شناسایی

Grapevine decline disease (GDD) complex is a major global viticulture problem associated with a multi-year decrease in plant productivity and an increase in vine mortality, resulting in important economic losses to the viticulture industry. More than 35 fungal genera have been involved in the GDD complex, and the genus Cytospora has also been reported as one of the genera included in the disease-causing complex. This study aimed to identify Cytospora species involved in GDD complex in the vineyards of Miyandoab (West Azarbaijan province) and Malekan (East Azarbaijan province) Counties. So, during the summer and autumn of 2020-2021, sampling was done from the diseased plants showing symptoms of shoot wilting and die-back, bark and wood discoloration, brown to black discoloration of vascular tissues, and wood canker. The fungal isolation was done based on common phytopathological methods, and 78 isolates with the common characteristics of the genus Cytospora were isolated and purified. Based on the results combining morphological characteristics and sequence data obtained from three genomic regions, ITS-rDNA, TUB2, and RPB2, four species viz., C. chrysosperma (15 isolates), C. ershadii (24 isolates), C. salicina (28 isolates), and C. viticola (11 isolates) were identified. Cytospora viticola is a new species for the fungal biota of Iran, and grapevine is reported as a new host (matrix nova) for C. ershadii in Iran and the world. Pathogenicity of the selected fungal isolates from the identified species was confirmed on shoots of the Thompson seedless cultivar based on Koch's postulates.

The first step in biodiversity studies and integrated pest management is to identify the species in the region. This research was conducted in order to identify the fauna of mites under the order Mesostigmata (Acari: Mesostigmata) from gardens and fields of the Kharameh region of Fars province during 2014-2016. In this research, 10 species from 5 families belonging to mites of the inter-stigma order were collected and identified. Among the collected families, Uroobovella obovata Canestrini & Berlese, 1884 from the Trematuridee family had the highest frequency (18.54%), and Neodiscopoma splendida and Nenteria stylifera Berlese, 1904 from the Uropodidae and Trematuridee families with frequencies of 14.83 and 90% respectively. 13% were in the next rank. It should be mentioned that the identification of these species has not been reported from the Kharameh region of Fars province.

Legumes are one of the primary protein sources in human and livestock diets worldwide. There are five different types of legumes (i.e., beans, peas, peanuts, lentils, and lupines), with beans as the most important. Fusarium root rot (FRR) is among the most challenging diseases of common beans (Phaseolus vulgaris). While soil-borne diseases are difficult to control, resistant bean cultivars significantly help reduce the losses caused by the disease. This study was conducted in a greenhouse to investigate the susceptibility of different bean cultivars to FRR caused by the F. solani species complex (FSSC).

Several bean fields in Fars, Kohgilouyeh and Boyer-Ahmad, Chaharmahaal and Bakhtiari, Hamdan, Lorestan, Markazi, Qazvin, Zanjan, East Azerbaijan, and Mazandaran provinces were explored during summer from 2017 to 2019. Infected plants were sampled, and the fungi were isolated in the laboratory. Once appeared on the culture medium, the fungal isolates were purified using single-spore isolation or hyphal tip methods. Fungal DNA extraction was performed using Doyle and Doyle’s method for molecular identification of the isolates. A part of the internal transcribed spacer (ITS) region of the ribosomal RNA (rRNA) gene and a translation elongation factor 1-alpha (EF-1α) were amplified from the polymerase chain reaction (PCR). PCR-amplified fragments were sent to the Cardiogenetics Department of Rajaie Cardiovascular, Medical and Research Center (Tehran, Iran) for sequence analysis. After editing, the Basic Local Alignment Search Tool (BLAST) was applied to ITS and EF-1α sequences of the isolates in the GenBank data set in the National Center for Biotechnology Information (NCBI) database. A preliminary pathogenicity test was performed on the Sadri bean cultivar-pathogenicity tests were fulfilled in 400ml plastic pots. An inoculum was prepared by pooling the isolates in a pot experiment utilizing Bilgi et al.’s (2008) method to evaluate bean cultivars. Ten representative isolates of F. solani with the highest pathogenicity were selected from different regions. The cultivar susceptibility was assessed in 3-liter pots as described in the preliminary pathogenicity test. Saleh, Sadri and Koosha chiti (pinto) bean cultivars, Akhtar, Goli and Sayyad red bean cultivars, Dorsa, Shekoofa white bean cultivars, and Valentino and Sanri green bean cultivars were compared based on disease severity and yield correlates (shoot/root fresh and dry weight).

