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Rice blast, caused by Pyricularia grisea, is one of the most important diseases of this crop in Iran and all over the world. To evaluate the relationship between spore population (SP) and meteorological factors, SP was measured daily using spore trap during growing seasons of 2006-2008 in Rasht and Lahijan regions (Guilan province, Iran). Weather data including precipitation, daily maximum and minimum temperatures, daily maximum and minimum relative humidity and duration of sunny hours were obtained from weather stations which were five kilometers away from the fields. The relationship between spore population and metrological factors was evaluated by Neurosolution 5.0 software. Weather data and spore population were considered as input and output data, respectively. In this study, multilayer perceptron neural network, regression model and Log(x + 1) transformation were performed. To evaluate the model efficiency, correlation coefficient and mean square error were used. The results showed that the correlation coefficient (r) and mean square error (MSE) parameters were 0.55 and 0.03 in Rasht and 0.1 and 0.03 in Lahijan, respectively. The results also showed the potential of this model for modeling SP using meteorological factors; however more data is needed for validation of this model. There has been no previous report on modeling the relationship between SP and meteorological data using artificial neural network in Guilan province (Iran).

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Stem rust caused by Puccinia graminis f. sp. tritici (Pgt) is one of the destructive diseases of wheat in the world. The fungal pathogen can infect 365 different grass and more than 70 Berberis species. DNA sequences for the ribosomal RNA internal transcribed spacer (ITS) have proven suitable to explore relationships at the species and subspecies levels. An isolate of Pgt which was collected from Iran and designated as TTSSK was used in this study. Three samples of the isolate were used. ITS region of the samples was amplified and sequenced. Consensus tree based on Maximum Parsimony clustering method was produced by Mega 6.0. Iranian isolate of TTSSK was placed in a clade with P. graminis which was isolated from Berberis sp. and Pgt isolate from Tajikistan. The results showed that more than one conserved genomic regions would be informative to identify phylogenetic relationship of Iranian Pgt isolates and samples from different parts of the world. Complementary studies with more sequence data from other genome loci are in progress.

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Stripe rust cause by Pucciniastriiformis f. sp. tritici is one of the most important diseases of wheat and can cause severe yield loss in many wheat growing regions of the world including Iran. To determine yield loss caused by this disease and evaluate the effect of some chemical components on reduction of yield loss in south of Iran, field experiments were carried out in split plot design with three replications at Ahvaz research station during 2014-2015. Three cultivars; Chamran, Virinak and Boolani, were used and artificial inoculation was performed using an isolate which was collected from south of Iran and designated as Yr27 race variant. Meanwhile the effects of propiconazole and some herbicides on yield loss reduction were studied. In this study, grain yield and area under disease progress curve (AUDPC) were measured. Statistical analysis showed that the level of the yield reduction was significantly different in the three studied cultivars and different treatments. Propiconazole could control the disease significantly. The highest yield loss was observed for cv. Boolani in both with (9%) and without (54%) fungicide treatments. Combined application of propiconazole and herbicides significantly reduced yield loss compared with using them separately. The results of crop loss modeling using integral and multiple point regression models showed that the integral model (L = 0.017AUDPC-17.831) could explain more than 69% of AUDPC variations in relation to crop loss in all cultivars. In multiple point models, disease severity at various dates was considered as independent variable and crop loss percentage as dependent variable. This model with the highest coefficient of determination had the best fitness for crop loss estimation. The results showed that the disease severity at GS39, GS45, GS50 and GS60 stages (Zadok's scale) were more important for crop loss prediction than those in other phenological stages.

