naser panjehkeh

Verticillium wilt disease is one of the most important damaging and limiting factors for cotton production worldwide. This pathogen causes leaf chlorosis, necrosis or wilt, leaf or pollen drop, and even plant death. It also reduces the quantity and quality of the product. Because of the economic importance of the cotton disease Verticillium wilt, the best way to control this disease is to use tolerant varieties. Therefore, breeding resistant varieties in a wide range is considered one of the most effective control methods. This experiment was conducted to determine the effect of the disease on the morphological and physiological characteristics of cotton cultivars in order to identify tolerant genotypes

The experiment was carried out during two years 2020-2021 and in a factorial form in a completely randomized design with three replications in the greenhouse of Khorasan Razavi Agricultural Education and Natural Resources Research Center (Plant Protection Department). In the first year, ten Iranian cotton cultivars belonging to Gossypium hirsutum were cultivated. In the first year experiment, cotton agronomic traits such as plant height, number of leaves, number of branches, crown diameter, leaf area size, disease severity, chlorophyll index, relative leaf water content and electrical conductivity were measured. In the second year, two tolerant cultivars (Bakhtegan) and sinsitive (Varamin) resulting from the first-year experiment were cultivated in the greenhouse along with the resistant cultivar of Thermous 14. At this stage, the amount of proline, soluble carbohydrates and total phenol was evaluated at different times after inoculation with the pathogenic fungus. All traits measured over two years using SAS statistical software were analysis of variance and the means were compared using Duncan's test.

In the first year, it was found that among the ten genotypes grown, all agronomic traits (except plant height) were higher in the Bakhtegan cultivar and lower in the Varamin cultivar than in the other cultivars. Under infection conditions, disease severity was highest in Varamin and Cocker100 cultivars. The lowest severity of the disease was in the variety Bakhtegan. Physiological traits such as chlorophyll index and relative water content were higher in Bakhtegan and lower in Varamin. The opposite was true for membrane electrolyte losses. In the second year, it was found that in the three cultivated genotypes Thermous14 (resistant), Bakhtegan (tolerant), and Varamin (sensitive), the amount of biochemical traits proline, carbohydrate, and total phenol was significantly increased in the infected plants compared to the control plants (no inoculation with pathogenic fungi).

Therefore, plants with more leaves, higher chlorophyll index and relative water content, lower electrolyte leakage, more proline, carbohydrates and phenols are more resistant to infection.

Verticillium wilt disease is one of the most important damaging and limiting factors of cotton cultivation worldwide. This disease reduces the quantity and quality of the product. Due to the economic importance of Verticillium wilt cotton disease, the best way to control this disease is to use tolerant cultivars. This experiment was performed to determine the effect of disease on morphological and physiological characteristics of cotton cultivars in order to identify tolerant genotypes.

The experiment was conducted in 2020 in the greenhouse of Khorasan Razavi Agricultural Education and Natural Resources Research Center (Mashhad Plant Protection Department). Ten commercial Iranian cotton cultivars belonging to Gossypium hirsutum including Varamin, Sahel, Bakhtegan, Khorshid, Armaghan, Mehr, Koker, Khordad, Kashmar and Deltapine were planted in factories in a completely randomized design with three replications in the greenhouse. The first factor was cotton cultivars and the second factor was the contamination of cotton cultivars with fungal isolates.

The results of analysis of variance of the measured traits on the studied genotypes showed that the tested cultivars in terms of leaf number, crown diameter, number of branches, leaf area, chlorophyll index, disease severity, relative leaf water content and electrolyte leakage membranes were significantly different at the 1% probability level. This difference was not observed in terms of plant height. Comparison of the mean of the above traits (except plant height) in the treatment of contamination levels, indicated that the cotton plants  inoculated with the pathogenic fungus Verticillium wilt compared to control plants (no fungal infection) had lower number of leaves, number of branches , leaf area and crown diameter. Mean comparisons of the above traits were performed between genotypes. Some genotypes can be selected for field experiments in terms of superior study traits. The results of comparing the mean interaction of infection × cultivar for all traits (except plant height) were significant at 1% level. Under the conditions of infection, the highest severity of the disease was related to Varamin and Cocker-handard cultivars. While the lowest severity of the disease was related to Bakhtegan cultivar.

The results showed that Verticillium wilt disease reduces the number of leaves, number of branches, leaf area, crown diameter, chlorophyll index and relative water content. While this disease increases the electrolyte leakage of cell membrane. In this regard, a negative and significant phenotypic correlation was observed between disease severity and number of leaves, branch, crown diameter and chlorophyll index. There was a positive and significant phenotypic correlation between disease severity and membrane electrolyte leakage. Therefore, plants with more leaves, higher chlorophyll index and relative water content and lower electrolyte leakage are more resistant to infection.

