نوع مقاله : مقاله پژوهشی
نویسندگان
1 گروه گیاهپزشکی، دانشگده علوم زراعی، دانشگاه علوم کشاورزی و منابع طبیعی ساری، ساری، ایران
2 گروه گیاهپزشکی، دانشکده علوم زراعی، دانشگاه علوم کشاورزی و منابع طبیعی ساری. ساری/ایران
3 گروه گیاهپزشکی، دانشکده علوم زراعی، دانشگاه علوم کشاورزی و منابع طبیعی ساری، ساری، ایران.
4 بخش تحقیقات گیاهپزشکی، موسسه تحقیقات برنج کشور معاونت مازندران (آمل)، سازمان تحقیقات، آموزش و ترویج کشاورزی، آمل، ایران
5 بخش تحقیقات کنترل بیولوژیک، موسسه تحقیقات گیاه پزشکی کشور، سازمان تحقیقات، آموزش و ترویج کشاورزی، تهران، ایران.
چکیده
کلیدواژهها
عنوان مقاله [English]
نویسندگان [English]
Rice blast, caused by Pyricularia oryzae, is a major rice disease that reduces crop yield annually. One method of controlling this disease is the use of fungicides, which pose risks to humans and the environment. Therefore, environmentally friendly inducers of resistance, such as potassium phosphite, may reduce chemical pesticide use and enhance plant resistance through induced defenses. In this study, the effect of potassium phosphite as a defense stimulant on reducing rice blast disease and on the activity of catalase, peroxidase, and superoxide dismutase enzymes was evaluated using a factorial design in a completely randomized layout. Samples were collected from rice seedlings treated with potassium phosphite and mock-treated at 0, 48, 96, and 144 hours after inoculation. Results showed that potassium phosphite significantly reduced disease severity by 48%. Moreover, the activities of the defense-related enzymes in treated plants were higher than those in control plants at all time points after inoculation. The highest activities were observed for peroxidase (protein1-U = 62.277 mg) and superoxide dismutase (protein1-U = 17.246 mg) at 144 hours after inoculation, representing 1.38- and 1.30-fold increases, respectively, compared with the control. These findings indicate that pretreatment of rice with potassium phosphite can enhance seedling resistance by inducing defense-related enzyme activity and may be effective for disease management.
کلیدواژهها [English]
Extended Abstract
Introduction
Rice blast disease, caused by Pyricularia oryzae, threatens rice production globally and annually reduces crop yield. Chemical fungicides used to control the disease pose risks to human health and the environment. Environmentally friendly inducers can reduce reliance on chemical pesticides and mitigate associated environmental concerns. One such compound is phosphite, which has been used to manage plant diseases for decades. Potassium phosphite salt is absorbed systemically and rapidly within the plant and can induce systemic defense responses against pathogen attack through priming. In the present study, the effect of potassium phosphite (KPhi) as a defense stimulant in the control of blast disease was investigated under greenhouse conditions.
Materials and methods
The experiment investigated the effect of potassium phosphite on disease severity in rice seedlings of the cv. Hashemi. A factorial experiment in a completely randomized design was used, with two factors:
1) Foliar treatment: potassium phosphite solution vs. sterile distilled water (control)
2) Sampling time: four levels—before inoculation (zero time) and 48, 96, and 144 hours after inoculation
Pathogen inoculation was performed two days after foliar spraying. Seedling samples were then collected for enzyme analysis. The activities of antioxidant enzymes were measured spectrophotometrically. Disease severity was assessed ten days after inoculation.
Research findings
The results showed a significant difference in rice disease severity between treated seedlings and control, with treatment reducing disease severity. In addition, the activities of antioxidant enzymes in treated plants were higher than in control plants at all time points. Catalase activity reached its peak at 4.69 U mg⁻¹ protein 48 hours after inoculation, while the lowest activity occurred in control plants on day six. Peroxidase and superoxide dismutase (SOD) activities showed a similar increasing pattern, with peak activities for peroxidase (GPX) at 62.277 U mg⁻¹ protein and for SOD at 246.17 U mg⁻¹ protein on day six after inoculation. These increases were 1.38- and 1.30-fold, respectively, compared with control.
Conclusion
Potassium phosphite treatment can enhance rice seedling resistance to rice blast by increasing the activity of defense-related enzymes. While these greenhouse results are promising, field trials are necessary to confirm the effectiveness of potassium phosphite for blast disease management under real-world conditions.
All authors contributed equally to the conceptualization of the article and writing of the original and subsequent drafts.
The data will be made available on request.
This research was supported by the Plant Protection Department of University of Kurdistan. We thank university of Kurdistan for providing research facility and support.
The study was conducted on plant-pathogen fungus and beneficial entophy-
tic bacteria that are abundant in the environment and do not require ethical
approva
The study was conducted on plant-pathogen fungus and beneficial entophytic fungi that are abundant in the environment and do not require ethical approval.
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
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