نوع مقاله : مقاله پژوهشی
نویسندگان
1 گروه گیاهپزشکی، پردیس کشاورزی و منابع طبیعی دانشگاه تهران، کرج، ایران.
2 گروه گیاهپزشکی، دانشکدگان کشاورزی و منابع طبیعی دانشگاه تهران، کرج، ایران
3 گروه بیوتکنولوژی، دانشکده کشاورزی دانشگاه صنعتی اصفهان. اصفهان. ایران
چکیده
کلیدواژه‌ها
عنوان مقاله [English]
نویسندگان [English]
Crown and root rot disease caused by Fusarium pseudograminearum is one of the growth-limiting factors in wheat cultivation. This disease is usually associated with the browning of the coleoptile, lower leaf sheaths, adjacent stems, and nodes. To deal with this disease, various strategies have been used, including the use of bacteria that increase plant growth. In this research, the bacterium Pseudomonas fluorescens strain EB298 was isolated and identified from the soil contaminated with this disease in Andimeshk city. This isolate was able to reduce the amount of plant ethylene from 30 nmol/g to 20 nmol/g. As a result of reducing the amount of ethylene, the amount of hydrogen peroxide, which was representative of active oxygen in this research, decreased from 45 M/gFWµ in the control sample to 27 M/gFWµ in the sample inoculated with bacteria. The damage caused by crown rot fungus (pathogenic intensity) was significantly reduced from grade 4 in the control to grade 2. The results of this research show that seed inoculation with P. fluorescens UTPf298 bacteria, in addition to controlling root rot disease, has reduced ethylene and hydrogen peroxide and ultimately the severity of pathogenicity in wheat. Also, this bacterium, by affecting the growth of the plant, strengthened the plant and the greenness of the wheat plant.
کلیدواژه‌ها [English]
Extended Abstract
Introduction
Fusarium crown and root rot (FCR) caused by Fusarium pseudograminearum reduces the yield and quality of many important plant species around the world, including cereals, especially in arid and semi-arid agricultural areas. This disease, like many different biotic and abiotic environmental stresses, induces the plant stress hormone ethylene. The increase in ethylene concentration causes plants to be unable to grow in adverse environmental conditions. Ethylene stress causes the accumulation of reactive oxygen species (ROS) in plant cells and tissues. Accumulation of ROS in cells and tissues causes lipid peroxidation, protein oxidation, nucleic acid damage, enzyme inhibition, activation of the programmed cell death pathway, and ultimately causes cell death. One of the ways to control oxidative stress is the use of Plant growth promoting rhizobacteria (PGPR) bacteria, including pseudomonads.
Materials and Methods
The pathogenic fungus F. pseudograminearum was obtained from Kermanshah Agricultural and Natural Resources Research Institute. In this research, to control this disease, the bacterium Pseudomonas fluorescens strain EB298 was isolated and identified from the soil infected with this disease in Andimeshk city. After the inoculation of this bacterium, the effect of fungal pathogenicity the control of the intensity of pathogenicity and growth, and the reduction of ethylene and H2O2 in wheat plants were investigated.
Results and Discussion
The results of this research show that the pathogenicity of this fungus was 4 under normal greenhouse conditions. Wheat seedlings face a decrease in growth and biomass during crown and root rot disease. At this time, the rate of seed germination is greatly reduced, the growth of roots and aerial parts of seedlings is reduced, and the rate of cell death and aging increases, which is due to the increase in the production of ethylene finally active oxygen, which in this research The amount of H2O2 was investigated as a representative of active oxygen. The obtained results indicate that plant aging and death during stress are directly related to the amount of ethylene and H2O2 production. After the inoculation of P. fluorescens strain EB298, this isolate was able to reduce the amount of plant ethylene from 30 nmol/gr to 20 nmol/gr. As a result of reducing the amount of ethylene, the amount of hydrogen peroxide, which was representative of active oxygen in this research, decreased from 45 M/gFWµ in the control sample to 27 M/gFWµ in the sample inoculated with bacteria. As a result, the damage caused by crown rot fungus (pathogenic intensity) was significantly reduced from grade 4 in the control to grade 2.
Conclusion
The results of this research also show that seed inoculation with P. fluorescens EB298 (UTPf298) bacteria, in addition to controlling root rot disease, has reduced ethylene and hydrogen peroxide and ultimately the severity of pathogenicity in wheat. Also, this bacterium, by affecting the growth of the plant, strengthened the plant and the greenness of the wheat plant.
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