valiollah babaeizad

Rice is the most important staple food in the world. Bacterial leaf blight of rice, caused by Xanthamonos oryzae pv. oryzae (Xoo), is a highly destructive and widespread disease. Chemical management approach to control this disease appears ineffective. In this experiment, the effects of three treatments of salicylic acid, potassium phosphite, and chitosan on susceptible rice plants inoculated with the bacteria were investigated  to assess the induction of resistance and activity of antioxidant enzymes including catalase (CAT), guaiacol peroxidase (GPX) and superoxide dismutase (SOD) during four days. The results showed that the highest and lowest activity of CAT was recorded in the chitosan and salicylic acid treatment, respectively. The maximum amount of catalase activity was 72 hours after inoculation.  Comparison of GPX and SOD enzyme activities at different sampling times  revealed that these enzymes reached their highest level at 48 and 72 hours after inoculation across all treatments, respectively. However, among different treatments, the highest activity of these enzymes was observed in plants infected with bacteria under potassium phosphite treatment. The findings show that potassium phosphite increases the activity of plant defense enzymes against the pathogen,  ultimately  reducing the symptoms of the disease.

Fusarium verticillioides (Sacc.) Nirenberg causes maize ear rot in all maize-growing regions of the world and produces mycotoxins that contaminate maize grains. Therefore, it is considered an important species in terms of food health for both animal and human in the world. One of the best approaches to address this disease is to identify highly tolerant or resistant genotypes that can be used for genetic improvement. In this experiment, the resistance of 16 late maize hybrids was evaluated for cob resistance, silk channel resistance, and resistance in the germination stage using three inoculation methods. The objective of the current study was to select the genotype with high resistance in all three developmental stages.

The seeds of 16 late maize hybrids were obtained from the Maize and Forage Crops Research Depatment (MFCRD), Seed and Plant Improvement Institute (SPII), Karaj, Iran, and were planted in a randomized complete block design with three replications in the research field of MFCDR, in 2021. To inoculate the plants, the Kj7 isolate collected from infected maize cobs in the field of MFCDR was used. Maize hybrids were screened with three methods. In the first method, the resistance of the studied hybrids was evaluated by the rolled paper method at the germination stage. In the second method, the cob resistance was assesed by creating a wound in the middle of the cob and injecting spore suspension, and in the third method, silk channel resistance was investigated by injecting spore suspension into the silk channel seven days after the appearance of silks. Data statistical analysis was done by analysis of variance and comparison of means with Duncan's test using SAS software.

The results of analysis of variance and comparison of means showed that there was a significant difference among the studied 16 maize hybrids in terms of disease resistance with all three methods of artificial contamination. According to disease severity measurement in all three evaluated methods, the hybrids H3, H8, H11, H12 and H13 were selected as hybrids with high resistance against pathogenic fungi. These hybrids showed suitable resistance against all main methods of fungal infection and were superior hybrids compared to the other hybrids evaluated in this study in terms of resistance to maize ear rot caused by F. verticillioides. The implementation of these screening assays in maize breeding programs can be effective for classifying the degree of flexibility of maize germplasms to fusarium head rot.

The results of this experiment indicated that to evaluate the fusarium ear rot resistance of maize genotypes, the cob resistance method can be used as the main evaluation method especially in dry regions. Silk channel resistance can be used as a control method to evaluate the possible sensitivity of resistant or semi-resistant genotypes in humid areas where contamination with this method is important. Also, due to the different reaction of a number of hybrids investigated at the germination stage in this study and the possibility of the fungus growing as an endophyte in the plant, it is recommended to evaluate the new cultivars being introduced at this growth stage. Finally, hybrids should be introduced as resistant to this disease, which have shown a suitable reaction to the fungus in all three methods.

Fusarium verticillioides is a fungal pathogen of maize that causes ear rot and contaminates the kernels with fomunisin mycotoxin. Induced resistance to diseases is one of the ways which plants use against pathogens. This research was conducted as a randomized complete block design with three replications for six different time courses (0, 24. 48. 72. 96 and 120 hours post inoculation) and with two resistant (K18) and susceptible (MO17) maize lines in the greenhouse of Seed and Plant Improvement Institute (SPII), located in Karaj. In order to better understand the defense systems of maize at the molecular level, plants were inoculated with a spore suspension of F. verticillioides at a concentration of 106 by creating a wound in the middle of the ear, one week after silk emergence. The expression rate of ZmCCoAOMT2 and CYP450 89A genes was checked using the Real-Time PCR evaluation method. The results showed that the expression level of both genes increased in the resistant line. The ZmCCoAOMT2 and CYP450 89A genes reached their maximum expression level 48 and 96 hours after inoculation respectively, in the resistant cultivar. A decrease in the expression level of ZmCCoAOMT2 gene was observed in the susceptible line after fungal inoculation, but the expression of CYP450 89A gene increased in this line. In general, the results of this research showed that the studied genes are related to the interaction of the plant with the pathogen and may help to induce resistance in the plant.

