Molecular Soil Biology 2024, Vol.15, No.5, 247-255 http://bioscipublisher.com/index.php/msb 251 Figure 2 Co-occurrence networks of the bacterial communities in the rhizosphere of rice across three soil types based on correlation analysis. The capital letters represent different soil type, where A represent albic soil, B represent black soil, C represent chernozem soil. A connection indicates a strong (Spearman's r >0.8 or r < −0.8) and significant (p < 0.01) correlation. Each node represents one genus; the size of each node is proportional to the number of connections (i.e., degree); nodes are colored according to the categories, in which red nodes represent abundant taxa, blue nodes represent rare taxa, and green nodes represent moderate taxa. Percentage inside parentheses represents the ratio of the number of genus with different categories to the number of all genus in the network. Each edge represents a strong and significant correlation between two nodes; the thickness of the edge is proportional to the value of the Spearman's correlation coefficient; and edges are colored according to the positive or negative correlation, in which red edges represent positive correlations, blue edges represent negative correlations (Adopted from Zhang et al., 2021) 5.3 Influence of seasonal environmental changes on microbial metabolic activity and community stability Seasonal changes in environmental conditions, such as temperature and moisture, can lead to shifts in microbial metabolic activity and community stability in the rice rhizosphere. The microbial community in the rhizosphere is generally more dynamic and responsive to these changes compared to bulk soil. For example, the abundance of certain microbial taxa, such as potential iron reducers and fermenters, can fluctuate with plant growth stages and associated environmental changes. Moreover, the stability of microbial communities is influenced by the interactions between environmental factors and microbial functional groups. High organic matter content in soil, for instance, can lead to more stable and convergent microbial communities, as observed in soils with rich organic matter (Zhang et al., 2021). Seasonal variations can also impact the metabolic activity of microbes, with certain functional groups becoming more active during specific growth stages of the rice plant, thereby contributing to the overall stability and functionality of the rhizosphere microbial community (Li et al., 2019; Fu et al., 2023). 6 Case Study of the Relationship between Rhizosphere Microbes and Rice Growth 6.1 Criteria for case study selection The case study was selected based on several criteria to ensure consistency and relevance. The geographic location chosen was Vercelli, Italy, known for its extensive rice cultivation, providing a representative
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