Fig. 2
Microbial interaction network and assembly processes in pearl millet microbiome. A Co-occurrence network analysis illustrating the correlation of operational taxonomic units (OTUs) abundance within the bacterial and fungal communities in the roots (RT) and root-adhering soil (RAS) of four pearl millet PM lines (A, L220; B, L3, C, L253; D, L132). Each dot in the network represents a node, corresponding to a distinct OTU representing a microbial population. Strong Pearson correlations, filtered at a 0.05 p-value threshold, are represented by connections (green lines indicate a positive correlation while red lines indicate a negative correlation) between nodes. Nodes are color-coded and shaped according to their major taxonomic classes. The size of each node reflects its significance, determined by the number of connections (degree), betweenness, and closeness within the network. B Topological roles of classified nodes, revealing potential keystone species within the correlation network. C–D Assessment of relative contributions of deterministic (ßNTI ≥ 2) and stochastic (ßNTI ≤ 2) processes on the bacterial and fungal assembly across the soil–plant root continuum of the four PM lines, employing a null model. Horizontal lines indicate upper and lower significance thresholds at βNTI < 2 and > 2. D The relative importance of 5 ecological processes for bacterial and fungal communities assembly respectively, along the BS, RAS, and RT of each PM line: heterogeneous selection (ßNTI <  − 2), homogeneous selection (ßNTI > 2), dispersal limitation (|βNTI|< 2 and RCBray > heterogeneous selection (ßNTI <  − 2), homogeneous selection (ßNTI > 2), dispersal limitation (|βNTI|< 2 and RCBray > 0.95), homogenizing dispersal (|βNTI|< 2 and RCBray <  − 0.95), and undominated (|βNTI|< 2 and |RCBray|< 0.95)