1株根瘤菌在甘蔗体内的定殖及固氮效率分析

Colonization and nitrogen fixation efficiency analysis of a strain of rhizobia in sugarcane

  • 摘要: 【目的】研究根瘤菌在甘蔗根内的定殖特点、根瘤菌接种对甘蔗生长的影响及与甘蔗的联合固氮效率,为根瘤菌在甘蔗生产中的应用提供理论依据。【方法】采用三亲结合法,将含有绿色荧光蛋白(GFP)基因和四环素抗性片段的pPROBE-pTetr-TT质粒导入分离自广西野生割手密根系的根瘤菌Rhizobium sp. CZGRD1,将标记GFP的根瘤菌CZGRD1与新台糖22号(ROC22)和RB928064(B9)甘蔗组培苗共培养,用激光共聚焦显微镜检测其在甘蔗根内的定殖特点。用15N同位素法研究盆栽条件下,CZGRD1对B9和ROC22组培苗和种茎苗的促生作用和固氮效率。【结果】CZGRD1对庆大霉素和氯霉素有抗性,对氨苄青霉素、链霉素、壮观霉素和四环素等抗生素敏感。CZGRD1与B9和ROC22甘蔗组培苗共培养过程中,能从根的裂缝、侧根伸出部位和根冠细胞侵入根内。接种CZGRD1使B9和ROC22甘蔗组培苗植株干重较不接种菌株对照分别增长12.11%和4.48%,氮含量分别增长25.00%和7.97%,植株从空气中获得的固氮百分率分别为12.35%和8.30%。接种CZGRD1使B9和ROC22甘蔗种茎苗植株干重较不接种菌株对照分别增长14.31%和10.26%,氮含量分别增长20.07%和10.90%,植株从空气中获得的固氮百分率分别为12.77%和10.28%。【结论】根瘤菌Rhizobium sp. CZGRD1能定殖在甘蔗根内,可促进B9和ROC22组培苗和种茎苗生长,并与甘蔗联合固氮。

     

    Abstract: 【Objective】The purpose of the study was to investigate the colonization characteristics of rhizobia in micropropagated sugarcane roots,the effects of inoculation rhizobia on the growth of sugarcane and the nitrogen fixation efficiency in association with sugarcane,and to provide a theoretical basis for the application of rhizobia in sugarcane production.【Method】The pPROBE-pTetr-TT plasmid containing green fluorescence protein(GFP)gene and tetracycline resistance fragment was introduced into Rhizobium sp. CZGRD1 isolated from Guangxi wild Saccharum spontaneum by a three-parent combination method. The GFP-labeled rhizobia CZGRD1 was co-cultured with Xintaitang 22(ROC22)and RB928064(B9)sugarcane cultured seedlings,and its colonization characteristics in the roots of sugarcane were examined by confocal laser microscope. The 15N isotope method was used to study the growth promotion and nitrogen fixation efficiency of CZGRD1 on B9 and ROC22 cultured seedlings and stem seedlings under potted conditions.【Result】 CZGRD1 was resistant to gentamicin and chloramphenicol,and was sensitive to ampicillin,streptomycin,spectinomycin and tetracycline. CZGRD1 invaded the roots in the root fissures,lateral root projections and root crown cells during cocultivation with B9 and ROC22 sugarcane cultured seedling. Compared with the uninoculated controls,inoculation of CZGRD1 increased plant dry weights of B9 and ROC22 sugarcane cultured seedlings by 12.11% and 4.48%,nitrogen content increased by 25.00% and 7.97%,respectively. The percentage of nitrogen fixation from air for seedlings was 12.35% and 8.30%,respectively. Inoculation of CZGRD1 increased B9 and ROC22 sugarcane stem seedlings plant dry weights by 14.31% and 10.26%,nitrogen content by 20.07% and 10.90%,respectively. The percentage of nitrogen fixation from air for seedlings was 12.77% and 10.28%,respectively.【Conclusion】Rhizobia Rhizobium sp. CZGRD1 is able to colonize in sugarcane roots,to promote the growth of B9 and ROC22 cultured seedlings and stem seedlings,and to fix nitrogen in association with sugarcane.

     

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