Microbial community in potato rhizosphere in the Bashang area

The composition and functional characteristics of bacterial community in crop rhizosphere soil played a crucial role in soil health, nutrient cycling, and crop growth. However, there had been limited research on the bacterial communities in the potato rhizosphere of the Bashang region, a major potato-producing area in China. This study aimed to analyze the bacterial community composition and functional diversity of potato rhizosphere soils in the Bashang region, focusing on potato fields from Zhangbei County and Guyuan County. To achieve this, we employed metagenomic sequencing to examine the bacterial community composition and functional traits of the potato rhizosphere soils across 3 sites in Zhangbei County and Guyuan County of the Bashang region (the site 1 is the Zhangbei Experimental Station of Zhangjiakou Academy of Agricultural Sciences, the site 2 is the Zhangbei Experimental Station of Hebei Agricultural University, the site 3 is Guyuan Experimental Station, Institute of Crop Sciences, Chinese Academy of Agricultural Sciences). The research aims to not only the understanding of microbial diversity in potato rhizospheres but also providing valuable insights into the ecological functions of the bacterial communities. The results revealed that Proteobacteria, Actinobacteria, and Acidobacteria were the dominant phyla in the potato rhizosphere soils of both Zhangbei and Guyuan Counties. There were significant differences in the alpha diversity of bacterial communities across different locations in Bashang, with Guyuan County showing higher richness and diversity indices compared to Zhangbei County. LEfSe analysis identified 16 bacterial groups that exhibited significant differences between the two counties, with Acidobacteria being an important differential group. The LDA score of Acidobacteria at site 3 was higher than that of other differential bacterial groups, indicating its greater impact on the intergroup differences. Overall, site 3 had the highest number of differential bacterial taxa in the rhizosphere soil, followed by site 2, while site 1 had the fewest differential bacterial groups. Further correlation analysis of soil fertility indicators and microbial community structure revealed that soil organic matter was significantly positively correlated with Steroidobacter, available potassium was positively correlated with Bradyrhizobium, and significantly negatively correlated with Luteitalea. These correlations suggested that certain bacterial groups played a role in nutrient cycling, especially in relation to soil fertility parameters, which may have influenced potato growth and yield in the region. The functional analysis of the potato rhizosphere soil bacterial communities highlighted that amino acid transport and metabolism, as well as energy generation and conversion, were the primary functional traits of the bacterial communities in the Bashang region. The relative abundance of these functions was highest at site 1 and lowest at site 3, indicating location-specific variations in microbial functional activity. Additionally, among the carbohydrate-active enzymes, glycosyltransferases exhibited the highest relative abundance, suggesting a significant role in carbohydrate metabolism in the rhizosphere. The relative abundance of carbohydrate-binding modules was highest at site 3 and lowest at site 2, further reflecting the functional diversity across locations. The alpha diversity index was highest at site 3, indicating that the bacterial communities in the potato rhizosphere soil at site 3 were the most diverse. However, the soil at site 3 had the lowest levels of available potassium and available phosphorus among the three sites, with organic matter content ranking second. This suggested that the levels of organic matter, available potassium, and available phosphorus in the potato rhizosphere soils of the Bashang region were not solely dependent on microbial diversity, but may have been related to the abundance of certain key microorganisms.