The genus Malva (family Malvaceae) includes species of herbaceous plants which are often pluriannual and very common in borders and boundaries of cultivated fields, making them proper reservoirs for plant pathogens. They are most commonly used as ornamental plants, although they may be used as a food resource and remedy for various diseases. Common mallow (Malva sylvestris) is the most important Malva species which is used as garden flower as well as widely recognized for food and medicinal purposes.  Malva sylvestris are reported to be affected by several viruses from different genera including malva vein clearing virus (MVCV, Potyvirus), alfalfa mosaic virus (AMV, Alfamovirus), malva-associated soymovirus 1 (MaSV1, Soymovirus) cucumber mosaic virus (CMV, Cucumovirus), and cotton leaf curl Gezira virus (CLCuGeV, Begomovirus). In this study, we attempted to identify important viruses infecting mallow plants and compare mallow isolates with other sequences in the GenBank.

In 2022-2023, twenty samples of mallow plants with viral-like symptoms on the leaves were collected from the urban landscape of Golestan province. Total RNA was extracted by DENAzist Total RNA Isolation Kit from fresh, infected mallow leaves. All samples were analyzed by RT-PCR with specific primer pairs for the detection of CMV, AMV, and MVCV. The amplified fragments in expected size of coat protein (CP) gene of each virus were visualized under UV light in agarose gel after electrophoresis, then amplified fragment of one isolate of each virus was bi-directionally sequenced. Obtained sequences were compared to data available in GenBank. The phylogenetic trees of viruses were constructed based on the nucleotide sequences of the coat protein gene using the neighbor-joining method by MEGA11.

All three viruses were detected in some symptomatic samples collected from Golestan province. The most typical symptoms in positive samples were mosaic, vein clearing, and leaf malformation. Of a total of 20 sampled plants, MVCV, CMV and AMV were detected by RT-PCR in nine, five and two samples, respectively. An amplicon of each virus was selected and sequenced in both directions. BLASTn analysis of the sequenced data confirmed that the PCR-amplified fragments belonged to MVCV, AMV, and CMV. Phylogenetic analysis based on the nucleotide sequence of CP gene of MVCV (n=21) including Iranian and GenBank isolates showed that all isolates are divided into six groups: G1 to G6. All Iranian isolates along with the isolate from the Netherlands were placed in group G5. The phylogenetic tree placed the CMV sequences (n=51) into two distinct phylogroups I and II; the obtained isolate CMV-IR-Ma clustered together with isolates from Iran, Netherlands, South Korea, Japan, China, Hungary, Australia, France and the USA into group II. According to the results of this study, AMV isolates (n=17) can be divided into two groups, I and II. Group I which includes isolates from Canada, China, Italy, Spain, Argentina, Australia and the USA, was divided into six subgroups. The obtained isolate AMV-IR-Ma was clustered in subgroup IB with a Chinese isolate (HZ) and forms a common branch with isolates (Ir-VM, Ir-WS, and Ir-WS2) from Iran. This is the first report of mallow (Malva sylvestris) infection with CMV and AMV in Iran using RT-PCR. In addition, mixed infection with two (MVCV+CMV and MVCV+AMV) or all three viruses (MVCV+CMV+AMV) was also confirmed in some samples. The phylogenetic trees showed that most of the viral isolates were not grouped according to their geographic locations. This suggests the dissemination and spread of these viruses through infected seeds. In Iran, M. sylvestris is a common weed found in fields, waste grounds, roadside verges and gardens. Considering the potential non-persistent aphid transmission as well as mechanical transmission, virus-infected mallows can act as a natural reservoir, thereby posing a threat to other ornamental plants and crops. Since the studied viruses were not detected in the other symptomatic plants, the observed symptoms can be caused by physiological disorders such as nutrient deficiencies, the presence of different viral strains, or other unknown and undetected viral species.

This study provides new knowledge on the diversity and molecular characteristics of viruses in mallow plants (M. sylvestris) affected by the viral disease. The information obtained from this study can be helpful in improving management strategies for disease caused by these viruses in Iran. Albeit M. sylvestris is a host of these viruses, but more comprehensive research on other viral species that may infect this plant need to be conducted. Weed management could be an effective way to eliminate inoculum sources of these viruses.

The aim of this study is to investigate the interaction effects of two Trichoderma spices (T.koningii and T. virens) mutants and endophyte Piriformospora indica on infected cucumber plants by Fusarium oxysporum f. sp. radicis-cucumerinum (Forc) and evaluating their mutual influence on growth indexes in cucumber plants.The efficient wild-type Trichoderma isolates were selected by dual-culture test (T.koningii NAS-108 with 50% and T.virens NAS-115 with 33% inhibition of pathogenic growth) and their spore suspension with a concentration of 106 (spore/ml) in a dose range of 250 Gy was irradiated with gamma rays. NARS-TKM101 and NARS-TviM112 mutants showed highest antagonistic activity by 20% and 100% increase compared to their wild-type strains and they with their wild-type strains, were used for greenhouse evaluations. The combined treatments of Trichoderama sp. (total wild types and total mutants) with P. indica showed the most positive effects on seedlings growth indices length and dry weight (stem and root). No significant difference was observed between un-irradiated and mutant strains of Trichoderma in reducing disease index, (p<5%), but the combined treatments of two Trichoderma fungi (total mixed Trichoderama wild types and total mutants) with P. indica led to significant reduction of disease index (p<5%) and were more successful than the carbendazim fungicide in the plants infected with Forc.