Fusarium isolates from the sampled provinces were identified using authentic scientific sources and Fusarium identification keys based on morphological properties. A Blast search of ITS and EF-1α sequences in GenBank yielded 100% nucleotide identity with the sequences of strains of FSSC. In the preliminary pathogenicity test, leaf yellowing and falling symptoms appeared on the Sadri cultivar in the greenhouse three weeks after inoculation. All FSSC isolates caused root rot on the tested bean cultivar. To evaluate the susceptibility of bean cultivars to the selected isolates, the plants were carefully removed from the 3-liter pots two months after inoculation. The results showed statistically significant differences (p=0.01) among the cultivars. Koosha chiti bean, green Sanri and Valentino cultivars with the lowest root rot severity (19.5%, 22.62% and 23.81%, respectively) and red Goli and Dorsa white bean cultivars with the highest root rot severity (66.67% and 70.24%, respectively) were the least and most susceptible bean cultivars to the pooled FSSC isolates, respectively. The results also indicated relatively significant differences in yield correlates (shoot/root fresh and dry weight) among the cultivars. Besides, the Koosha cultivar was shown to be the most resistant to the disease, followed by Akhtar, Sanri, Valentino and Saleh cultivars. Dorsa white bean and Goli red bean cultivars were demonstrated to be the most susceptible to the disease. This study identified several cultivars with low susceptibility to bean root rot caused by FSSC isolates. A good variation was observed in the spectrum of bean plant responses to the disease. Koosha, Akhtar, Valentino, Sanri and Saleh cultivars with low susceptibility to the selected FSSC isolates may be considered for further studies. Proper soil management with cultivating resistant cultivars is an integral part of any disease management program for FRR.

Iran’s Khuzestan province ranks first in wheat production. Root-lesion nematodes (RLN) are a group of plant parasitic nematodes that includes several closely related species of economically significant cereals. There have been eight species of RLN recorded for small grains. Four species (P. thornei, P. crenatus, P. neglectus and P. penetrans) are found worldwide, particularly in temperate zones. P. neglectus, P. thornei, P. pseudopratensis and P. penetrans prevalent in Iranian wheat fields. However, there is insufficient information regarding the status of RLN in the province of Khuzestan’s cereal fields. The objective of this study was to determine the occurrence, distribution and population density of RLN in wheat and barley fields in Khuzestan province.

A survey was conducted over three years (2008-2011), where 169 wheat and 31 barley fields were inspected and sampled in 21 regions during the grain filling and harvesting periods in the Khuzestan province of Iran. A stereomicroscope was used to examine the root tissue of 10 wheat and barley plant samples for disease symptoms. The Whitehead tray method was employed to process 250 cm3 of soil from each collected soil sample. The RLN species were identified using morphological and morphometric characteristics. ArcGIS 9.3 software was utilized to map the distribution of RLN on the map of Khuzestan.

Results indicated that 37% of wheat fields in the regions of Ahvaz, Andika, Andimeshk, Baghmalek, Behbahan, Dasht-e Azadegan, Dezful, Gotvand, Hoveyzeh, Izeh, Lali, Omidiyeh, Ramshir, Ramhormoz, Shadegan, Shushtar, and Shush were infested with P. thornei and P. neglectus, with mean population densities of 39 and 101 nematodes per gram of root and 250 cm3 of soil, respectively. In addition, 42% of barley fields in Andika, Baghmalek, Izeh, Lali, Omidiyeh, and Ramhormoz were infested with the nematode, with mean population densities of 9 and 72 nematodes per gram of root and 250 cm3 of soil, respectively. The regions with the highest and lowest nematode populations were Shush, Shusthar, Baghmalek, and Hendijan, with densities of 1,334, 904, 11, and 100 per 250 cm3 of soil, respectively. Ten percent of the surviving fields exhibited nematode populations exceeding 1-2 per gram of soil, which is extremely likely to cause cereal crop damage.

