جستجوی مقالات مرتبط با کلیدواژه « amylase » در نشریات گروه « گیاهپزشکی »

Fusarium dry rot is one of potatoes' most significant postharvest fungal diseases, reducing crop yield and seed tuber quality. Utilizing certified seed tubers treated with chemical fungicides is the simplest and most cost-effective method for preventing dry rot disease damage to potatoes. Monitoring for diseases transmitted by tubers enhances the quality of seed tubers produced and reduces the risk of disease establishment and soil contamination. This study aimed to identify the causal fungal agents of potato seed tubers dry rot, determine the susceptibility of seed samples from potato seed farms to Fusarium dry rot agents, as well as to evaluate some of the effective factors in disease severity, particularly the levels of extracellular enzyme activity and fusaric acid production on the disease index and dry rot volume of potato tubers.

To identify Fusarium species responsible for dry rot disease in the seed tubers of Agria, Banba, Jelly, Challenger, Ramus, Sagitta, Sante, Sifra, Fabula, and Colomba cultivars of potato grown in Ardabil (Ardabil), Chaharmahal & Bakhtiari (Borujen), Razavi Khorasan (Fariman and Torbat-e Heydarieh), Zanjan (Khodabandeh), Fars (Abadeh and Eqlid), Lorestan (Khorramabad), Markazi (Arak) and Hamedan (Razan, Kabudarahang, and Bahar) provinces were sampled according to the standard guidelines of the National Seedling Health and Propagation Materials Laboratory. The pathogenicity test was carried out on artificially inoculated potato tubers tubers cv. Agria for determining the volume of dry rot caused by Fusarium isolates. Furthermore, spectrophotometry and high-performance liquid chromatography (HPLC) methods were used to evaluate in vitro activities of amylase and cellulase, as well as fusaric acid production.

The results indicated that approximately 18% of the seed tubers samples collected from different fields were infected with Fusarium dry rot disease in the 1 to 3% range. A total of 26 isolates were identified based on morphological and molecular characteristics belonging to F. solani sensu lato (13 isolates, 11%), F. oxysporum (8 isolates, 7%), and F. sambucinum (5 isolates, 5%). Analyzing the activity of extracellular enzymes revealed that all recovered Fusarium isolates were capable of producing amylase and cellulase enzymes but at varying levels. The maximum amount of extracellular enzymes produced by Fusarium spp. isolates ranged from 286 to 675 μg mL-1 for cellulase and from 103.5 to 317 μg mL-1 for amylase. According to the results, cellulase peaked sooner than amylase, but both enzymes contributed to the development of dry rot in potato tubers. The results revealed that approximately 38% of the isolates produced fusaric acid in the 13-32 μg kg-1 range. Moreover, the disease index level and the volume of dry rot caused by different Fusarium species isolates on potato tubers varied.

It appears that the amount of dry rot caused by Fusarium spp. isolates on potato tubers are affected by the production of fusaric acid and the activity levels of cellulose and amylase. This research provides new insights into the health status of potato seed tubers, the predominant Fusarium species causing dry rot disease, and the effect of the level of extracellular enzymes and fusaric acid secreted by fungal isolates on the disease progress in potato tubers, which can be applied to the revision of the national standard for seed tuber health and effective disease management during storage. The dry rot disease and its detrimental impact on tubers significantly threaten the official seed tubers certification system, production, and storage procedures. The current study is the first report on identifying the Fusarium dry rot disease agents from potato seed tubers in Iran and investigating the relationship between the disease severity of isolates and their extracellular enzyme activity, and fusaric acid production.

Barley is known to be an allelopathic plant and its allelopathic potential on weeds, and some other crops has been proven. Increasing use of herbicides has an adverse environmental impact and increases the weed resistance to herbicides. Eco-friendly methods for controlling weeds reduce the amount of herbicide use and reduce the damage caused by it. Some plants have alternate properties (allelopathies) that can be used to reduce or stop the growth of other plants, especially weeds. Allelopathy is an interference mechanism based on any direct or indirect effect (primarily inhibitory) by one plant on another through the release of chemicals that escape into the environment. Barley (Hordeum vulgare L. ssp. vulgare) is well known for its allelopathic compounds. The decomposition of barley plant residues in the soil, release numerous allelochemical compounds such as phenolic compounds, flavonoids, synoglycosides, alkaloids and polyamines. Till now 44 chemicals have been identified as potential allelochemicals that contribute to its allelopathic activity in Hordeum vulgare. The present work aimed to study the allelopathy potentials expressed by residues as straw among two barley genotypes on rhizome growth and physiological attribute of bindweed (Convolvulus arvensis L.).

