发光酶基因(luxAB)标记的荧光假单胞菌CP1108的定殖能力研究

Colonization ability of luxAB gene-marked Pseudomonas fluorescens CP1108 in cotton rhizosphere

利用三亲本杂交方法,将luxAB发光酶基因标记至荧光假单胞菌(Pseudomonas fluorescens)CP1108上,研究标记菌株CP1108L的个体生态学特征及其在棉花根圈的定殖动态。结果表明,标记菌株连续传代20次均未发生质粒丢失现象,标记质粒在受体菌株中较为稳定,CP1108L菌株的生长及部分生理生化特性没有受到标记质粒的影响;标记菌株能够在棉花根圈中成功定殖,棉花生长14 d时,CP1108L在所有深度的根段均达到最高定殖水平,定殖密度分别为2.31×105 cfu.g-1根土、3.18×105 cfu.g-1鲜根,而其中以0～2 cm根段处标记菌株的定殖密度最大,根际和根表的菌数分别为9.08×104 cfu.g-1根土、1.44×105 cfu.g-1鲜根;接种CP1108和CP1108L菌液处理棉花植株的干重、主根长和株高显著高于对照组;两个菌株处理之间差异不显著。

By the method of tri-parent conjugation,the luxAB gene was introduced into P.fluorescens CP1108.This study aimed at the autecology of P.fluorescens CP1108L and its colonization ability in cotton rhizosphere.The results showed that the marker gene luxAB was successfully transferred into strain CP1108,and the plasmid with luxAB did not lose after 20 generations.Plasmid transformed had little effect on the growth and physiological and biochemical character of strain CP1108L.Strain CP1108L successfully colonized in the rhizosphere of cotton.The total population reached to the highest level 2.31×105 cfu·g-1 and 3.18×105 cfu·g-1 after 14 days,and the population reached to 9.08×104 cfu·g-1 and 1.44×105 cfu·g-1 at the root segment of 0~2 cm.Pot experiment results showed that strain CP1108L had a good advance on the plant height,root length and dry weight of cotton.