محسن فرزانه

Over the past two decades, biological control of wheat septoria tritici blotch (STB) caused by Zymoseptoria tritici has been evaluated as a reliable and safe alternative or complement to chemical control. The genus Trichoderma includes several biocontrol agents (BCAs) widely used worldwide against plant diseases. Besides direct control of plant pathogens, Trichoderma spp as BCAs provide numerous other beneficial features for their plant hosts. The current study aimed to assess the potential biocontrol ability of several antagonistic Trichoderma isolates with endophytic potential on STB reduction in wheat cultivar Tirgan under greenhouse conditions. The antagonists were used as a seed-coated treatment at the sowing time and sprayed on the plants 72 h before Z. tritici IPO323 inoculation. STB severity was calculated 21 days after the pathogen inoculation. The biocontrol isolates significantly (α = 0.01) reduced the disease severity on cv. Tirgan. T. harzianum AS12-2 provided the highest average percentage of STB inhibition in both application methods. Application of T. harzianum AS12-2 led to a reduction in the percentage of leaf area covered by lesions (PLACL) and the percentage of leaf area covered by pycnidia (PLACP) by 80.12% and 77.71%, respectively. Trichoderma biocontrol isolates could be considered safe and reliable alternatives/complements for sustainable agriculture in integrated management programs of wheat STB.

The effect of dietary administration of combination of hydro-alcoholic extracts of turmeric (Curcuma longa L.) and thyme (Zataria multiflora Boiss) on growth performance, nutritional parameters, digestive enzymes activity and antioxidant properties of rainbow trout (Oncorhynchus mykiss) was investigated. Three experimental diets including basal diet (control group) and diets containing 0.5% and 1.5% of combination of turmeric and thyme (ratio of 1:2) extracts were prepared. A total of 234 juveniles of rainbow trout were randomly divided into three experimental groups in triplicates (providing 26 fish per replicate) and reared for eight weeks. Feeding diets contained 0.5 % of the extract increased the feed efficiency ratio and condition factor of rainbow trout compared to the control group (P<0.05). Supplementing 1.5 % plant extract increased the Average Daily Growth (ADG) of the fish in comparison to control group (P<0.05). Both dietary levels of the extracts increased protein productive value and lipid productive value of fish compared to control group (P<0.05). Viscerosomatic and hepatosomatic index were affected by both dietary extract levels compared to control group (P<0.05). Dietary plant extract inclusion significantly increased the activity of amylase and lipase (P<0.05). Similarly, the activity of superoxide dismutase and glutathione peroxidase significantly increased in the liver tissue of rainbow trout following feeding on diets containing the extracts, while malondialdehyde content of the tissue decreased in comparison to the control group (P<0.05). Therefore, considering the promising effects of dietary supplementation of turmeric and thyme extracts, inclusion of 0.5% of the extracts in rainbow trout feed is recommended.

15acetyl-deoxynivalenol (15ADON) is the most common chemotype of dioxynivalenol (DON) mycotoxin, which cannot be controlled by common methods such as absorbents. Hence, enzyme-based methods are suggested for detoxification of these types of mycotoxins, which requires bioinformatics studies before laboratory investigations. Therefore, the aim of the present study was to investigate the binding energy of DEP-A and DEP-B enzymes with 15ADON through molecular docking. The three-dimensional structures of DEP-A and DEP-B proteins were predicted using the SWISS MODEL server. Then, the stability of these structures was evaluated in molecular dynamic conditions. For this purpose, the simulation was carried out with GROMACS software and then the RMSD curve of these two enzymes was drawn to check the stability of the predicted structure. H-DOCK online server was used to performed the interaction of DEP-A enzyme with 15ADON and DEP-B with Oxid15ADON intermediate. Checking the accuracy of the predicted structures by ERRAT Verify3D, Z-score and Ramachandran plots showed that the prediction of tertiary structures successfully performed. The RMSD curves showed that DEP-A and DEP-B were stabilized in 240 and 40 nanoseconds with 0.58 and 0.35 nm, respectively. The results of molecular docking also showed that both DEP-A and DEP-B enzymes could bind to their substrates with relatively strong binding energy -157.90 and -141.78, respectively. Overall, it can be concluded that both studied enzymes were able to bind to the 15ADON chemotype of DON in the appropriate position, which shows that these enzymes can be effective in deactivating this chemotype, although laboratory studies are needed to confirm the results

