苏云金芽胞杆菌基因工程菌WG-001和1125BG在盆栽土壤中的安全性评估

Biosafety evaluation of genetically engineered Bacillus thuringiensis WG001 and 1125BG in potting soil

自从遗传改造微生物诞生以来,其安全性问题受到了持续关注和研究。本文报道了苏云金芽胞杆菌基因工程菌WG 001和1125BG在盆栽大白菜的土壤环境中的安全性评估结果。实验结果表明:当用工程菌WG 001和1125BG分别以1013cfu/cm2和1010cfu/cm2的高土壤密度喷洒盆栽大白菜后,工程菌菌数迅速上升而后逐渐下降,最后分别以相对较低的菌数水平(105cfu/g干土样和106cfu/g干土样)在实验土壤中稳定存在;对土壤中土著细菌群落在有限时间(15d)内产生了一定影响,而对土著真菌与放线菌无显著影响;未发现工程菌WG 001中特异基因发生丢失;未检测到工程菌WG 001和1125BG中特异基因(WG 001为cry1Aa和cry1Ac,1125BG为gfp)向土著细菌、真菌、放线菌和盆栽大白菜的水平转移。本文实验结果显示,高密度喷洒的两种工程菌未显著影响实验土壤环境,具有很高的安全性。同时发现以不同的喷药量喷洒两种工程菌后,在盆栽土壤中其存活水平、菌数降低的速率以及对土著细菌的影响能力都表现出不同的特点。

This paper is inclined to report the authors＇ research on the bio-safety evaluation of the genetically engineered Bacillus thuringiensis WG-001 and 1125BG in the soils with the Chinese cabbages being planted in. As is known, since the generation of genetically modified microorganisms （GMOs）, its bio-safety has been given serious consideration. The results of our research indicate that, after spraying the WG-001 and 1125BG to potted Chinese cabbages at high density, the numbers of WG-001 and 1125BG in the potting soil in fact increased quickly and then decreased gradually, and finally keeping at relatively low levels with 105 cfu/g fresh soil and 106 cfu/ g fresh soil, respectively. The indigenous bacteria could be influenced at a certain extent in limited time （15 d）. However, the indigenous fungi and actinomycetes prove not to have been influenced noticeably. At the same time, the specific genes of WG-001 had not lost and the horizontal transfer of the characteristic genes （crylAa and crylAc of WG-001, and gfp of 1125BG） had not been detected from the genetically engineered B. thuringiensis to the indigenous microorganisms or potted Chinese cabbages. Thus, it can be concluded that the genetically engineered B. thuringiensis WG-001 and 1125BG does not have any ability to influence observably the ecosystem of the soil potting Chinese cabbage. And, in turn, it has been found that, after spraying the B. thuringiensis WG-001 or 1125BG with different quantities, the numbers, the declining speed and the ability to influence the indigenous bacteria of existing WG-001 or 1125BG in the soil may demonstrate different characteristic features.