青藏高原毛柱黄耆根际土壤细菌多样性研究

Study on bacterial diversity in Rhizosphere soil of Astragalus heydei in Qinghai-Tibet Plateau

毛柱黄耆(Astragalus heydei)在青藏高原广泛分布,固氮效率较高,研究价值较高。本研究以青藏高原4个样点的毛柱黄耆根际土壤细菌为研究对象,采用高通量测序及生物信息学等方法,分析毛柱黄耆根际土壤菌群多样性,及其与环境因子之间的关联,并基于Spearman等级相关系数,绘制根际土壤菌群与环境因子的相关性Heatmap图。结果显示,4个样点的毛柱黄耆根际土壤细菌Shannon多样性顺序为:XB>ZR>NM>SH,变形菌门(Proteobacteria)、厚壁菌门(Firmicutes)、放线菌门(Actinobacteria)、拟杆菌门(Bacteroidetes)是4个毛柱黄耆根际土壤细菌的主要菌门;4个样点根际土壤菌群在嗜发酵菌属(Zymophilus)、乳杆菌属(Lactobacillus)、毛球菌属(Trichococcus)、沙雷氏菌属(Serratia)、哈夫尼菌属(Hafnia)、Lachnoclostridium_5、乳球菌属(Lactococcus)共7个属上存在显著性差异(P<0.05);CCA典型分析表明速效磷、铵态氮与电导率菌群相对丰度呈显著正相关(P<0.05),速效磷对菌群相对丰度影响最大;相关性Heatmap图分析表明,环境因子与22个优势菌属相对丰度呈显著正相关(P<0.05),与26个优势菌属丰度呈显著负相关(P<0.05)。本研究将为进一步研究根际土壤细菌在毛柱黄耆适应青藏高原极端环境的过程中可能产生的影响提供参考依据。

Astragalus chinensis is a leguminous plant with high research value,which is widely distributed in Qinghai-Tibet Plateau.This research take the rhizosphere bacteria of Mao Zhu astragalus in four sampling point of Qinghai-Tibet plateau as the research object,and adopt the method of high-throughput sequencing and bioinformatics to analysis the rhizosphere bacteria diversity of Mao Zhu astragalus,as well as the link between the environmental factors.Then draw the Heatmap figure based on the Spearman rank correlation coefficient,to show the correlation of rhizosphere bacteria and environmental factors.The results showed that the Shannon diversity sequence of the 4 sample points was XB>ZR>NM>SH,and Proteobacteria,Firmicutes,Actinobacteria and Bacteroidetes are the main phyla,accounting for more than 99.5%of the total bacteria.The four samples showed significant differences in seven genera including Zymophilus,Lactobacillus,Trichococcus,Serratia,Hafnia,Lachnoclostridium_5,and Lactococcus(P<0.05).CCA typical analysis showed that there was a significant positive correlation between available phosphorus,ammonium nitrogen and the relative abundance of the conductivity flora(P<0.05).Available phosphorus had the greatest influence on the relative abundance of the flora.The correlation Heatmap analysis showed that environmental factors were significantly positively correlated with the relative abundance of 22 dominant genera(P<0.05),and negatively correlated with the abundance of 26 dominant genera(P<0.05).This study will provide reference for further research on the influence of rhizosphere soil bacteria on the adaptation of Astragalus to the extreme environment of Qinghai-Tibet Plateau.