samin hosseini

The behaviour of steel circular hollow section (CHS) T-joints under combined fire load and out-of-plane bending (OPB) is investigated. A review of the literature indicates that the subject has not been previously considered by researchers. The authors carried out the first laboratory experimental study on OPB behaviour of simple steel tubular T-joints under standard fire. The results of an experimental and numerical study performed on three small-scale steel tubular T-joint specimens is reported. One specimen was tested at ambient temperature under quasi-static incremental OPB moment in the brace and the other two specimens were tested under OPB moment plus exposure to ISO-834 standard fire.In order to have a deeper insight into the strength and failure mechanism of steel tubular T-joints under fire, their OPB behaviour was also studied using a coupled mechanical-thermal finite element modelling. The numerical model was validated against the experimental results and reasonable agreements were achieved. A parametric study was then performed on the OPB fire behaviour of full-scale steel tubular T-joints. The results showed that the superimposed OPB ratio in the brace and the diameter ratio parameter had more pronounced effects on the fire response of the joint as compared to other geometric and loading parameters. Increasing the the diameter ratio parameter from 0.2 to 1, reduced the joint’s residual rotation by 56 % and increased the critical temperature by 23 %. By increasing OPB ratio from 0.2 to 1, the residual rotation increased by 245 % and the critical temperature decreased by 37%.

The present study aimed to investigation of root colonization percent and spore population of Arbuscular mycorrhizal fungi (AMF) in soils of 9 regions of Rafsanjan city. Also the effect of climate and some physical and chemical properties of soil including pH, EC, organic carbon, amount of absorbed P and B soil and amount of silt, sand and clay on these two factors were evaluated. Samples were collected from the rhizosphere of different plants and AMF spores were isolated from the soil samples using the wet sieve method. After root staining and spore extraction of spores from soil, root colonization and spore population determined. Az the results all samples have arbuscular mycorrhizal symbiosis. The average root colonization percent ranged from 17.7% in Western suburb to 83.3 % in Raviz and the average spore population per 10 gr of soil samples ranged from 5.68 in Western suburb to 139.2 in Davaran. There was significant and positive correlation between the spore population and root colonization percent (α= 0.01). There was significant and positive correlation between the percent of sand and organic carbon with spore population and root colonization percent (α= 0.01). correlation of measured indices with pH, EC, P, B, silt and clay showed significant and negative correlation(α= 0.01). furthermore, the results showed that the root colonization percent and spore population in each region is related to the host plant and climate as wel.

Arbuscular Mycorrhizal Fungi (AMF), as the most abundant mutual symbiotic association between fungi and plants in the soil, are of great ecological and economic importance. The present study aimed to identify AMF species associated with different plant roots based on morphological and molecular characteristics of ß-tubulin gene sequences of collected samples in Raviz and Daveran regions of Rafsanjan city.

Samples were collected from the rhizosphere of different plants and AMF spores were isolated from the soil samples using the wet sieve method. The identification was performed based on morphological characteristics of the spores such as the color, shape, surface ornamentation, size, wall structure as well as characterization of the spores in water. The DNA of the fungi was extracted from single spores and partial sequences of ß-tubulin gene were amplified by three nestedPCR using appropriate primers. The PCR products of the selected samples were sent for Sanger sequencing. The phylogenetic relationship of the selected sequences with other available isolates in GenBank was analyzed using the Maximum likelihood method.

Based on morphological characteristics and phylogenetic analysis of the partial sequence of ß-tubulin gene, the following species were detected: Funneliformis mosseae, Funneliformis coronatum, Gigaspora gigantean, Scutellospora calospora, andSeptoglomus constrictum. F. mosseae followed by F. coronatum were recognized as the dominant species in the present study.

The partial sequence of ß-tubulin gene was well separated from the studied orders, families, and genera of arbuscular mycorrhiza fungi. All the identified species in this study were placed in the expected taxonomic level. The results of the molecular analysis confirmed the classification of species based on morphological characterization.

Bean Yellow Mosaic Virus (BYMV) belonging to Potyvirus genus and Potyviridae family has a worldwide distribution and a broad host range. In the present study, the phylogenetic relationships of eight virus isolates isolated from different geographical regions of Iran (East Azerbaijan, Ardabil, Ghazvin, Zanjan, Hamadan, Khuzestan, Fars, and Kerman) during the 2017 and 2018 growing seasons were compared with other isolates that were available in the GenBank.

Plants leaves with viral symptoms were sampled from faba bean fields of different geographical regions of Iran and were transferred to the laboratory. Then, to detect the virus-infected samples, first, DAS-ELISA test was performed using specific antisera. Then, the total RNA of the infected samples was extracted and HC-pro region of selected isolates was amplified and sequenced. Sequence evaluation, phylogenetic relationships, protein structure analysis, and the recombination detection of HC-pro region of the selected isolates were performed using various software.

The selected Iranian isolates were placed in two separate monophyletic groups in the reconstructed phylogenetic tree. Five isolates collected from East Azerbaijan, Ghazvin, Zanjan, Fars, and Kerman and two Australian and Japanese isolates, all isolated from faba bean, were clustered in a monophyletic group. The isolates collected from Ardabil, Hamadan, and Khuzestan, with two other Iranian isolates available in the GenBank, two Indian isolates, and two Japanese isolates were clustered in another group. According to the recombination detection analysis, none of the selected Iranian isolates has been detected as a recombinant isolate. 