This experiment was conducted in 2013 at Islamic Azad University, Shoushtar Branch. The experiment was factorial based on completely randomized design (CRD) with four replications. Four different amounts (10, 20, 30 and 40 g per one kg soil) of two barley cultivars (local ecotype and Sarasary 10) residual were prepared. Rhizomes were harvested from a depth of 30 cm soil and cultivated in the pot. The culture medium included plastic pots of 30 cm in diameter. The traits included seedling weight and length, malondialdehyde concentration, fatty acid percent, α-amylase activity, catalase activity, peroxidase activity, glutathione reductase activity, GA and ABA concentration of bindweed rhizome. The concentration of GA and ABA hormones was investigated based on the Kamal method. Statistical analysis was made using the SPSS Ver.13 statistical program. Significantly different means were separated at the 0.05 probability level (p = 0.05) by the least significant difference (LSD) test. Pearson’s correlation analysis was also conducted among different variables.

Results indicated the effect of genotype, residual amount and their interaction on rhizome malondialdehyde concentration, fatty acid percent, α-amylase activity, catalase activity, peroxidase activity, Glutathione reductase activity, GA and ABA concentration. Increasing the amount of residues for the local genotype caused a significant decrease in seedling fresh weight. The lowest fresh weight of bindweed was 40 g residues of local genotypes, in which was 73.6% lower than the control without residues. Increasing the amount of local and Sarasary 10 residues in the soil caused a significant reduction in the length of the bindweed seedlings. The negative effect of local ecotype residual on α-amylase activity was more than modern genotype. The mixing of 40 g residues of local ecotype and Sarasary10 genotype with soil decreased this enzyme by 38% and 79.5%, respectively, compared to the control without residues. Increasing the amount of residuals, reduces gibberellin hormone and increased rhizome the ABA content. The slope of the changes in gibberellin hormone and the increase of ABA in the local ecotype was higher than the modern genotype. Antioxidant enzymes increased in response to an increase in the amount of residues up to about 20 grams in the pot and then decreased significantly. Reducing antioxidant enzymes at high levels of barley residues led to an increase in the amount of fatty acids and Malondialdehyde, indicating the peroxidation of the cell membrane. In general, the residuals of local genotype compared to cultivar Sarasary 10 had a more harmful effect on all studied traits of bindweed rhizome and seedling. It seems that in areas where bindweed is dominant, it is possible to use local barley residuals to reduce the damages.

Anagasta kuehniella Zeller (Lepidoptera: Pyralidae) causes the quality loss of the bread by feeding on flour. Disruption in insect’s digestive enzymes through transgenic plants, expressing enzyme inhibitors, is a methods of pest control. So, the aim of the current study was to investigate the inhibitory effects of proteinaceous extracts of two varieties of wheat (Sivand, Sardari) and Triticale against activity of digestive α-amylase of fourth (L4) and fifth (L5) instars larvae of A.kuehniella. Ammonium sulfate (70%) was used to extract proteins from seeds. The optimal temperature and pH of α-amylase activity was found 40°C and 10, respectively. The results showed that the highest dose of proteinaceous extracts of Sivand and Sardari (13 µg ml-1 protein) and Triticale (16 µg ml-1 protein) reduced the enzyme activity, 73.08%, 71.07% and 65.88% of L5 and 58.16%, 42.14% and 50.25% of L4, respectively. The lowest dose of proteinaceous extracts of Sivand and Sardari (0.812 µg ml-1 protein) and Triticale (1 µg ml-1 protein) inhibited the enzyme activity, 19.93%, 17.8% and 25.26% of L5 and 11.78%, 12.81% and 10.09% of L4, respectively. In the gel electrophoresis of enzyme without usage of inhibitors, one band was observed. At the highest dose of extracts, in the L5, amylase band disappeared and in the L4, waned band clearly. Band resolution was increased by reducing inhibitor dose. It was concluded that Sivand, Sardari and Triticale proteinaceous extracts can be used for management of A.kuehniella.