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This study was undertaken to find out the optimum physicochemical parameters of fermentation, i.e. pH, incubation temperature and incubation time for the cellulase enzyme production of Trichoderma harzianum. The extracellular protein content was estimated by the dye binding method of Bradford. Endo-glucanase (EG), exoglucanase (or Cellobiohydrolase; CBH), β-glucosidase and total cellulase activity were investigated. The molecular weight of cellulase enzymes was studied using SDS-PAGE. To identify the predominant catalytic components in optimum conditions of enzyme production, cellulases were separated by an adapted two-dimensional electrophoresis technique. Estimated optimum conditions for cellulase enzyme were found as: pH 6.5, incubation temperature 28°C and incubation time 72 h. The SDS-PAGE profiles showed several enzyme bonds such as CBHs, EGs and BGLs. The T. harzianumhad both enzyme bonds of Cel7A (CBHI) and Cel7B (EG). Finally, the results of the 2D PAGE analysis showed that the profile of protein in optimium conditions of enzyme production had several enzymes such as CBHs, EGs and the high values of cellulose activity due to synergism that occurred between the CBH and EG.
 

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Fusarium solani f. sp.cucurbitae races cause crown, fruit and root rots of cucurbits and economic problem for farmers. The aim of this study is identification of Fusarium solani f. sp. cucurbitae races which collected in Shahrood, Jiroft and Varamin, provinces of Iran using morphological characteristics and fungal-specific primers. Symptomatic cucurbit plants were collected from different fields in three provinces. After isolation and purification of the causal agents, pathogenicity test and DNA extraction were performed. Specific primers for TEF-1α gene were used to distinguish among different species of Fusarium and Fusarium solani. The isolates that showed a specific 658 bp amplicon on agarose gel were selected for subsequent PCR assay in order to detection of F. solani f. sp. cucurbitae race 1 and 2. PCR assays were performed with taxon-specific primers race 1 (505bp PCR product) and race 2 (425bp PCR product). Some samples amplified a 505bp amplicon which is specific for race 1 and was in accordance with morphological characteristics. In these isolates, 5 septate macroconidia were dominant that is specific to Fusarium solani f. sp.cucurbitae race 1 macroconidia. None of the isolates were amplified by race 2 taxon-specific primers. Our study showed that, race 1 of F.solani is the dominant race of the pathogen in Shahrood, Jiroft and Varamin provinces which can help to implement effective disease management strategies.
 

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In this study the cellulytic activity of different species of Iranian Trichoderma isolates including Trichoderma harzianum (NAS-H101), T. aureoviride (NAS-AV106), T. pleuroticola (NAS-P109), T. longibrachiatum (NAS-L110), T. ghanens (NAS-K108), T. virens (NAS- Vi114), T. atroviride (NAS-A113) and T. atroviride (NAS-A112) was studied. The extracellular protein concentration of these isolates was determined by the dye binding method of Bradford. The molecular weight of cellulase enzymes was studied using SDS-PAGE. The lowest extracellular protein production was observed in NAS-K108. The highest Endo and Exo-glucanase activity were observed in NAS-L110 and NAS-A113, respectively. The SDS-PAGE profiles had several enzyme bands such as cellobiohydrolases, endoglucanases and β-glucosidases. The NAS-K108and NAS-P109 had both enzyme bands of CBH I and CBH II, but other isolates had only a sharp enzyme band correlated to CBH I or CBH II. The highest synergy was observed in FPase of NAS-A112, that contained a large amount of Cel 6A (CBH II) and a minor amount of Cel 7B (EG I). The results indicated that NAS-A113 overproduces cellulases, ß-glycosidase, and the extracellular enzymes, which suggest that this species might be utilized as a biological agent and or a source of enzymes for cellulose degradation in colloidal cellulose.
 

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Beans are major feed crops belonging to the family Leguminosae, representing one of the most consumed legumes in Iran. Root rot diseases account for high yield losses in bean crops annually, driving the need to identify causative pathogenic agents. During the cropping season of 2019, samples were collected from rhizosphere and infected plant tissues in Khomein county. Of the total 80 purified isolates, 19 fungal isolates were selected for morphological and molecular identification studies. Fusarium equiseti, Fusarium acuminatum, and Macrophomina phaseolina were isolated from the infected crown and root tissues. Their pathogenicity on bean cultivars (Yaghout, Dorsa, and Koosha) is reported for the first time from Markazi province. However, the pathogenicity of fifteen saprophytic and pathogenic fungi species that are isolated from the rhizosphere needs to be confirmed in further studies. Disease symptoms were found to be more severe on pinto beans than red and white beans. In all cases, molecular studies using ITS and tef genomic region confirmed the morphological results. Briefly, these fungal species are introduced as bean root rot causal agents in Khoemin county, which needs to be considered in upcoming breeding programs.

