بررسي تاثير باكتري هاي استرپتوميسس بر كاهش تنش زيستي ناشي از قارچ Fusarium oxysporum f. sp. cumini در گياه زيره سبز (Cuminum cyminum L.) در شرايط گلخانه

Effects of Streptomycetes on Reducing Biotic Stress Induced by Fusarium oxysporum f. sp. cumini in Cumin (Cuminum cyminum L.) under Glasshouse Conditions

زيره سبز گياهي يكساله از خانواده Apiaceae با نام علمـي Cumin cyminum L. مـيباشـد، از جملـه مهمتـرين مشـكلات كاشت اين گياه، پژمردگي ناشي از قارچ Fusarium oxysporum f.sp. cumini ميباشدوقتي محصول حدوداً يك ماهه است، اين بيماري ظاهر ميشود و هنگامي كه گياهان به طول 2/5-0/5سانتيمتر ميرسند، پژمرده شـده و مـي ميرنـد، بـذرهـا هنگام برداشت محصول آلوده ميشوند و بيمارگر به مناطق جديدتر گسترش مييابـد .(2) در ايـن تحقيـق از بـين 80 ايزولـه استرپتوميسس جداسازي شده از خاك ريزوسفر گياه گون 3 جدايـه M15, M26, M80 انتخـاب شـدند بـه منظـور بررسـي بيشتر تست هاي مختلفي روي جدايه هاي مزبور صورت گرفت، ارزيابي فعاليت آنتاگونيستي جدايه هاي منتخب تحت شـرايط گلخانه انجام پذيرفت. پس از رشد گياهچه ها، مرگ ومير و شاخصهاي رشد در بين تيمارهاي مختلف مقايسه و نتـايج ثبـت گرديد. تحقيق حاضر قدمي جهت كنترل بيماري مذكور با استفاده از استرپتوميسس ها بوده و هدف نهايي معرفي يك محصول زيستي مناسب براي كنترل تنش زيستي ناشي از قارچ خاكزاد فوزاريوم ميباشد.

Cumin )Cuminum cyminum L.) is a one-year-old plant and belongs to the Apiaceae family. One of the most important biotic stress regarding this precious plant species is induced by Fusarium oxysporum f.sp. cumini and damaging crop when plants are about one-month old; while plants reach to 0.5-5 cm in height die as the cause of wilt disease. In the current research, 80 isolates of Streptomyces isolated from the rhizosphere soil of Astragalus sp. and screened against Fusarium under laboratory condition. Three out of 80 isolates including M15, M26 and M80 were revealed the highest antagonistic activity and selected for further evaluation under glasshouse conditions. After emergence of cumin seedlings, mortality and growth indices were compared between different treatments weekly and results were recorded. Plants were harvested after 10 weeks and growth indices such as height and weight were recorded. The Streptomyces sp. No. M15 showed the strongest effects on plant growth and suppression of the wilt disease compare to the controls. This research candidates Streptomyces sp. No. M15 as a potential biocontrol agent for further research as a plant growth promoting bacterium which has the ability to suppress the biotic stress caused by Fusarium oxysporum f.sp. cumini.