新疆耐盐苜蓿根瘤菌的分离和高效菌株的筛选

【目的】人工接菌苜蓿根瘤菌和筛选高效菌株。【方法】采集新疆14个地州不同生态区、不同类型土样132份,采用苜蓿捕获法分离、纯化获得81个苜蓿根瘤菌菌株。【结果】快速PCR检测鉴定发现,分离得到的根瘤菌菌株均属于苜蓿中华根瘤菌(Sinorhizobium Meliloti)。【结论】耐盐实验表明,这些菌株在YMA培养基上的耐盐能力在3.5%~5%NaCl,进一步分析发现土壤中盐含量与苜蓿根瘤菌的耐盐能力没有明显的相关性。对耐5%NaCl的8个根瘤菌菌株的16S rDNA序列进行分析,发现这些其序列同源性很高,相似性达到99.8%。根瘤菌接种实验表明,这8个菌株均能明显增加紫花苜蓿植株地上部分生长,但不同菌株其固氮效率存在显著差异,其中TC-Y菌株共生固氮效率最高。

Isolation of Salt-tolerant Sinorhizobium meliloti in Xinjiang and Screening for High-efficient Strains

Objective]In this study, Sinorhizobium populations were isolated from 14 different regions in Xinjiang,using Medicago sativa as trap host plants. Method]A total of 81 rhizobial isolates were obtained and were confirmed that all of them fell into S. meliloti by PCR. Result]Analysis of salt tolerance revealed that they can survive in YMA medium whose salt tolerance was between 3.5% to 5% NaCl, and there was no apparent correlation between salt tolerance in Sinorhizobium meliloti and the salt content of the soil samples.Conclusion]The 16S rDNA sequence of 8 isolates,which had salt tolerance to 5% NaCl,were high,its similarity was high and reached 99.8%.The innolation test indicated that all the 8 isolates could increase the growth of aboveground part of alfalfa plant. Additionally, there is difference in the symbiotic nitrogen-fixing efficiency of these 8 isolates with alfalfa, and the nitrogen-fixing efficiency of TC-Y is higher than that of other isolates.