Leptinotarsa decemlineata (Say) is a key pest of potatoes worldwide. Need for the new control methods are inevitable regarding undesirable effects of chemical pesticides. In this study inhibitory activities of seed extracts of some legume plants were investigated on α-amylase activity of Colorado potato beetle larvae and adults. Enzyme and inhibitory activities were measured by using diagnostic α-amylase Kit (Pars Azmon, Iran). Percent of inhibition was calculated by comparing activity in control and inhibitor incubated enzyme solutions. Among 17 legumes seeds (8 bean and 2 pea genotypes, lentil, vetches, broad bean, peanut, tamarind, sainfoin and alfalfa), four genotypes of Phaseolus vulgaris L. (Pinto bean, green bean, kidney bean and white bean) as well as tamarind, had high inhibitory activity against the enzyme in comparison with the other studied legumes. In this study three fractions of five effective legumes prepared by precipitation of proteins in 0-20, 20-40 and 40-60% Ammonium sulfate. Three concentrations of inhibitors (1, 0.7 and 0.3 mg protein/ml) were compared for inhibitory activity. Overall 20-40 and 40-60% fractions of all five selected legumes had more inhibitory activity compared to 0-20 fraction (70-90% inhibition vs. 5-30%). In the studied range of concentrations, the inhibitory activity was concentration dependent and increased by increasing the concentration of inhibitors in constant concentration of enzyme. Crude proteinaceous extracts and fractions of different types of beans evaluated in this study showed high inhibitory activity against alpha-amylase of last larval instar and adults of Leptinotarsa decemlineata (Say).

Amylases and glucosidases are the major enzymes for carbohydrate digestion in herbivorous insects. Any interruption in enzymatic carbohydrate digestion and blocking of carbohydrases by inhibitors can deprive insect from utilizing the sources of carbohydrate energy efficiently. It can reduce insects’ survival and reproduction and retard their growth. The control strategies interfering with carbohydrate digestion are known to have been proposed as a practical and safe method for control of herbivorous pests. Therefore, in this research, enzymatic properties of α-amylase and α-/β-glucosidases from digestive system oflarvae of the fall web worm, Hyphantria cunea Drury were determined in order to better understand the nutritional physiology of the pest.
The α-amylase activity was determined with 1% (w/v) starch as substrate. Absorbance of product was measured at 540 nm with a Microplate Reader Model Stat Fax® 3200. The activities of α-/β-glucosidases were measured with pNαG (p-nitrophenyl-α-D-galactopyranoside) and pNβG (p-nitrophenyl-β-D-glucopyranoside) as substrates, respectively. P-nitrophenol absorbance was measured at 405 nm. To obtain the optimal pH and temperature for the enzyme activity, various pH 4.0 to 12.0 and different temperatures ranging from 15 to 75ºC were examined. The enzymes activity was assayed in the presence of chemicals including EDTA, Hg2Cl2, ZnCl2, CoCl2, FeCl2, MgCl2, KCl, BaCl2, CaCl2 and MnCl2 at two concentrations of 10 and 20 mM. Electrophoresis was performed and the realized bands in the native gel were observed.
The mean specific activities of α-amylase and α-/β-glucosidases in gut of fifth larval instar were obtained as 9.1, 3.6 and 6.8 μmol/min/mg protein, respectively. Maximum activity of α-amylase in salivary gland and gut of fifth instar larvae was at pH 10.0 and α/β-glucosidases in gut and hemolymph was at pH of 8, 7, 8 and 8, respectively. The optimal temperature of α-amylase in gut and salivary gland was at 55 and 45°C. The values for α and β-glucosidases in gut and hemolymph were 35, 45, 45 and 35°C, respectively. The highest inhibition effect of enzyme activity was caused by Na and Co2 ions (at concentrations of 10 and 20 mM, respectively) on α-amylase activity, Fe2 (concentration of 20 mM) on α-glucosidases activity and Mn2 (concentration of 10 mM) on β-glucosidases activity. Mn2 (at concentrations of 10 and 20 mM), Ba2 (at concentration of 20 mM) and Mg2 (at concentration of 10 mM)significantly increased the activity of α-amylase, α–glucosidase and β–glucosidase, respectively. The zymogram pattern showed the presence of 2 bands for α-amylase and α-/β-glucosidases in gut of fifth instar larvae of H. cunea.
According to the results, α-amylase, α and β glucosidases are present in gut of larvae of H. cunea. These findings can be used in future research about using digestive enzymes inhibitors for management of H. cunea.