The pathogens causing white blister rusts (Albuginales, Oomycota) comprises three genera including Albugo, Pustula and Wilsoniana infecting species of Brassicaceae, Caryophyllales and Asteridae, respectively. The current study contributes with new knowledge on Albuginales in Iran. An extensive survey for sampling white blister rust specimens was performed during the 2017-2020 growing season in some regions in Eastern and Northern Iran. Based on morphological and molecular (Cox2 and ITS) data Albugo lepidii on Lepidium sativum, A. koreana on Camelina transcaspica, Albugo arenosa on Strigosella africana, A. candida on various hosts, A. occidentalis on spinach and Wilsoniana portulacae on Portulaca sp. were identified. Our results, represent the first morphologically and molecularly verified report of A. candida on Goldbachia laevigata, Raphanus sativus, Eruca sativa from Iran and on Sinapis arvensis, Savignya parviflora, Isatis leuconeura and Sisymbrium altissimum worldwide. Sisymbrium septulatum is reported as Matrix nova for A. candida. White blister rust caused by A. candida is reported for the first time on a member of the genus Savignya in Iran. Albugo lepidii and A. koreana are new records for Iranian mycobiota. Detailed descriptions and illustrations along with phylogenetic placement here are provided for Wilsoniana portulacae and Albugo occidentalis.

Pepper Capsicum annuum is one of the important vegetable crops in Iran, especially north of Iran. Various symptoms of stolbur, including limited growth, small and chlorotic leaves, spoon-shaped leaflets, and sterility or fruit alterations, were detected in samples collected from the pepper field in Qazvin province. DNA was extracted from midribs and petioles of pepper leaves using CTAB-based methods. The phytoplasma in all symptomatic pepper plant parts was detected by direct and nested polymerase chain reactions (PCR) using primer pairs P1/P7 and R16F2n/R16R2. The 16S rDNA sequences of phytoplasma isolate were deposited in GenBank (MN877916). Based on phylogenetic studies of the 16S rDNA region, the results of enzymatic digestion of the fragment obtained by amplification with R16F2n/R16R2 primer and virtual RFLP, phytoplasma agent associated with stolbur pepper disease was detected to belong to 16SrXII group and 16XII-A subgroup. According to our knowledge, this is the first report of pepper stolbur disease in Iran.

Aspergillusniger is one of the microorganisms that produce the pectinase enzymes group of the at high levels. In this fungus, PgaA genes code Glycoside hydrolase family 28 that secrete polygalacturonase enzymes. Green algae (Chlorophyceae) and blue-green algae (Myxophyceae) having pectin, cellulose and hemicellulose compounds such as xylan, arabinoxylan in their structure could act as a precursor to the production of cellulase, xylanase and pectinase enzymes in fungi. In this work, the effect of green algae extract ; Spirogyra sp. at 500 and 1000 mg/mL concentration on the rate of pectinase enzyme secretion and the relative expression of PgaA gene at 4 and 8 day after adding algae extract to culture medium was evaluated using qRT-PCR analysis. . The highest level of enzyme secretion was observed at 8th days after algae extract adding to culture medium at 1000 mg/mL concentration( 4.28 U/ml). Gene expression analysis of PgaA gene showed that the highest expression level was relted to 4th days time interval after adding alge extract at 1000 mg.mL (10/142). According to positive effect of spirogyra algae compounds on expression level of PgaA gene responsible to pectinase production and increase of enzyme secretion, it is concluded that microalgaes could be used as important sources of enzyme production from favorable fungi and could be useful in biotechnological industry

The effects of salicylic acid (SA) nano-formulation on expression of peroxidase (113-114) genes and peroxidase and phenylalanine ammonia lyase (PAL) were investigated in wheat cultivar (Bezostaya) susceptible to Heterodera filipjevi. The wheat roots and leaves were randomly divided into control group and groups exposed to 62.5, 125 and 250μg/ml SA. A spectrophotometric analysis was carried out using root extracts from infected plants at 4, 7 and 11days post inoculation with nematode (DAI) for peroxidase and PAL. The expression of peroxidase (113-114) genes was evaluated by Real time PCR analysis. Peroxidase activity was significantly increased in treatments exposed to 250μg/ml of nanosalicylic acid at 11 DAI. Phenylalanine ammonia lyase activity was induced in the treatments exposed to 250 and 125μg/ml  nanosalicylic acid compared to the control at 4 and 7 DAI, respectively. Phenylalanine ammonia lyase activity was also increased in the treatments exposed to 62.5 and 250μg/ml of nanosalicylic acid compared to the control at 7 DAI. The expression level of peroxidase 113-114
in wheat leaves was significantly raised at 4 DAI when 62.5μg/ml of nanosalicylic acid was used. There was also a significant difference between expression levels of peroxidase 113-114 genes at applications of 125 and 250μg/ml of SA in comparison with the control at 4 and 7 DAI, a significant decrease was revealed in the gene expression in treatments exposed to 62.5, 125 and 250μg/ml of nanosalicylic acid compared to the control at 11 DAI. It was concluded that higher concentrations of nanosalicylic acid have a potential effect on peroxidase and PAL activities in wheat infected by H. filipjevi. High concentration of nanosalicylic acid has inhibitory effects on the expression level of peroxidase gene.