一株对玉米螟高毒力的苏云金芽胞杆菌的鉴定及其杀虫活性
为分离并鉴定对玉米螟具有高毒力的苏云金芽胞杆菌菌种,从田间土壤中收集并分离获得野生菌株,进行了菌体、伴孢晶体形态学观察及分子生物学鉴定,并测定了其对玉米螟及水稻二化螟的室内生物活性。结果显示：该菌株革兰氏染色阳性,产生的伴孢晶体形状多为不规则形。16S rDNA序列与苏云金芽胞杆菌属的BMB 171同源性达99%,鉴定为苏云金芽胞杆菌,命名为JN002。该菌株对亚洲玉米螟具有较高毒性,对水稻二化螟毒性不及玉米螟,对粘虫几乎无活性。以1.0×109个/mL菌体浓度接种玉米螟和水稻二化螟3龄幼虫后,其LT50分别为46.82 h和55.64h。表明该菌株是1株对亚洲玉米螟具有较强毒力的苏云金芽胞杆菌新菌株,同时也具备防治水稻二化螟的潜力。
英文摘要:
To isolate and identify new strains of Bacillus thuringiensis against Ostrinia fumacalis, a new wild strain was obtained from the experimental field of Jilin Academy of Agricultural Sciences by chessboardSsampling method, its gram and parasporal crystals morphology and molecular biology identification were undertaken, furthermore, its biological activity against O. furnacalis and Chilo suppressalis were detected. The results showed that it was a gram-positive strain and produced irregular parasporal crystals mostly. The result of 16S rDNA analysis revealed that the strain was homologous to B. thuringiensis strain BMB 171 with 99% similarity. All these results suggested that the strain was a new member of B. thuringiensis and designated as B. thuringiensis JN002. It gave a high toxicity against O. fumacalis, and lower of that against C. suppressalis, while showed extremely low activity against Mythimna separate. The LC50 were 46.82 and 55.64h against O. furnacalis and C. suppressalis, respectively. It demonstrated that JN002 was a new strain for O. furnacalis control, and also was potential for C. suppressalis control.
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