نوع مقاله : مقاله پژوهشی
نویسنده
عضو هیات علمی گروه بیوتکنولوژی و به نژادی گیاهی، دانشکده کشاورزی، دانشگاه فردوسی مشهد
چکیده
کلیدواژهها
موضوعات
عنوان مقاله [English]
نویسنده [English]
Introduction: Stem rust disease of wheat, caused by Puccinia graminis f. sp. tritici, (Pgt) is the most devastating disease affecting wheat crops. Findings have demonstrated that antioxidant enzymes play a vital role in conferring resistance to biotic stresses, particularly against biotrophic fungi. This study aims to compare the effects of three distinct races of Pgt on the activity of antioxidant enzymes in both susceptible and resistant wheat cultivars at three time points 24, 48, and 72 hours after inoculation (hai).
Materials and methods: Seeds of two wheat genotypes including susceptible (Morocco) and resistant (Btsr24Agt) to stem rust and spores of three stem rust races (PTRTF, TKTTF and TTKTK) were obtained from Seed and Seedling Breeding and Production Research Institute of Karaj, Iran. The experiment was carried out as a factorial in a completely randomized design with three replications. The seeds were planted in 24 cm diameter pots containing a mixture of peat moss, sand and soil and were maintained under conditions of 16 hours of light and 8 hours of darkness at 22-24°C. Inoculation of Pgt races on the whole leaf surface of seedlings was carried out by a brush paint when they were in stage 12 of the Zadox scale. Control seedlings were treated in the same way with sterile distilled water. In order to establish the disease, the inoculated and control plants were kept in the darkness for 18 hours at 18°C with 100% relative humidity and then maintained in a growth chamber with the above conditions. The leaves of the inoculated and control plants were harvested at 24, 48 and 72 hours after inoculation and the activities of superoxide dismutase (SOD) and guaiacol peroxidase (GPX) were measured.
Results: The activity of the GPX enzyme was significantly increased in infected plants compared to the control at all time points. The lowest GPX activity was recorded at 24 hours, followed by increases at 48 and 72 hai, the highest activity observed at 72 hai. Notably, the resistant genotype exhibited higher GPX activity than the susceptible cultivar. In contrast, SOD enzyme activity increased in both cultivars at 24 hai compared to 48 and 72 hai. The PTRTF and TKTTF races showed a significant increase in SOD activity compared to controls, while the TTKTK race did not exhibit any change. Additionally, the susceptible cultivar demonstrated increased enzyme activity compared to controls, whereas the resistant cultivar showed no significant change.
Conclusion: The consistently higher GPX activity observed in resistant genotype compared to susceptible cultivar. Across all time points and races indicates that this enzyme likely plays a crucial role in scavenging reactive oxygen species (ROS) induced by pathogens, thereby contributing to the plant's defense mechanisms. In plant-biotrophic pathogen interactions, the activity of antioxidant enzymes is influenced not only by the type of interaction (compatible or incompatible) but also by the specific race, host variety, and hours after inoculation.
کلیدواژهها [English]
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