Distribution Characteristics of phoD-Harbouring Bacterial Community Structure and Its Roles in Phosphorus Transformation in Steppe Soils in Northern China

Abstract

The phoD-harbouring bacterial community is responsible for much of the hydrolysis of organic phosphorus (P o ) in soils and is therefore significant for the improvement of soil phosphorus (P) availability. However, the distribution of phoD-harbouring bacterial community structure and how it regulates the soil P fractions in steppe soils remain largely unknown. It is necessary to assess these relationships to maintain sustainable development on the steppe. We sampled soils from three steppe types across Inner Mongolia, China. Illumina high-throughput sequencing was used to quantify the bacterial phoD gene. The dominant phoDharbouring genera were Amycolatopsis (5-11%), Bacillus (6-13%), Bradyrhizobium (3-8%) and Pseudomonas (3-5%) across all steppe soils. The relative abundances of phoD-harbouring Amycolatopsis and Bacillus increased significantly as available P (AP) decreased, while the relative abundances of Bradyrhizobium, Pseudomonas and Methylobacterium were significantly positively correlated with AP content. Redundancy analysis showed that the soil stoichiometric ratio of carbon (C), nitrogen (N) and P had a strong effect on the phoD-harbouring bacterial community structure. Correlation analyses further indicated that only phoD-harbouring Dietzia and Sphingomonas had a significant correlation with alkaline phosphatase activity and that they increased P availability by mineralizing P o . phoD-harbouring Frankia and Methylobacterium were positively correlated with labile-P o and negatively correlated with non-labile inorganic P. Moreover, phoD-harbouring Bacillus and Bradyrhizobium promoted the conversion of the non-labile P o pool into the labile P o pool, which can be attributed to microbial immobilization. Not all bacteria carrying the phoD gene promote soil P availability through mineralization or are induced not only in a Prepressible manner. Members of the phoD-harbouring bacterial community employ flexible P use strategies and can be strongly activated by their nutrient preferences and environmental conditions.

Land reclamation increased organic P fractions and phosphatase activities, and strengthened the co-occurrence networks of phoD community in calcareous soils

“…These suggested that Cupriavidus, Pseudomonas, Streptomyces and Xanthomonas can be used as powerful species to mineralize soil organic phosphorus. In consistent with us, Gou et al (2021) noted that Amycolatopsis, Pseudomonas and Streptomyces were positively correlated with soil available P. Similarly, Zhu et al (2021) found that the relative abundances of Bradyrhizobium were positively correlated with labile-Po, suggesting that these bacteria possessed strong ability to mineralize organic P and promote organic P transformation (Godwin and Cotner 2015). We must acknowledge that, in some sense, the linkage between functional microorganisms, phosphatase activity and Po transformation is still a challenge, even though culture-independent approach in this study rapidly screened out the potential species in driving Po mineralization.…”

Labile carbon facilitated phosphorus solubilization as regulated by bacterial and fungal communities in Zea mays

“…3b and d). As previously demonstrated, Bradyrhizobium has the ability to promote the conversion of non-labile P to labile P forms through microbial immobilization and subsequent mineralization (Luo et al, 2017;Ibny et al, 2019;Zhu et al, 2021). Additionally, Bradyrhizobium harbors a N-fixing gene (Kaneko et al, 2002;Yao et al, 2014), suggesting that this genus could play an important role in coupled N/P cycling in soils with sufficient C. However, this was not observed in G10-rhizosphere soil (Fig.…”

Different mechanisms driving increasing abundance of microbial phosphorus cycling gene groups along an elevational gradient

“…Specifically, we found that Bradyrhizobium is one of the major genus from Proteobacteria in this study (relative abundance range of 22.69–11.36% along low-elevation to high-elevation gradient). Previous study showed that Bradyrhizobium harbors phoD gene in steppe soil, which attributed to microbial immobilization by promoting the conversion of the non-labile organic P pool into the labile organic P pool ( Zhu et al., 2021 ). In addition, Acidobacteria were favored in acidic soils ( Rousk et al., 2010 ).…”