The use of medicinal plants’ essential oils, as an alternative to chemical fungicides, is limited due to their low solubility in water, poor chemical stability, and their volatile nature. To solve this problem, encapsulation of essential oil on a nanometer scale and combining it with coating polymers has been suggested recently. In this study, nanoemulsions of Satureja khuzistanica (Khuzestani savory) essential oil (containing 87.4% carvacrol) and Mentha piperita (peppermint) essential oil (containing 33.6% menthone and 35.3% menthol) were prepared with an average particle size of 295 and 186 nm, respectively. After confirming their effectiveness against the fungus Penicillium expansum, they mixed with tragacanth coating polysaccharide (0.5% and 1%) to inhibit the penicillium decay of tomato fruit as well as improve fruit physicochemical indicators during storage at 10°C. Fruit treatments by nanoemulsion of essential oil (NEO) of S. khuzistanica 0.1% in combination with tragacanth 0.5% and 1% showed the greatest effect to inhibit the penicillium decay. The fruits treated with the NEO of peppermint was placed in the next statically group. Furthermore, the effect of the superior treatments on some physicochemical indicators of fruit showed a significant positive effect of them in terms of the fruit firmness and its total soluble solids (TSS). In addition, the total phenolic content of the treated fruits was significantly higher than non-treated healthy fruits. However, it seems that nanoencapsulation of antifungal and antioxidant essential oils compounds and combining them with the tragacanth, caused to increases the shelf life of the fruit during storage.

Grape gray decay disease caused by Botrytis cinerea is one of the important factors causing rotting and reducing the quantity and quality of the grapes during the stages before and after harvesting, which makes the use of chemical fungicides inevitable. Considering the environmental issues with the excessive use of chemical fungicides for humans and the environment, the use of products based on biological agents has received special attention. Among biological agents, some yeasts have been shown to possess antagonistic activity against fungi and are considered as safe and sound alternatives for chemical pesticides. The present study aimed to identify grape epiphytic yeasts and investigate their ability against the pathogenic fungus B. cinerea in the post–harvest stage. A total of 67 yeast isolates were isolated from the surface of grape fruits in the vineyards of West Azarbaijan province. Based on morphological studies and nucleotide sequence analysis of the D1/D2 domain of the large subunit 26S rDNA gene, the isolates belong to 21 species and 11 genera. Aureobasidium pullulans was recognized as the dominant species of grape flora. The ability of 67 yeast isolates to control B. cinerea growth by the dual–culture method showed that 16 isolates belonging to 7 genera succeeded in inhibiting the growth of the gray mold, which isolates Rhodotorula glutinis G54 and Metschnikowia pulcherrima G9 showed the greatest of capability against B. cinerea. A significant difference (P≤0.01) was observed between the 16 selected isolates in terms of inhibition of gray rot on grape berries, as a completely randomized design with four replications. The isolates Meyerozyma guilliermondii G30, Rh. glutinis G54 and M. pulcherrima G9 were the most effective isolates in reducing the disease on grape berries with 92.59, 91.37 and 90.15 percent rot inhibition, respectively. Studies of mechanisms involved in biological control showed that 12 isolates were able to produce protease, 6 isolates were able to produce pectinase and 12 isolates produced amylase. Also, it was found that 9 isolates can form biofilm and 8 isolates produced a siderophore. Finally, it was found that the grape flora has a high diversity of yeasts and the superior yeast isolates including G30, G54 and G9, with various biocontrol mechanisms (such as antibiosis, protease and amylase activities as well as siderophore production), have a high potential to inhibit the gray rot of grape. However, it is necessary to conduct more studies on selected isolates to creat practical formulations for biological control or integrated management of fungal diseases of fruits and vegetables..

Zearalenone (ZEA), which is one of the most prevalent wheat and corn seeds mycotoxins causes acute and chronic toxicities in ruminants, poultry, and aquatic animals. Among commercial toxin binders, only a few active charcoals have the significant ability to adsorb ZEA contamination; nevertheless, active charcoal is not considered a sound additive by the feed industry.

