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毛萼田菁茎瘤菌(Azorhizobium caulinodans)吸氢活性缺陷株的筛选及特性

王南, 吴永强, 洪莉, 樊庆笙

南京农业大学资源环境系.江苏,南京 210095；中科院上海植物生理研究所.上海 200032

摘要

利用转座子Tn5随机插入突变法,从毛萼田菁茎瘤菌中筛选得到两株吸氢活性缺陷突变株(Hup~(-))R-49和R-309,基固氮酶活性也大大降低,约为野生型固氮酶活性的6%-8%。以带有Bradyrhizobium japonicum的5.9kb的hup基因的质粒pHR11为探针与A. caulinodansORS571和B. japonicum122DES(Hup~(+))的总DNA进行分子杂交,放射自显影表明,A. coulinodans基因组含有与B. japonicum的hup基因同源的DNA片段,将携带B. japonicumhup基因的嵌合质粒pHR11与A. caulinodansHup~(-)突变株进行体内遗传互补,接合转移子吸氢酶活性可以恢复至野生型的60%,同时固氮酶的活性亦有所提高。

关键词： 毛萼田菁茎瘤菌; 吸氢酶; 固氮酶; 转座子Tn5

Screening and characterization of H_(2)-uptake hydrogenase (Hup~(-)) mutants of Azorhizobium caulinodans

Wang Nan, Wu Yongqiang, Hong Li, Fan Qingsheng

Nanjing Agricultural University.Nanjing 210095,Jiangsu；China

Abstract

Two Hup~(-) mutants (R-49 and R-309) from Azorhizobium caulinodans were obtained by Tn5 insertion mutation and their nitrogenase activities were significantly decreased to about 6%--8% of their wild type. Southern hybridization indicated that A. caulinodans genomic DNA contained homological DNA fragment with B. japonicum hup genes. When a plasmid (pHR11) containing 5.9kb hup genes of B. japonicum was transferred to A. caulinodans Hup~(-) mutants, the hydrogenase activities of transconjugants were able to restore to about 60% of their wild type and the nitrogenase activities also increased.

Key words: Azorhizobium caulinodans;Hydrogenase;Nitrogenase;Transposn Tn5

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引用本文：

王南, 吴永强, 洪莉, 樊庆笙. 毛萼田菁茎瘤菌(Azorhizobium caulinodans)吸氢活性缺陷株的筛选及特性[J]. 生理学报 1997; 49 (4): .

Wang Nan, Wu Yongqiang, Hong Li, Fan Qingsheng. Screening and characterization of H_(2)-uptake hydrogenase (Hup~(-)) mutants of Azorhizobium caulinodans. Acta Physiol Sin 1997; 49 (4): (in Chinese with English abstract).