【作者】 王可美；

【导师】 张小平； 李登煜； 陈强；

【作者基本信息】 四川农业大学 ， 微生物学， 2003， 硕士

【摘要】 本试验采用大肠杆菌和根瘤菌接合的方法，将gusA和celB两种标记基因分别导入了三株慢生型花生根瘤菌Spr3-5，Spr3-7和Spr4-5中，检测结果表明，gusA和celB基因在三株慢生型花生根瘤菌Spr3-5，Spr3-7和Spr4-5中可以有效表达。 利用标记基因进行生态学研究，首先要考虑到标记基因对受体菌的影响，对出发菌株和标记菌株的代时测定结果表明，二者之间没有显著差异，说明导入标记基因的菌株其生长速率没有发生改变。 通过水培试验研究了标记基因对受体菌株的竞争结瘤能力和固氮有效性的影响。在标记菌株与出发菌株等量接种的前提下，比较了二者的竞争结瘤能力，结果显示，标记菌株形成的根瘤(蓝瘤)的占瘤率与50％相比差异不显著，说明标记菌的竞争结瘤能力与出发菌株相比没有发生显著改变。 为了研究标记菌株与出发菌株的固氮有效性，测定了标记菌株与出发菌株各自共生植株的干重、全氮和叶绿素含量，结果表明，标记菌株与出发菌株的这三项指标之间没有显著差异，从不同角度说明标记后的三株慢生型花生根瘤菌和出发菌株相比，其固氮有效性并未发生显著改变，而且它们之间的相关系数分别为0.864(P＜0.01)，0.809(P＜0.01)，0.854(P＜0.01)，说明用这三个指标来指示慢生型花生根瘤菌的固氮有效性是可靠的。 通过盆栽试验研究了标记菌与土著菌的竞争结瘤试验，结果表明本试验所采用的三个菌株与土著菌相比有更高的竞争结瘤能力，其固氮有效性也较高。同时证明利用gusA和celB基因研究根瘤菌的竞争结瘤能力是简单可行的方法，可以较为直观的对标记菌形成的根瘤进行检测。当然，从检测所需费用来看，celB基因标记法成本更低一些。更多还原

【Abstract】 The gusA and celB genes were introduced by conjugation into three peanut bradyrhizobiol strains , Spr3-5, Spr 3-7and Spr 4-5 respectively. Testing for gusA and celB activity showed the gusA and celB genes in Spr3-5, Spr 3-7and Spr 4-5 could express.Using any maker gene system for ecological studies the effect on recipient strains must be evalucated. The generation time of marked and parental strains demonstrated there was no significant difference between them,which indicated their growth rate was the same.In N-free solution pot experiment the nodulating competitive ability of parental and marked strains and their nitrogen fixing efficiency were tested. Coinoculating parental and marked strains at a 1:1 ratio their competitive ability was tested. The results showed the proportion of blue nodules didn’t differ significantly from 50%.It indicated the competitiveness of maked strains was not changed significantly compared with the parent strains.To study nitrogen fixing efficiency of marked and parental strains , the symbiotic shoot dry weight, total nitrogen and contents of chlorophyll of marked and parental strains were tested, and the result showed there was no significant difference between them., which indicated the nitrogen fixing efficiency of marked strains didn’t differ from parental strains markedly in different ways.The correlation coefficients among shoot dry weight, total nitrogen and contents of chlorophyll were 0.864 (P<0.01), 0.809 (P<0.01) and 0.854 (P<0.01) respectively, which indicated they were reliable indexes reflecting nitrogen fixing efficiency of Eradyrhizobiwn sp.(arachis).The results of soil pot experiment showed that three peanut bradyrhizobial strains, Spr3-5, Spr 3-7and Spr 4-5,had higer nitrogen fixing efficiency and stronger competitive ability than indigenous bradyrhizobia.Besides,it indicated that use of gusA or celB genes in competition studies of rhizobium is simple,reliable and the nodules occupied by gusA-marked strains or those occupied by celB -marked strains cound be observed intuitionisticly.However.the cost of gusA marker was lower than that of celB marker.更多还原