This study aimed to screen and identify the ZEA-degradation compounds of the Zataria multiflora (Shirazi thyme) in the cattle rumen fluid.

In this investigation, essential oil and different extracts (n-hexane, ethyl acetate, and methanol) of the aerial part of Shirazi thyme (at three concentrations of 0.5, 1, and 2 mg/ml) were screened to reduce ZEA contamination conditions (2 µg/ml) in rumen fluid. ZEA-content was analyzed by high-performance liquid chromatography (HPLC) with a fluorescence detector. In addition, Shirazi thyme phytochemical compounds responsible for eliminating ZEA were localized by HPLC-based activity profiling and then identified by mass spectrometry (LC-MS).

Both n-hexane and methanol extracts of Z. multiflora, considerably remediated ZEA (63-78%) from rumen fluid. According to HPLC-based activity profiling of Z. multiflora extract and LC-MS analysis, two triterpene compounds, including ursolic and oleanolic acids were introduced as ZEA degradation agents.

Z. multiflora could be recommended as a new botanical source, and ursolic and oleanolic acids could be introduced as new phytochemical compounds that degrade ZEA.

Plant viruses are a limiting factor in agriculture. Natural compounds, especially herbal plant metabolites, have been considered to control viruses. In this regard, the effect of aqueous–ethanolic extract (50% water) and essential oil nanoemulsion of Satureja khuzistanica were investigated to reduce the infection of cucumber mosaic virus on the local lesion test plant of cowpea (Vigna unguiculata) in greenhouse conditions. The extract and essential oil nanoemulsion were applied in four concentrations of 0.5, 1, 2 and 4 percent (g/100 mL) and three different times including simultaneously, two hours before, and after inoculation of plant leaves with virus inoculum (concentration 2 mg/ml). The lowest number of local lesions was obtained by using 2 and 4% of hydro–ethanolic extract (by 66–78% disease reduction) and nanoemulsion of essential oil with a concentration of 2% (by 59% disease reduction), and two hours after inoculation with virus inoculum. The particle size of the nanoemulsion after preparation was 119.4 nm, which reached 232.8 nm after 60 days of storage, which indicates the good physical stability of the nanoemulsion. According to GC–MS analysis, the main constituents of essential oil were carvacrol (91.5%), para–cymene (1.5%), beta–caryophyllene (1.1%) and beta–pinene (1.1%). Nanoemulsion of this essential oil improved its efficiency to inhibit the cucumber mosaic virus on cowpea. This study is the first report of the antiviral effect of phytochemical compounds of Khuzistani savory to inhibit a plant virus.

Plant pathogens cause great damage on crops during harvest and post–harvest stages. The use of synthetic chemical fungicides is inevitable and causes irreparable damage to the environment and human health. Replacing chemical fungicides with beneficial biological agents can be effective in reducing these risks and damages. Among biological agents, yeasts are promising alternatives to chemical plant protection compounds due to their widespread distribution, bioavailability, environmental friendliness, and safety for human. Over the past few decades, the study of biocontrol mechanisms of yeasts against plant diseases has been extensively studied. Here, the fundamental researches on the mechanisms (e.g. competition, enzyme secretion, toxin production, volatiles compounds, mycoparasitism, and induction of resistance) of biocontrol yeasts as plant protection agents are reviewed.  It also provides an overview of the commercialization process and registered yeast–based bioproducts. In general, this study shows the lack of fundamental studies on the biocontrol mechanisms of yeasts and registered yeast agents. Therefore, identifying the biocontrol mechanisms of yeasts in more detail is still one of the research fields and better understanding of them can pave the way for the development of yeast–based commercial products for plant protection.

Present study was carried out to assess effects of aflatoxin B1 on different rainbow trout tissues. In the present study, 207 rainbow trout fingerlings with an average body weight of 9.67±0.2 g were reared for eight weeks in three distinctive treatments (control group, 25 and 50 ppb aflatoxin B1). At the end of the trial, various tissues of experimental groups were studied regarding probable histological alterations. Histological alterations due to dietary aflatoxin B1 exposure including hyperplasia and lamellar necrosis in the gill, necrotic and vascular changes in the brain along with inflammatory cell infiltration and necrotic changes in the intestinal and pyloric region were evident. The severity of pathologies was more pronounced in those fish received 50 ppb aflatoxin B1 content in comparison to the group fed 25 ppb toxin contaminated diet.

