امیررضا امیرمیجانی

The present study aimed to evaluate the resistance of 14 common tomato cultivars in the south of Kerman province and Hormozgan province, including Afra, Badro, Basimo, Bernetta, Brivio, Canyon, Comodoro,Elisa, Golsar, Karun, Matin, Sunseed 6189, 4129 and 8320 at the stage of four true-leaves against Fusarium oxysporum f. sp. radicis-lycopersici, under greenhouse conditions and to study the presence or absence of frlresistance gene in the tomato cultivars based on the SCARFrl marker. Based on the results of comparison of the disease index, morphological characteristics including root length, shoot height, root fresh and dry weight, shoot fresh weight and total fresh weight as well as frl gene amplification using SCARFrl-F/SCARFrlR primers, Canyon, Comodoro, Karun and 4129 were recognized as the most resistant and Bernetta, Elisa, Golsar and Matin were recognized as the most sensitive cultivars to FORL UJFCC1919. Other cultivars including Afra, Badro, Basimo, Brivio, Sunseed 6189 and 8320 showed different degrees of sensitivity to this pathogen. Using SCARFrl-F/SCARFrl-R primers, a 1000 bp fragment was amplified in the cultivars Canyon, Comodoro, Karun and 4129 which indicates the presence of frl gene with dominant homozygous (RR) alleles. Using this primer, a 950 bp fragment was amplified in Bernetta, Elisa, Golsar, Matin and 8320 cultivars, which indicates the absence of the frl gene and the presence of homozygous recessive (rr) alleles. In addition, in Afra, Badro, Basimo, Brivio and Sunseed 6189 cultivars, two 900-1000 bp fragments were amplified, which indicates the existence of heterozygous (Rr) alleles in these cultivars.

Root and crown rot is a common tomato disease in the major production areas of Hormozgan province. The present study was conducted to isolate, identify, and determine the frequency of fungal agents associated with tomato root and crown rot in Hormozgan province. In total, 984 fungal isolates were obtained from tomato plants with yellowing, wilting, and root and crown rot symptoms. Identification of the isolates was done based on the morphological characteristics and the comparison of the obtained sequences of the ribosomal internal transcribed spacer region (ITS-rDNA) and parts of the translation elongation factor-1 alpha (tef1-α) gene with relevant sequences available in GenBank. According to the results, the highest frequency belonged to Fusarium oxysporum isolates (73%), and afterward to Rhizoctonia solani and F. acutatum species with eight and one percent frequencies, respectively. The results of the pathogenicity tests of the fungal species on tomato seedlings hybrid Sunseed 6189 at the stage of four true-leaves revealed that all three species were pathogenic on tomato seedlings and caused root and crown rot, yellowing, and death of the plant aerial tissues. Pathogenic isolates of F. oxysporum were identified as F. oxysporum f. sp. radicis-lycopersici using sprl-specific primers. To the best of our knowledge, this is the first report of F. oxysporum f. sp. radicis-lycopersici on tomato in Hormozgan province, and the first report of F. acutatum as tomato root and crown rot agent in the world.

During the visit of some banana cultivation areas in 2021 and 2022, sampling of leaves and roots with symptoms of leaf spot and wilting was done in Sistan and Baluchistan, and Hormozgan provinces. After being transferred to the laboratory, twenty-eight isolates belonging to the genus Fusarium sensu lato were isolated from the infected samples.. The isolates were identified by carnation leaf agar and SNA under 12 hours of near UV light and 12 hours of darkness. The results of the morphological investigation and phylogenetic analysis based on Elongation factor 1-α (EF 1-α) gene region showed that isolates belonged to Fusarium oxysporum (12 isolates), Fusarium incarnatum (10 isolates), Neocosmospora sp. (7 isolates), and two unknown isolates of Fusarium. The pathogenicity test was conducted to compare the pathogenicity of the species on the Dwarf Cavendish banana variety. Pathogenicity test results showed the isolates could cause leaf spot (Fusarium sp. and Fusarium incarnatum) and wilting (Fusarium oxysporum, Fusarium incarnatum and Neocosmospora sp.) in banana plants under greenhouse conditions. Based on our knowledge, this is the first report of F. incarnatum and Neocosmospora sp. pathogenicity of banana in Iran.

