جستجوی مقالات مرتبط با کلیدواژه "its rdna" در نشریات گروه "گیاهپزشکی"

Pleosporalean fungi are important plant pathogens, saprobes, and endophytes found in a wide range of economically important plants. To identify the fungi associated with branch and stem canker symptoms in plants, the gardens and forests of Guilan and Mazandaran provinces were surveyed, and infected plant samples were collected from common hawthorn (Crataegus monogyna), common rue (Ruta graveolens), and oriental persimmon (Diospyros kaki) plants during the autumn of 2021. Fungal strains were isolated and purified by common procedures, and then were morphologically identified. Molecular identification of the fungal strains was performed using the sequence data of the ITS rDNA region. Based on the combined data, three fungal genera and their related species belonging to the order Pleosporales including Acrocalymma walkeri from oriental persimmon, Setophaeosphaeria badalingensis from common rue, and Tremateia chromolaenae from common hawthorn, were identified and characterized. All these three species are new to the funga of Iran. In addition, Diospyros kaki, Crataegus monogyna, and Ruta graveolens have been reported as new hosts (matrix nova) for the respective identified fungal taxa worldwide

Distoseptispora generally is  regarded as a saprobic lignicolous fungal genus and presently comprises 64 species. Of these, 42 of them were found in freshwater and 22 in terrestrial habitats. Most Distoseptispora species are reported from China and Thailand, which are subtropical and tropical regions. In this study, we report Distoseptispora bambusae as a saprobic fungus on decaying leaves of common bamboo (Bambusa vulgaris) based on morphological characteristics and sequence data of the ITS‒rDNA region. Distoseptispora bambusae was described, illustrated, and its morphology and phylogenetic relationships with similar Distoseptispora species were discussed. To the best of our knowledge, this is the first report of D. bambusae on common bamboo for the mycobiota of Iran and the Middle East.

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.

Oomycete species occupy many different environments and many ecological niches. The family Saprolegniaceae from Oomycota includes widely distributed water molds which usually behave as saprophytes on plants and animal debris. Members of some species may also be pathogenic for plants and fish. Oomycete species identification based on DNA is well established, but DNA barcoding with cytochrome c oxidase subunit I (COXI) and II (COX II) are a relatively new approach. In this study, 57 isolates were obtained from water samples in mazandaran province, Iran. After morphological identification by morphological keys, ITS, COXI , and COX II gene regions of 10 representatives of the isolates were sequenced and 3 genera and 6 species (Newbya recurva, Achlya bisexualis, Dictyuchus monosporus, Saprolegnia ferax, S. bulbosa , and S. debaryana) were identified through BLASTn in NCBI gene bank. The results described in this paper were indicated that except for ITS, COXI and COXII sequencing could also be valuable resources to Saprolegniaceae identification. Except for S. ferax, other described species were new reports for oomycete biota of Iran.

Phytophthora species are a serious threat to plant products worldwide. Therefore, identifying them is the first step in finding a way to treat the disease. The aim of this study was to identify Phytophthora species causing root and crown rot of persimmon trees in Fars province.

Samples were taken from the crowns and roots of diseased persimmon trees, in the summer of 2018-2019. Infected root and crown tissues were cultured in CMA-PARPH medium. Isolates of Phytophthora species were purified by single spore method and morphological and molecular characteristics were used to identify them.

Six isolates were obtained from the roots of diseased persimmon trees and identified as Phytophthora citricola based on their morphological characteristics. Phylogenetic studies based on beta-tubulin (βtub) and 28S rDNA genes showed that all isolates (Iran-Pc1 to Iran-Pc6) were grouped into clade 2 with a validation scale of 100 and confirmed the identification of P .citricola.

This is a new report of persimmon root and crown rot caused by Phytophthora citricola in Fars Province.

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.

Bdellovibrio bacteriovorus is an obligate predator of other Gram-negative bacteria. It grows in the periplasm of the prey cell and finally lyses them, so it has high potentials to be used in biocontrol of plant pathogenic bacteria. The objective of the present study was to isolate and characterize Bdellovibrios bacteria from soil and water samples of Rafsanjan (Kerman province) in Iran. To do this, after sampling, two Bdellovibrios isolates (Sar and Pj) were isolated by using Escherichia coli strain K12 as prey on the two layers agar. The isolates were identified by phenotypic and 16S rDNA PCR amplification and sequencing. The sequencing and phylogenetic studies showed that the strains have more than 99% similarity to B. bacteriovorus. Then, the host range and specificity of the strain were evaluated on 9 different Gram negative bacterial species. The results showed that the strains have predatory effects only on E. coli as prey.