Rice (Oryza sativa L.) is one of the most important cereals which known to have high nutritional value in foods population worldwide. Rice sheath blight is considered as a critical diseases and Rhizoctonia solani (Teleomorph: Thanatephorus cucumeris) is the causal agent of the disease. Induction of resistance by chemical compounds is a very interesting alternative approach in plant disease management. Various biotic and abiotic factors have a role in activation of resistance genes expression in plants. Potassium phosphite is among the chemical compounds which is able to induce of resistance genes in plants and leads to suppression of diseases by directly affecting the pathogens and indirectly by stimulating the host defense responses. In this study, the effects of potassium phosphite application was considered on the expression of some pathogenesis related genes in both Tarom (Resistance) and Khazar (susceptible) cultivars in challenging with R. solani.

The factorial experiment completely randomized design was used in this research. The effect of Potassium phosphite on Tarom (Resistance) and Khazar (Sensitive) rice cultivars in challenging with R. solani was considered. Four weeks old rice treated with potassium phosphite and as well mock plants were infected with the disease causal agent, R. solani. The sampling carried out at 0, 24, 48, 72 and 96 hours after infection. After total RNA extraction and cDNA synthesis, real-time quantitative PCR was performed to studying the expression pattern of PAL, LOX, PR1, PR3 and PR5 genes using specific primers.

In this research, findings demonstrated that there is a significant increase in the expression of PAL, LOX, PR1, PR3 and PR5 genes in potassium phosphite treated rice when compared to the mock plants. The effects of the treatments in all traits in the expression level of LOX, PR1, PR3 and PR5 genes were significant, but in the expression level of the PAL gene, in the treatment-cultivar and treatment-cultivar-time traits were not significant. Nevertheless, for the other traits it was significant. Between the Tarom (Resistance) and Khazar (Susceptible) cultivars, except for the PR1 gene, there was a significant difference in the rest of mentioned genes. As well, between the treatments, all five genes had a significant mean comparison.

These findings show that potassium phosphite causes a rapid and intense response of the rice plant against R. solani through the induction of different genes and leads to increase in sheat blight disease resistance. Actually in Tarom cultivar, resistance genes were expressed faster and further than Khazar cultivar.

Plant diseases are one of the major limitations in agricultural production. Citrus blast disease is one of the most common diseases in citrus producing regions of the world, with the exception of tropical regions. Plants respond to bacterial pathogens by activating genes encoding defense proteins. One of the defense mechanisms of plants against pathogens is the accumulation of Pathogenesis related proteins associated. The aim of this study was to evaluate the expression of several defense genes against Pseudomonas viridiflava after treatment of seedlings with Salicylic acid and Jasmonic acid.

The expression levels of PR1, PR2, PR3, PR4, PR5, POX, LOX pathogenesis related and PAL genes in the early stages of citrus blast disease in Citrus aurantium were assessed using RT-PCR. In this study, UBI gene was used as a housekeeping gene. The total RNA of the samples was extracted and after cDNA synthesis, the expression level changes of the declared genes were calculated and measured using the formula 2 - (ΔΔCT).

Increased expression of PR1, PR2, PR3, PR4, PR5, POX, LOX Pathogenesis related and PAL genes in the early stages of citrus blast disease in sour orange mostly occurred at 24 and 48 hours after challenging with the citrus blast causal agent P. viridiflava.

The results of this study was showed that salicylic acid treatment had a greater effect on the expression of PR1, PR2, PAL, POX and PR5 genes than jasmonic acid and jasmonic acid treatment was showed a greater effect on the induction of PR4, PR3 and LOX genes than salicylic acid. Furthermore, the expression of PR1, PR2, LOX, PR4, PAL and PR5 genes peaked in 24 hours after infection in sour orange plant by both treatments and it seems that these mentioned inducer of resistance genes involved in citrus blast disease resistance in host plant

Bacterial blight of rice caused by Xanthomonas oryzae pv. oryzae is one of the destructive diseases of this product in different parts of the world. Due to the inefficiency of chemical management and environmental contamination, the use of resistant cultivars is one of the most effective and economical ways to manage this disease. In addition, the lack of sufficient information to understand the mechanism of resistance in Iranian rice and in resistant cultivars, show that molecular evaluation of genes expression in sensitive and resistant cultivars in interaction with the disease agent, is needed.

In this study, the expression pattern of NPR1 and several PR genes (including PR1b, PR3 and PR5) in different time courses after inoculation was evaluated. Quantitative Real time PCR was performed in resistant and sensitive populations (Khazar and Tarom) to bacterial blight.

In the study of gene expression, the trend of increasing gene expression in the Khazar resistant cultivar compared to the sensitive cultivar was confirmed from the early hours after inoculation. The maximum expression of NPR1 gene in resistant cultivar was at 12 hours after infection (hai). In the case of pathogen-related genes expression, the activity of PR1b gene at 72 hai in resistant cultivar was 11.2 fold and in 96 hai was 25.7 fold higher than sensitive cultivar. High expression levels of PR3 gene at 12 and 48 hai in resistant cultivar was evaluated 38 and 10.4 times higher than sensitive Tarom local cultivar, respectively. The expression level of PR5 gene in resistant Khazar cultivar at 48, 72 and 96 hours was 4.1, 7.6 and 22 fold higher than the sensitive cultivar, respectively.