The experiment was carried out to investigate the effect of aluminum silicate (AS), humic acid (HA), Saccharomyces cerevisiae cell wall (SC), herbal powder (HP) and a commercial toxin binder to alleviate the effects of aflatoxin B1 (AFB1) in broiler diet.  In this experiment we used 320 day old chicks in a completely randomized design with 8 treatments and 4 replications, and 10 birds in each replicate, from 7 to 28 days of age. Experimental treatments were: 1) negative control (NC; without AFB1), 2) positive control (PC; contaminated by 0.3 mg AFB1 / kg diet), 3) PC + AS, 4) PC + AS + HA, 5) PC + AS + SC, 6) PC + AS + HA + SC, 7) PC + Magnotox as a commercial binder and 8) PC + HP. Feeding AFB1 contaminated diet reduced broiler performance, increased relative weights of liver, heart, pancreas and reduced serum albumin, total protein and glucose concentrations (P <0.05). Inclusion of AS in PC diet individually improved the negative effects of AFB1. However, supplementation of SC boosted AS effects, HA supplementation was rarely effective. Finally, it can be concluded that the combination of AS + SC has the highest adsorbing ability of AFB1.

Zearalenone (ZEA) is a nonsteroidal estrogenic mycotoxin that is usually found in animal feed and causes disorder in genital organs activity. Most commercial adsorbents do not have ZEA absorbency and may have side effects on the animal performance. Therefore, the discovery and introduction of natural compounds are necessary to reduce ZEA.

The introduction of some medicinal plants to degrade ZEA in rumen fluid is the main objective of this study.

In the present study, essential oil and different extracts (methanol, n-hexane and ethyl-acetate) of seed of four medicinal plants belonging to Apiaceae family including coriander (Coriandrum sativum),Cumin (Cuminum cyminum), Fennel (Foeniculum vulgare) and Persian hogweed (Heracleum persicum) were investigated to reduce ZEA in rumen fluid (0.4µg ZEA in ml 20% rumen fluid) at the ratio of essential oil/extract to toxin 125:1, 250:1 and 500:1 in 48h.The ZEA-content was extracted by the immunoaffinity column and analyzed by high-performance liquid chromatography (HPLC-FLD).

The results showed that essential oil of coriander (contains 76.5% of linalool), n-hexane extract of coriander and methanol and ethyl acetate extracts of Persian hogweed exhibit acceptable efficiency (more than 30%) in ZEA degradation. ZEA evaluation in the presence of various concentrations of promising essential oils and extracts exhibited that the essential oil of coriander has the highest effect to remove ZEA from rumen fluid with 79.5% after 48 h. The n-hexane extract of coriander at the rate of 500:1 caused 67.8% and 74.2% reduction in ZEA content after 36 and 48 h incubation time respectively and located at the next statistical level. In addition, methanol and ethyl- acetate extracts of Persian hogweed at the rate of 500:1 reduced 46% and 41.8% ZEA content in rumen fluid respectively.

Coriander and Persian hogweed are introduced as promising botanical additive sources to remove ZEA in animal feed.

The application of phytogenic additives in the form of essential oils have attracted considerable attention in poultry industry. An experiment was conducted to evaluate effects of the blends of essential oils (EO) isolated from some medicinal plants including savory, thyme, fennel and rosemary on performance, blood metabolites, intestinal microflora, and meat quality of broilers. Two hundred 1-day-old broilers were randomly allocated to 5 treatments with 4 replicates of 10 chicks. The dietary treatments included 1) NC (negative control; without EO), 2) PC (positive control; 300 mg commercial EO of oregano/kg diet), 3) SR (300 mg EOs of savory and rosemary/kg diet), 4) SRT (300 mg EOs of savory, rosemary and thyme/kg diet), 5) SRTF (300 mg EOs of savory, rosemary, thyme and fennel/kg diet). Neither PC nor combinations of EOs affected growth performance of broilers. Serum cholesterol reduced (P<0.05) by feeding the blend of EOs compared with NC. The lowest ileal Lactobacillus counts were observed in chicks fed diets supplemented with EO of oregano or SR (P<0.05). Dietary supplementation of oregano EO decreased (P<0.05) lipid peroxidation of thigh meat after 30 and 60 days of frozen storage compared with NC group. Broilers fed diets supplemented with EOs of oregano or SR had the lowest ileal Lactobacillus spp. counts probably due to their large amount of carvacrol contents which suppress growth and proliferation of Gram-positive bacteria. Contrary to blended EOs, oregano EO did not reduce serum cholesterol concentration, suggesting hypocholesterolemic effect of other compounds except carvacrol in EOs. The highest stability to meat oxidation was achieved in oregano EOs-fed broilers. This antioxidative effect was lower in treatments with less carvacrol contents