Discussion and conclusion:

Understanding the genetic and recombinant changes of the viral population is an important prerequisite for the efficient diagnosis, effective management, and long-term disease control. The results are helpful in developing strategies that lead to BYMV resistance and may be effective in the future if the disease becomes widespread in line with adopting management strategies.

Mycoviruses or fungal parasitic viruses have dsDNA, dsRNA or ssRNA genome. Some of these viruses have a restricted host range and can infect certain strains of host species. In contrast, some other viruses have wider host range and can infect different species of a fungal family. In most cases these viruses are transmitted by anastomosis of mycelium. In a phenomenon called hypovirulence, most of these viruses decrease the virulence of their host fungus. Discovery of hypovirulence revealed the biocontrol ability of mycoviruses. In summary, mycoviruses could be implemented as powerful agents for biocontrol of fungal pathogens and induction of resistance in plants.

Bean yellow mosaic virus (BYMV) is a member of genus Potyvirus within the large and economically important family Potyviridae. During 2010-2012 growing seasons, a BYMV isolate was detected in sunflower fields of Isfahan province (Iran), tentatively designated as BYSun. Virions of BYSun were purified using two cycles of differential centrifugation on 20% and 30% sucrose cushions. SDS-PAGE of purified virus preparations revealed a single protein band with MW of about 33.5 kDa for BYSun. The prepared antiserum against BYSun reacted specifically with infected but not with healthy broad bean sap in serological tests. A 680 bp DNA fragment, corresponding to the partial CI (cylindrical inclusion) region of the viral genome of four selected isolates, was amplified using CIRev/CIFor primers able to detect members of the family Potyviridae. BLAST search showed that the most similar sequence in the databases was that of BYMV-S. Nucleotide sequence identities of BYSun whole genome to those of other BYMV isolates ranged from 75 to 98%. The deduced amino acid sequence of BYSun polyprotein was 85-99% identical to other isolates of BYMV. Phylogenetic analysis of most parts of the genome (especially CP) of different BYMV isolates sequences revealed eight distinct groups including General, Lupin, Monocot, Broad bean, W, Pea, Canna and S. These groups correlated with original natural isolation hosts. BYSun and BYMV-S grouped apart from other isolates, so it was placed within a distinct group called “S”. BYSun is the first isolate of BYMV with fully sequenced genome in Iran.

Tomato (Lycopersicum esculentum Mill.) is one of the most important crops in Iran and throughout the world. In the previous survey conducted in 2013, PVY was introduced as the dominant virus in Yazd (Iran). In the present study, the partial genome sequence of a selected isolate called T5 was determined and analyzed. Following total RNA extraction of the T5 isolates, three fragments with 824, 1700 and 837 bp lengths were amplified using CPr/CPf, M4T/Sprimer and P1/P2 primer pairs respectively in RT-PCR. According to the nucleotide and amino acid sequences comparison of the CP, NIb and P1 regions of the isolate with the other PVY isolates in the Genebank, T5 is a member of NTN strain.

Bean yellow mosaic virus (BYMV) is one of the most difficult to manage viruses because of having a wide host range and numerous vectors. In this survey the effect of three bacterial strains of Pseudomonas fluorescens, including CHA0, VUPF5 and ΔVUPF5 on BYMV in 16 common bean genotypes has been investigated. Common bean seeds were saturated with suspension of bacterial strains with concentration of 108 cfu/cc before cultivating. The experiment was performed in a completely coincidence model with three replications. Afterwards, all plants except controls were mechanically inoculated with a BYMV isolates. Finally, the concentration of chlorophyll a/b, total chlorophyll, carotenoid and three nutritional elements including Mg, Zn and Fe in common bean genotypes were determined. The results revealed that the mentioned strains could significantly reduce viral damages in most of genotypes. In general, ΔVUPF5 isolate had the best biocontrol effect among three selected bacteria.

Faba bean is an important legume in Iran and many other countries. Bean yellow mosaic virus (BYMV) has been found in faba bean fields in a number of countries. In this survey، during 2010 growing season، a total of 240 faba bean samples with mosaic، distortion and stunting symptoms suspected for BYMV infection were collected from faba bean fields of Jiroft، Kerman province. These samples were analyzed using BYMV polyclonal antibody in serological tests (DAS-ELISA and TPIA). In faba bean fields of Jiroft، the percentage of infection with BYMV was 62. 5. Among the collected weeds، only two samples of Chenopodium quinoa were infected by BYMV. In greenhouse mechanical inoculation assays، the virus induced local lesions and systemic symptoms on a number of plant species of Chenopodiaceae، Amaranthaceae، Fabaceae، Solanaceae and Brassicaceae families. A fragment of 1700 nt length from the NIb، CP and 3´-UTR regions of a BYMV isolate (J2) was amplified in IC-RT-PCR using a Potyviridae universal primer pairs. BLAST analysis on the partial NIb region of the isolate and comparison of the nucleotide sequence showed that this isolate is similar to a Japanese isolate. This is the first report of occurrence of BYMV in faba bean fields of Kerman province.