Since the accumulation of mRNA transcripts and increased activity of these genes is an important indicator of the development of a defense response in interaction with the disease agent, the activity of these genes indicates the presence of resistance potential in the Iranian Khazar cultivar is important against this disease. In general, activation of different pathways of systemic resistance (SAR) and induction of resistance genes in the emergence of resistance of Khazar cultivar compared to Tarom susceptible cultivar, is part of the defense mechanism of rice against Xoo. The results of this research along with the evaluation of the gene expression can promise the proper efficiency of the Khazar variety during the epidemic of the mentioned disease or a potential for transferring the resistance gene to sensitive cultivars in integrated management or pyramidal resistance.

Twist disease of wheat caused by Dilophospora alopecuri is one of the diseases that is observed along with wheat seed gall nematode (Anguina tritici) in Golestan province. In order to investigate the pathogenicity of the fungus, an experiment was performed in two cases including inoculation of the fungus alone, D. alopecuri and the nematode together and nematode alone on 4 cultivars of wheat known as Ehsan, Kouhdasht, Morvarid and Line 17 under greenhouse condition. Traits such as decrease of dry weight of infected plant, decrease of plant height, number of fungus-infected plants, number of spike infected by the fungus, number of nematode-infected plants, total weight of nematode galls, number of nematode galls and average galls weight per plant were measured in different cultivars. The analysis was performed using SAS software, and the comparison of the means was achieved by the LSD test. The results of analysis of variance showed that the interaction between D. alopecuri and wheat cultivars and the effect of the fungus on the measured indices in wheat cultivars was significant. The results showed that D. alopecuri can cause disease on wheat only in the presence of A. tritici and the presence of nematode is necessary for fungal pathogenicity and its distribution in the wheat spike.

Huanglongbing (HLB) is one of the most destructive diseases of citrus worldwide. The disease keeps spreading in several citrus-growing areas of southern Iran. The potential of (GTG)5-rep marker in revealing the genetic diversity of geographic isolates of Candidatus Liberibacter asiaticus was evaluated in the present study. Twenty-one HLB-infected samples collected from the Hormozgan and Sistan and Baluchestan provinces were used in the trial. PCR with the (GTG)5 primer produced 16 scorable bands, of which nearly 100% were polymorphic among or within the populations. The most observed variation resided within (80.56, P < 0.10) and a substantially less (19.44, P < 0.10) between the populations. The isolates were distributed in two main (A and B) clusters, each consisting of several subgroups. Group A included Sistan and Baluchestan and Hormozgan isolates and the group B embraced Hormozgan isolates. Based on pairwise genetic differences, the Haji Abad and Hashtbandi populations exhibited the highest between-population variation, and the Siahoo, Hashtbandi, Nikshahr, Haji Abad, and Sarbaz showed the greatest within-population variation. The first three coordinates of the principal coordinate analysis explained more than 72.39% of the variation among or within the populations. The first two coordinates explained 58.20% of band variation in plotting, and the first and third coordinates explained 55.54% of band variation. These results may be inferred that the Hormozgan populations might have diverged from the Sistan populations, or both might have originated separately from an initial or parental population possessing a high genetic diversity.

Citrus bacterial blast disease is one of the prevalent diseases in most citrus-growing regions in the world. Plants use a wide range of mechanisms to defend against pathogens, and the plant-pathogen interaction induces the expression of genes involved in the plant resistance. Furthermore, symbiotic association between plant and mycorrhizal fungi could effectively promote growth and protect the plant against adverse environmental conditions. In the present study, Serendipita indica-root colonized sour orange seedlings were infected by Pseudomonas viridiflava and the expression patterns of PR1, PR2, PR3, PR4, PR5, PAL, POX, and LOX genes in the early stages of citrus blast disease were investigated using the qRT-PCR at different sampling times. According to the results, the response of defense genes to bacterial infection was time dependent. In the S. indica-colonized sour orange plants, the highest level of PR1, PR4, PAL, POX, PR3, and PR5 genes expression was observed at 48 h after infection, but the expression of PR2 and LOX genes was increased at 72 h after infection compared to the control plants. It seems that S. indica can induce systemic effects and prepare the host plant to increase the expression of defense genes more rapidly once it receives a signal for the presence of the pathogen.

Rice is one of the most important crops in the world, which occupies a large area of arable land. Blast disease is one of the most important and destructive rice diseases, which reduces production of this product. Due to environmental pollution caused by overuse of fungicides to control this disease and on the other hand, the pathogen resistance to these chemicals, development of better and healthier strategies to control this pathogen is necessary. Biological control of plant diseases using antagonists can be a promising alternative method.

In this study, indirect effect of Trichoderma harzianum fungus on pathogenic fungus, Magnaporthe oryzae, under greenhouse conditions was investigated by induction of systemic resistance in susceptible Tarom cultivar. For this purpose, expression of several important defense genes was investigated using real-time qPCR technique in plants symbiont with Trichoderma compared to control plants (without Trichoderma) at different times after infection with pathogenic fungi.

The results showed increasing expression level of NPR1, PR2 and PR3 genes after pathogen inoculation in plants symbiont with Trichoderma compared to the control plants that there was statistically significat difference about PR2 and PR3 genes. Nevertheles in a number of times, there was no significant difference in expression level of the evaluated genes between two treatments. Examination of various morphological traits such as root, stem and leaf dry weight, root length, stem diameter and plant height showed an increase in plants symbiont with Trichoderma compared to control plants (without Trichoderma), although this difference was not significant about these traits except for plant height. Chlorophyll a and b levels were also measured as physiological traits in both treatments. Although amount of chlorophyll a was higher in plants symbiont with Trichoderma than control plants, but no significant difference was observed. Phenotypic study of interaction of rice plant and pathogen in presence of Trichoderma showed a significant difference about disease severity in plants symbiont with Trichoderma compared to control plants.

