نوع مقاله : مقاله پژوهشی
نویسندگان
1 دانشجو دکتری، گروه گیاهپزشکی، دانشکده علوم زراعی، دانشگاه علوم کشاورزی و منابع طبیعی ساری، ساری، ایران
2 استاد، گروه گیاهپزشکی، دانشکده علوم زراعی، دانشگاه علوم کشاورزی و منابع طبیعی ساری، ساری، ایران
3 دانشیار، گروه گیاهپزشکی، دانشکده علوم زراعی، دانشگاه علوم کشاورزی و منابع طبیعی ساری، ساری، ایران
4 دانشیار، پژوشکده ژنتیک و زیست‌فناوری طبرستان، دانشگاه علوم کشاورزی و منابع طبیعی ساری، ساری، ایران
چکیده
کلیدواژه‌ها
موضوعات
عنوان مقاله [English]
نویسندگان [English]
Introduction
Wheat (Triticum aestivum) is one of the most important food crops worldwide, and it faces several challenges, including fungal diseases such as powdery mildew caused by Blumeria graminis f. sp. tritici (Bgt). This pathogen can reduce wheat yield and quality. Fungicides and increasing plant genetic resistance are indeed common methods for controlling plant diseases but, these methods face limitations such as pathogen resistance and environmental concerns. As a result, there has been increased demand to alternative methods such as biological control by beneficial fungi and bacteria. These microbial agents not only combat pathogens, but also enhance the plant immune system. Also, non-host resistance is considered as a sustainable and widespread strategy to combat incompatible pathogens, and its induction can create a high level of sustainable immunity in plant. Finally, enhancing defense responses, such as the production of reactive oxygen species and the activation of their associated enzymes, plays an important role in plants defense response against fungal diseases.
Material and methods
This study examined the effect of several biological agents such as Blumeria graminis f. sp. hordei, Tricoderma harzianum, Alternaria alternate, Serendipita indica, Pseudomonas fluorescences and Bacillus subtilis in susceptible and resistant wheat cultivars against powdery mildew disease. For this purpose, two wheat cultivars Ehsan and Tirgan were used as susceptible and resistant cultivars, respectively. This study was conducted as a factorial experiment on a completely randomized design with three replications. The treatments were sprayed on wheat seedlings at the two-leaf stage. Leaf sampling of control and with biological agents-treated wheat plants at 0, 24, 48, and 72 hours after inoculation with Bgt, and then the samples were used to asses the activity of catalase and polyphenol oxidase enzymes, as well as the expression of PAL gene. The pathogenicity intensity was evaluated 7 days after Bgt inoculation. SPSS software was used to analysis of variance and comparative means using Duncan's test at a 5% probability level, and Excel software was used to create the figures.
Research findings
Results of this study showed that different biocontrol agents had varying effects on two wheat cultivars (susceptible and resistant) in response to the wheat powdery mildew pathogen. The number of fungal colonies significantly reduced in the resistant wheat cultivar compared to the susceptible one. In the resistant wheat cultivar, treatment of S. indica resulted in the lowest number of colonies. In the susceptible wheat cultivar, catalase activity was highest upon treatment of P. fluorescens, showing a 160.7% increase compared to the control, whereas in the resistant wheat cultivar, catalase activity increased by about 62% in P. fluorescens and B. graminis f. sp. hordei treatments. Additionally, the highest activity of polyphenol oxidase in the susceptible wheat cultivar was observed in S. indica tratetment, with a 190.2% increase compared to the control. In the resistant wheat cultivar, the highest activity of this enzyme was recorded in treatments with P. fluorescens and S. indica, indicating 155.2% and 145.7% higher activity than the control, respectively. Moreover, PAL gene expression level revealed that most biocontrol treatment up-regulated PAL expression after Bgt inoculation, with the highest induction recorded in wheat plants treated with P. fluorescens at 24 hours post-inoculation (hpi).
Conclusion
These results indicate that biological treatments can have different effects on disease resistance and enzyme activity in wheat. These agents can be considered as a suitable option for plant disease management in wheat.
کلیدواژه‌ها [English]
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