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To investigate the infection of carnations (Dianthus caryophillus) to common viruses, a total of 130 samples showing suspected viral disease symptoms were collected from 10 commercial greenhouses located in Mahallat City, Markazi Province. Total DNA and RNA were extracted and amplified by PCR and RT-PCR methods, respectively, using generic primers for the genera Potyvirus and Orthotospovirus and also specific primers of Carnation mottle virus (CarMV), Carnation necrotic fleck virus (CNFV), Carnation etched ring virus (CERV), Carnation latent virus (CLV), Carnation vein mottle virus (CVMV) and Cucumber mosaic virus (CMV). Results revealed that the estimated rates of infection in the collected samples for different viruses in decreasing order were for CarMV, CNFV, CERV, CMV and CVMV, while CLV and species of genus Orthotospovirus were not detected. Mixed viral infections were also investigated and among all of the 130 collected samples, 3.1% showed mixed infections with CarMV, CNFV, CVMV, CERV and CMV, 32% with CarMV, CNFV, and CERV, 20% with CarMV and CNFV, and 9% with CarMV and CERV. For phylogenetical assays, NIb-CP fragment of the CVMV genome was amplified, cloned, and sequenced. Phylogenetic trees of two isolates of this virus revealed that the two Iranian isolates of CVMV (IBR and RCM) were phylogenetically divergent. Mechanical inoculation of CVMV on 16 different indicator plant species showed specific symptoms on six of the indicators that were confirmed by RT-PCR. To the best of our knowledge, this is the first report of CMV and first partial genome sequencing of CVMV from a carnation plant in Iran. [ABSTRACT FROM AUTHOR]

Differential induction of genes in wheat (cv. Chamran) in response to Mycosphaerella graminicola was studied using cDNA-AFLP analysis. The three weeks old wheat seedlings were inoculated by the fungal pathogen, then the samples were collected at six time points (0, 12, 24, 48, 72, 96 hours) after inoculation with pathogen. By comparing the expression patterns of induced (infected) with non-induced (uninfected) plants, 276 differentially expressed fragments were identified and sequenced. Blast search of wheat genes assigned these sequences to different functional categories including defense, metabolism, energy, transcription, transport, signal transduction, stress response, secondary metabolism, and unknown sequences. Eight defense-related genes including lipoxygenase, peroxidase (PR 9), chitinase (PR 2, 4, 8), PR-1, thaumatin-like protein (PR5), Phenylalanine Ammonia Lyase (PAL), β-1-3 glucanase (PR3), disulfide isomerase, and methionine sulfoxide reductase were induced 12 to 24 hours after inoculation in this cultivar of wheat. Induction of glucosyltransferase, Catalase, and putative xylanase inhibitor genes were observed around 48 h after inoculation with pathogen. Expression patterns of the other three genes, i.e., chalcone synthase, EXECUTER 1 protein, and nonspecific lipid transfer protein showed that these genes were induced later after inoculation (72-96 hours). Our data showed that expression of the PR- proteins were enhanced 24 h after inoculation, suggesting that they may play a role in the defense against M. graminicola. Expression of lipoxygenase, glycosyltransferase, thaumatin like protein, putative xylanase inhibitor, EXECUTER 1 protein and Nonspecific lipid transfer protein are reported for the first time in this interaction. [ABSTRACT FROM AUTHOR]