The formation of mycotoxins in feedstuffs is a worldwide issue affecting digestive physiology of aquatic animals and resulting in lower animal performance. Total of 540 rainbow trout with an average body weight of 3±0.2 g were allotted to 9 distinct treatments including various dietary levels of aflatoxin B1 (0, 25 and 50 ppb) and zearalenone (0, 200 and 400 ppb) for 4 weeks. At the end of the trial, pyloric ceaca samples were taken for determining alkaline protease, lipase and amylase activity. Results revealed that feeding on diets contaminated with aflatoxin B1 and zearalenone for 4 weeks did not significantly affect alkaline protease activity (p<0.05), however, did significantly affect lipase and amylase activity of rainbow trout fingerlings (p<0.05). The highest lipase activity was recorded in control group (feeding on diet devoid of any mycotoxins) and treatment co-contaminated with containing 25 ppb aflatoxin B1 or 200 ppb zearalenone. However, the lowest lipase activity belonged to treatments contaminated with only 400 ppb zearalenone or 25 ppb aflatoxin B1. The highest amylase activity was assayed in group fed on diet without any mycotoxin contamination in comparison to those fed diet contaminated with any levels (25 or 50 ppb) of aflatoxin B1 (p<0.05). It can be concluded that co-contamination with both aflatoxin B1 and zearalenone reduced their negative effect on lipase activity of fish.

In this study the effect of spermidine on proline, soluble sugars, peroxidase, ascorbate peroxidase, membrane stability and chlorophyll a and b, under irrigation period were evaluated. This study was conducted in pots and as a factorial completely randomized design in four replications. Espermidine was applied at 0, 1 and 2 mM and irrigation period was imposed at three days, five days and seven days in between. The Results showed irrigation period in seven days compared to control group increases proline content, activity of peroxidase and ascorbate peroxidase and membrane stability, and decrease in soluble sugars, chlorophyll a and b. The plants that have been irrigated for seven days, treatment with 2mM spermidine (relative to concentrations of 0 and 1 mM) increased proline content, soluble sugars, activity of peroxidase and ascorbate peroxidase at the highest level (class a). The membrane stability in these plants the concentration of 0 mM spermidine was highest (77.75%). Spermidine had no significant effect on chlorophyll a and b. Generally treatments with 2 mM spermidin in plants that were irrigated for seven days Increased proline content (1.11 mM/g.FW), soluble sugars (0.96 mg/gFW), peroxidase activity (0.91 OD.g-1.FW.min-1) and ascorbate peroxidase activity (0.98 OD.g-1.FW.min-1) at the highest level (class a).

Chemical fungicide is the most affordable and easiest way to fight against plant diseases, but they increase concerns about endangering human health and residual in the environment. Barley is one of the most important and consumable cereals in the world. Plant essential oils are volatile compounds from plants that have strong antimicrobial properties with phenolic and antioxidant components. The aim of this study was to investigate the four plant essential oil including Savory, Thyme, Rosemary and Fennel on the growth and production of ochratoxin of Aspergillus ochraceus pathogen in barly. In this study, the effect of four plant essential oils (Satureja khuzestanica, Thymus daenensis, Rosmarinus officinalis, Foeniculum vulgare) on the growth pathogen in the petri dishes and the level of ochratoxin A produced by A. ocraceus was investigated in addition, it was studied the essential oils effect on ochratoxin in the culture medium. Measuring of ochratoxin was performed by High Performance thin-layer chromatography. The results of this study showed that the essential oils can significantly decrease the growth of the A. ocraceus and the production of ochratoxin by the pathogen. Savory essence at a concentration of 250 μg/ml inhibits the production of detectable ochratoxin in the medium by preventing the growth of the pathogen. In this concentration, essential oils of Rosemary and Thyme were 79.1% and 53.2% respectively, and the dry weight of the fungi decreased completely. Rosemary essential oil at the highest applied concentration (1000 μg/ml) did not inhibite it was investigated the growth of the pathogen it was investigated, but prevented the production of toxin. Essential oils of Savory, Thyme, Rosemary and Fennel showed fungicidal properties. These essential oils affect the ochratoxin and degrade it in the culture medium.

