不同基因型转Bt水稻种植对土壤螨类群落的影响

Effects of Bacillus thuringiensis rice with single and fused transgenes on the soil mite community

随着转基因技术的飞速发展,越来越多的转基因作物新品种被培育成功并得以推广应用,但转基因作物对非靶标生物的生态安全性问题日益引起人们的广泛关注.为加强转基因作物的生态风险评估,以Cry1Ab纯合基因型转Bt(Bacillus thuringiensis)水稻"克螟稻"和Cry1Ab/Ac融合基因型转Bt水稻"华恢1号"及其对照亲本水稻稻田土壤螨类为研究对象,系统调查研究了纯和基因型和融合基因型转Bt水稻种植下土壤螨类的群落组成、数量动态及其群落多样性的变化.研究结果显示,转Bt水稻对土壤螨类的群落组成无负面影响,仅一些稀有类群(<1%)和常见类群(介于1%和10%)消失或出现.且与对照亲本相比,纯和基因型转Bt 水稻中仅上罗甲螨科(Epilohmanniidae)上罗甲螨属(Epilohmannia)的百分比含量显著增加了525%.此外,转Bt 水稻与其对照亲本稻田土壤螨类的数量动态、群落多样性、群落均匀度和科属丰富度之间均差异不显著(P>0.05).而与纯合基因型转Bt 水稻相比,融合基因型转Bt 水稻可显著提高大田土壤螨类的数量和科属丰富度(P<0.05).可见,融合基因型转Bt 水稻种植比纯合基因型转Bt水稻更有利于土壤螨类等非靶标生物的发生及其生物多样性保护.

With the rapid development of genetic modification technology, more and more transgenic crop lines have been successfully bred and widely applied in fields, but the environmental risks on the non-target organisms have been the cause of increasing concern worldwide. In this study, the effects of different transgenic Bacillus thuringiensis (Bt) rice (KMD producing single Cry1Ab protein as well as HH1 expressing fused Cry1Ab / Ac proteins) and their respective parental lines (non-transgenic rice: XSD and MH63) on the abundance dynamics and diversity of soil mites were investigated under field conditions. The results showed that transgenic Bt rice had no negative effect on the composition of soil mites. Only some specifically rare groups (<1%) and common groups (≥1% and <10%) of soil mites disappeared or appeared in paddy field soil due to the planting of transgenic Bt rice. Besides, the percentage of the common group of Epilohmannia belonging to Epilohmanniidae in the paddy field soil of transgenic Bt rice with single Cry1Ab (KMD) increased by 525% compared to the paddy field soil of its parental line ( XSD). The abundance dynamics showed no significant differences, and the measured indexes of Shannon diversity (H′), Pielou evenness (J), and Margalef′s richness (SR) of soil mites between the paddy fields of transgenic Bt rice (KMD and HH1) and their respective parental lines (XSD and MH63) throughout the growth season (P>0.05). However, compared with the planting of transgenic Bt rice with a single Cry1Ab transgene, the planting of transgenic Bt rice with fused Cry1Ab / Ac transgenes resulted in significant increase in the abundance and genus richness of the soil mites (P<0.05). It is presumed that the planting of transgenic Bt rice with fused Cry1Ab / Ac transgenes in contrast to single Cry1Ab transgene is advantageous for the occurrence and diversity conservation of non-target organisms (including soil mites).