The Severe strain of Beet Curly Top Virus (BCTV-Svr) and Beet Curly Top Iran Virus (BCTIV) are considered as the main causal agents of sugar beet curly top disease in Iran and mixed infections of BCTV-Svr and BCTIV usually occur in nature. As the use of resistant cultivars is the safer and stable tool for management of the disease, the objective of current work was to identify sugar beet genotypes resistant to both agents. To this end, the reaction of thirty-eight sugar beet genotypes to infection by each of BCTV-Svr and BCTIV was separately evaluated using their infectious clones under the greenhouse condition. Incubation period, recovery, and disease severity index were considered for selection of resistant genotypes. As a result, ten and seven sugar beet genotypes resistant to, respectively, BCTV-Svr and BCTIV were selected. To evaluate the resistant genotypes, the experiments were repeated under greenhouse condition. In the field experiment with natural infection of viruses, the resistant genotypes were assessed and six sugar beet genotypes (S1 91019, S1 91022, S1 91023, S1 91028, S1 91029, and S1-91041) resistant to BCTV-Svr and BCTIV were identified; which could be used in future breeding programs. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Trichoderma species are known as effective agents used for biological control of plant pathogenic fungi. The Trichoderma harzianum and its mutant isolates were cultured and their traits including, mycelial growth, antagonistic activity and extracellular proteins and enzymes production (Chitinase and Cellulase) were investigated to select the most effective mutant isolates against plant pathogenic fungus Rhizoctonia solani. Also, the purity and composition of enzyme-rich protein samples were evaluated under denaturing gel electrophoresis. This study clearly showed the possibility of improving mycelia growth rate (from 1.18 to 1.33 cm d-1), the antagonistic capability of Trichoderma (from 54.9% growth inhibition of R. solani to 66%), extracellular proteins and enzymes production for biological control of plant diseases through mutation with γ-radiation. Also, compared to wild type strain, protein production in the mutant isolates increased. Moreover, the highest specific chitinase enzyme activities were observed in mutant isolates T. h M8 (42.48 U mg-1) and T. h M15 (38.25 U mg-1). Trichoderma mutant of T. h M8 maintained higher mycelia growth rate and higher ability to inhibit growth of R. solani. The SDSPAGE profiles had several enzyme protein bands such as CelloBioHydrolases (CBHs), EndoGlucanases (EGs), β-Glucosidases (BGLs), endochitinases, and β-(1, 4)-N-acetyl glucoaminidases. SDS-PAGE analysis indicated the presence of different protein bands in the range of 10.5 to 245 KDa. Interestingly, expression of chitinase in 95 percent of mutants was higher than wild type of T. harzianum. The results showed that gamma mutation could increase the efficiency and amount of enzymes in T. harzianum, while these enzymes are involved in antagonistic properties of T. harzianum. [ABSTRACT FROM AUTHOR]

Seventy five bacterial strains were isolated from cucurbits rhizosphere and examined for antagonistic activities against Macrophomina phaseolina isolate 44, the causal agent of melon charcoal root rot disease. The results of screening strains including B2, B11, B12 and BKN showed high potential of antagonistic activities against the pathogen in laboratory experiments. Inhibition of mycelial growth varied from 54.3 to 62.22%, 39.43 to 54.82%, 78.52 to 100%, and 64.45 to 88.89% in dual culture, volatile metabolite, antibiotic production, and cell free culture tests, respectively. In greenhouse experiment, seed treatment with strain B2 significantly (P= 0.01) controlled the disease by increasing plant growth indices including height, shoot and root fresh weight, shoot and root dry weight by 37.98, 36.27, 32.97, 34.44, and 30.39%, respectively, as compared to the control. The biochemical and physiological tests as well as gyrA sequence confirmed these four strains as Bacillus amyloliquefaciens. Results indicated that strain B2 could be an important new biological control agent for charcoal root rot disease of melon. [ABSTRACT FROM AUTHOR]

Apple Stem Pitting Virus (ASPV) is one of the most common viruses of apple and pear trees. During 2012 to 2013, a total of 1053 symptomatic and asymptomatic leaf samples were collected from orchards in nine provinces of Iran. ASPV infection was detected by DAS-ELISA and PCR in 54 samples (5.12%) from seven provinces. Based on the geographical origin, 22 representative isolates were selected for phylogenetic analysis. Twenty-two amplicons with a size of about 370 base pair (bp) comprising partial sequence of the Coat Protein (CP) coding regions of the viral genome were sequenced. Sequence data analysis, showed that the identities of 3'-terminal region of CP gene at both nucleotide and amino acid levels among the Iranian isolates were 95-100% and these isolates were closer to the Asian ASPV isolates than to the other isolates. Constructed phylogenetic tree by Neighbor-joining on the basis of the 3'-terminal region of CP gene sequences showed that the Iranian isolates were categorized into two major groups. Furthermore, phylogenetic and population genetic analysis were carried out on the basis of 3'-terminal region of CP gene which revealed that ASPV isolates were not geographically resolved. Also, all values in the GABranch analysis showed a ratio of substitution rates at Non-synonymous and Synonymous sites (dN/dS) below one, suggesting strong negative selection forces during C-terminal region of the ASPV CP gene history. To the best of our knowledge, this is the first report of distribution and partial genome sequence analysis of the ASPV in Iran. [ABSTRACT FROM AUTHOR]

