用Tn5-mob-sacB转座子对华癸中生根瘤菌HN3015质粒进行定向标记、消除或缺失

采用Tn5-mob-sacB转座子对Mesorhizobium huakuii HN3015菌株含有的3条大质粒(pMhHN3015a,150 kb; pMhHN3015b , 294 kb 和pMhHN3015c,390 kb)进行定向标记,获得各个质粒标记菌株.利用sacB基因对蔗糖的敏感性,对标记质粒进行消除实验,获得HN3015质粒消除或缺失的突变株.并对HN3015及其突变菌株的培养特征、生长速度和共生结瘤能力进行了研究,结果表明:质粒消除或缺失的突变株的培养特征和生长速度与出发菌株基本一致,但是,pMhHN3015a与固氮有关,pMhHN3015b消除的菌株则失去结瘤能力,只有pMhHN3015c消除或缺失菌株不影响结瘤与固氮能力.

Labeling, Curing or Deletion of the Plasmids of Mesorhizobium Huakuii HN3015 by Tn5-mob-sacB Transpon

Three megaplasmid(pMhHN3015a,150 kb;pMhHN3015b, 294 kb and pMhHN3015c,390 kb) were labeled by Tn5-mob-sacB transpon,and the mutant strains labeled its plasmids were obtained.Plasmid curing experiment was carried out using the positive selection method to obtain the derivatives of plasmid cured or deleted.Cultural characteristics,growth rate of HN3015 and its derivatives were probed and proved to be similar.The nodulation tests presented that the mutant strain cured with its largest plasmid pMhHN3015a formed only white null nodules,and that the mutant cured with the second-largest plasmid pMhHN3015b lost nodulation ability,and only the mutant cured or deleted with its smallest plasmid pMhHN3015c could form pink effective nodules.