  Taxanes are a family of diterpene alkaloids which is currently known as the most important anticancer compounds to suppress and inhibit cell growth, differentiation and proliferation in indefinitely known cancer cell lines. The most well recognized member of the taxane family is taxol (paclitaxel), a minor cytotoxic component derived originally from yew bark (Taxus brevifolia). 10-Deacetylbaccatin III (10-DAB), which is a homolog of taxol, can be extracted at high yields from the needles of Taxus baccata and is currently considered the most appropriate precursor for semi-synthesizing taxol and its analogue, taxotere (docetaxel). The natural source of both compounds is the inner bark and needles of several Taxus species, especially T. baccata and T. brevifolia. Plant cell culture is an environmentally sustainable source of taxol and offers several advantages as it is not subjected to weather, season or contamination. The aim of the present study was to evaluate taxol and 10-DAB content of two Taxus species and their ability in production of both taxanes through cell culture. The plant materials of T. baccata and T. berevifolia were collected from Shahid Beheshti University (35° 48' N, 51° 23' E at an altitude of 1785 m) and botanical garden of Faculty of Agriculture, University of Tehran, Karaj (35° 48' N, 50° 59' E at an altitude of 1238 m), respectively. Callus culture of both species was initiated from internodal segments on B5 medium supplemented with plant growth reaulators. Cell suspension culture was established on the medium supplemented with 2.0 mg L−1 naphtalene acetic acid (NAA) and 0.1 mg L−1 benzyl amino purine (BAP). Cell viability was determined by Evan’s blue staining test. After 21 days, the amount of taxol and 10-DAB was analysed by HPLC. The results showed that mother stocks of T. baccata and T. brevifolia contain 45 and 27 µg/g DW of taxol and 40 and 4 µg/g DW of 10-DAB, respectively. Cell growth was estimated by measuring fresh weight (FW) and dry weight (DW). Results showed that the maximum growth was reached after 21 days of cultivation. Cell cultures of T. baccata and T. brevifolia produced 540 and 20 µg/l taxol and 1 and 110 µg/l of 10-DAB, respectively. Taxol production in T. baccata cell culture was 26-fold higher than in T. berevifolia cell culture. As far as our literature survey could ascertain, growth and taxol production in T. baccata cell cultures have previously been reported. Although, T. baccata cells are more potent for the production of taxol, T. brevifolia cell culture can be considered for the production of 10-DAB, a homolog of taxol, as an appropriate precursor for semi-synthesizing taxol and its analogue, taxotere (docetaxel). However, it is essential to study and quantify the effect of selected key medium components on growth as well as product accumulation and strike a balance between the two to enhance the yield and productivity

Spermidine effect on biochemical properties consisted of activity of peroxidase, ascorbate peroxidase, relative water content, soluble sugar, and electrolyte leakages in cucumber (Cucumis sativus L.) was investigated. An experiment was conducted based on CRD with three replications in Islamic Azad University, Shiraz Branch. The first factor was included different irrigation courses at three levels; irrigation every other day, irrigation three days in between and irrigation five days in between. Second factor was included foliar application with three different concentration of spermidine (0, 1 and 2 mM). The resuls of variance analysis for interaction effect of different courses of irrigation and various concentration of spermidine on peroxidase enzyme activity, ascorbate peroxidase activity and relative water content was significant. The results also showed that plants that recived irrigation five days in between with 2mM Spermidine had the highest activity of peroxidase and ascorbate peroxidase enzyme. The interaction of different levels of irrigation and Spermidine foliar applciaiton on sugar solution and electrolyte leakages was not significant. In conclusion the effect of 2mM Spermine on peroxidase enzyme activity, ascorbate peroxidase activity and relative water content was significant.

