Extracts from the leaves of Bryophyllum pinnatum and Kalanchoe
crenata were screened for their antimicrobial activities. Solvents
used included water, methanol, and local solvents such as palmwine,
local gin (Seaman's Schnapps 40% alcoholic drink,) and "omi ekan-ogi"
(Sour water from 3 days fermented milled maize). Leaves were dried and
powdered before being soaked in solvents for 3 days. Another
traditional method of extraction by squeezing raw juice from the leaves
was also employed. All extracts were lyophilized. These extracts were
tested against some Gram-negative organisms ( Escherichia coli	 ATCC
25922, Escherichia coli, Pseudomonas aeruginosa , Klebsiella
pneumoniae , Shigella flexneri , Salmonella paratyphi , Citrobacter
spp); Gram-positive organisms Staphylococcus aureus ATCC 25213,
Staphylococcus aureus, Enterococcus faecalis , Bacillus subtilis )
and a fungus ( Candida albicans ). Agar well diffusion and broth
dilution methods were used to determine the minimum inhibitory
concentration (MIC) and minimum bactericidal concentration (MBC) at
concentrations of 512mg/ml to 4mg/ml. All the organisms except Candida
albicans were susceptible to the extracts obtained from the traditional
method. The squeezed-leaf juice of Kalanchoe crenata was the most
active one with MIC of 8 mg/ml against Pseudomonas aeruginosa,
Klebsiella pneumoniae and Bacillus subtilis, 32 mg/ml against Shigella
flexneri, 64 mg/ml against Escherichia coli and 128 mg/ml against the
control strain Staphylococcus aureus while its MBC is 256 mg/ml against
these organisms except Bacillus subtilis and Klebsiella pneumoniae. The
Gram-positive organisms were more sensitive to the methanol and local
gin-extract of Bryophyllum pinnatum. Extracts from other solvents
showed moderate to weak activity.

/pdf/in-vitro-antimicrobial-activity-of-crude-extracts-from-2nk3s03gpy.pdf

In Vitro Antimicrobial Activity Of Crude Extracts From PlantsBryophyllum Pinnatum And Kalanchoe Crenata

Trichoderma spp. are well-known biological agents that have significant antagonistic activity against several plant pathogenic fungi. In the present study, Trichoderma spp. were tested in vitro for...

Antagonistic assessment of Trichoderma spp. by producing volatile and non-volatile compounds against different fungal pathogens

Members of the fungal genus Trichoderma (Ascomycota, Hypocreales, Hypocreaceae) are ubiquitous and commonly encountered as soil inhabitants, plant symbionts, saprotrophs, and mycoparasites. Certain species have been used to control diverse plant diseases and mitigate negative growth conditions. The versatility of Trichoderma’s interactions mainly relies on their ability to engage in inter- and cross-kingdom interactions. Although Trichoderma is by far the most extensively studied fungal biocontrol agent (BCA), with a few species already having been commercialized as bio-pesticides or bio-fertilizers, their wide application has been hampered by an unpredictable efficacy under field conditions. Deciphering the dialogues within and across Trichoderma ecological interactions by identification of involved effectors and their underlying effect is of great value in order to be able to eventually harness Trichoderma’s full potential for plant growth promotion and protection. In this review, we focus on the nature of Trichoderma interactions with plants and pathogens. Better understanding how Trichoderma interacts with plants, other microorganisms, and the environment is essential for developing and deploying Trichoderma-based strategies that increase crop production and protection.

Deciphering Trichoderma-Plant-Pathogen Interactions for Better Development of Biocontrol Applications.

The genus Trichoderma is ubiquitous in the environment, particularly in soils. Trichoderma species could be readily isolated from soil by all available conventional methods, largely because they grow rapidly and also because of their abundant conidiation. Based on the phylogenetic study, several researchers reported that Trichoderma and Hypocrea form a single holomorph genus, within which two major clades can be distinguished. The species of Trichoderma possess diverse biotechnological applications such as they act as biofungicide for controlling various plant diseases, as biofertilizers for plant growth promotion. Trichoderma secrete diverse volatile compounds including alcohols, aldehydes and ketones, ethylene, hydrogen cyanide, and monoterpenes, as well as nonvolatile compounds including peptaibols and diketopiperazine-like gliotoxin and gliovirin which are known to exhibit antibiotic activity. The interaction of Trichoderma with the host plant results in parasitism/predation; production of antibiotic is combined with mycoparasitism (penetration and infection), production of cell wall-degrading enzymes or lytic enzymes, competition for nutrients or for space, and establishment of induced resistance in the plant.