Pratylenchus thornei, P. neglectus, and a mix of the two species were observed in 62, 18, and 20% of the surveyed fields in Khuzestan, respectively. In both wheat and barley fields, P. thornei was the dominant species. Globally, P. thornei is deemed more dangerous than P. neglectus. This is the first report of the presence of root lesion nematodes in wheat and barley fields in Khuzestan province, with contamination rates of 37 and 42%, respectively. Disease incidence was higher in irrigated fields than in rain-fed fields, indicating that soil moisture and nutrients positively influence the nematode population. The nematode population density was higher in wheat fields than in barley fields, confirming that barley is a poor host for RLN. The economic damage thresholds for P. thornei and P. neglectus on wheat have been reported to be 1-2 nematodes per gram of soil in various parts of the world. The most important management practice is the use of resistant and tolerant wheat varieties to RLN.

Aphids are one of the most important agricultural and forest pests that may directly injure by sucking the sap of plant organs and indirectly by the transmission of microbial pathogen agents into the plant hosts. Moreover, other indirect forms of damage from feeding may be seen as gall formation, deformation of plant organs, chlorosis / necrosis spotting of the leaves all three due to the injection of poisonous saliva, and the presence of sooty mold view resulting in the honeydew excretion as a food source for the saprophytic fungi. The number of aphids is currently more than 5200 species, of which about 69 species within six genera belong to the family Phylloxeridae. Apart from the grape Phylloxera, a commercial pest of grapevines worldwide, the habitats of remaining species are forest trees and non-agroecosystems. The oak leaf phylloxeran aphids have a complex life cycle as exclusively egg-laying with parthenogenic forms. These aphids overwinter as egg inside seams and shell gaps of small branches or sometimes as first nymphal instar in branches. This study aimed to identify an aphid species feeding of Brant's oak, Quercus brantii, as a probable cause of yellow chlorosis spotting on the leaves of infected trees. Various methods have been proposed to assign unknown specimens to known species using their DNA barcodes.

Aphid specimens were collected on Q. brantii oak trees in eight selected forest sites around Khorramabad County, Lorestan Province. They were identified based on molecular and morphological evidences and was subjected to molecular characterization. DNA sequencing of partial COI gene fragment was performed, and the phylogeny of this species was compared with other species within the genus Phylloxera. In order to identify, the mounted aphid samples (microscopic slides) were morphologically identified by the conventional method under a light microscope with the help of taxonomical keys. 

Samples were recognized as Phylloxera quercina (Ferrari, 1872) based on molecular and morphological identification. The phylogenetic tree was constructed as a fully resolved tree with Phylloxera genus as monophyly, dichotomous branching, and near-full bootstrap values.

The present study is the first report showing the occurrence of P. quercina as a pest in the Zagros vegetation zone. Here we suggest the annual monitor of seedling oak and investigation of the geographical distribution of pest species. The utility of COI barcode gene fragment, along with the morphological characters, can help accurately identify Phylloxera species in Iran.

Alternaria leaf spot disease, with the common agent of Alternaria alternata, is one of the most important seed-borne diseases of coriander. The present study aimed to identify seed-borne fungi isolated from native coriander seed populations based on morphological and molecular characteristics. In addition, the efficiency and effectiveness of seed treatment with chemical fungicides on vigor and germination indices, as well as the control of seed-borne diseases were evaluated.

In order to identify the seed-borne fungi of coriander, seed populations from the fields in South Khorasan, Alborz, Markazi, Qazvin, and Hamedan provinces of Iran were sampled according to the International Rules for Seed Testing. After isolation and purification, fungal isolates were identified and confirmed based on morphological characteristics and species-specific primers. Furthermore, the level of pathogenicity and the aggressiveness of isolates were assessed by pathogenicity test on seedlings. The effectiveness of seed treatment with Iprodione-Carbendazim (Rovral-TS®) and Mancozeb (Dithane M-45®) fungicides on germination and vigor indices, as well as the rate of disease progression were investigated.

