila Hafeez ◽  
...  

A large number of metallic nanoparticles have been successfully synthesized by using different plant extracts and microbes including bacteria, fungi viruses and microalgae. Some of these metallic nanoparticles showed strong antimicrobial activities against phytopathogens. Here, we summarized these green-synthesized nanoparticles from plants and microbes and their applications in the control of plant pathogens. We also discussed the potential deleterious effects of the metallic nanoparticles on plants and beneficial microbial communities associated with plants. Overall, this review calls for attention regarding the use of green-synthesized metallic nanoparticles in controlling plant diseases and clarification of the risks to plants, plant-associated microbial communities, and environments before using them in agriculture.


Antibiotics ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 552
Author(s):  
Suraj Arora ◽  
Shahabe Saquib ◽  
Youssef Algarni ◽  
Mohammed Kader ◽  
Irfan Ahmad ◽  
...  

Background and objectives: This study aimed to evaluate the synergistic antimicrobial activity of extracts obtained from Salvadora persica (Miswak), Commiphora molmol (myrrh) and Azadirachta indica (neem) in combination with commercially available antimicrobial agents: penicillin, tetracycline, ofloxacin and fluconazole on endodontic pathogens such as Enterococcus faecalis, Streptococcus mitis, Actinomyces naeslundii and Candida albicans. Materials and Methods: Microbiological samples from the root canals of the teeth undergoing retreatment were taken using sterile paper points kept at full length in the canal for 30 seconds. The disc diffusion method was used to check the susceptibility of microbes to the plant extracts and antimicrobials by measuring the diameter of the inhibition zones. Against the microbes, minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC)/minimum fungicidal concentration (MFC) of the plant extracts were assessed. The fractional inhibitory concentration index (FICI) was used to estimate the synergistic effect of plant extracts combined with antimicrobials against the resistant endodontic microbes. Results: The findings clearly indicate the effectiveness of all the three plant extracts, Commiphora molmol, Azadirachta indica, Salvadora persica, against all the experimental pathogenic microorganisms except for the ineffectiveness of Azadirachta indica, Salvadora persica against Candida albicans. Maximum antimicrobial activity was displayed by Azadirachta indica against Enterococcus faecalis (MIC = 0.09 ± 1.2 mg/mL, MBC = 0.78 ± 1.25 mg/mL) and the minimum antimicrobial activity was displayed by Commiphora molmol against Actinomyces naeslundii (MIC = 12.5 ± 3.25 mg/mL, MBC = 100 ± 3.75 mg/mL). The best synergy was displayed by Commiphora molmol with fluconazole against Candida albicans (FICI = 0.45). Conclusions: The current study delineates the variable antimicrobial activity of plant extracts against the experimental endodontic pathogenic microorganisms. Plant extracts in conjunction with various antimicrobials can be valuable aids in combating relatively resistant endodontic microorganisms that have been the cause of worry in recent years, leading to failure even in treatment procedures following all required protocols.


RSC Advances ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 2804-2837
Author(s):  
Chhangte Vanlalveni ◽  
Samuel Lallianrawna ◽  
Ayushi Biswas ◽  
Manickam Selvaraj ◽  
Bishwajit Changmai ◽  
...  

Herein, we have reviewed new findings in the research domain of the green synthesis of silver nanoparticles using different plant extracts and their potential applications as antimicrobial agents covering the literature since 2015.


2012 ◽  
Vol 1 (2) ◽  
pp. 229 ◽  
Author(s):  
P. K. Baidoo ◽  
J. I. Adam

<p>The effects of ethanolic extract of neem, <em>Azadirachta indica</em> (Meliaceae), seeds and petroleum ether extract of <em>Lantana camara</em> leaves (Verbenaceae) on the populations of three cabbage pests, <em>Plutella xylostella</em>, <em>Brevicoryne brassicae</em> and <em>Hellula undalis</em> were studied. The study was conducted between January and April 2008. Extracts of the two plants were sprayed on cabbage plants to control these pests. A standard synthetic chemical insecticide (Mektin) was used as reference product. The experiment was conducted in a randomized complete block design and each treatment was replicated four times. The effects of plant extracts on the population dynamics of the pests’ species, the level of infestation and yield were assessed. Significantly more of the pests infested the control plants than the treated plants (<em>P</em>&lt; 0.01). The mean weight of cabbage heads on the sprayed plots was significantly heavier than that of the control unsprayed plots. The use of <em>A. indica</em> seeds and <em>L. camara</em> leaf extracts increased yield by 37.05% and 25.80%, respectively. Spraying the cabbage plants with the plant extracts significantly reduced the numbers of pests compared with the control plants. The use of these plant extracts can be incorporated into an overall control programme of these pests.</p>


2015 ◽  
Vol 10 (3) ◽  
pp. 529 ◽  
Author(s):  
Huawei Zhang ◽  
Chuanfeng Ruan ◽  
Xuelian Bai

<p>Ten fungal strains isolated from <em>Edgeworthia chrysantha</em>, one of traditional medicinal plants in China, were evaluated their antimicrobial activities against three human pathogens, <em>Escherichia coli, Staphyloccocus aureus and Candida albicans</em>, and two phytopathogens, <em>Rhizoctonia cerealis</em> and <em>Colletotrichum gloeosporioides</em>. The results indicated that most ethyl acetate extracts of fermentation broth of these fungal endophytes had stronger antimicrobial activities than their fermentation broth. Among these endophytic strains, both fermentation broth and the ethyl acetate extract of strain D showed the strongest inhibitory effects on all pathogens. Strains 5-19 and BZ also exhibited potent antibacterial activities. However, other strains had weak or no antimicrobial effect. This was the first report on the isolation and antimicrobial effects of endophytic fungi from <em>E. chrysantha</em>.   </p><p> </p>


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