Trichoderma: Biodiversity, Ecological Significances, and Industrial Applications

Various experiments were carried out to promote biological control under semi-arid ecological conditions. In vitro assay, Aspergillus flavus seemed to be the most effective bioagent against Fusarium oxysporum f. sp. niveum and Fusarium solani f. sp. cucurbitae with mycelial inhibition rate above 50%. Aspergillus flavus, Aspergillus niger, and Aspergillus terreus exhibited an exceptional hyperparasitism against F. oxysporum f. sp. melonis. The mycelial growth of five Macrophomina phaseolina isolates decreased in the presence of Trichoderma harzianum (44.42%). In greenhouse experiments, both A. flavus and A. fumigatus used preventively of melon inoculated with FOM generated the highest damage reduction rate of top and root dry weights (40–42 and 51–52%, respectively) and the lowest disease severity index (DSI). A. flavus was also effective in improving the plant development with the highest shoot (SDW) and root (RDW) dry weight values. Penicillium digitatum, Trichoderma harzianum, and Trichoderma viride treated preventively on watermelon and melon plants inoculated with M. phaseolina decreased the damage of SDW and RDW and DSI. The development rate revealed the growth improvement potential of T. harzianum (watermelon, 15%) and A. flavus (melon, 12%). Watermelon plants inoculated with F. solani f. sp. cucurbitae and treated curatively with Trichoderma erinaceum, T. viride, and A. flavus and other inoculated by F. oxysporum f. sp. niveum and treated by Trichoderma helicum recorded the highest values of growth parameters, similarly for T. erinaceum on melon plants inoculated by F. solani f. sp. cucurbitae. Among all treatments for plants inoculated by F. oxysporum f. sp. melonis, those three bioagents T. viride, T. erinaceum, and A. flavus revealed efficiency in plant growth. Trichoderma harzianum is the best bioagents against cucurbit soil-borne pathogens. Preventive treatment represents an effective strategy. Dipping roots with bioagent fungi suspension improve a good interaction pathogen antagonist.

/pdf/evaluation-of-the-efficiency-of-trichoderma-penicillium-and-4umiauo9vu.pdf

Evaluation of the efficiency of Trichoderma , Penicillium , and Aspergillus species as biological control agents against four soil-borne fungi of melon and watermelon

Macrophomina phaseolina (Tassi) Goid remains the prevailing causal agent of charcoal rot disease that significantly suppresses the yield of a variety of oilseed crops. Its wide host range and ability to survive under arid conditions, coupled with the ineffective use of fungicides against it, have spurred scientific endeavours for alternative avenues to control this phytopathogen. Hence, the present study aimed to provide empirical evidence of the efficacy of three fungal isolates (T2, T10 and T12) of Trichoderma harzianum as biological control agents against charcoal rot in soybean (Glycine max L.). The results of the in vitro studies revealed that all three fungal isolates significantly inhibited the growth of M. phaseolina phytopathogen, with T12 showing considerably higher inhibition effect than T2 and T10 isolates. T12 inhibited the growth of M. phaseolina in the dual culture (72.31%) and volatile production (63.36%) assays, and the hyperparasitism test indicated cell lysis following the inter...

https://tandfonline.com/doi/pdf/10.1080/13102818.2016.1147334

Evaluation of Trichoderma isolates as potential biological control agent against soybean charcoal rot disease caused by Macrophomina phaseolina

Broomcorn as an ancient crop is a variety of Sorghum vulgare planting in Iran to produce
traditional cleaning broom. Miyaneh is one of the major broomcorn-growing regions in where farmers crop it
intensively since old ages. The crop is so profitable that they prefer not to include any other crops in rotation.
One of the problems in continuous cropping might be related to crop auto-toxicity. To evaluate of broomcorn
auto-allelopathic potential on its seed germination and initial growth, a sequence of laboratory and
greenhouse experiments were conducted by aqueous extract of broomcorn roots and shoots, instant and burnt
residues and root exudates using by Equal Compartment Agar Method as well. Shoot extracts were more
auto-toxic than roots’. Root exudates were negatively more effective on coleoptile growth than radicle.
Burning of residue could be considerable depression of auto-toxic potential of broomcorn. Auto-toxicity was
also reduced by residue aging up to 30 days.