These results could somewhat indicate the systemic protection of the rice plant against M. oryzae due to symbiosis of the plant root with Trichoderma harzianum and induction of resistance and increase in pathogenesis-related genes, but this is not enough. Therefore, it is necessary to repeat greenhouse experiment to ensure that there is a significant difference in expression of the studied genes between symbiotic and control plants.

Septoria tritici blotch (STB) caused by fungus Zymoseptoria tritici, is one of the important wheat (Triticum aestivum L.) diseases difficult to control because of the lack of wheat resistant cultivars. The use of biological control agents is one possible way for triggering host plant resistance to biotic and abiotic stresses. In this study, we examined the ability of Serendipita indica and Pseudomonas protegens CHA0-mCherry in inducing the local wheat cultivar Tajan resistance to STB. The interaction between biological control agents and the roots of wheat was evaluated. The experiment was conducted in a completely randomized design by three replicates. Spore suspension was supplied at concentrations of 107 and 109 for S. indica and bacteria isolate (CHA0-mCherry) respectively. Five treatments were applied including S. indica, CHA0-mCherry, S. indica and CHA0-mCherry co-inoculation, positive and negative control. Twentyone days after inoculation, the interaction between biological agents and plant roots were evaluated through morphological traits and qPCR. The plant resistance, disease severity, and the correlation between resistance and disease severity were assessed. Pycnidial variation and agronomic traits were also evaluated. Twenty-one days after inoculation, both biological agents clearly colonized all treated roots of all treatments except in control plants as demonstrated by qPCR analysis. Chlamydospores were observed in the S. indica-treated hosts with the CHA0-mCherry colonizing assessment showing 5×109 CFU g-1 in the root. The asexual phase of the fungal pathogen, pycnidial diameter, was reduced in S. indica treated plants more considerably than in the other treatments. There was a positive correlation between resistance and disease severity mean when calculated by Pearson’s correlation. There was a significant difference between the root length, fresh, and dry weight of root. Spore density was inversely correlated to resistance and disease severity, when compared with control, with CHA0-mCherry being the most effective in reducing the spore density. S. indica was the most effective in promoting root growth and stem biomass, when compared with control. Serendipita indica and Pseudomonas protegens CHA0-mCherry colonies showed a potential biological control activity and efficiently enhanced the plant resistance to Z. tritici in the treated wheat roots. The microbial biological control agents are very practical in crop protection against plant disease and can be very useful in sustainable agriculture. Abbreviations: PLSN: percentage of leave surface necrosis, DPI: day past inoculation, PLACL: percentage of leaf area covered by lesions, PPMLA: pycnidia per millimeter in leaf area.

Blast is one of the most important and destructive rice diseases in the world. Nanoparticles are antimicrobial agents used as biological and non–biological stimulants and can induce resistance in plant against pathogens. Effects of different biological and non–biological nanoparticles on inhibition of various plant fungal pathogens has been proved. However, no study has been done about the effect of biological nanoparticles on control of this disease through induction of resistance and expression of defense genes. In this study, in addition to direct effect of biological silver nanoparticles synthesized using Trichoderma harzianum fungus in vitro, its indirect effect was investigated by inducing systemic resistance in susceptible local Tarom cultivar on pathogenic fungus Magnaporthe oryzae under greenhouse conditions. For this purpose, expression of several important defense genes investigated in biological silver nanoparticle–treated plants in comparison with control plant (without biological silver nanoparticle) using real–time qPCR technique at different times after pathogen inoculation. The results showed a positive effect of different concentrations of biological nanoparticles in reduction of pathogen growth in comparison with the control treatment so that the amount of inhibition of pathogen growth in different concentrations (36, 27, 18, 9, 4.5 ppm) was 92, 81, 56, 28 and 7 percent compared to the control treatment, respectively. Phenotypic study of rice plant interaction with the fungus causing blast disease in presence of biological nanoparticle showed that there was no significant difference between the disease severities in biological nanoparticle–treated plants compared to control plants. Also, accumulation of transcripts of NPR1, PR2, PR3 and LOX genes between two mentioned treatments did not show significant increase. Therefore, indirect effect of biological silver nanoparticle on pathogenic fungus by induced resistance and increasing the rice plant defense genes is not considerable.

In this study, to isolate and identify the root endophyte fungi, root samples of herbaceous plants were collected from the central regions of Mazandaran province during 2016-17. In laboratory, each root sample was cultured on PDA medium after surface disinfestation and incubated for a month at 25°C and continuous darkness. Fungal isolates were purified using the single spore and hyphal tip methods. Fungal species were identified based on morphological characteristic and ITS sequence data. In this study, 27 species belonging to 14 different genera including: Alternaria alternata, A.arborescens, A. burnsii, A. dumosa, A. solani, A. tenuissima, Botryosphaeria dothidea , B. auasmontanum, Curvularia australiensis, C. buchloes, C. spicifera, Cladosporium tenuissimum, Daldinia concentrica, Diaporthe bohemiae, Fusarium acuminatum, F. avenaceum, F. equiseti, F. oxysporum, F. tricinctum, F.verticillioides، Microsphaeropsis arundinis، Nigrospora sphaerica، Paraconiothyrium cyclothyrioides, Periconia macrospinosa, Poaceascoma helicoides, Preussia minima and Xylaria heliscus were identified. Among identified fungi Botryosphaeria auasmontanum, Curvularia australiensis, C. buchloes, C. spicifera, Diaporthe bohemiae, Microsphaeropsis arundinis, Nigrospora sphaerica, Paraconiothyrium cyclothyrioides, Periconia macrospinosa, Poaceascoma helicoides and Preussia minima are new for mycoflora of Iran. Except Alternaria arborescens, other fungi are introduced from their hosts for the first time, in Iran.

