Journal of Applied Research in Plant Protection
Year:2019 | Volume:8 | Issue:2|Papers Count:8

In this study, 25 samples containing root, stem and leaf of the asymptomatic, salt-and heat-tolerant plants growing around Abadan and Ahvaz, were collected and their endophytic fungi were isolated on potato-dextrose-agar (PDA). Thirty five isolates were obtained, 11 out of them were selected based on the morphology of sexual and asexual structures for molecular identification. In molecular assay, the identity of representative isolates was determined using the sequence data of ITS-rDNA and GAPDH (for Curvularia isolates). Based on a combination of morphological and molecular data, the representative isolates were identified and described as following; Alternaria chlamydospora, A. phragmospora, Chaetomium olivaceum, Curvularia ahvazensis, Curvularia sp., Fusarium chlamydosporum and Fusarium sp. To the best of our knowledge, these fungal endophytes are here reported from Aeluropus littoralis, Atriplex lentiformis, Carthamus oxyacantha, Salicornia subterminalis and Scirpus maritimus for the first time.

Fusarium Head Blight (FHB) is one of the most important diseases of wheat causing considerable yield losse annually. Commonly management practices of the disease are not effective, so adopting new strategies to control are seriously needed. For this purpose, in the present study, efficiency of commercial and local Trichoderma strains was evaluated in the control of Fusarium Head Blight on wheat. For isolation of the pathogen and antagonists, samples were taken from infected wheat spicke and wheat rhizosphere, respectively. Identification of fungal isolates (Trichoderma and Fusarium isolates) was performed based on combination of morphological characteristics and molecular data. Accordingly, the identity of the 10 isolates of the pathogen and 13 isolates of the antagonists was determined as Fusarium graminearum and Trichoderma harzianum, respectively. In lab, after a preliminiary screening, a superior Trichoderma isolate from wheat rhizosphere (T. harzianum Tr5), one commercial product (T. harzianum T22) and T. longibrachiatum N (prepared from culture collection of Tabriz University, ) were used to study their antagonistic activity against F. graminearum under laboratory and greenhouse conditions. Antagonistic strains were furhter assessed in the production of chitinase and protease enzymes. The results of laboratory tests showed that all fungal antagonist strains significantly inhibited the growth of the pathogen compared to control. In dual culture assay, the highest inhibitory percent was detected in the interaction of F. graminearum with T. harzianum Tr5 and T. longibrachiatum N. Furthermore, only T. harzianum Tr5 was able to show mycoparasitism mechanism directly. The volatile compounds of the antagonist strains showed the lowest inhibitory against pathogen, without any significant difference between them. In non-volatile compounds assay, the highest inhibitory percentage was detected for T. longibrachiatum N and the lowest inhibitory percentage was detected for T. harzianum Tr5 and T. harzianum T22, respectively. All antagonists were able to produce chitinase and protease enzymes, with more capability for local isolates. Finally, the results of the greenhouse assay were positively in consistent with the laboratory tests. The results of greenhouse assay showed that the antagonist isolates significantly inhibited the adverse effects of the pathogen on weight loss of wheat grain.

Intelligent systems have received considerable attention as a modern modeling methods in recent years. These models is used for prediction and classification in situations where the classic statistical models are not able due to their constraints. This study is aimed to compare the ability of ANFIS and multi factor linear regression models for predicting density of all growing stages of Sunn pest. The data population fluctuation of Sunn pest in the years 2015 and 2016 on a farm with an area of one hectar in chadegan city was obtained. Predictor variables including variables sampling date, average temperature, average relative humidity, wind speed, wind direction, rainfall, height from sea level and degree-day were processed as input data to achive an output of number of developmental stages as response variable. In the ANFIS model, 70% of the data was assigned to training and 30% for validation. After network training and assessment of the best structure according to type, number of membership function and related rules with the use of MATLAB software, the appropriate model was selected based on statistical indices of, root mean square error (RMSE) and coefficient of determination (R2). After sensivity analysis the results showed that ANFIS method (RMSE= 0. 051, R2= 0. 97) had higher accuracy than multi linear regression (RMSE= 0. 26, R2= 0. 47) and better predicts the population fluctuation of Sunn pest Eurygaster integriceps.