/pdf/assessment-of-auto-allelopatic-potential-of-broomcorn-2pcpt68ijf.pdf

Assessment of Auto-allelopatic Potential of Broomcorn (Sorghum vulgare var. technicum)

Silybum marianum (L.), is an important herbal medicine. Silymarin, the active component obtained from its edible seeds, is known for its antioxidant and antimicrobial activity. This  research was aimed to study the effect of foliar application of salicylic acid (SA) at four concentrations of 1250, 2500, 5000 and 10000 μmol l-1 on the improvement of phytochemical composition, antioxidant and antimicrobial activity. Significant increase was found in the content of silibinin, silybin A and silybin B in plants treated with increasing concentrations of salicylic acid. The antioxidant activity was improved with increasing the SA concentration reaching the highest amount under 5000 μmol l-1 SA treatment (p < 0.05). Irrespective to the bacterial strain, an increasing pattern in the amount of antibacterial activity was found by increasing SA concentration. The study suggest that treatments with medium doses of SA could be a promising way to improve the health beneficial flavonolignans compounds of Silybum marianum resulting in a higher antioxidant and antimicrobial activity. Nevertheless, it should be considered that the responses to SA are highly concentration dependent and application of higher concentrations can have an adverse effect by triggering a hyper sensitive cell death pathway.

/pdf/effect-of-salicyllc-acid-foliar-application-on-phytochemical-380v26q6za.pdf

Effect of salicyllc acid foliar application on phytochemical composition, antioxidant and antimicrobial activity of silybum marianum

Potato is one of the main crops which is suffering from the great losses in storage and the most conventional method of its tuber rot is using hazardous chemicals. Using antimicrobial potential of lichens can be one of the safe, green, environment friendly methods for plant diseases management. In this study, antimicrobial activity of acetone, methanol, chloroform extracts of Ramalina capitaat, Xanthoparmelia stenophylla, Umbilicaria cylindrical, Rhizoplaca crysoleuca and Anamylopsora pulcherrima were evaluated against two potato rot agents vic. Fusarium equiseti and Pectobacterium carotovora pv. carotovora in laboratory and storage conditions. Bioassay tests were disc diffusion and minimum inhibitory and bactericide concentration methods. Dimethyl sulfoxide solvent on paper disc was used as negative control. Positive controls were considered as %0.2 benomyl and gentamicin antibiogram discs for fungus and bacterium, respectively. There were no effect of lichens extract on fungus. R. chrysoleuca especially methanol and chloroform extracts of had remarkable bactericide and bacteriostatic effect on bacterium. The study with selected extracts in storage condition showed preventive effect of 80% of extracts on bacterium. The most protective effect was observed in methanol extract of R. chrysoleuca. Therefore, lichen extract would be promising biological product would be a potential replacement instead of chemicals.

http://www.ijabbr.com/article_9713_da4c27427b5765bbef28d495852b2cd6.pdf

Antimicrobial in Vitro and in Vivo Potential of Five Lichen Species on Fusarium Equiseti and Pectobacterium Carotovora Pv. Carotovora Causal Agents of Potato Rots

Walnut anthracnose is the most important fungal dis ease in Persian walnut in Iran and all over the world caused by Ophiognomonia leptostyla. Limit ed attempts to genetic variation uncovering in this species were not successful by now. In this study, genetic diversity of 75 Ophiognomonia leptostyla isolates collected from the northwest of Iran was studied by RAPD and ISSR primers. RAPDs revealed more polymorphism in studied isolate s than ISSRs, but fewer bands were produced. There were slight correlations with obtai ned RAPD dendrograms with homothallism and collection site, but no correlation with phenot ypic traits in ISSRs. Population analysis identified genetic relationship between neighbor pr ovinces but isolates from Tehran and West Azarbaijan with reasonable distance were relative ato trees were obtained by RAPD and ISSR fingerprinting. Using both markers were us eful in genetic variation understanding of the species unlike ITS and LSU RFLP techniques were used in previous researches.

/pdf/genetic-diversity-of-iranian-ophiognomonia-leptostyla-fr-26ffhwlefh.pdf

Soleiman Jamshidi

Papers

Evaluation of Trichoderma isolates as potential biological control agent against soybean charcoal rot disease caused by Macrophomina phaseolina

Assessment of Auto-allelopatic Potential of Broomcorn (Sorghum vulgare var. technicum)

Effect of salicyllc acid foliar application on phytochemical composition, antioxidant and antimicrobial activity of silybum marianum

Antimicrobial in Vitro and in Vivo Potential of Five Lichen Species on Fusarium Equiseti and Pectobacterium Carotovora Pv. Carotovora Causal Agents of Potato Rots

Genetic diversity of Iranian Ophiognomonia leptostyla (Fr.)populations using RAPD and ISSR markers