Septoria leaf blotch (STB) caused by Zymoseptoria tritici, is one of the important wheat disease. The endophytic fungus Serendipita indica and the plant-protecting bacteria Pseudomonas protegens induce systemic resistance to plant pathogens. In this study, the expression rate of several defense genes in Tajan susceptible wheat cultivar treated by S. indica and P. protegens and in control plants at different times point after inoculation with Z. tritici were investigated by Real-time qPCR technique. The results showed that, the expression of PAL and LOX genes in plants treated with P. protegens was higher than other treatments. The expression of NPR1 and PR5 genes were higher in co-inoculated plants that treated by S. indica and P. protegens. The results of phenotypic evaluation of two mentioned treatments also show, the expression of these genes is effective in inducing resistance.The results indicate the active role of these two biocontrol agents in protection of susceptible Tajan cultivar against STB due to increased expression of these genes compared to control.

Rice bacterial blight caused by Xanthamonos oryzae pv. oryzae is one of the most destructive bacterial diseases of rice in some areas of rice cultivation in the world, especially in the tropics of Asia. The low efficiency of disease management methods, especially chemical methods, has led to more research on recognizing resistant cultivars and understanding resistance mechanisms through the study of biochemical interactions and recognition of resistant genes. This study aimed to evaluate the resistance of 24 commercial Iranian rice cultivars against bacterial blight and to study some mechanisms of resistance at biochemical levels and the pattern of PAL gene expression by the qRT-PCR method. The results of the greenhouse assessment showed that different cultivars varied in the development of leaf spot length as the most important trait for disease evaluation. The Khazar and Nemat commercial cultivars at the highest level of resistance and the Tarom (mahalli) and Dilamani cultivars showed the highest sensitivity based on the evaluation index (quantitative resistance) of this disease. Biochemical evaluation of Catalase, guaiacol peroxidase, superoxide dismutase enzymes and total phenol in the resistant and sensitive cultivar shows the high activity of these enzymes in the resistant cultivar compared to the sensitive cultivar in the early hours after inoculation. The difference between resistant and sensitive cultivars was significant at the level of one percent. The PAL gene expression rate was also significantly higher in the resistant Caspian cultivar in the early hours (12h) after inoculation than the sensitive cultivar. Overall, it seems that the induction of the PAL gene and the subsequent increase in the accumulation of oxidative and antioxidant enzymes in the resistance of Khazar cultivar to the sensitive cultivar of Tarom, it is part of the defense mechanism of rice against Xoo bacteria.

Faba Bean (Vicia faba) is an important legume among cultivated plants and Alternaria leaf spot is a serious disease that causes broad damages and yield loss in Golestan and Mazandaran provinces. In current research, sampling was carried out from Mazandaran and Golestan provinces. Morphological and molecular surveys of the obtained isolates showed that they belong to A. alternata species. In order to evaluate resistance of nine Faba Bean cultivars against Alternaria leaf spot, area under disease progress curve (AUDPC) were calculated in greenhouse condition. In addition, variation of some resistance related enzymes between resistant and susceptible lines were tested at different time intervals after inoculation. Statistical analysis showed significant difference between cultivars (P≤ 0.05). The Otono cultivar with the highest AUDPC and Zereshki cultivar with the least AUDPC were suggested as susceptible and resistance cultivars, respectively. The ANOVA of antioxidant enzymes showed positive effects on CAT, APX and GPX levels after inoculation (P≤ 0.01). Increasing in the amount of enzymes in incompatible interaction (Zereshki resistant cultivar) was greater than that of compatible interaction (Otono susceptible cultivar), indicates the role of these enzymes in activating plant defense responses in Faba Bean to interact with the pathogen and induce resistance. In general, the results showed that Zereshki cultivar with low level of AUDPC and high expression of antioxidant enzymes has high potential to be used in breeding programs for resistance to Alternaria leaf spot.

In order to evaluate the rol of mycorrhiza-like fungus Piriformospora indica on rice grain yield and water use efficiency under different limited irrigation regimes a field experiment was conducted in split factorial design with three replicates during 2014. Treatments were different irrigation methods at three levels (flooding, flooding after falling water depth less than 10 and 20 cm of soil surface) in main plot, two levels of P. indica inoculation (control and inoculation of six days old seedlings) and two rice cultivars (Tarom-Hashemi and Shiroudi) in sub plots as factorial. Results showed that maximum grain yield was obtained in Shiroudi cultivar in flooding (7801 kg/ha), followed by -10 and -20 cm irrigation regimes (5592 and 5575 kg/ha, resectively). This reduction in Tarom-Hashemi cultivar, however, was only significant where falling water depth was less than 20 cm of soil surface and yield loss was about 18 percent as compared to the flooding treatment. Nevertheless, P. indica inoculation in Shiroudi cultivar increased biological yield by 8 %, as compared to Tarom-Hashemi cultivar. Water use productivity and efficiency amounts in limited irrigation regimes was increased significantly in falling water depth less than 20 cm of soil surface treatment by 55 and 57 % , respectively as compared to flooding treatment. In conclusion, results represented a positive effect of coexistence between P. indica and rice plants particularly to ameliorate water deficit negative effects.

