Enhanced complexity of interkingdom co-occurrence networks in blueberry rhizosphere microbial communities under soil pH stress

Abstract

Blueberry prefers acidic soils, resulting in its growth and development being limited by soil pH across various habitats. However, the effect of soil pH stress on the structure and interactions within its root-associated microbiome remains unclear. In this study, we investigated how varying soil pH conditions affect the composition, assembly processes, network complexity, and stability of blueberry root-associated bacterial and fungal communities. The results showed soil pH affected both bacterial and fungal community structures, with community assembly predominantly governed by stochastic processes. Notably, fungal communities were more influenced by stochastic drift than bacterial communities. Higher network complexity (nodes, edges, and average degree) and lower network stability were observed in the rhizosphere under low and high pH conditions compared to optimum pH conditions. A total of 24 and 29 keystone taxa were identified in the rhizosphere and endosphere, respectively. Collectively, these findings suggested that soil pH stress modulates the blueberry root-associated microbiome by reshaping community composition and enhancing interkingdom network complexity, though accompanied by reduced network stability. This study shed insights into changes in microbial interaction networks within the root-associated microbiome of host plants under abiotic stresses and lay essential groundwork for leveraging keystone microbes to improve plant health and resilience.