A total of eight isolates of Alternaria alternata were identified based on morphological and molecular characteristics. The germination and vigor indices varied among seed populations and it seemed that a part of the observed differences was due to infection by seed-borne fungi. The results of the pathogenicity test showed that approximately 62.5% of the isolates were pathogenic and 37.5% were non-pathogenic. Diverse levels of pathogenicity and aggressiveness were observed for various isolates of A. alternata. Seed treatment with chemical fungicides had a significant influence on germination and vigor indices. Fungicides did not completely control the seed-borne Alternaria leaf spot disease of coriander.

The findings of the current research demonstrated that the effective inhibitory concentrations of chemical fungicides varied based on the pathogenicity of distinct isolates of A. alternata. Disinfection of seeds with Iprodione-Carbendazim fungicide caused a lower disease index of A. alternata on coriander seedlings, compared to Mancozeb. In conclusion, the cultivation of Nahavand seed population out of all the evaluated coriander populations and the disinfection of seeds with Iprodione-Carbendazim fungicide before sowing in all areas suitable for the cultivation of this product are recommended.

Barley is one of the most important cereals in the world after corn, wheat and rice. Powdery mildew is one of the important fungal parasites of the plants which cover their above ground parts with the formation of a white fungal vegetative organs causing yellowing, drying and reducing the quantitative and qualitative traits of the field crops, fruit trees and ornamental plants. In order to locating the powdery mildew resistance QTLs in the F3 generation derived from the cross Badia and Kavir cultivars, a population consisted of 104 families was cultivated in 2017 at Gonbad-e-Kavos University. To provide a genetic map, several groups of markers including of 28 SSR, 9 ISSR, 3 IRAP and 5 iPBS (93 alleles) that were related to barley chromosomes used. Genetic maps were covered 617.5 cM and the mean gap between flanking markers was 5.41 cM. Four QTLs were detected on chromosomes 3, 4 and 6 to powdery mildew resistance. The results of this study led to a new QTL trace for the desired trait. The QTL qSPM-4b with LOD=3.26 that was between the two ISSR13-1 and ISSR16-4 markers, controlled 13/.6 of the phenotypic variations of the respective attribute with an incremental decrease of 0.12. The QTLs detected could be used in breeding programs to increase the resistant sources against the disease and to increase the yield of the new produced cultivars. The results of the current research can be used in breeding programs after determining the validity of markers.

The plant pathogen Phytophthora melonis is morphologically similar to some other non-papillate Phytophthora spp. especially P. drechsleri and therefore it is difficult to discriminate these convergent taxa. This study was performed to design specific primers based on nuclear and cytoplasmic genome, examine their specificity against other convergent species, and optimize the specific primers’ conditions to detect P. melonis. Nine nuclear and four cytoplasmic genes were appropriate to design thirteen specific primers based on their nucleotide polymorphism. PCR conditions were optimized. Phytophthora melonis were detected by specific primers in inoculated plants such as cucumber, watermelon, melon, sugar beet and pistachio. All specific primers detected pathogen in 1:100 (pathogen: soil) inoculated soil.Up to 10 zoospores per milliliter were detected using nested polymerase chain reaction. ITS-MF1 and ITS-MR2 (ITS-M2 set, from internal transcribed spacers of rRNA gene) were selected as the most efficient primers based on their specificity and sensitivity. The optimized annealing temperature for this primer set was 68 °C. It seemed that nested PCR by ITS-M2 primer set together withthe universal primers ITS6 and ITS4 as external primers is at least 106 times more sensitive than simple PCR. Multiplex polymerase chain reaction simultaneously detected the three cucurbits’ pathogens including P. melonis, P. nicotianae and P. drechsleri. This study showed that the designed primers could be effective tools for detection of P. melonis isolates from infected tissues, and infested water and soil.

