AUTHOR=Lang Ming , Li Haoming , Lakshmanan Prakash , Chen Yuanxue , Chen Xinping 

TITLE=phoD-harboring bacterial community composition dominates organic P mineralization under long-term P fertilization in acid purple soil

JOURNAL=Frontiers in Microbiology

VOLUME=13

YEAR=2022

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2022.1045919

DOI=10.3389/fmicb.2022.1045919

ISSN=1664-302X

ABSTRACT=<sec><title>Introduction</title><p>A better understanding of the regulatory role of microorganisms on soil phosphorous (P) mobilization is critical for developing sustainable fertilization practices and reducing P resource scarcity. The <italic>phoD</italic> genes regulate soil organic P (Po) mobilization.</p></sec><sec><title>Methods</title><p>Based on the long-term P application experiments in acid purple soil of maize system in Southwest China (started in 2010), the experiment included five P levels: 0, 16, 33, 49, and 65.5 kg P hm<sup>–2</sup> (P0, P16, P33, P49, and P65.5, respectively). The molecular speciation of organic P in soil was determined by 31P-nuclear magnetic resonance (NMR), high-throughput sequencing technology, and real-time qPCR were used to analyze the bacterial community and abundance of <italic>phoD</italic>-harboring bacterial genes, exploring the bacterial community and abundance characteristics of <italic>phoD</italic> gene and its relationship with the forms of Po and alkaline phosphatase (ALP) activity in the soil.</p></sec><sec><title>Results</title><p>The results showed that the orthophosphate monoesters (OM) were the main Po speciation and varied by P fertilization in acid purple soil. ALP activity decreased as P fertilization increased. Co-occurrence network analysis identified the overall network under five P fertilizations. The keystone taxon base on the network showed that <italic>Collimonas</italic>, <italic>Roseateles</italic>, <italic>Mesorhizobium</italic>, and <italic>Cellulomonas</italic> positively correlated with both OM and Po. The random forest showed that <italic>Cellulomonas</italic>, <italic>Roseateles</italic>, and <italic>Rhodoplanes</italic> were the key predictors for ALP activity. The keystone taxon was a more important predictor than the dominant taxon for ALP, OM, and Po. The structural equation model (SEM) showed that soil organic matter (SOM), available P (AP), and OM were the main factors influencing the ALP by reshaping <italic>phoD</italic>-harboring bacteria alpha diversity, community composition, and <italic>phoD</italic> abundance.</p></sec><sec><title>Discussion</title><p>The <italic>phoD</italic>-harboring bacterial community composition especially the keystone taxon rather than alpha diversity and abundance dominated the ALP activity, which could promote P utilization over an intensive agroecosystem. These findings improve the understanding of how long-term gradient fertilization influences the community composition and function of P-solubilizing microorganisms in acid purple soil.</p></sec>