Iranian Journal of Plant Protection Science
Year:2019 | Volume:49 | Issue:2|Papers Count:15

Turnip mosaic virus (TuMV) a species of the genus Potyvirus in the family Potyviridae, is one of the most prevalent viruses of canola fields in Iran. So far, commercial resistant lines or varieties against TuMV have not been known in Iran. In this research, the possibility of inducing resistant to TuMV in transgenic canola lines carrying a short fragment of the coat protein gene of the virus was evaluated. Therefore, a 130 nucleotide fragment of TuMV coat protein gene, as sense or antisense orientations, were cloned in the pFGC5941 vector independently and then were transformed to canola cotyledonary (Hayola R-Line 401 variety) explants using Agrobacterium tumefaciens strain LBA4404. Selection and confirmation of transgenic T0 and T1 lines were carried out via PCR and glufosinate ammonium herbicide (selective marker) resistance assay under greenhouse conditions. After virus inoculation to T1 lines, resistance assay was done by the scoring system. The obtained results confirmed that transgenic lines with sense construction did not show any resistant. However, several transgenic lines with antisense construction showed a different level of resistant to TuMV including delay in symptoms appearance and a decrease in symptoms severity (0-30% of T1 progeny) or symptoms recovery (10-66% of T1 progeny). This is the first report of increased resistant against TuMV via transformation of a short viral fragment sequence with the antisense orientation in canola.

Anthomyiidae with about 1560 described species are one of the largest families of the order Diptera containing the highest number of pests in order Diptera in the Palaearctic region. During the year 2016, the Anthomyiidae fauna of central part of Ardebil Province was studied leading to the identification of 11 species of 7 genera of which two genera (Botanophila Lioy, 1864 and Calythea Schnabl & Dziedzicki, 1911) and six species [Anthomyia confusanea Michelsen, 1985, Botanophila discrete (Meigen 1826), Calythea dedecorata (Rondani 1866), Delia megatricha (Kertesz, 1901), Hylemya urbica (Wulp, 1896) and Hylemya variata (Fallé n, 1823)] were found to be new to the Iranian fauna.

In order to assess the dynamic of Pyricularia oryzae at leaf and panicle neck blast stages, population genetic structures of the 142 isolates were investigated in a rice field and at three levels using SSR markers and five primer pair combinations. All the isolates were collected from the two-leaf and panicle stages at three levels. In the first level, isolates collected from leaf and panicle neck blast stages in the rice field were analyzed. In the second level, isolates belonged to the leaf and panicle neck populations were collected from tillers of the same rice hill and analyzed. In the third level, the ienvestigated isolates belonged to three populations and were obtained from three distinct leaf spots from the same rice leaf in a rice tiller. Based on constructed dendrogram for all of the 142 isolates, genetic similarity varied from 89 to 100% among the isolates. Population genetic estimations at the three studied levels showed that the amount of gene flow was 57. 62, 10. 68, and 4. 783, respectively between the isolates. Detection of mating type idiomorphs of the studied isolates using multiplex PCR showed that all the isolates had Mat1-1 idiomorph. This indicates the absence of sexual reproduction within the M. oryzae populations in rice fields in Guilan province and the fungus reproduces only in an asexual way. Low genetic variation and high genetic similarity among the populations of the causal agent of rice blast disease in Guilan province confirm this result.

In a survey conducted to identify terrestrial nematodes of Roodghat area, Sufiyan-East Azerbaijan province, Iran, 80 soil samples were collected during 2016 and 2017. The soil samples were processed and the nematodes were extracted, killed, fixed, and transferred to anhydrous glycerin as usual. Permanent microscopic slides were prepared from the nematodes. Their morphological characteristics and morphometric properties were studied under an optical microscope consisting of a drawing tube. In this study, 35 species belonging to 25 genera (plant parasitic and non-plant parasitic) were identified that among them Axodorylaimellus deviatus (Baqri & Jairajpuri, 1969) Jairajpuri & Ahmad, 1980, Kochinema tenue Argo & Van Den Berg 1971, Laevides laevis (Thorne, 1939) Thorne, 1974, Metaporcelaimus labiatus (de Man, 1880) Andrá ssy, 2001 and Metaxonchium bihariense (Popovici, 1990) Andrá ssy, 1996 were new records for the nematode fauna of Iran and are described here.

