جستجوی مقالات مرتبط با کلیدواژه "پروبیوتیک" در نشریات گروه "گیاهپزشکی"

Root knot nematodes (Meloidogyne spp.) are one of the most damaging nematodes among plant parasitic nematodes and cause significant damage to agricultural products. Probiotic bacteria, by having a direct effect on the pathogen, inducing plant resistance and stimulating plant growth, have shown high efficiency in controlling plant diseases. In this study, three species probiotic bacteria Pseudomonas chlororaphis RO1, Bacillus subtilis RO9, and Bacillus subtilis RO8 were used to control root–knot nematodes under laboratory, greenhouse, and kiwifruit orchard conditions. The nematode infection indices including gall number, egg mass number per gram of root, population of juveniles and eggs per gram of root, number of second–stage juveniles per 100 grams of soil, and the reproduction factor were evaluated. In the laboratory conditions, this investigation was carried out in a completely randomized design with 11 treatments and three replicates for each stage, while the field experiment was conducted in complete randomized blocks with four treatments and three replicates in a kiwifruit orchard located in the Pashaki region of Siahkal and the population of nematodes in the soil and roots was investigated before applying the treatments and also at the end of the research. The results showed that all treatments were successful in controlling nematode infection indices and significantly differed from the control treatment. So, they caused the reduction of nematode infection indices in all the investigated indicators. In the laboratory conditions, bacteria Bacillus subtilis RO9 showed the highest impact, with an increase in larval mortality rate (48.8%) compared to the control. Additionally, in the greenhouse conditions, the reapplication of, B. subtilis RO9 and P. chlororaphis RO1 bacteria led to a significant decrease in the number of galls, egg mass, and population of second–stage juveniles in the soil, as well as the population of eggs and juveniles in the roots. The field experiment results indicated that after Rugby nematicide, the B. subtilis RO9 bacteria (41.2%) was more effective than the P. chlororaphis RO1 bacteria (31.1%) in reducing ‘eggs and juveniles’ population in the roots. P. chlororaphis RO1 bacteria had the best effect in reducing the population of second–stage juveniles in the soil and the number of galls in the root (32.3%, 47.3%), after Rugby nematicide. Both bacterial strains showed very favorable performance in reducing the reproduction factor with (0.64 and 0.7), with little difference compared to the chemical nematicide Rugby (0.41). In different stages of the experiment (laboratory and greenhouse), the combined treatment (simultaneous application of both bacteria RO1 and RO9) was not significantly effective in nematode disease indices compared to the individual application of these bacteria. Therefore, the results indicated that the use of probiotic bacteria P. chlororaphis RO1 and B. subtilis RO9 at two times can control the nematode and it is worthwhile to investigate the effect of bacteria on nematode damage and plant performance indicators..

Heliothis (or tomato fruit borer) with the scientific name Helicoverpa armigera (Lep.: Noctuidae) is one of the most important and the oldest pest of crops in the country, especially in Golestan Province, which causes huge management costs for farmers, and also due to the use of various types of chemical pesticides every year it causes environmental damage for the agricultural ecosystem of the country. In order to prevent unnecessary spraying and due to the resistance of this pest to many pesticides, it is necessary to consider the effectiveness of other control methods, including the use of insect pathogenic fungi and biological pesticides containing Bacillus thuringiensis. In this research, the effectiveness of three different formulations of the insect pathogenic fungus Beauveria bassiana and a biological insecticide based on the active ingredient B. thuringiensis subsp. kurstaki (Biolep P) and an organic insecticide based on plants (Rui Agro) were studied in laboratory conditions and also in two tomato field of Golestan Province. The perforation rate of tomato fruits was also investigated. The laboratory bioassay results of different formulations of B. bassiana with a concentration of 1×107 conidia/ml on 3rd instar larvae showed that all three different formulations of the pathogenic fungus caused between 84 and 91% mortality. The laboratory bioassay of different concentrations of Biolep P on the 3rd instar larvae of the H. armigera after eight days showed that when the concentration of Biolep P increased, the mortality rate also increased significantly. The highest mortality rate was observed with 93.33% in the concentration of 1.5 ml/L and the lowest mortality rate was observed with 48.89% in the concentration of 0.5 ml/L. The results in the tomato fields of Qaleh Mahmud village showed that the efficiency of the applied treatments increases with time. The highest percentage of efficiency in all experimental treatments on the 7th and 10th days after foliar spraying was between 50 and 60 percent. In the tomato field of Chalaki Agricultural Research Station, the efficiency (%) of fungal formulations was reduced on the 10th day of foliar application. In relation to the percentage of fruit perforation in both fields studied, the control treatment and the fungal treatment containing distilled water were placed in the same experimental group and showed the highest percentage of fruit perforation. In general, it can be concluded that repeated foliar spraying of biological control agents is necessary for better pest control or the combination of these methods with low–risk or organic pesticides should be considered..

This study was conducted to investigate the ability of bees to consume starch as a substitute for nectar and influence a commercial probiotic namely Protexin® on starch absorption. In the first experiment, 36 honey bee hives were randomly allocated into six similar groups and fed using one of the diets, first group received sugar syrup as control treatment, second group received sugar syrup supplemented with 1 g/L of Protexin® (P), third group received sugar syrup supplemented with 10% of the starch (S10), fourth group fed using sugar syrup supplemented with 20% of the starch (S20), fifth group received sugar syrup supplemented with 10% starch and one g/L of Protexin® (S10P) and sixth group fed using sugar syrup supplemented with 20% of starch and one g/L of Protexin® (S20P). In the second experiment, newly emerged worker bees were kept in laboratory cages and fed using the above-mentioned experimental treatments for 21 days (at 34 ± 1 ˚C and 50% R.H.). At the end of both experiments, 100 worker bees from each treatment were selected to evaluate the starch absorption, the microbial population at the bee’s digestive tract, body weight, body protein, and lipid content. The results indicated that the starch absorption in the colonies fed by S20P treatment was significantly higher than that in the rest of the treated colonies (P≤0.05). The supplementation of diet with starch significantly enhanced their body weight, protein, and lipid content in both of the experiments (P≤0.05). Moreover, Protexin® increased the bee’s gut microbial population at colony and cage conditions (P≤0.05). It is concluded that the dietary supplementation of the corn starch and Protexin® could have a beneficial effect on the health and strength of the bee colonies.

A total of 11 probiotic strains of Bacillus subtilis were used to evaluate the potential of biofilm formation and wheat root colonization. Experiments carried out in a completely randomized design with four replications. According to results of this study, biofilm formation and biosurfactants production showed a high diversity in studied rhizobacteria, B3, B1 and B4 strains produced the maximum amount of mentioned metabolites. Evaluation of root colonization was performed using rifampicin and nalidixic acid resistant mutants. B4 and B3 with 4.41×107 cfu/gand 4.35×107 cfu/g had the highest root colonization compared to other strains. Correlation of 0.74 and 0.80 was obtained between biofilm formation and biosurfactants production with wheat root colonization, respectively. In another part of this study, the effects of studied strains were evaluated on wheat plant growth factors. All probiotic rhizobacteria strains increased the length of roots and aerial part of wheat and most of them increased dry weight of roots and aerial part. Based on the findings of this research, strains with high potential in biofilm formation and biosurfactants production were colonized wheat root very well and most of studied strains showed the effect of increasing on wheat growth factors.