Pectobacterium carotovorum is one of the most important bacterial pathogens of potato in the world.The expression of numerous genes including those involved in the production of virulence determinants in this bacterium are regulated by quorum sensing (QS). The signal molecules involved in QS in P. carotovorum belong to the group of N-acyl homoserine lactones (AHLs). Recently, several soil bacteria were found to degrade AHLs, thereby interfering with the QS system. In this research, 1280 bacterial strains were isolated from potato rhizosphere in Iran. For the screening of isolates for AHL-inactivating, Chromobacterium violaceum CV026 and Escherchia coli pSB401 was used as biosensors. The 69 isolates have highly AHL-degrading potential. The AHL degradation measurement by HPLC showed that residue of C6-HSL was not detected in some isolates that means completely degradation of it by antagonists. The screened isolates tested for protect potato tubers against soft rot. 40 strains reduced tuber soft rot more than 50 percent. 16 of the best isolates were used for inhibition of stem tissue maceration. Bacillus toyoensis 2L, Escherchia coli 1M and Acinetobacter calcoaceticus 32P reduced stem maceration more than 70 percent. These strains were identified by 16s rDNA sequencing. These results showed that interference with P. carotovorum quorum sensing system can be considered as an attractive target for development of biological control method of this disease.

Today, the use of essential oils and extracts of medicinal plants in food and pharmaceutical industries is growing because of their medicinal, antifungal, antibacterial and antioxidant properties. In this way, the effects of various extracts of Scrophularia striata, a medicine plant, were studied for inhibiting Aspergillus flavus mycelial growth and reducing aflatoxin B1-level in culture liquid potato-dextrose (PDB) as well as the pistachio nut. Aflatoxin B1 (AFB1) was evaluated by high performance thin layer chromatography (HPTLC) method. Application of different concentrations of the extracts (250, 500, 1000, 2000 mg/L) in order to inhibit the growth of Aspergillus flavus and also Aflatoxin B1 production in PDB medium demonstrated that the aqueous extract at a concentration of 2000 mg/L could significantly inhibit the A. flavus growth (41.02% loss in dried weight). Ethyl acetate, methanol and aqueous extracts had amazing effect (92-100%) to inhibit toxin production. The results of AFB1 degradation assay indicated that the application of aqueous and methanolic extracts led to significant degradation of aflatoxin by 33.7 and 29.2%, respectively. It is shown that only aqueous extract at concentrations of 2000 and 4000 mg/L could significantlly inhibit (37.14- 58.91%) fungal sporulation on pistachio nuts, while both  methanol and aqueous extracts showed the strongest impact on inhibiting toxin production and caused a reduction of 96.85% and 75.48%, respectively, in AFB1 content. At the concentration of 2000 mg/L only methanol exract was able to reduce AFB1 (40.35%) on the pistachio nuts. Finally, the use of Scrophularia striata can possibly inhibit the aflatoxin contamination on agricultural products.

In this research, the interaction between two biocontrol strains of Pseudomonas fluorescens (PF153mcherry andCHA0gfp2)and three wheat cultivars (Boulani, Roushan, Forno) were studied to control wheat leaf rust disease (Puccinia triticina) under greenhouse conditions. Bacteria were appliedusing the seed treatment method. Results showed a reduction in disease severity on the leaves in certain combinations of bacterial strains and wheat cultivars. This was particularly evident for the interaction between CHA0gfp2 and Forno with 69.74% decrease in the number of pustules on leaves. The Bolani and Forno cultivars that were not treated by bacteria exhibited the highest infection of leaf rust. Study of bacteria–wheat-pathogen interactions showed that the interaction between PF153mcherry with infected and non-infected Forno showed the highest bacterial colonization (7801.1 and 8154.4 cfu per mg dry root, respectively). Interaction between CHA0gfp2 with infected and non-infected Roushan cultivar induced the lowest colonization on the rhizosphere by 938.2 and 887.3 cfu per mg dry root, respectively. However, interaction between pathogen and cultivars resulted in the increase of peroxidase and phenylalanine ammonia lyase (PAL) activity in the leaves. In summary, we observed negative correlations between the bacterial colonization (cfu per mg dry root) and the number of rust pustules on the leaves. There was significant correlation between PAL activity and disease severity. Overall results of this study indicate that there is a promising beneficial interaction between the bacterial isolates and wheat cultivars which induce systemic resistance and suppress the leaf diseases in the sustainable agricultural system.