This study aimed to predict the population of Laelapid mites in Shahrood region using an artificial neural network. The data of this family were obtained in the year 2015. In this model, the variables sampling date, longitude and latitude as the input variables, and the population of Laelapid mites were used as the output variable. The network type used was GMDH neural network that was optimized by genetic algorithms. To evaluate the ability of GMDH neural networks to predict the distribution, statistical comparison parameters such as mean, variance, statistical distribution, and coefficient determination of linear regression between predicted values and actual values were used. Results showed that in training and test phases of GMDH neural network, there was no significant effect between variance, mean, and statistical distribution of actual values and predicted values. Our map showed the patchy distribution of these predatory mites. Maps obtained from artificial neural networks help program planners to use the pest control programs, particularly if maps coordinate with geographical conformity of each location. Therefore, control was focused on areas with decreased densities of these predatory mites.

Almond (Prunus amygdalus L. ) is a deciduous tree in the Rosaceae family and is grown mostly for its edible seed. It is one of the most popular nuts on a worldwide basis and widely grown in Iran in Isfahan and Chaharmahal and Bakhtiari provinces. Root and crown rot causal agents which are caused by several pathogens were studied. According to morphological characteristics, 53 isolates were identified as Phytopythium litorale (13 isolates), Phytophthora cactorum (19 isolates), and P. crytogea (21 isolates). Out of 53 isolates, 25 isolates were selected for molecular studies. Specific primer pairs of BPhycacL87FRG (F)/BPhycacR87RRG and Cryp1(F)/Cryp2 were used to confirm morphological identification of species. The reaction of crown and root of 8-month-old almond cultivars Sangi, Rabee, Shahrood12 and GF677 to virulent isolates of P. cactorum, P. cryptogea, and Pp. litorale was evaluated under greenhouse conditions. Comparison of pathogenicity means revealed that there are significant differences among P. cactorum, P. cryptogea, and Pp. litorale isolates. The results also showed that Pp. litorale was more aggressive than P. cactorum. On all tested almond cultivars, disease severity percentage showed that Sangi is the most susceptible cultivar and GF677 showed the least susceptibility. In this study, phylogenetic relationships of some Phytophthora and Phytopythium species based on sequencing of the rDNA-ITS region is provided. This is the first report of isolation and pathogenicity of Phytopythium litorale from almond orchards in Iran.

The common pistachio psyllid (CPP: Agonoscena pistaciae) is the key pest of pistachio orchards in Iran. At the moment, insecticides despite their known adverse effects on human health and environment, are the only and the last option for controlling CPP in most cases. However, selection pressure of insecticides has resulted in establishing highly resistant populations of CPP. Nowadays, volatile organic compounds (VOCs) of plants presenting opportunities for sustainable plant protection. In this regard, VOCs of pistachio trees (Ohadi and Kaleh ghoochi cultivars) were collected by headspace method in the pistachio orchards and identified chromatographically (GC– MS). VOCs, including monoterpenes, esters, acids, alcohols, aldehydes, and aromatics, were identified in both cultivars, numbering 43 in the Ohadi cultivar and 37 in the Kaleh ghoochi. The quantitatively dominant constituents were (E)-β-Ocimene (32. 5%), limonene (14. 8%) and methyl benzoate (12. 1%) in the Ohadi cultivar and (E)-β-Ocimene (29. 2%), limonene (20. 1%) and α-Thujene (6. 6%) in the Kaleh ghoochi. To study whether olfactory cues elicit responses in adult CPP, the odor of pistachio leaves (Ohadi cultivar) were offered in a Y-tube olfactometer to field-collected populations. Significant positive responses to volatiles of leaves were found in both males (P<0. 03) and females (P<0. 001). These data may be useful in semiochemically-based management strategies in the pistachio orchards such as mass trapping or deter of CPP or attraction of natural enemies.

Crown gall is one of the most destructive bacterial diseases of plants. Nowadays, special attention has been focused on the biological control of plant diseases as an alternative to chemical control. This study was conducted to better understanding the molecular mechanism of Surfactin on Agrobacterium tumefaciens as a prerequisite for the use of Bacillus as a biocontrol agent of this pathogen. In this study, Tobacco plants (Nicotiana tabacum), IBRC-M10701 strains of A. tumefaciens, and pure commercial Surfactin (25 μ m) were used. miRNAs and lox genes have an important effect in the auxin signalling pathway. Using Real-time PCR, the expression level of miR167 and lox gene measured 1, 3, and 6 days after inoculations in the interaction of A. tumifaciens IBRC-M10701 and Surfactin. The expression level of lox gene in Agrobacterium treatment showed 0. 47, 22. 9, and 61. 8 increased. In Surfactin treatment it was 4. 6, 3. 6 and, 11. 6 fold and in Surfactin-Agrobacterium treatment this amount was 4. 2, 38. 8, and 20. 3 fold. In addition, the expression level of nta-miRNA167 in Agrobacterium treatment indicated an increase of 3. 4 and 214. 4 fold (in the first and third day after inoculation), then decreased to 2. 5 fold (in the sixth day), in treatment with Surfactin the amount of expression level was detected as 3. 2, 13. 2 and 4. 5 fold and in Surfactin-Agrobacterium treatment this amount was 1. 6, 2. 2 and 9. 6 fold compared with the control. All of the results indicated the positive effect of Surfactin in suppression the strain IBRC-M10701 of Agrobacterium. The results indicated the key role of Surfactin in biocontrol which reflected the possible use of Bacillus strains producing Surfactin in biological control.