In this research, examineation of the disease distribution, the physiological relationship between disease agent and its sites and evaluation of cultivars resistance were done. The disease agent identified as Zymoseptoria tritici, by morphological and molecular identification based on the ITS-rDNA. Distribution map prepared by ArcGIS v.10.2 software. Five isolates selected from different regions. The isolates growth tested in different temperature and its relation to their region climatic conditions evaluated. 26 cultivars planted in the greenhouse by completely randomized design, inoculated and evaluated. As a result, the isolates growth average at different temperatures was statistically significant in P=0.01. Isolate growth average had correlation with region climatic conditions. In terms of growth, the Nokandeh isolate was the most and the Ramian isolate was lowest. The highest isolates growth was at 15°C and the lowest growth rates were at 10°C. The disease observed in 9 eparchies. Ramians and Kurdkoy identified as disease contaminated sites. Of the examined cultivars, 4 cultivars such as Falat, Mehrgan, Ghabos, and Roshan were resistant, 14 cultivars such as Shirodi, Morvarid, Moghan, Kohdasht, Gaspar, Aftab, Shahriar, Gonbad, Alamoot, Aflak, Zarin, Karaj-1, Tous, and Azar-2 were moderately resistant and 7 cultivars such as Karim, Dez, Khazar-1, Star, Hamoon, Ofogh, Eram and Tajan were evaluated as susceptible. Between isolates, the most disease severity belongs to Ramian. Considering to width distributions of STB, the existence of favorable conditions and identification of disease region center, it is possible to monitor the appearance of infection at February and March and make abroadcast of the disease prevalence. Also, by evaluating of wheat genotypes, introducing and planting the resistant cultivars, it could reduce the disease in later years.

Powdery mildew is one of the most important diseases of wheat that make yield damage annually. In recent years, the use of induction elicitors has been widely welcomed. Therefore, in this research in order to examine the ability of chitosan , Flat were selected as susceptible cultivar, and the leaves were sprayed with chitosan. Then treated plant together control plants were inoculated with Bgt pathogen.Finally, The expression rate of MLO, B-I1 and NPR1 genes was examined in using Real Time PCR technique Results showed that in both chitosan treated plants and the controls, rate of gene expression were increased after infection for all genes, So that, in the first hours after inoculation, treated plants showed NPR1 expression more rapidly than control. Maximum expression level of this gene was observed at 24 hours after infection. But, in treated plants, the expression rate of BI-1 and MLO were less than the control and they showed minimum expression at 24 hours after infection. These results indicated these genes by decreasing their expression rate in order to increase the level of active oxygen species causes induction of cell death in the plant to inhibition of fungal growth and development in the early stages after infection. The gene expression rate in plants treated with 250 mg/L was more indicative than those treated with chitosan 500 mg/L. Overall; results showed that chitosan could induce systemic resistance in susceptible wheat against powdery mildew in low concentration.

Pythium ultimum is one of the major causative agents responsible for damping off disease in cucumber plants. In the present study, the effect of potassium phosphite (KPhi) on defense response of P. ultimum-inoculated cucumber plants was investigated. Different plant growth parameters as well as chlorophyll a content were studied to evaluate the healing effects of KPhi. Furthermore, the expression pattern changes of a pathogenesis-related chitinase gene was analyzed via qPCR. Results revealed that KPhi treatment significantly increased growth parameters i.e. shoot length, diameter and mean leaf number in cucumber seedlings. KPhi treatment at 1 and 4 gL-1 caused 31.37% and 94.48% increase in shoot diameter respectively compared to control plants while shoot length of plant treated with 1 and 4 gL-1 KPhi were increased 72.14% and 78.85%, respectively compared to control plants. The chlorophyll a content as well as plant leaf number was significantly increased in plants treated with 1 or 4 gL-1 KPhi compared to control plants. It was interestingly revealed that KPhi application decreased Chitinase gene expression compared to control plants. The findings of the present study would be implemented for designing a controlling strategy to decrease the adverse effect of P. ultimum on cucumber plants.

Cucumber is one of the economically important vegetables in Iran which is extensively attacked by powdery mildew. Identification and application of disease resistant genotypes is an efficient method to escape the disease epidemic. A number of 23 greenhouse and field cucumber cultivars were evaluated and screened for powdery mildew resistance and putative resistant cultivars were identified based on percent Disease Index (PDI) measurement. In addition, leaf chlorophyll fluorescence was measured and analyzed in 5 cultivars selected from resistant, semi-resistant and sensitive groups. Based on the results of PDI measurements, a considerable variation between the cultivars was observed so that the cultivars classified to four groups including resistant, semi-resistant, semi susceptible and susceptible. Two greenhouse cultivars i.e. CLE and Green Magic with the PDIs of 7.78 and 8.33 were the most resistant and the two field cultivars Beit Alpha and SuperN3 with the PDIs of 31.11 and 31.67 were the most susceptible cultivars. Based on the ANOVA of chlorophyll florescence parameters, a significant infection effect on minimal florescence (Fo), variable florescence (Fv) and vitality index (Fv/Fm) and a significant genotype effect on Fo parameters was observed (P

