مطالعه پراکسیداسیون لیپید در سلول قارچ در برهمکنش قارچ بیمارگر گیاهی – باکتری بیوکنترل

Atomic oxygen has two unpaired electrons in separate orbits in its outer electron shell. This electron structure makes oxygen susceptible to radical formation. The sequential reduction of oxygen through the addition of electrons leads to the formation of a number of Reactive oxygen species (ROS). They cause detrimental chemical changes in proteins, lipids, carbohydrates, DNA, RNA, and even in small metabolites. Lipid peroxidation generally refers to the oxidative degradation of cellular lipids by reactive oxygen species. Peroxidation of unsaturated lipids affects cell membrane properties, signal transduction pathways, apoptosis, and the deterioration of foods and other biological compounds. For fungal cell status estimation considering lipid peroxidation measurements in microbial interaction, Fusarium graminearum head blight (FHB) in cereals was used as a model fungus, whereas Pseudomonas fluorescens strains UTPf105, UTPf125، UTPf127، P13 and B4 were used as model biocontrol bacteria. The biological control ability of them against f. graminearum were demonstrated in vitro and greenhouse conditions. Fungal mycelia has interacted with biocontrol bacterial cells, in a microcosm system, for 24 h. In this system fungal hyphae was the only food source of biocontrol bacteria. Then microcosm was stained by BODIPY which localizes to membranes throughout live cells and acts as a sensitive fluorescent reporter for lipid peroxidation. Microbe interaction was observed by an inverted NICON fluorescence microscope and BODIPY signals were estimated by plate reader under λ =488 nm. Experiment was carried out using a completely randomized experimental design in four replicates and analyzed by using SAS version 9.2. A Duncan test with a probability of 0.05 was used to show significant differences between treatments. Results showed that different bacterial strains caused the different responses of lipid peroxidation in fungal cell. All biocontrol strains increased lipid peroxidation in fungal cell. In this case, P. fluorescens UTPf105 was more successful.