Molecular Soil Biology 2026, Vol.17, No.1, 26-37 http://bioscipublisher.com/index.php/msb 30 directly points to the function of inorganic phosphorus dissolution: Metagenomic studies have shown that gcd is relatively common in soil samples, and its relative abundance can be an important factor in explaining the differences in bioavailable phosphorus, and can appear multiple copies and potential horizontal transfer signals in the genomes of different bacterial phyla (Rasul et al., 2019). Combined with the results from long-term nitrogen input studies in tea gardens, such as "soil pH has a significant direct effect on microbial phosphorus cycling, and phoD-related communities change with nitrogen application levels", it can be seen that including functional genes and environmental factors in the analysis is the key path to distinguish "changes in community composition" from "changes in functional intensity". 4.3 Metagenome and functional prediction (PICRUSt/KEGG Pathways) analysis Metagenomes can directly obtain the functional gene profile of the community, which is suitable for analyzing the potential metabolic network of phosphate-solubilizing bacteria and processes such as phosphorus transport/ phosphorus starvation response; however, when the sample volume is large or resources are limited, the functional prediction method based on amplicon data still has practical value (Yang et al., 2025). PICRUSt proposes a "function prediction based on phylogenetic inference" prediction framework, and PICRUSt2 further expands in aspects such as placing ASVs in reference trees, gene family inference, and pathway summarization, making it a common strategy to infer KEGG homologous genes and pathways from 16S data; KEGG, as a pathway knowledge base, also provides standardized coordinates for mapping gene abundance to metabolic networks (Douglas et al., 2020). It should be emphasized that the prediction results reflect "potential" rather than "expression", and in the study of acidic tea gardens, it is necessary to try to verify the prediction results with enzyme activity, available phosphorus, phosphorus components, and key genes (phoD/gcd/pqq) measured in practice to reduce the risk of over-prediction. 5 Effects of Soil Environmental Factors on Phosphorus-Degrading Bacterial Communities and Functions 5.1 Correlation analysis of pH, organic matter and available phosphorus content pH often becomes the dominant factor influencing the structure and function of phosphorus-degrading bacteria (especially the phoD carrying community) through multiple pathways such as influencing Al activity, mineral surface charge, and microbial physiological adaptation; organic matter determines the supply of carbon sources, the source of complexing agents, and the microbial active substrate pool, and is coupled with the phosphorus mineralization process (Hegyi et al., 2021; Jindo et al., 2023). In the study of the acidification gradient of tea garden soil, soil pH was significantly positively correlated with various active/moderately active phosphorus components, phoD gene abundance, and tea yield and quality indicators, while the increase of non-active phosphorus due to acidification suggested a consistent direction of "acidification-phosphorus pool transfer-functional group attenuation" (He et al., 2025). Short-term phosphorus supply potting experiments also showed that phosphorus input could significantly increase available phosphorus and change the diversity and metabolic pathways of rhizosphere microorganisms, indicating that available phosphorus is not only a response variable but may also participate in the feedback regulation of the community (Che et al., 2025). 5.2 The regulatory role of soil trace elements on the activity of phosphorus-depleting bacteria Trace elements in the soil-microbe-plant system are both essential nutrients and potential stressors: metals such as Fe, Mn, Zn, and Cu participate in various enzyme systems and electron transfer processes, and may alter the efficiency of phosphorus release by influencing microbial metabolism and rhizosphere chemical reactions; in acidic soils, the toxicity of Al and the increased metal activity may inhibit microbial biomass and enzyme activity, thereby weakening the phosphorus cycling process (Asirifi et al., 2025). Recent studies have further proposed that mineral ions can enhance soil phosphorus availability through the "microbial phosphorus dissolution process" (such as zinc ions promoting microbial phosphorus dissolution and improving phosphorus utilization efficiency), providing new experimental clues for understanding the coupling of "trace elements-phosphorus dissolution mechanism" (Adeyemo et al., 2025; Barzgar et al., 2025; Chandrika et al., 2025). For tea plantations, a balance window needs to be found between "supplementing trace elements to promote metabolism" and "acidification increasing metal activity leading to stress" (Yu et al., 2024; He et al., 2025).
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