Plodia interpunctella Hubner (Lepidoptera: Pyralidae) is a cosmopolitan species known to infest a wide range of dried plant materials, including legumes and cereals. In this study, after confirmation of the presence of alpha-amylase gene in samples using gene specific primers, total RNA was extracted from fifth instar larvae of P. interpunctella, grown on the five different nutrition regimes including pistachio, white mulatto, plum, wheat and artificial diet (as control). After synthesis of cDNA, change in gene expression was studied with Real-time PCR assay. PCR performance test indicates 99 and 98% amplification efficiency for SiAmy and SiAmyC primers, respectively. Different nutrition regimes caused differential change in the expression of the gene. In comparison with the control, pistachio regime caused 5% increase in the expression of the alpha-amylase gene, wherease 10%, 27% and 60% decreases were observed in the larva grown on plum, wheat and mulatto respectively. Maximum variation in expression of alpha-amylase gene was observed in the larvae fed on mulatto. The results showed that the inhibition of alpha-amylase gene expression varied in the different sources of glucose in larvae fed on different diets and there was a negative correlation between the amount of sugar in the diet and alpha-amylase gene expression.

Epilachna chrysomelina is one of major pests of cucurbitaceous plants. Biochemical properties of α- amylase were studied in melon ladybird. The optimal pH for α- amylase was found at 4. Also، high amylolytic activity was found at temperature 50 °C. The specific activity of this enzyme in digestive system of different larval instar، foregut، midgut، hindgut and female and male adults were determined. Results showed that the highest specific α- amylase activity was detected in the digestive system of 3rd instar larvae and the enzyme activity in males and females digestive system did not show any significant difference. The enzyme specific activity in midgut was 5- and 8. 3-fold higher than foregut and hindgut. The Michaelis–Menten constant (Km) of α-amylase was obtained as 0. 69 mg/ml. Zymogram analysis of α- amylase showed one isoform. Also، inhibitory effect of inhibitors extracted from seeds of Lathyrus sativus، Trifolium alexandrium، Zea mays، Faba vulgaris، Lentis culinaris، Vigna unguiculata، Phaseolus vulgaris and Vigna radiate were evaluated on E. chrysomelina α- amylase activity. Among these inhibitors، the inhibitors extracted P. vulgaris and V. radiate were able to inhibit E. chrysomelina amylase.

The pistachio red bug, Lygaeus pandurus is one of the most destructive true bugs of pistachio in Kerman province. In order to better understanding about the nutritional physiology of the pest, after dissecting adults under stereomicroscope their midguts and salivary glands were removed. The tissues were homogenized and centrifuged and the supernatants were used as the enzyme source in subsequent experiments. Using specific substrates, carbohydrase activity and some of their characteristics were determined. The optimal pH for activity of a- amylase in the midgut and salivary glands were 5 and 6, respectively. Maximum activity of a- and b- glucosidase were observed at pH 5 in the midgut and at pH 5 and 6, in salivary glands, respectively. Optimal temperature for a-amylase activity in midgut and salivary glands obtained 50 and 40 °C, respectively. Midgut
- and -glucosidase were optimally active at 4 °C and maximum activity of a and b- glucosidase in salivary glands were determined at 30 and 35 °C, respectively. Midgut a amylase activity of this pest decreased in presence of Ca2+, Mg2+ and EDTA. Midgut
-glucosidase activity was highest in the presence of Ca2+. In contrast, Mg2+ increased midgut b-glucosidase activity. Zymogram analysis showed one form of a-glucosidase and one form of b glucosidase in both midgut and salivary glands of this pest. Two isoforms of a-amylase were detected in salivary glands and three isoforms of a amylase in midgut of this pest.

