中国Btken-Ag的特性及其杀虫毒肽的研究

苏芸金芽孢杆菌肯尼亚亚种Ag株(Bacillus thuringiensis serovar.kenyae strainAg,以下简称为Btken-Ag)是血清型H4a-4c中对棉铃虫、粘虫等多种夜蛾科害虫具有高毒力的优良品系,经生理生化、H抗原、酯酶谱、抗生谱和质粒谱等性状比较分析,与标准株肯尼亚亚种023大体相同,但其质粒谱及伴孢晶体多肽组分与023明显有别.该菌株伴孢晶体多形,其主要杀虫成分为61000多肽,经ELISA同源分析,此毒肽与同血清型中的023、7501晶体蛋白高度同源,与商品生产株H3a-3b—HD-1株部分同源,与对蚊虫高效的H14-1897及球形芽孢杆菌Ts-1无同源性.此外,对H4中10株相关株、H7-5、HD-1及1897共13株进行了对棉铃虫、粘虫及蚊虫的杀虫毒力比较测定,其中Btken-Ag的优选株H4-1及b1-4对棉铃虫的毒力高于023株及HD-1株.

CHARACTERS AND INSECTICIDAL POLYPEPTIDE OF A NEW STRAIN OF BACILLUS THURINGIENSIS SUBSP. KENYAE IN CHINA

A new strain of Bacillus thurinigiensis Bt with high toxicity againstnoctuidae larvae has been screened for many generations since isolated from larvaecandle of Aphomia gularts in Yiyang County, Jiangxi Province, in China. By comparison and analysis of results of physiological and biochemical test, flagella antigen identification and esterase type, the strain is identified as H4a-4c Bt serovar.kenyae. Since its crystal protein type and plasmid type are different from those ofBt serovar. kenyae's type 023. The strain is assigned a novel strain: Btken-Ag.Btken-Ag's parasporal crystals are multi-morphorous: bipyramid, cube, small irregular sphere and embedded. After UMT dissolve, PAGE and SDS-PAGE separationpreparation and analysis, it is found that its major insecticide component to Helio-this armigera is 61kD toxic protein. By ELISA homology analysis, it is found thatthis toxic protein has high homology with crystal protein of 023 and 7501 (H4a-4c), partly homology with that of HD-l(H3a-3b), but no homology with that ofBti(H14) and (Bacillus sphaericus) Ts-1 strain, in bioassay with larvae from Cu-lex pipiens, Pseudaletia unipuncta and Heliothis armigera, together with other tenBt strains, Btken-Ag is toxic to 3 star larvae of Culex pipiens; two isolates of Btken-Ag (b1-4 and H4-1) show higher toxicity than type strain 023 and HD-1 doto Pseudaletia unipuncta and Heliothis armigera.