In order to investigate the Pythium species of the rice paddy fields of Fars Province, Iran during 2013 to 2015, infected roots and crowns together with soil around seedlings and irrigation water were sampled. According to the morphological, morphometrical and physiological studies along with phylogenetic analyses based on internal transcribed spacer (ITS) of ribosomal DNA, fourteen Pythium species including Py. aphanidermatum, Py. catenulatum, Py. coloratum, Py. debaryanum, Py. dissotocum, Py. hydnosporum, Py. inflatum, Py. kashmirense, Py. nunn, Py. oopapillum, Py. plurisporium, Py. porphyrae, Py. pyrilobum, and Py. rhizo-oryzae were identified. All species are reported for the first time in the world from rice rhizosphere except Py. dissotocum, Py. inflatum and Py. rhizo-oryzae. Pythium oopapillum, Py. plurisporium, Py. porphyrae and Py. rhizo-oryzae were new to Iran. Pythium aphanidermatum, Py. rhizo-oryzae and Py. catenulatum were the most abundant species. Pathogenicity of Py. debaryanum, Py. oopapillum, Py. porphyrae, Py. plurisporium and Py. rhizo-oryzae on rice plants were reported in this study for the first time, worldwide.

This study was conducted to identify cereal cyst nematodes (CCNs), distribution and disease incidence, population density and preparing map of distribution based on interpolation using geographic information system (GIS), as well as determination of relationship between climatic factors with population density of dominant species. Totally 280 soil and root samples were randomly collected from 140 wheat fields of Isfahan province during 2012-2014. The soil samples were processed for cyst extraction and number of cysts, second stage juveniles (J2) and eggs inside each sample were counted. Species was identified based on morphological and morphometric features and molecular characters. Analysis was performed by Arc GIS software using interpolation technique for determination of raster maps of population density of J2, eggs and direction of disease progression. After preparing the raster maps, direction and the correlation of J2 and eggs populations with some climatic factors and altitude determined by GIS using Pearson's correlation coefficient. Heterodera filipjevi was the only species of cereal cyst nematodes found in Isfahan province, and 56.4% of soil samples were contained H. filipjevi with an average population of 6.02 eggs and J2/g of soil. Based on interpolation of population density, Ardestan, Natanz, Kashan, Aran va Bidgol, Mobarekeh, Naein and Isfahan districts had the most mean population density of H. filipjevi, respectively. Population density of the nematodeshowed direct correlation with the long term mean of temperature and inverse correlation with the long term mean of precipitation, relative humidity percent and altitude.

In order to identify of plant parasitic nematodes of Tea plantation, 340 samples of soil around the roots of Tea were collected from different parts of the provinces of Guilan and Mazandaran during different season of 2010-2011. After extraction, killing, fixing and transferring to anhydrous glycerol, the nematodes were mounted on permanent microscopic slides and nematodes identified by using light microscope equipped with digital camera, based on morphological and morphometric characters using valid keys. In this study, 24 species belonging 12 genera were identified. Aphelenchoides asteromucronatus and Paratylenchus holdmani are reported for the first time from Iran, Paratylenchus elachistus, described.

Phytophthora drechsleri, P. cryptogeaand P. erythroseptica are phylogenetically closely related Oomyceteous plant pathogens which are morphologically similar. In order to discriminate these taxa from each other and from species with convergent morphological characteristics a simple as well as a nested-PCR based method was developed. A collection of isolates of each species from different hosts representing world-wide diversity of species were examined for unique regions of nuclear as well as mitochondrial genes. Six candidate PCR primers were designed and calibrated for species-specific amplification of P. drechsleri based on the DNA sequences of rDNA internal transcribed spacer regions and the cytochrome c oxidase subunit I, and also three candidate PCR primers specific for P. cryptogeaand P. erythroseptica were designed and calibrated based on cytochrome c oxidase subunit I. Studies showed that the best primer set for identification of P. drechsleri was the combination of ITS-DF2 and ITS-DR2, which amplified a 567 bp band. The combination of COX-CF1 and COX-CR2 was the best set for discrimination of P. cryptogea/P. erythroseptica from other species which amplified a 415 bp product from both species. A restriction map analysis of P. cryptogea/P. erythroseptica indicated that the non-palindromic Mnl I enzyme restriction site was unique to amplicons of P. erythroseptica isolates and could be employed to distinguish this species from P. cryptogea. Based on this study, nested-PCR was at least 100 times more sensitive than conventional PCR for detection of these species.