粘虫颗粒体病毒对苏云金杆菌的增效特性及对Bt毒蛋白的降解活化作用  

Synergistic effects of Pseudaletia unipuncta granulosis virus (PuGV-Ps) on Bacillus thuringiensis (Bt) and the involved degradation of Bt toxins

作　　者：徐健[1] 刘琴[2] 谭永安[1] 祝树德[1] 

机构地区：[1]扬州大学园艺与植物保护学院,江苏扬州225009 [2]江苏里下河地区农科所,江苏扬州225007

出　　处：《昆虫学报》2008年第1期26-32,共7页Acta Entomologica Sinica

基　　金：国家重点实验室开放课题(ChineseIPM0703);国家科技支撑计划(2006BAD02A03);江苏省自然科学基金项目(BK2006067);江苏省科技攻关项目(BE2005612);江苏省研究生培养创新工程项目(CX07B-1902)

摘　　要：以小菜蛾Plutella xylostella为试虫,采用生物测定方法测定了粘虫颗粒体病毒（Pseudaletia unipuncta granulosis virus,PuGV-Ps）对苏云金杆菌（Bacillus thuringiensis,Bt）的增效作用。结果表明：不同配伍PuGV-Ps和Bt间的共毒系数在105.3至195.0之间,PuGV-Ps对Bt毒力具有增强作用,其中以Bt∶PuGV-Ps为4∶1增效作用最明显,72hLC50为0.039mg/mL。不同温度和pH值都影响PuGV-Ps对Bt的增效作用,16℃-20℃增效程度明显高于24℃-32℃,而碱性条件下（pH8-9）增效作用更显著。PuGV-Ps对Bt的增效作用因小菜蛾龄期不同而变化,2、3龄幼虫死亡率较单独使用Bt分别提高了50%和30.31%,而作用于低龄（1龄）和高龄（4龄）幼虫时对Bt的增效作用不显著。PuGV-Ps饲喂2h后再接毒Bt,小菜蛾死亡率明显提高,48h死亡率达66.67%,较直接饲喂Bt＋PuGV-Ps处理死亡率提高了53.87%,差异极显著。SDS-PAGE表明PuGV-Ps具有碱性蛋白酶的活性,离体条件下能促进δ-内毒素酶解为47kD,60kD和61kD的毒性肽。The synergistic effects of Pseudaletia unipuncta granulosis virus （PuGV-Ps） on Bacillus thuringiensis （Bt） were tested by bio-assays employing larvae of the diamondback moth Plutella xylosteUa. The results indicated that the co-toxicity coefficients （CTC） of Bt combined with PuGV-Ps in different ratios were diverse from 105.3 to 195.0, showing a positive synergistic effect of PuGV-Ps on Bt. Among the mixtures, the most significant effect was in the 4：1 ratio of Bt and PuGV-Ps, in which the LC50 was 0. 039 mg/mL. When environmental temperature was low （16℃ and 20℃）, the synergistic effects were statistically significant, while there were no differences under temperatures of 28 ℃ and 32 ℃ compared with the treatment of feeding the insects with Bt alone, pH value influenced the synergistic effect gravely, which was elevated along with increase of pH value. In higher pH value of 8 and 9, PuGV-Ps elevated mortalities of P. xylosteUa larvae by Bt up to 16.67% and 23.33%, respectively. The co-effects of Bt and PuGV-Ps were also varied along with the larval age. Mortalities of the 2nd and 3rd instar larvae increased by 50% and 30.31%, respectively, in the treatment of Bt ＋ PuGV-Ps compared with that of Bt only, but no significant synergistic effects were found in tests with the 1st and 4th instar larvae. Much higher synergistic effect was observed in treatments with oral inoculation of PuGV-Ps 2 h prior to Bt treatment, and the mortality 48 h after treatment increased 66.67 % compared with the treatment of oral inoculation with Bt and PuGV-Ps simultaneously. SDS-PAGE analysis showed that in vitro the δ-endotoxin with molecular weight about 130 kD could be degradated by PuGV-Ps into 47 kD, 60 kD and 61 kD activated toxins that resisted further degradation.

关 键 词：粘虫颗粒体病毒 苏云金杆菌 增效特性 BT毒蛋白 小菜蛾 

分 类 号：Q965[生物学—昆虫学]