Secondary metabolites play an important role in plant responses to environmental stresses and some of these compounds are significantly increased under stress conditions. The use of biotic and abiotic elicitors for promoting the production of secondary metabolites reduces the processing time to achieve high concentrations of the metabolite. In this study, the effects of pathogenic fungus, Rhizoctonia solani (AG2-2) SBUka2, as biotic elicitor, were studied to better understanding of plant reactions to microorganisms and enhance yield and quality of secondary metabolites of Thymus daenensis in tissue culture. In this way, rosmarinic acid and caffeic acid contents of two ecotypes (Ilam and Isfahan) of T. daenensis were determined by High Performance Thin Layer Chromatogharapghy (HPTLC), while essential oil variations were studied by Gas Chromatoghraphy-Mass Spectrometry (GC-MS). The results showed that in the presence of R. solani, rosmarinic acid content of inoculated plant was decreased by 26.82% and 8.25% in Ilam and Isfahan ecotypes, respectively whereas caffeic acid content decreased to 4.51 and 4.16, respectively. The analysis of essential oils exhibited that in the presence of R. solani, the yield of essential oils increased by 33% and 20% in Isfahan and Ilam types, respectively. In addition, the content of some essential oil compositions such as thymol and carvacrol were increased in infected plants whereas other compounds such as para-cymene and gama-terpinene were decreased.

In this study, the effect of carbon and nitrogen sources, on production of yeast biomass was determined as well as the efficacy of various formulations of Candida membranifaciens to decrease blue mold on apple. The media containing sugar cane molasses as carbon sources caused more yeast growth than the media supplemented with permeate powder. Yeast extract as nitrogen source produced higher biomass than urea and Corn steep liquor (CSL). The best growth was obtained in medium that composed of sugar cane molasses, yeast extract and CSL. Viability of C. membranifaciens differed in various carriers significantly (p < 0.01). The number of viable cells in Kaolin and Talc-based formulations was gradually reduced whereas the viability in wheat bran based formulations increased in 4 months and then gradually declined. In general, the formulations stored at 4 °C had longer shelf life than those stored at 24 °C. The antagonistic efficacy of prepared formulations of C. membranifaciens was evaluated against Penicillium expansum on apple at storage conditions. There were no significant differences among Talc-based, Kaolin-based and Wheat bran-based formulations of C. membranifaciens in reduction of blue mold.

The use of essential oils and extracts of medicinal plants for thefood, feed, and pharmaceutical industries is growing in response to their medicinal, antifungal, antibacterial, and antioxidant properties.The inhibitory effect of nettle and Mentha piperita on the growth of Aspergillus flavus and decrease in aflatoxin B1level was studied. Essential oils (62.5, 125, 250, 500 and 1000 mg/l) and aqueous, ethanol, and 70% ethanolextracts (500, 1000, 2000, 4000 and 6000 mg/l) of the plants were testingfor reducing A. flavus growth and AFB1content in a liquid culture. The AFB1 content was evaluated using high-performance thin-layer chromatography. Essential oil of M. piperita and nettle at the 1000 mg/l concentration decreasedthe dried mycelia weight 79.40% and 53.30% and decreased AFB1production 88.25% and 57.3%,respectively. The extracts of M. piperita were stronger thannettle for reducing AFB1 content and mycelial growth; the ethanol extract of M. piperita at 6000mg/l decreasedmycelial growth 95.25% and FB1 production 89.58%. Essential oils, ethanol and 70% ethanolextracts of both plants did notsignificantly decrease AFB1 content, whereas aqueous extracts of nettle and M. piperita at the 4000 mg/l concentration decreased AFB1 content 78.15% and 56.1%, respectively. In general, essential oil and extracts of M. piperita were stronger than those from nettlefor reducing AFB1 content and mycelial growth. Aqueous extracts of nettle showed strong AFB1degradation activity andshould be considereda promising new candidate for decreasing AFB1 content.Keywords: