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【目的】研究分离自四川凉山州新银合欢根瘤菌的遗传多样性和共生有效性。【方法】采用16S rRNA RFLP、BOX-PCR、AFLP、多位点持家基因序列的联合分析及无氮水培法对33株供试新银合欢根瘤菌的遗传多样性和共生有效性进行研究。【结果】分析表明,3种方法在属水平的分群结果具有较好的一致性,有1个Mesorhizobium属的菌株、3个Bradyrhizobium属的菌株、3个Rhizobium属的菌株,26个相似度较高的菌株属Sinorhizobium。16S rRNA-recA-atpD-glnII序列联合构建的新银合欢根瘤菌系统发育树表明,SCAU203、SCAU211可能分别是Rhizobium和Bradyrhizobium的新类群,另外3个代表菌株分别位于Sinorhizobium、Mesorhizobium、Bradyrhizobium分支,分别与S.americanum、M.Plurifarium、R.huautlense亲缘关系最近。无氮水培接种试验筛选出2个共生固氮效果好、与不接种对照处理差异达显著水平的菌株SCAU229和SCAU307,有3个菌株不仅不具共生有效性,甚至不利于宿主的生长,其余84%的供试菌为低效或无效菌株。【结论】凉山州新银合欢根瘤菌具有丰富的遗传多样性,分布于4个属:Rhizobium、Bradyrhizobium、Mesorhizobium、Bradyrhizobium,79%为Sinorhizobium属的菌株,优势菌群为Sinorhizobium。该区的新银合欢根瘤菌大多数的共生有效性差。
【Objective】 The objective of this study was to investigate the genetic diversity and symbiosis of Rhizobium isolated from Acacia Rhizobium in Liangshan Prefecture, Sichuan Province. 【Method】 The genetic diversity and symbiosis of 33 new strains of Rhizobia were tested by 16S rRNA RFLP, BOX-PCR, AFLP and multi-site housekeeping gene sequence analysis and nitrogen-free culture. 【Result】 The results showed that there was a good agreement among the three methods in the genus level. There were 1 strain of Mesorhizobium, 3 strains of Bradyrhizobium and 3 strains of Rhizobium. Of the strains are Sinorhizobium. 16S rRNA-recA-atpD-glnII sequence showed that SCAU203 and SCAU211 might be new taxa of Rhizobium and Bradyrhizobium, respectively. The other three representative strains were located in Sinorhizobium, Mesorhizobium and Bradyrhizobium branches, respectively Closely related to S.americanum, M.Plurifarium, R.huautlense. Three strains SCAU229 and SCAU307 with good symbiotic nitrogen fixation effect and significant difference with non-inoculation control were screened out by nitrogen-free hydroponic culture test. Three strains not only did not have symbiosis effectiveness, even detrimental to host growth, the other 84% The test bacteria are inefficient or ineffective strains. 【Conclusion】 Rhizobia of Rhizobium, Bradyrhizobium, Mesorhizobium, Bradyrhizobium and 79% of Sinorhizobium belonged to Rhizobium, Sinorhizobium. Most of the symbiotic effectiveness of the new Rhizobium in the area is poor.