جستجوی مقالات مرتبط با کلیدواژه « its-rdna » در نشریات گروه « گیاهپزشکی »

Mirzaeipour Z, Bazgir E, Zafari D, Darvishnia M (2023) Effect of temperature and culture medium on the growth and sporulation of eight Trichoderma species. Plant Pathology Science 12(2):105-116. DOI: https://doi.org/10.2982/PPS.12.2.105

Trichoderma species are important agents of biological control of soil-borne plant pathogens. The growth and reproduction of these fungi are influenced by the culture medium and temperature. This study was conducted to determine the effect of temperature and culture medium on the growth and sporulation of Trichoderma species. Ten isolates of Trichoderma species were isolated from agricultural soils of different regions of Lorestan Province, Iran. The study of morphological characteristics and sequencing of ITS-rDNA, and tef1α gene regions showed that they are belong to eight species of Trichoderma. Investigating the effect of four types of culture medium and five temperatures to determine optimum culture medium and temperature for the growth and reproduction of these fungi, showed that the Potato/Dextrose/Agar (PDA) medium is the best, and the temperature of 20 to 30 degrees Celsius is optimal for the growth and reproduction of these fungi. Evaluation of their ability to inhibit the growth of the soil-borne plant pathogenic fungus Rhizoctonia solani in vitro, showed that T. harzianum LT8 has the most inhibition ability. Therefore, this isolate can be used as a potential biocontrol agent for this plant pathogenic fungus in future research.

Ghaderi F, Mohammadi H (2023) Occurrence of jujube brown spot disease in Iran. Plant Pathology Science 12(2):95-104. 

Jujube tree has a natural distribution in tropical and sub-tropical regions of Asia. Symptoms of brown-to-black spots on leaves, and fruits, and twigs blight were observed in the hills of the suburbs of Nurabad County, Fars Province, Iran, in 2022. This research was conducted to identify the cause of this disease based on morphological and genetic characteristics. The diseased leaves and branches of the neighboring trees in this area were sampled. The pathogen was isolated and purified after surface disinfection of disease tissues on potato/dextrose/agar medium. Its morphological characteristics were studied and the fungus Nothophoma quercina was identified. Phylogenetic analysis base on the comparison of beta-tubulin (tub2), and ITS-rDNA genes sequences, with related fungi in NCBI Gen Bank, confirmed the of N. quercina species. Its pathogenicity was proved on the side cut jujube branches based on Koch's postulates in vitro. This is the first report of brown spot and twigs blight of the jujube trees caused by N. quercina in Iran.

Strawberry is a major fruit cultivated in Kerman greenhouses. During visiting strawberry cultivation greenhouses, black root rot symptoms were detected on strawberry plants. In order to identify the causal agents of the disease, symptomatic tissues were collected and transferred to the laboratory. Cylindrocarpon-like isolates were consistently recovered from infected tissues.  Based on morphological characteristics as well as sequence data, the causal agent was identified as Dactylonectriamacrodidyma. Colonies of D. macrodidyma on PDA were brown with yellow (honey) pigmentation at the margins. Macroconidia on SNA medium were 1–3 (–4) septate, straight, cylindrical (sometimes widening toward the tip), apical cell slightly bent to one side, 40 (±11) × 6.3 (±1.8) µm with free-standing, slender, unbranched conidiophores. Microconidia with 0–1 septum, ellipsoid and ovoid 10.5 (±3.2) × 4.1 (±1.6) µm. The results of pathogenicity tests showed that the tested isolates were pathogenic to strawberry. According to the knowledge, this is the first report of D. macrodidyma on strawberry.