In this research nutritional indices of pomegranate neckworm on the three cultivars of pomegranate including Malas-Daneh-Sia، Gabri and Shahvar were studied under controlled conditions (30 ± 1ºC، 70 ± 5% RH and 16L: 8D). Enzymatic activity in the midgut of larvae reared on these cultivars was also compared. Results indicated that the relative consumption rate (RCR) was significantly different among three cultivars. The highest amounts of the relative growth rate (RGR)، efficiency of conversion of ingested food (ECI) and efficiency of conversion of digested food (ECD) were observed on Shahvar cultivar. The approximate digestibility (AD) on Malas-Daneh-Sia was the highest. The highest enzymatic activities of α-amylases and lipases were observed in the midgut of larvae reared on Shahvar cultivar. In contrast، proteases demonstrated the lowest activity in these larvae. The present findings showed that the shahvar cultivar has a higher feeding quality for pomegranate neckworm.

Elm leaf beetle, Xanthogaleruca luteola, is a serious pest (particularly at its larval stage) of elm trees in many areas. The existence of three important enzyms namely: α-amylase, α- glucosidase and β-glucosidase in the midgut of the insect at its larval stage was investigated. Optimum activity for α-, β-glucosidase and α-amylase was recorded at pHs 5.0, 6.0 and 6.0 against p-nitrophenyl-α-D-glucopyranoside, p-nitrophenyl-β-D-glucopyranoside and starch respectively. α and β-glucosidase exhibited more stability at pHs 4.0-6.0 than at either highly acidic or and alkaline pHs. These enzymes were respectively more stable at pH 5.0 and 6.0 with increased incubation time. α -amylase was stable at pHs 4.0-8.0. α and β-glucosidase and also α-amylase, when incubated at different temperatures were found to be maximally active at 45, 60 and 40°C, respectively. Alpha- glucosidase activity significantly decreased in the presence of Ca2+ and Mg2+. On the contrary, the ions K+ and Na+ did not significantly affect the enzyme’s activity. The ions K+, Mg2+ and Na+ did not significantly affect the enzyme activity. Zymogram analysis revealed the presence of one band each of amylase, α- and β-glucosidase activity in the insect’s larval midgut extract.

The cigarette beetle, Lasioderma serricorne, is a serious infesting pest of warehouses and retail stores thorough the world. Partial biochemical characterization of carbohydrases was performed in the larval digestive system of the pest. Midgut extracts from larvae showed an optimum activity for
-glucosidase, -glucosidase and
-amylase activity against, p-nitrophenyl-
-D glucopyranoside, p-nitrophenyl-- D-glucopyranoside and starch at pH 5, pH 6 and pH 7, respectively. Larval midgut
-glucosidase was more stable in acidic conditions (pH 4 to pH 6.0) than highly acidic and alkaline conditions. However, the enzyme showed to be more stable in slightly acidic condition (pH 5) when incubation time was increased. -Glucosidase was also stable in acidic conditions (pH 5 to pH 7) and its maximum stability occurred at pH 6. The range of stability for
-amylase was determined in slightly acidic to weakly alkaline conditions (pH 6 to pH 8). Maximum activity for
-glucosidase, -glucosidase and
-amylase incubated at different temperatures was observed at 35, 40 and 50°C, respectively. The KM and Vmax values for
-glucosidase and -glucosidase were 2.77 mM and 0.017 mmol min-1 mg-1 protein and 0.6961 mM and 0.0004 mmol min-1 mg-1 proteins, respectively. The KM and Vmax values for
-amylase were 3.2 mg ml-1 and 0.01 mmol min-1 mg-1 protein. Zymogram analysis revealed the presence of one band of
-amylase activity, one band for each
-glucosidase and  glucosidase activity in the larval midgut extract.