Carob moth, Ectomyelois ceratoniae, is the most important pest of pomegranate in Iran and is one of the most effective threats to the export of this product, but only a few studies have been done on the diversity and genetic structure of its populations. Therefore, in order to increase knowledge about the structure and genetic diversity of this pest populations, infested pomegranates were collected from 12 provinces of the country during 2016 and 2017 and genetic diversity components were investigated using a part of the mitochondrial DNA gene, cytochrome oxidase I (COI). Also, the haplotypic network and the phylogenetic tree was drawn using the maximum likelihood method. In the present study, six haplotypes were obtained. The first haplotype (H1) was common in all populations, which can be considered as the ancestral haplotype so that other haplotypes have been evolved from it. This haplotype is connected to other haplotypes with a mutation and forms a star-like shape in the haplotypic network. Results of the grouping populations indicate that the northern part of Iran has the most diversity of haplotypes in comparison to the central and southern parts, which can be related to native cultivars, genetic diversity of cultivars, and natural habitat of Pomegranates in this area. The adaptation of pomegranates to different micro-climates, development of commercial cultivation of traditional varieties, and the role of the human in product transformation lead to high gene flow and genetic differences reduction even at wide geographical distances.

In this research, pathogenicity tests were done using two different methods including inoculation of leaf discs under laboratory conditions and infecting the seedlings in the greenhouse in order to determine resistance levels of bean cultivars to Rhizoctonia solani AG4 HG-II, the causal agent of the crown and root rot. Furthermore, the most susceptible bean cultivar (cv. Naz, because of economic justification) was used to examine the possibility of inducing resistance against the pathogen, using flavonoids such as quercetin and naringenin and investigate some mechanisms involved in induced resistance. To study the effects of different concentrations of flavonoids in the induction of resistance in bean against R. solani, the seedlings were treated with 100 to 400 μ g/mL concentrations of flavonoids. The treated and control plants were inoculated with the pathogen and the disease index was calculated one week following inoculation. Results showed that various concentrations of quercetin and naringenin had different effects in reducing the disease index. Quercetin at 200 to 400 μ g/mL significantly decreased the progression of the disease caused by R. solani in the bean. The best time interval between treatment and inoculation was 3 days. Naringenin at 100 and 200 μ g/mL and quercetin at 100 μ g/mL did not significantly reduce the disease progression. Investigating callose, superoxide, and hydrogen peroxide levels at various time points after R. solani inoculation in the seedlings pretreated with quercetin revealed that quercetin-induced resistance in bean against the fungal pathogen via priming the defense components.

The common pistachio psyllid, Agonoscena pistaciae Burckhardt & Lauterer (Hemiptera: Aphalaridae), is one of the most important pests of pistachio trees in Iran. To investigate the spatial distribution pattern of egg and nymph of this pest, samplings were done weekly in a pistachio orchards cultivar Kalleh-ghochi. The pistachio terminal leaflet was selected as sampling unit and the number of egg and nymph was recorded in three canopies of tree, up, middle and down parts. The spatial distribution pattern of egg and nymph of A. pistaciae was determined using mean-variance ratio, Taylor´ s power low, Iwao´ s patchiness regression model and Lloyd's mean crowding index. Based on the mean-variance ratio and Lloyd index, the spatial distribution of egg and nymph, at three canopies of tree was estimated, aggregated. The slope of the regression for Taylor´ s power low and Iwao´ s patchiness regression model for egg, in middle canopy of tree was significantly more than one, then the spatial distribution was estimated, aggregated and in up and down canopies was estimated, random distribution. In both Taylor´ s power low and Iwao´ s patchiness regression model, the slope of the regression model for nymph, at three canopies of tree was significantly more than one, then the spatial distribution was estimated aggregated. The results of present study are usefull for developing sampling programs of the common pistachio psyllid.

