缩二脲降解菌在作物根际的GFP标记示踪

通过三亲结合对缩二脲降解菌GW-1菌株成功进行了绿色荧光蛋白（Green fluorescent protein, GFP）基因标记，标记菌株命名为GW-1-GFP。实验证明外源质粒对宿主菌的生长未带来不利的影响，且经高效液相色谱测定该标记菌株降解缩二脲的能力与出发菌株无显著差异（p<0.05）。经抗生素抗性和荧光追踪证明标记菌株GW-1-GFP能够很好地在土壤中定殖，第25天时在不同处理的土壤中标记菌株对缩二脲的降解能力都超过50%，45天后该标记菌株在土壤中已难以检测。经标记菌株GW-1-GFP菌悬液浸润的小麦种子发芽后，通过荧光观察显示降解缩二脲的标记菌株GW-1-GFP在小麦根部定殖良好，且该标记菌株能在一定程度上缓解缩二脲对小麦的毒害作用。该研究为验证、追踪土壤中功能微生物菌剂与作物根部的亲和性和生态有效性提供了简易、直观的检测方法。

Labeling of biuret degrading bacteria with gfpp and colonization of the bacteria in crop rhizosphere

Strains of biuret-degrading bacteria GW-1 were successfully isolated and labeled with green fluorescent protein with the triparental mating method and then the GFP-tagged strains were named GW-1-GFP. The expression of GFP in Strain GW-1-GFP was visualized under the fluorescent microscope and its dynamics was analyzed and stability tested. It was found that heterogenous plasmid did not bring any adverse effect to growth of the host strain GW-1-GFP and the strain was stable. HPLC analysis did not show any significant difference (P<0.05) between the origin stain GW-1 and the tagged strain GW-1-GFP in biuret-degrading ability. The tagged strain GW-1-GFP, proved by the antibiotics resistance screening and fluorescence tracing, could colonize well in the soil and was found to have degraded 50% of the biuret in soil in all the treatments on D25 after the application of Strain GW-1-GFP. It was also found in the experiment that the tagged strain was safe to the environment and vanished from the soil after 45 days. Good colonization of Strain GW-1-GFP in the rhizosphere of wheat seedlings which emerged from wheat seed inoculated with Strain GW-1-GFP was observed and the tagged strain could alleviate the toxic effects of biuret on wheat to a certain extent. The study provides a simple, intuitive method to trace functional microbial agents and corroborate their ecological effectiveness and affinity with crop roots in the soil.