Walnut tree is one of the most important nut crops in Iran. Dieback and decline of walnut trees are some of the factors limiting the cultivation and sustainability of this crop. During 2017 and 2018, field surveys were conducted on walnut orchards in Yazd province to study of fungal pathogens associated with diseased trees. Wood samples were collected from diseased branches showing canker, dieback and gumming symptoms. In the laboratory, affected branches were cut transversally and infected wood tissues were cut into small pieces. Wood pieces were plated on a potato-dextrose-agar (PDA) after surface sterilization. In this study, 10 isolates of a fungus were obtained from affected trees. Based on morphological and molecular (for two selected Iranian isolates based on ITS-rDNA and tef1-α gene sequences) characteristics, all isolates were identified as Graphium carbonarium. Based on literature reviews, this is the first report of this speciesassociated with necrotic wood of walnut trees in the world.

Mauginiella scaettae is one of the most critical and devastating fungal pathogens causing date palms inflorescence rot (khamedj). This pathogen, in severe attacks, can cause 80% loss of the annual harvest. In this study, seven SSR loci (have previously been isolated and characterized in Phaeosphaeria nodorum) were evaluated for transferability on 13 single-spore isolates ofM. scaettae obtained from eight different regions of Khuzestan province, Iran. A high level of transferability of SSRs was detected. Five primer pairs, including SNOD1, SNOD26, SNOD22, SNOD17, and SNOD21, were successfully amplified and produced an amplification product of the expected size range in thirteen isolates collected from eight locations. Two microsatellite markers, including SNOD5 and SNOD16, were not amplified and showed no amplification. The rate of amplification of five amplified SSR loci was different among isolates. A total of sixteen alleles were obtained across the five SSRs loci for thirteen isolates. Among all isolates examined, the highest rate (92.3%) and the lowest rate (7.7%) of amplification were done for SNOD26 and SNOD21 SSR loci, respectively. The loci SNOD1, SNOD26, and SNOD22 generated four, and SNOD17 locus generated three alleles, and the lowest number of alleles (one allele) was identified in the SNOD21 locus.

In order to isolate and identify endophytic fungi of Phragmites australis, numerous samplings were conducted from the plants grown in the southern areas of the Caspian Sea in Guilan, Mazandaran and Golestan provinces and saline soils around the Lake Urmia at province of East Azarbaijan. Twenty-one isolates of the genus Radulidium were obtained from healthy tissues of P. australis plants. Morphological studies and molecular analysis based on ITS-rDNA sequence revealed that the isolates belong to the R. subulatum. To the best of our knowledge, this is the first report of R. subulatum from P. australis to the mycobiota of Iran.

Common and dwarf bunt of wheat are recognized as being caused by three closely related species, Tilletia caries and T. laevis as common bunt, and T. controversa as dwarf bunt. The morphological characteristics of two species including T. controversa and T. caries were studied from wheat grown in two provinces of Iran, Lorestan and Chaharmahal–o-Bakhtiari during 2014-2015. In this study, morphological characters could not completely distinguish these pathogens, as in some properties, they showed similarity to T. laevis. So, a collection of twenty wheat bunt isolates was used to compare species in morphological characteristics and phylogenetic relationships. Phylogenetic analyses were presented based on three PCR amplified nuclear DNA fragments including elongation factor 1 alpha (EF1α), the second largest subunit of RNA polymerase II (RPB2) genes and ITS-rDNA region. Maximum likelihood (ML) method was used to determine the phylogenetic relationship among isolates using MEGA v.6 and BEAUti and BEAST v1.6.1 software. Maximum likelihood bootstrap (BS) values and Bayesian posterior probabilities (PP) values were applied as criteria for strongly supported clades. Two species including T. controversa and T. caries were distinguished as different species with DNA sequence information.

Moldy Boletus sp. and Xerocomus sp. were collected from several locations at the campus of the University of Tabriz, Iran. Fungicolous fungal isolates were recovered and characterized by the combination of morphological traits and phylogenetic analyses of combined ITS and LSU sequence data. Fungal isolates were identified as Sepedonium microspermum. This is the first report of S. microspermum on Xerocomus sp. from Iran which is comprehensively described and illustrated.