转Bt基因玉米叶面微生物区系和细菌生理群多样性变化

Changes in Microbial Flora and Bacterial Physiological Group Diversity on Leaf Surface of Transgenic Bt Corn

大田栽培条件下,以转Bt基因玉米Mon810及其亲本玉米DK647作为材料,在玉米的不同生育期,于2010年和2011年连续2年测定玉米叶面细菌、真菌和放线菌的数量变化,并对细菌生理群的数量和多样性进行分析。结果表明,虽然不同年份和生育期2个玉米品种叶面微生物数量存在差异,但年度间和相同的发育时期叶面微生物的数量变化趋势一致,由苗期开始增多,到生育后期达到数量高峰。转Bt基因玉米对叶面细菌和真菌影响较大,大部分生育期内Bt玉米叶面真菌和细菌数量与亲本玉米有显著差异,而放线菌数量与亲本相比差异不显著。2010年,苗期、拔节期和完熟期Bt玉米叶面细菌生理群Shannon-Wiener群落多样性指数、Simpson优势集中性指数和均匀度指数高于亲本玉米,2011年除喇叭口期Bt玉米细菌生理群的3种群落特征参数均大于对照。

In order to evaluate the effect of transgenic maize on epiphytes, the transgenic Bt maize Mon810 and its parental non-transgenic maize were grown in field to study the quantitative changes of culturable microorganisms and the diversity of bacterial functional groups at different growth stages in 2010 and 2011. Although there were differences in the colony-forming unites of culturable bacteria, actinomycetes and fungi of phyllosphere between Bt maize and non-Bt maize in different growing periods and different years, the trend of annual differences was basically consistent at the same growth period： the quantity of microbes in seedling stage is fewest and reaches the peak in the late of growing period. Compared with the controls, transgenic Bt maize seemed to stimulate the reproduction of phyllosphere fungi. However, no significant effect on the populations of actinomycete was observed. Significant differences were detected for bacteria at jointing stage, trumpet stage, silking stage and milking stage. In 2010, the Shannon-Wiener index, Simpson index and evenness index of bacteria physiological groups were higher at seedling, jointing and full-ripe stage, but lower at trumpet stage, tasseling stage, silking stage and milk stage. In 2011, the population characteristic parameters of the microorganisms of Bt-corn are more than the ones of non-Bt corn in the whole growing period except trumpet stage. It may be concluded there was some difference in terms of impacts between transgenic maize and non-transgenic maize, while the main impacts on microbial community composition were likely due to different years and different ~rowth periods.