In the spring and summer of 2021, stems and branches of Jand trees (Prosopis cineraria L.) with canker symptoms were collected from the forests of Sahara-Sandy region, Sistan, and Baluchestan province, Iran. Disease incidence was calculated by counting the number of infected trees and part of each tree, ranging from 70 to 100%. Stems and branches with canker symptoms and necrosis were incubated at room temperature in a moist chamber and Water-Agar 2%. After seven days' incubation, black conidia and conidiophores developed. A fungus belonging to the genus Alternaria was isolated from surface-sterilized samples. To identify isolates by morphological criteria, purified cultures were incubated at 23-25°C on Potato Carrot Agar (PCA) medium under 8/16 h light/ dark cycle photoperiod for 5-7 days (Simmons, 2007). Based on morphological characteristics such as colony color, sporulation pattern, sizes of primary and secondary conidiophores, conidia, and surface ornamentation of conidia, isolates were grouped into infectoria sections of Alternaria. On PDA after 7 days, colonies dark with gray aerial mycelia. Conidia were obclavate in long or short chains predominantly with longitudinal septa (Figure 2). The isolate was further identified by sequencing the internal transcribed spacer (ITS) region, glyceraldehyde 3-phosphate dehydrogenase (gpd), and plasma membrane ATPase (ATPase) (White et al. 1990; Berbee et al., 1999). In phylogenetic tree is constructed for the Infectoriae section based on three gene regions (Poursafar et al. 2017; Marin-Felix et al., 2019), the S3BK isolate lied with Alternaria infectoria CBS 210.86, and A. frumenti CBS 119401 in the same clade.

Pyriculariaceae family has newly been established several new genera and species. Indeed, some species originally described Pyricularia subsequently have been synonymized or transferred to other genera. In this study an overview of taxonomical and phylogenetic findings, symptomology of Pseudopyricularia species and an identification key to Pseudopyricularia species by morphological criteria are provided.

During a survey of leaf spots on tropical trees, symptomatic leaf tissue of mango trees was collected from several sites in the Hormozgan, and Sistan and Baluchestan provinces. Isolations were performed on potato dextrose agar (PDA) and wet paper media at 25 °C. As a result, several fungal species were obtained, that three isolates belonging to Bartalinia and four of Beltrania. Phylogeny based on DNA sequences of the large subunit of the ribosomal RNA (LSU) and internal transcribed spacer (ITS-rDNA) regions combined with morphological criteria revealed the species of Bartalinia pini and Beltrania rhombica. To our knowledge, both species, B. pini and Be. rhombica are new species for the Funga of Iran.

Gray mold, caused by Botrytis cinerea is one of the most important diseases in strawberry, causing pre– and postharvest fruit rot. One of the safe and healthy ways to reduce this disease is biocontrol and the use of biological control agents. In this study, using culture–based methods, 268 bacterial strains, and 136 fungal isolates, were isolated and purified from the phyllosphere of strawberry plants in the greenhouse and field in Jiroft city. The antagonistic effect of the isolates against the pathogen B. cinerea was investigated using dual culture and investigation of the inhibition zone, and the effect of volatile compounds under in vitro conditions, as well as the antifungal properties of the antagonistic bacteria on strawberry fruit. Identification of the selected bacterial and fungal strains was made by polymerase chain reaction, respectively, by determining the nucleotide sequence of a part of the 16S–rDNA gene and its region. The results showed that among the examined isolates, bacterial isolates UJB1, UJB3, UJB4, UJB10, UJB5, UJB6, UJB7, UJB11, UJB2, UJB8 and UJB9 and fungal isolates UJF1300, UJF1301, UJF1302, UJF1303, UJF1304, UJF1305 had an effective inhibitory effect against B. cinerea and their volatile compounds reduced pathogenic mycelium growth. In evaluating the antifungal impact of bacterial isolates on strawberry fruit, bacterial isolates UJB8, UJB2, UJB11, UJB6, UJB5, UJB10, UJB4, and UJB1 significantly increased the disease index caused by B. cinerea compared to They reduced the witness. According to morphological and molecular data, bacterial isolates belonging to the genera Delftia (isolates UJB1, UJB3, UJB4, UJB10), Bacillus (isolates UJB5, UJB6, UJB7, UJB11, and UJB2) and Stenotrophomonas (isolates UJB8 and UJB9) and fungal isolates belonging to Albifimbria verrucaria, Aspergillus terreus, Leptosphaerulina australis, Pilidium lythri, Pseudozyma flocculosa, and Seimatosporium pistaciae species.

In 2018, a drastic Ascochyta blight epidemic on chickpea crops occurred in the Northwest of Iran. A survey was conducted in the region to identify races of Ascochyta rabiei and estimate the yield loss. Infected plant samples were taken from an infected field in Pasvah region and transferred to the lab at Dryland Agricultural Research Institute (DARI), Maragheh. In addition to A. rabiei, a Cladosporium-like taxa is also isolated from plants showing disease symptoms. Based on morphological characteristics and DNA sequence comparisons, isolates of this fungus were identified as Cladosporium halotolerans. Pathogenicity tests and Koch’s postulates were verified and fulfilled on chickpeas under controlled conditions. The disease symptoms developed on the host plant after 5 days after inoculation (dai) under controlled conditions included appearing yellow-brownish leaflets on the branches that latterly turned to wilt and were covered with gray-black mold. Histological studies also confirmed the pathogenicity of this fungus on chickpeas. Host range investigations were carried out on the further six species belonging to the Fabaceae, including garden pea, lentil, garden vetch, narbon vetch, bitter vetch, and grass pea. Results showed that this pathogen can produce the same disease symptoms on all inoculated, as well. This study represents the first attempt to pathogenicity of C. halotolerans on legumes in the world.