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The potential of Trichoderma spp. for biocontrol of phytopathogenic fungi has been well documented. In this study, the wild-type isolate of Trichoderma aureoviride (Tv59) was treated with the target dose of 250 Gy as the optimum dose. Twenty-six mutants were preliminarily screened based on better growth rates. In vitro, antagonistic evaluation of the 26 mutants and wild-type was performed against two Macrophomina phaseolina isolates (F33 and H7). Six mutants (Tv2(4), Tv20(6), Tv25(6), Tv3(3), Tv4(5), and Tv3(4)) showed remarkable inhibitory activity and were selected for further examination in greenhouse trials. Greenhouse assessment of the selected mutants against M. phaseolina isolates revealed Tv20(6) and Tv25(6) as the most highly effective treatments screened for the measured indices. Moreover, the total genomic DNA of the wild-type isolate and its 26 corresponding mutants were analyzed to determine their genetic variability through the RAPD technique. Five RAPD primers generated different banding patterns and yielded a total of 178 amplified fragments, 172 amplicons (96.62%) were polymorphic. While the dendrogram obtained by UPGMA cluster analysis of combined RAPD fingerprints differentiated the wild-type from its mutants at approximately 40% similarity level, the mutants were categorized into two clusters. Based on Jaccard similarity coefficients, eight mutants (Tv25(6), Tv1(5), Tv14(5), Tv20(6), Tv3(4), Tv40(6), Tv33(6), and Tv14(6)) showed the lowest genetic similarities with the parental isolate. The possibility of improvement in biocontrol effectiveness of T. aureoviride through random mutagenesis and detection and differentiation of genetic changes induced by gamma rays using RAPD analysis was successfully proved in the present study.

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To identify the endophytic fungi of the caper plant, samples were collected from the healthy leaves, stems, and roots from Bushehr and Qom provinces during the summer and early autumn of 2022. Isolation and purification of fungal isolates were performed on potato dextrose agar and 2% water agar culture media, respectively. A total of 102 fungal isolates were obtained. Morphological characteristics and molecular data of the ITS region and TUB gene were used to identify the fungal species. Based on the results, Microascus cirrosus and M. terreus were identified as new endophytic fungi of caper for the first time in the world, and M. terreus was introduced as a new record for the funga of Iran.


 

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 Stem rust, caused by Puccinia graminis f. sp. tritici (Pgt), is one of the most important diseases of wheat with devastating epidemics in Iran and the world. In this study, we evaluated some Iranian wheat landraces in a greenhouse at the seedling stage against a new pathotype related to Ug99 of Pgt, which was collected from Iran and designated as TTSSK. Marker analysis was done on resistant landraces. Molecular markers for detecting some Sr genes were used. The results showed that Sr22, Sr35 and SrWeb provided resistance against TTSSK in the resistant landraces. In addition, some of the susceptible landraces that were resistant at adult stage were used for Sr2 analysis. The results showed that some of these landraces were carrying other adult plant resistance gene/genes except Sr2. To evaluate the defence gene expression in compatible and incompatible interactions, cv. Morocco (susceptible) and KC-440 landrace (resistant) were used. Sampling was done at 0, 12, 18, 24, and 72 hours post inoculation (hpi) with stem rust isolate and water as mock treatment. β-1,3 glucanase gene expressions were studied using qGLU-S and qGLU-AS primers. Also, 18srRNA, β-tubulin and EF1-α genes were used as internal control. The results showed that in incompatible interactions, the defence gene expression was increased at 24 hpi, but in compatible interactions, expression level reached the peak at 12 hpi and it significantly decreased at 18 hpi. The results revealed that the expression of defence genes such as β-1,3 glucanase was earlier in compatible interactions than in incompatible interactions, but the quantity of expressed gene was less than in incompatible interactions.