【摘要】 目的研究标记菌株在水稻国丰1号幼根根表的吸附动态规律和不同类型土壤中存活情况,为禾本科植物凝集素介导作用、吸附的影响参数和联合固氮的研究及应用提供科学依据。方法采用三亲本杂交法将发光基因luxAB导入水稻根际促生菌黄单胞菌(Xanthom onassp)P5310菌株中,标记菌株P5310-luxAB能稳定遗传,luxAB基因的导入不影响标记菌株生长特性。结果 P5310-luxAB菌株存在稳定型和松散型两种吸附,随标记菌株浓度变化的吸附规律符合Langmu ir等温吸附方程,水稻根表最大吸附量qm=3.33×109CFU/g,吸附系数α=2.86×10-8。凝集素处理的水稻根表对标记菌株的亲和力增强,吸附量也随之增大。标记菌株在灭菌土壤和不灭菌土壤中都能很好的存活。在前25 d,不灭菌土壤中菌落数要低于灭菌土壤,随着营养的消耗,细菌明显减少;但补充营养后,在灭菌土壤和不灭菌土壤中标记菌株数量都快速增加,证明标记菌株与不灭菌土壤中的土著微生物的竞争占优势,很快与灭菌土壤中的菌数接近,证明菌株能在土壤中很好地存活与定植。结论以上研究结果为菌株P5310的开发应用提供了可靠的实验数据。更多还原

【Abstract】 Objective To study the dynamic adsorption of the labeled strain to the root surface of the rice and its survival in different soils.Method Luminescence gene luxAB was transferred into the rice PGPR Xanthomonas sp P5310 strain by the tri-parent conjugation method to obtain P5310-luxAB strain.The labeled strain could pass down steadily,and the expression of luxAB gene did not affect the growth of the labeled strain.Result There were two types of adsorption,loose and stable adsorption.The adsorption of the strain conformed to Langmuir isothermal adsorption equation along with the changing of bacteria cell density.The maximum adsorption of the strain to rice root qm=3.33×109 CFU/g with adsorption coefficient α =2.86×10-8.The adsorption was enhanced by treating the rice roots with rice lectin.And the adsorption capacity was also strengthened.The labeled strain could successfully survive both in sterilized and non-sterilized soil.In the first 25 days the number of bacteria in non-sterilized soil was lower than that in sterilized soil.The labeled strain evidently decreased with consuming of nutrition.But after the supplement of nutrition,the labeled strain could compete predominantly with native microorganisms in non-sterilized soil.The number of bacteria in non-sterilized soil quickly closed to those in sterilized soil.The labeled strain could well survive and colonize in rice rhizosphere.Conclusion The above results provide credible data for the study and application of strain P5310.更多还原