The genus Cladosporium is one of the largest genera of fungi. Its species live in different ways: as plant pathogens, as saprobes in the soil or on decaying plant materials, or as hyperparasitic on other fungi. Morphological characteristics of conidia such as shape, formation and surface ornamentation, the features of conidiophores including shape, ramification and conidiogenous loci, and sequencing data from different regions of DNA are very important for identification of Cladosporium species. In this article the important morphological characteristics and genomic regions which are useful for identification of closely related or cryptic species of this genus, are illustrated.

Cucumber downy mildew caused by Pseudoperonospora cubensis is one of the most important diseases of cucumberin Iran. In this investigation the role of β-Aminobutyric acid (BABA) in reducing this disease was studied via spraying of leaves and soil drench. The plants were treated with BABA and after 24 hours leaves were detached and inoculated with the pathogen and kept in a plastic box with favorable conditions for the disease agent. The disease was evaluated six days after inoculation with pathogen by scoring the leaves between 0-9 and the disease index calculated. Result showed that spraying the leaves by BABA had no effect on the disease reduction but soil application of this compound statistically reduced the disease (p≤0.05). The second phase of the experiment was done for evaluating the effect of BABA on the activity of enzymes such as β-1,4-Glucanase, phenylalanine ammonia-lyase, peroxidase and polyphenol oxidase. Enzymes activity was assayed at 0, 24, 48, 72 and 96 hours after inoculation with the pathogen. Results showed an increas jn enzyme activity at 48-hours post-inoculation with the pathogen and then β-1,4-Glucanase, PAL, and POX enzymes activities decreased slowly, while PPO enzymes activity decreased rapidly.

Biological control of soil-borne diseases of plants has received serious attention among plant pathologists in recent years. In this regard, Rhizobacteria, more specifically fluorescent pseudomonads are known as an effective biocontrol of plant diseases. Pseudomonas spp. are promising agents to manage the disease caused by Sclerotinia sclerotiorum and Pythium aphanidermatum. In this study, we screened 81 bacterial isolates from cucumber rhizosphere for their antagonistic effects against the pathogens using dual culture method and investigating their ability to produce inhibiting volatile metabolites. Results indicated that isolates 19C, 21B, 24A, 33B, 33C, 38A, 42D, and 43C had significant inhibitory effects on the pathogens and their volatile metabolites significantly reduced the mycelial growth of the pathogens in comparison with controls. In greenhouse trials, isolates 19C and 24A reduced disease index of Pythium aphanidermatum more than 70% and that of Sclerotinia sclerotiorum more than 60% compared with controls. The isolates 19C, 24A, 33B, and 33C were able to produce protease. Isolate 19C was able to produce surfactin and isolates 33B and 33C were able to produce hydrogen cyanide. Molecular identification of isolates was conducted based on partial sequence of 16srDNA amplified by specific primers fD1 and rD1 thereby the isolates showed significant homology with Pseudomonas spp., Stenotrophomonas spp. and Flavobacterium spp.

In a taxonomic survey on Cladosporium species in Iran، 35 specimens were collected from different substrates of various localities in Guilan (N. Iran) during 2011–12. Seven species viz. C. cladosporioides s. str.، C. oxysporum، C. halotolerans، C. perangustum، C. pseudocladosporioides، C. sphaerospermum، and C. tenuissimum are identified and the latter five species are new records to Iran.

Rice aggregate sheath spot disease is caused by Rhizoctonia oryzae-sativae (Sawada) and occurs more or less at all paddy fields in Guilan province. In this study some aspects of biology of Rhizoctonia oryzae-sativae and optimal growth temperatures were examined. Rice straw colonized with mycelia and sclerotia of Rhizoctonia oryzae-sativae were incubated in different field conditions such as natural field soil surface, 5 cm deep under the soil, flooding condition, on soil surface at the borders of the field. The effects of variable conditions on viability of fungus were studied. Moreover, the effects of different temperatures (5, 0, -5, -10, -15, -20 and -72) on germination and viability of sclerotia were assessed during one month. Optimum growth rate was found to take place at 32 ºC. Results showed that R. oryzae-sativae overwinters as mycelia on the rice straw on the soil surface in the field, soil surface at field margins and as sclerotia in the soil. According to the results 30.4% of sclerotia were able to germinate after one month storage at minus 72 ºC.

Several species of mitosporic fungi collected from Guilan and Mazandaran provinces were examined and as a result، four species viz.، Pestalotiopsis acaciae (on Diospyros lotus)، Prathigada condensata (on Gleditschia caspica)، Stigmella effigurata (on Castanea sativa)، Teratosperma uniappendiculatum (on perthecia of Cryphonectria parasitica) are reported as new records for Iranian mycobiota. Moreover، Teratosperma uniappendiculatum is recorded for the first time on perithecia of Cryphonectria parasitica in the word. Cornus sp. and Vigna unguiculata are reported as new hosts for Seiridium unicorne and Corynespora cassiicola، respectively.