Macrophomina phaseolina is an important soil-borne pathogen causing charcoal rot in many important crop plants including sesame, in Iran. A total of 60 isolates of M. phaseolina were collected from the main sesame producing regions in ten provinces of Iran. The genetic diversity among M. phaseolina populations was estimated using InterSimple Sequence Repeat (ISSR), focusing particularly on geographic differentiation. Five ISSR primers generated 105 discernible DNA bands, of which 85 (77.11%) were polymorphic. The greatest value of variability (PPB: 60.00%; H: 0.185; I: 0.284) was estimated for Fars population, whereas the least variability (PPB: 9.52%; H: 0.042; I: 0.060) was estimated for Kerman population. Total gene diversity exhibited high levels of variability (HT = 0.186). Analysis of molecular variance indicated a large proportion of genetic variability within populations. [ABSTRACT FROM AUTHOR]

Bacterial leaf streak (BLS) caused by Xanthomonas translucens pv. cerealis (Xtc) is an important disease of wheat (Triticum aestivum L.) worldwide. The management methods presently in practice are insufficient to meet current safety and/or efficacy standards. Therefore, use of resistant genotypes is the best approach to manage BLS. The present study was undertaken to identify possible sources of resistance to Xtc in cereal cultivars and germplasm. Twelve strains of Xtc were isolated from symptomatic leaves in several regions in Kerman province. Out of twelve, nine strains produced the expected Xtcspecific 120 bp fragment using PCR and the primer pairs PABr/PBf. Six strains produced water-soaked streaks covered with exudates on wheat cultivars, whereas the three remaining strains incited only chlorotic streaks with no water-soaking on leaves. A highly virulent strain that caused conspicuous water-soaking and necrosis was used for inoculation of 645 winter and spring wheat, barley, and rye accessions to identify possible sources of resistance to BLS. The fourth leaves of test plants were infiltrated with bacterial suspension and scored after seven to ten days. Among all the accessions evaluated, only two rye accessions, namely, 4538 and 4794, were resistant to BLS. These two rye accessions can potentially be used in breeding rye and triticale cultivars for resistance to BLS. [ABSTRACT FROM AUTHOR]

To study molecular evolutionary characteristics and genetics of beet necrotic yellow vein virus (BNYVV) isolates population from Iran, nucleotide sequences of p25 and coat protein (CP) were determined and the amino acids sequences thus deduced were analyzed using phylogenetic and population genetics methods. A survey of BNYVV in Iran indicated the infection of 288 collected samples out of 392 samples in most beet growing areas and that most of the isolates (92%) were of the A-type and the rest of isolates (8%) were P-type. Our molecular evolutionary analysis showed that CP was highly conserved but allowed to assign all isolates to three distinct groups. Different parts of p25 coding regions were under different evolutionary constraints. The most positive selection was detected at the position 68, the second amino acid of the tetrad motif. Iranian isolates were found to cluster with European isolates into three distinct clusters based on p25 sequences. Population genetics analysis revealed that BNYVV populations have low differentiation (Kt= 3.97145) and low diversity (πT= 0.006, Hd= 0.860) with frequent gene flow indicating lack of phylogeographic structure between populations. [ABSTRACT FROM AUTHOR]

Genetic structure and pathogenic diversity of Sclerotinia sclerotiorum, the causal agent of canola white stem rot, were assessed through Mycalial Compatibility Groupings (MCGs), a comparison and comparing of isolate virulence. Fifty-seven isolates from three different regions in Golestan Province were selected for mycelial compatibility and as well for virulence tests. Within the 57 tested isolates, 35 MCGs were identified, 42.86% of which being constituted of single isolate specimens, were all collected from Ali Abad region. The observed MCGs differed within the three regions. From among the 35 MCGs, 25.71%, 28.57% and 45.72% belonged to Kalaleh, Hashem Abad and Ali Abad, respectively. In Kalaleh, nine MCGs were identified all of which fell into two isolates. Ten MCGs were identified within the Hashem Abad region, eight of which represented two isolates and the remaining were constituted from three isolates. Sixteen MCGs were detected in Ali Abad for which, except one MCG which was constituted of two isolates, the rest belonged to one isolate. Moreover, no MCG was identified as common among these regions. Shannon diversity index (Ho) of MCGs for the whole regions found to be was 0.86 (Htot). Partition of total diversity (Htot) showed that 95.45% corresponded to a variation in diversity within S. sclerotiorum populations. Variation in isolate virulence was tested using a petiole inoculation technique under greenhouse conditions. Isolate virulence varied within the three regions. Moreover, in most cases the differences in virulence of isolates within MCGs were significant. The data indicated that populations of S. sclerotiorum obtained from the studied regions were composed of a heterogeneous mix of MCGs, therefore the population structure of this pathogen as well as variations in virulence of isolates must be considered in disease management systems in these regions. [ABSTRACT FROM AUTHOR]