القای مقاومت به بیماری بلایت خوشه گندم با استفاده از PGPR

Wheat is one of the most important crops in the country which is widely cultivated in most agricultural lands. This plant suffers a lot of damage every year under the influence of various fungal diseases such as Fusarium head blight. This disease causes damage to wheat by reducing the grain yield and the crop quality due to the production of fungal toxins such as nivalenol and doxynivaleol in the seeds and can completely destroy the wheat product within a few weeks before harvest. Seed inoculation with native plant growth promoting rhizobacteria (PGPR) stimulates systemic resistance against plant pathogens. In this research, the change in the expression of some important defense genes in two resistant (Irana) and sensitive (Bag) cultivars treated with and without bacteria at different times after infection with Fusarium head blight caused by Fusarium graminearum was investigated using Real-time qPCR technique. At first, 25 different genotypes of wheat were investigated with the aim of evaluating the reaction of different genotypes to the disease in greenhouse conditions. Finally, Irana and Bag cultivars were selected as resistant and sensitive cultivars, respectively which were exposed to PGPRs and FHB fungus. The results showed the transcript level of PAL, CHI, GLU and PDR genes in resistant and sensitive wheat plants treated with Pseudomonas sp., Pseudomonas brassicacearum, Exiguobacterium sp. and Acinetobacter calcoaceticus gradually increased and reached its maximum expression on the third day and 72 hours after inoculation of plants with F. graminearum spore suspension. The maximum expression of all genes in the resistant cultivar was significantly higher than the sensitive cultivar which according to the results of these genes along with the main genes cause the intensification and maintenance of resistance. In Irana cultivar, at this time, the expression levels of PAL, CHI, GLU and PDR genes in the bacterial treatment were 2.74, 4.75, 2.07 and 3.63 times that of the control treatment, respectively. The results indicate the active role of the biocontrol agent in protecting wheat against FHB due to the increased expression of the mentioned genes compared to the control.