IntroductionGreen bean (Phaseolus vulgaris L.) is one of the four species of the genus Phaseolus with the highest protein among a variety of commercial plants (Nasri and Khalatbari, 2011(. This plant can be grown in different times in Mazandaran weather conditions (Motaghian et al., 2010). Green beans as well as other crops during their growth stages faced with environmental stresses such as chilling. Chilling stress referred to conditions as temperature between 0 and 10 ᵒC which resulted in damages to the plant (Baninasab, 2009). Chemical and biological inducers can be used to increase chilling stress tolerance of plants. Paclobutrazol (PBZ) is a member of the Tryazol families with growth regulating effect (inhibitors) and increased stress tolerance through changes in plant growth and morphological, anatomical and biochemical changes (Berova et al., 2002; Chaturvedi et al., 2009). Meanwhile, Piriformospora indica fungus is one of the soil microorganisms which form a symbiotic relationship with plants and could increase plant growth and resistance to environmental stresses throughout systemic changes or defense induction (Deshmukh et al., 2006). Hence, the present research was aimed to determine PBZ and P. indica efficiency in green bean tolerance against chilling stress.
Materials and MethodsThe experiment was conducted under controlled conditions at Genetics and Agricultural Biotechnology Research Institute, Sari Agricultural Sciences and Natural Resources University in factorial arrangement based on completely randomized design with three replications in 2013. Treatments were three levels of chilling stress (control, three and six days exposure to five centigrade degree temperature), two levels of fungi inoculations (control and inoculation with P. indica) and three levels of PBZ (0, 40 and 80 mg/L). To inoculate the plants with P. indica, fungal spore suspension was prepared (5×105 spore/ml). The sprouted seed were soaked for four hours in fungal suspension and were sown in pots containing two kg of sterilized soil. PBZ was sprayed twice at two stages of five and six week after sowing. Then pots were transferred to growth chamber after eight weeks from sowing and then chilling stress was imposed. After 12 hours of stress, aerial dry weight, SPAD value, chlorophyll a, b and a, carotenoid content and electrolyte leakage were measured. The data were analyzed using SAS statistical software and significant differences between means were estimated using least significant difference (LSD) test at PResults and discussionResults showed that chilling stress particularly for six days decreased aerial dry weight, chlorophyll a and b and carotenoid content (nearly 19, 18 and 8%, respectively) as compared to the uninoculated control. In all levels of chilling stress, however, P. indica inoculation increased plant dry weight in which the most beneficial effect (up to 65%) was recorded in severe stress. Mean comparison of three factors indicated that at all levels of chilling stress and PBZ, P. indica increased leaf and whole plant dry weight at the range of eight to 280% and 0 to 143%, respectively. The maximum increase for leaf dry weight (2.68 g/plant) was recorded where inoculated plants grown in normal conditions in no applied PBZ. Furthermore, the highest value of aerial dry weight (3.42 g/plant) recorded in plants which inoculated both with P. indica and sprayed with 80 mg/L of PBZ under normal conditions. PBZ spraying at the rate of 40 mg/L increased chlorophyll a, carotenoid and SPAD value by 5, 9 and 7%, respectively. In inoculated plants, however, PBZ spraying decreased plant dry weight particularly at the rate of 40 mg/L (nearly 17%). PBZ spraying, also, reduced electrolyte leakage in which the maximum reduction (up to 20% lower than non-application) was obtained with 80 mg/L of PBZ.
ConclusionIn conclusion, the results indicated that P. indica inoculation along with Paclobutrazol spraying had a positive effect on chilling tolerance in green beans. Therefore, these factors can be used to induce chilling stress tolerance. However, further tests should also be applied to other growth stages of plant.

Barley is one of the most important cereals in animal nutrition and it has a role as a substitute source of wheat and rice in diet nutrition. This product is always exposed to damaging factors such as pests and diseases which lead to reduce yield and quality. The Powdery mildew agent, as a biotrophic fungus, seriously causes damage in some barley plantation areas. Similar to other plants, barley employs diverse mechanisms against the disease based on proteins and other antimicrobial agents such as pathogenesis- related proteins which have essential roles in disease resistance. In this study, morphological and molecular analyses were conducted on some barley genotypes after challenge inoculation with Blumeria graminis f.sp hordei (Bgh), the causal agent of powdery mildew. For this purpose, 11 barley cultivars were selected for initial screening. Result from data analysis showed that Mb-86-5 was the most susceptible cultivar and in Avt/Attiki, Ceres, BIR, L.1242, Yousef, Nosrat, Mahoor, Comp-1-71E and Rihane-03 cultivars, the rate of Bgh colony number significantly decreased when compared to susceptible Cv. The susceptibility rate between Beecher and Mb-86-5 was not significant. Determination of the genes expression involving in disease resistance, carried out on one- week old seedling. For all samples total RNAs were extracted. Molecular investigation showed that PR1, PR5, NH1, POX genes enhanced significantly in resistant cultivar Ceres when compared to Mb-86-5 susceptible genotype. Results of this study indicate that the mentioned genes are involved in powdery mildew disease resistance in Ceres barley genotype.