转cry1Ac＋CpTI基因水稻对大螟的致死和亚致死效应

Lethal and Sub-Lethal Effects of Transgenic Rice Containing cry1Ac and CpTI Genes on the Pink Stem Borer

【目的】研究转cry1Ac+CpTI基因水稻对大螟的致死和亚致死效应,为转基因抗虫水稻的生态风险评价提供依据。【方法】采用活体取食生测的方法系统研究苗期、分蘖拔节期、孕穗期和灌浆成熟期4个生育期的转cry1Ac+CpTI基因水稻KF6和ⅡYouKF6对大螟的致死和亚致死效应。【结果】两转基因水稻在苗期对大螟的致死效应最为明显,其对50%和100%个体的致死作用时间最短,大螟在该生育期的转基因水稻上取食3d及6d后,校正死亡率最高;其次为分蘖拔节期,两转基因水稻在4.0d和10.0d内能分别对50%和100%的大螟个体产生致死作用,在该生育期的两转基因水稻上取食6d后,校正死亡率均明显高于孕穗期和灌浆成熟期;KF6在孕穗期对大螟的致死效应显著下降,其对50%大螟个体的致死作用时间显著延长,且取食6d后的校正死亡率也显著下降。但ⅡYouKF6对大螟的致死效应并没有明显下降;两转基因水稻在灌浆成熟期对大螟的致死效应显著下降,对50%大螟个体的致死作用时间显著长于其它生育期,取食3d和6d后的校正死亡率均显著低于其它生育期;部分大螟能在转基因水稻的孕穗期和灌浆成熟期完成个体发育。不同生育期的两转基因水稻对大螟的亚致死效应也存在显著差异,取食苗期和分蘖拔节期的转基因水稻能抑制大螟幼虫和蛹的发育,降低化蛹率,但对羽化率没有显著影响;取食孕穗期的转基因水稻能显著抑制大螟幼虫的发育,但对蛹历期、化蛹率和羽化率均无影响;灌浆成熟期的转基因水稻对幼虫和蛹的发育速率、化蛹率和羽化率均无明显影响。在任一生育期的转基因水稻上取食,均能降低大螟幼虫的体重和蛹重,但不影响成虫的生殖力。【结论】不同生育期的转基因水稻,对大螟的致死和亚致死效应存在显著差异,随生育期的增加,致死和亚致死效应逐渐减弱。

[ Objective ] Lethal and sub-lethal effects of transgenic rice containing crylAc and CpTI genes on the pink stem borer（Sesamia inferens） were studied to collect information for ecological risk assessment on insect-resistance to transgenic rice. [Method] In vitro insect-feeding bioassay was conducted to evaluate the lethal and sub-lethal effects of transgenic rice lines （Ⅱ YouKF6 and KF6） on S. inferens at four different growing stages, i.e., seedling, tillering and elongation, booting, milk and maturing. [Result] Transgenic rice at seedling stage showed significantly high lethal effect on S. inferens with the shortest lethal duration of 50% and 100% of individuals and the highest corrected mortalities after feeding on transgenic lines at this stage for 3 and 6 days. Secondly followed by filleting and elongation stage, 50% and 100% of S. inferens were dead after feeding on transgenic lines at this stage for 4 and 10 days, respectively. Moreover, corrected mortalities for 6 days feeding on transgenic lines at this stage were significantly higher than that at booting and milk and maturing stages. Lethal effect of KF6 on S. inferens decreased significantly at booting stage. Lethal duration of 50% of S. inferens significantly extended and its corrected mortalities for 6 days feeding also declined remarkably. However, lethal effect of Ⅱ YouKF6 on S. inferens did not decrease significantly at this stage. Transgenic rice at booting and milk and maturing stages did not present significantly lethal to S. inferens and it showed the longest lethal duration of 50% of individuals and the lowest corrected mortalities for 3 and 6 days feeding. A few larvae of S. inferens could survive, pupate and emerged on these two transgenic lines at boot and milk and maturing stages. Sub-lethal effect of two transgenic lines on S. inferens also differed significantly between different developmental stages. Continuously feeding on transgenic rice lines at seedling and tillering and elongation stages could delay the development of larvae and pupae and decrease pupation rate, but no effect was shown on eclosion rate. Larval development was significantly inhibited after feeding on transgenic rice at booting stage, but no obvious effects were observed in pupal stages, pupation and eclosion rates. There were no significant differences for larval and pupal development, pupation and eclosion rates between feeding on transgenic and control rice lines at milk and maturing stages. Larval and pupal weights significantly declined, but no influence was shown on fecundity, when S. inferens infested on transgenic rice at any stage. [ Conclusion ] There were significant differences in lethal and sub-lethal effects of transgenic rice on S. inferens at different developmental stages, and the effects gradu/dly decreased with the increase of growing stages of rice plant.