Gummosis (Crown and root rot) is the most important disease of pistachio trees caused by different species of Phytophthora which destroy significant numbers of fertile and non-fertile trees each year in Iran. Different approaches have been applied to reduce the severity and incidence of the disease. In recent years, biological control as an eco-friendly approach has been increased in the world. The effectiveness of Talk powder and Wheat bran formulations of five Pseudomonas strains (T17-4, VUPF760, VUPF5, VUPF506, and CHA0) was assessed on seedlings inoculated with Phytophthora drechsleri under greenhouse conditions. The highest and lowest reduction rates of disease severity belonged to VUPF760 and VUPF506 with 55 and 11%, respectively compared to the control and other treatments. Seedling inoculated with bacterial strains had higher heights, fresh and dry weights of shoot and roots. VUPF5 increased the ratios of height, fresh and dry weight of shoot and root by 1. 4, 1. 3, 1. 1, 1. 2, and 1. 1 respectively, compared to non-inoculated control seedlings.

In this study, 12 native strains and 80 strains from the known species of Allophoma, Didymella, and Neodidymelliopsis were selected. The ITS, D1/D2 LSU rDNA, tub2 and rpb2 regions of the mentioned strains were compared for species delimitation using phylogenetic analysis. The genomic regions of the native strains were amplified using DNA extracted from freeze-dried mycelia and sequenced. The phylogenetic analysis was performed using the maximum likelihood algorithm. The regions of the D1/D2 LSU rDNA, ITS, tub2, and rpb2 delimited 0, 20, 43, and 46 out of 61 species studied, respectively. In the phylogenetic analysis based on combined regions, all datasets (ITS-tub2, ITS-rpb2, tub2-rpb2, ITS-tub2-rpb2, and ITS-28S-tub2-rpb2) could delimit 49 out of the 61 species under survey. Results showed that the sequencing and phylogenetic analysis of the ITS, tub2, and rpb2 regions in combination with morphological studies are necessary for species delimitation of the Allophoma, Didymella and Neodidymelliopsis genera. In a single-locus phylogeny, tub2 or rpb2 genes are the best markers among the genomic regions used.

Crown and root rot caused by Fusarium culmorum is one of the most important wheat diseases in Ilam. In order to determine genetic diversity, 66 samples were collected from wheat farms in different regions of Ilam province. The molecular test was carried out with a set of five pairs of SSR primers after purification and identification of the isolates. The SSR primers amplified a total of 25 alleles. The average allele number was 5. 2 per each primer. The polymorphism index content value was the highest in primers F3 with 0. 409 and the lowest in primers F11 with 0. 179. Cluster analysis using the Neighbor-Joining method and Jaccard's coefficient in 50% similarity level divided the isolates into 18 groups. Results of AMOVA showed 78% of the genetic diversity related to isolates and 22% related to different geographical regions. Therefore, there is a high genetic similarity between isolates from different geographic regions. High genetic similarity can be attributed to the emigration of gene or genotype as a result of various factors.

Tomato leaf miner, Tuta absoluta (Meyrick) (Lep.: Gelechiidae), is one of the most important pests of tomato in the world. In the current study, effects of four insecticides, abamectin, emamectin benzoate, acetamiprid, and flubendiamide were tested against 1st larval instar and pupae of the tomato leaf miner. Also, their lethal effects were studied on the adult stage of two species of egg parasitoids, i. e., Trichogramma brassicae and T. evanescens. The leaf miner collected from greenhouses near Arak (Markazi province, Iran) were reared for three generations under laboratory conditions and then treated by the leaf-dip method at larval or pupal stages. The parasitoids were tested by coated vial residue method. Insect mortality was recorded 24 h after initial exposure. The LC50 values of abamectin, emamectin benzoate, acetamiprid, and flubendiamide were 0. 92, 0. 13, 1. 51, and 0. 34 μ g/ml, respectively for the 1st larval instar and 4. 99, 2. 25, 3. 22, and 3. 48 μ g/ml, respectively for the pupae. Similarly, the LC50 values of the above-mentioned compounds were 0. 0013, 0. 0029, 0. 0058, and 1. 53 μ g/ml, respectively for T. brassicae and 0. 0014, 0. 0025, 0. 0052, and 1. 71 μ g/ml, respectively for T. evanescens. The maximum number of parasitized eggs was seen on the 2nd day after the emergence of both parasitoids. These amounts for T. brassicae after treatment by LC25 of flubendiamide, acetamiprid, emamectin, and abamectin, were 14. 70 ± 0. 17, 14. 00 ± 0. 20, 13. 1 ± 0. 20, and 11. 8 ± 0. 14, respectively which statistically differed with the control (16. 00 ± 0. 12). For T. evanescens, the related values were 13. 10 ± 0. 21, 12. 37 ± 0. 12, 11. 50 ± 0. 18, and 11. 23 ± 0. 16, respectively which differed meaningfully from the control (14. 00 ± 0. 19). Risk quotient categorized flubendiamide in class 2 (slightly harmful) and other compounds in class 3 (harmful). Based on our results, flubendiamide showed selectivity and it can be used as an effective tool for integrated pest management programs of tomato leaf miner.