马衔山中国沙棘根瘤内共生细菌多样性研究

采集甘肃省兰州市马衔山中国沙棘(Hippophae rhamnoidoes)根瘤样品,采用高通量测序和纯培养方法,分析中国沙棘根瘤内定殖的内共生细菌的组成、相对丰度和物种多样性,并比较两种方法研究结果的差异。在不同的微生物分类单元,高通量测序检测到中国沙棘根瘤内共生细菌24门50纲90目167科215属;而纯培养方法仅检测到3门5纲7目8科8属。进一步分析沙棘根瘤内共生细菌主要类群的相对丰度,发现高通量测序与纯培养方法的结果有明显差异,在科和属的分类单元上差异尤其显著。两种方法都表明中国沙棘根瘤内共生细菌具有丰富的多样性,但高通量测序能够较为全面的反映中国沙棘根瘤内共生细菌的群落组成,而纯培养方法仅能够分离到部分可培养的中国沙棘根瘤内共生细菌,在很大程度上极可能低估中国沙棘根瘤内共生细菌的物种组成并高估其丰度。

Diversity of endophytic bacteria in root nodules of Hippophae rhamnoides in the Maxian Mountains

Root nodules of Hippophae rhamnoides were collected in the Maxian Mountains. The plate culture method and high-throughput sequencing were used to study the diversity of endophytic bacteria in the root nodules of Hippophae rhamnoides. Microbial composition, abundance, and diversity of the nodule endophytic bacteria were analyzed. The differences in the results of the two techniques were compared. The results showed that 24 phyla, 50 classes, 90 orders, 167 families, and 215 genera of nodule endophytic bacteria were detected by high-throughput sequencing, and 3 phyla, 5 classes, 7 orders, 8 families, and 8 genera were obtained by plate culture. The relative abundances of the dominant nodule endophytic bacteria revealed that the differences between the results of the two techniques were greater at lower classification levels, especially at the family and genus levels, than at higher levels. Both plate culture and high-throughput sequencing showed an abundant diversity of nodule endophytic bacteria. High-throughput sequencing provides a more comprehensive and accurate picture of microbial community structure than the plate culture method does. Plate culture can only detect a few dominant taxa of nodule endophytic bacteria. The results of this study indicated that plate culture greatly underestimates microbial community composition and overestimate their abundance.