AUTHOR=Liu Chao , Zhuang Jiayao , Wang Jie , Fan Guohua , Feng Ming , Zhang Shutong 

TITLE=Soil bacterial communities of three types of plants from ecological restoration areas and plant-growth promotional benefits of Microbacterium invictum (strain X-18)

JOURNAL=Frontiers in Microbiology

VOLUME=13

YEAR=2022

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2022.926037

DOI=10.3389/fmicb.2022.926037

ISSN=1664-302X

ABSTRACT=<p>Microbial-assisted phytoremediation promotes the ecological restoration of high and steep rocky slopes. To determine the structure and function of microbial communities in the soil in response to changes in soil nutrient content, the bacterial communities of rhizospheric soil from three types of plants, i.e., <italic>Robinia pseudoacacia</italic>, <italic>Pinus massoniana</italic>, <italic>and Cynodon dactylon</italic>, were analyzed using Illumina sequencing technology. High-quality sequences were clustered at the 97% similarity level. The dominant genera were found to be <italic>RB41</italic>, <italic>Gemmatimonas</italic>, <italic>Sphingomonas</italic>, <italic>Bradyrhizobium,</italic> and <italic>Ellin6067</italic>. The Tukey HSD (honestly significant difference) test results showed that the abundance of <italic>RB41</italic> and <italic>Gemmatimonas</italic> were significantly different among three types of plants (<italic>p &lt; 0.01</italic>). The relative abundances of <italic>RB41</italic> (13.32%) and <italic>Gemmatimonas</italic> (3.36%) in rhizospheric soil samples from <italic>R. pseudoacacia</italic> were significantly higher than that from <italic>P. massoniana</italic> (0.16 and 0.35%) and <italic>C. dactylon</italic> (0.40 and 0.82%), respectively. The soil chemical properties analyses suggested that significant differences in rhizospheric soil nutrient content among the three plant types. Especially the available phosphorus, the content of it in the rhizospheric soil of <italic>R. pseudoacacia</italic> was about 280% (<italic>P. massoniana</italic>) and 58% (<italic>C. dactylon</italic>) higher than that of the other two plants, respectively. The soil bacterial communities were further studied using the correlation analysis and the Tax4Fun analysis. A significant and positive correlation was observed between <italic>Gemmatimonas</italic> and soil nutrient components. Except total nitrogen, the positive correlation between <italic>Gemmatimonas</italic> and other soil nutrient components was above 0.9. The outcomes of these analyses suggested that <italic>Gemmatimonas</italic> could be the indicator genus in response to changes in the soil nutrient content. Besides, the genes involved in metabolism were the major contributor to soil nutrients. This study showed that soil nutrients affect the soil bacterial community structure and function. In addition, pot experiments showed that <italic>Microbacterium invictum</italic> X-18 isolated from the rhizospheric soil of <italic>R. pseudoacacia</italic> significantly improved soil nutrient content and increased <italic>R. pseudoacacia</italic> growth. A significant increase in the numbers of nodules of <italic>R. pseudoacacia</italic> and an increase of 28% in plant height, accompanied by an increase of 94% in available phosphorus was measured in the <italic>M. invictum</italic> X-18 treatment than the control treatment.</p>