导入额外拷贝nifA基因对费氏中华根瘤菌HN0 1NL根圈定殖与竞争结瘤的影响

本文研究了导入额外拷贝的肺炎克氏杆菌 (Klebsiellapneumoniae)nifA基因对受体费氏中华根瘤菌 (Sinorhizobiumfredii)HN0 1在大豆根圈的定殖和竞争结瘤的影响。将HN0 1分别与带有标记基因luxAB的参照菌株HN0 1L和带有nifA基因和标记基因luxAB的重组菌株HN0 1NL按照 1∶1等量比例接种于大豆黑龙 3 3种子表面 ,在灭菌土和非灭菌土中研究其定殖动态。每一供试菌株在根圈中的比例依次于播种后第 3天、第 7天、第 1 0天、第 1 2天、第 1 4天、第 1 6天、第 2 1天和第 3 6天进行测定 ,占瘤率在播种后第 4 0天进行比较测定。盆栽实验结果表明 :导入了额外拷贝nifA基因的重组菌HN0 1NL与受体菌HN0 1和参照菌HN0 1L相比较 ,在灭菌土和非灭菌土中均表现出显著增强的大豆根圈适应性和竞争能力

Influence of Introduced Extra nifA Gene on Rhizosphere Colonization and Competition for Nodule Occupancy by Sinorhizobium fredii Strain HN01NL

Root colonization by introduced strains of Sinorhizobium fredii was exa m ined to determine if the introduction of extra copy Klebsiella pneumoniae nifA g ene into the recipient strain HN01 could increase its competitiveness for rhizos phere colonization and root nodulation of Glycine max in soil. Seeds of Gl ycine max were inoculated with HN01 and either of the two luxAB marked strains H N01L a nd HN01NL that differ only in carrying extra Kp nifA gene or not . The pair of s trains were inoculated with 1:1 mixtures in sterile and non-sterile soil in pl an t pot experiment system. The representation of strains in the rhizosphere was de termined at 3 d, 7 d, 10 d, 12 d,14 d,16 d,21 d, 36 d after inoculation and nodu le occu pancy was determined at 40 d after sowing. The results indicated that the extra -Kp -nifA-carrying strain HN01NL was significantly more competitive in soybean r hizo sphere than recipient strain HN01 and reference strain HN01L both in sterile and non-sterile soil.