The Lysin motif in receptor-like kinases (LysM-RLKs) bind to chitin or chitin components of the fungal pathogen cell wall to perceive their invasion. To study the LysM-RLK domains of potato genome involved in Alternaria solani response, the putative LysM-RLKs were bioinformatically assessed, sequenced and their expression levels were measured in a susceptible (Russet Burbank) and relatively resistant (F06037) genotypes, following inoculation of the pathogen. A total of 35 putative LysM-RLKs were detected in potato genome, of which 26, 5 and 4 LysM-RLK had none, one and two LysM motifs, respectively. Among 9 receptors containing LysM-RLK domains, two proteins showed a significant overexpression following A. solani infection. PGSC0003DMP400061331 protein with two LysM motifs had a higher expression level than PGSC0003DMP400060418 protein with one LysM motif. Both proteins had 98% and 81% coverage with Arabidopsis thaliana CERK1 protein, respectively. Multiple sequence alignment (MSA) of LysM motifs from both proteins of two potato genotypes with that of Arabidopsis thaliana CERK1 revealed no difference between genotypes with respect to LysM motif sequence. Interestingly, the LysM motifs from PGSC0003DMP400061331 protein had an “ NRD” insertion as compared to its second LysM motif, PGSC0003DMP400060418, and Arabidopsis taliana CERK1 LysM motifs. Such changes may have occurred through deletions or duplications. Alteration of DNA sequences by genome editing methods may shed light on the role of these genes in the field of resistance or susceptibility to A. solani leading to generation of resistant transgenic plants to devastating fungal diseases.

Grape erineum mite (GEM) Colomerus vitis (Pagenstecher), is one of the major pests of grapevine which directly and indirectly influences the quality and quantity of grape annually. Hence to reduce and control the leaf infestation, a research was conducted in a completely randomized block design in an experimental vineyard in Urmia city, West-Azerbaijan province, Iran during 2016 to 2017 with 10 treatments including abamectin, volk oil, detergent, abamectin+ volk oil+ detergent, abamectin+ volk oil, abamectin+ detergent, volk oil+ detergent, sulfur 3. 5 and 4. 5% wp., water (testifier) with 70 replicates. Abamectin (0/5 l/1000 l of water, 1. 8% EC), volk oil (2. 5 l/100 l of water, 80% L), detergent (0. 5 l/1000 l of water) and sulfur (3. 5 and 4. 5%) applied with the mentioned concentrations. Spraying operation organized in three and sampling in seven times with biweekly intervals. Percentage of efficiency, calculated with Henderson-Tilton formula then corrected with GLM. According to results, all treatments including abamectin in first spraying stage (late winter) showed ≥ 90% efficacy whereas; other treatments without abamectin like volk oil and detergent in first spraying stage showed 57-91 and 55-88% mortality, respectively. Sulfur 3. 5 and 4. 5% wp. in both second and third spraying stages by 48-69 and 51-65%, respectively controlled the GEM less than abamectin. To control this pest around economic threshold and also less adverse impacts to the nature, applying volk oil (2. 5 l/100 l of water) with detergent (0. 5 l/1000 l of water) in late winter is advisable.

In this research, interaction between Fusarium graminearum and wheat including the change in rate of some anti-oxidant enzyme activity and expression level of PR2 (b, 1-3gluconase), PR3 (chitinase) andPR4 (wheatwin) genes was studied. Tajan cultivar was used in greenhouse and experimental condition in a completely randomized blocks design with four repetitions. Spraying of aerial parts of plants by methyl-jasmonat at 200, 400 and 600 ppm concentration was done one, three and five days after inoculation with fungal spore of Fusarium graminearum (105 spore per milliliter). Also, inhibition effect of methyl jasmonat on growth of fungal colony was investigated on PDA culture medium. The results showed that the total phenol production and peroxidase, polyphenol oxidase and guaiacol peroxidase reached to highest level three days after inoculation at concentration of 600 ppm and reduced significantly 5 days after inoculation. Gene expression analysis at three days after inoculation time interval showed the highest and lowest expression level for b, one-three gluconase and chitnase respectively. Assay of growth inhibition effect by methyjasmonat showed that this material has the highest inhibition activity at concentration of 600 ppm. These results indicate that exogenous application of methyl jasmonat as chemical inducer to induce plant resistance against head scab disease could be considered in plant disease management.

In order to study the population fluctuations and spatial distribution of onion thrips, Thrips tabaci (Lindeman) (Thysanoptera: Thripidae) in alfalfa fields of Eyvan city (Ilam province), sampling were done weekly in different growth stages of alfalfa from the beginning of April to late September 2017. The results of population fluctuations showed that the highest population of adult and immature thrips stages were average 6. 20 ± 0. 85 and 1. 35 ± 0. 44 in 20 plants in August and September, during the 3th cutting of alfalfa. The study of the relationship between the population dynamics of adult and immature stages with temperature showed that there was a significant and positive correlation between population changes and temperature. Based on Taylor’ s power law, the spatial distribution for both adult and immature stages was randomized, but the total stages were aggregated. Whereas, based on Iwao's patchiness, regression between Log S2 and Log m in immature stage was not statistically significant (P> 0. 05). The spatial distribution pattern of adult stages was randomized and for both adult and immature stages was aggregated. The parameters derived from population fluctuations and the spatial distribution pattern of this species can be used in the sampling program and estimates of population density of this pest in alfalfa fields.