جداسازي جدايه هاي بومي باكتري Bacillus thuringiensis از خاك تاكستان هاي شهرستان سلماس و ارزيابي سميت آن روي لارو و حشرات كامل Tribolium castaneum(Herbst) (Coleoptera: Tenebrionidae)

Extraction of local isolates of Bacillus thuringiensis from vineyard soils in Salmas and evaluation of its toxicity on larva and adults of Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae)

Bacillus thuringiensisيك باكتري گرم مثبت، اسپورزا و خاكزي است كه در سراسر جهان و در بيشتر شرايط آب و هوايي يافت مي شود. به دليل وجود ژن هاي vip و cry و cyt، اين باكتري پروتيين هايي توليد مي كند كه به طور اختصاصي آفات مهم محصولات كشاورزي از جمله سخت بالپوشان، بالپولكداران، دوبالان و حتي نماتدها را آلوده و كنترل مي كند. بدين منظور سميت 25 جدايه بومي باكتري Bt جداسازي شده از خاك هاي زراعي شهرستان سلماس روي لارو و حشره كامل Tribolium castaneum مورد بررسي قرار گرفتند. جدايه هاي Bt بر اساس روش استات جداسازي شدند. ويژگي هاي مرفولوژيكي كريستال با استفاده از ميكروسكوپ نوري مطالعه شد. براساس نتايج، 25 جدايه Bt جداسازي شد و 40 درصد جدايه ها داراي كريستال پروتيين دو هرمي بودند. در مرحله حشره كامل اين آفت 40 درصد جدايه ها و در مرحله لاروي 8 درصد جدايه ها به ترتيب تلفاتي بيش از25% و 75% نشان دادند و بطور كلي نتايج نشان داد كه باكتري تاثير قابل توجهي روي لارو و حشره كامل حشرات مورد بررسي داشت.

Bacillus thuringiensis is a gram-positive, spore-forming bacterium and terrcolous with abundant agricultural and scientific attractions throughout the world and are found in most climatic conditions. Due to genes Cyt, Cry and Vip proteins produced by this bacterium that infest and control specific agricultural pests including Lepidoptera, Coleoptera, Diptera, and even nematodes. For this purpose, 25 strains of indigenous Bt. bacteria separated from agricultural soils (Salmas city) and the amount of their toxicity were examined on the larvae and adult of T. castaneum. Bt. isolates based on morphological characteristics were isolated using acetate method. The morphological characteristics of Bt. crystal were studied by light microscopy. 25 isolates of Bt. was isolated and the most commonly isolates were pyramidal shapes. In the adult stage of this pest 40 percent of the isolates and in the larval stage eight percent of isolates were showed more than 25% and 75% losses respectively. General results showed that the bacteria have significant effect on larvae and adult of examined insects.