Geographical Differences Weaken the Convergence Effect of the Rhizosphere Bacteria of Rubber Trees

Abstract

The rhizosphere has been observed to both enrich and deplete soil microorganisms, but it remains unclear whether rhizosphere microorganisms of the same species exhibit convergence in different climatic regions. This study employed high-throughput sequencing technology to analyze the bacterial communities in the soil, rhizosphere, and rhizoplane of rubber trees across varying climatic regions. The findings revealed the following: Firstly, the rhizoplane bacteria demonstrated a convergent effect. In Hainan and Xishuangbanna, two core operational classification units (OTUs) were enriched from the soil, while four core OTUs were depleted, indicating that the rhizoplane bacteria were influenced by host regulation and exhibited a certain degree of convergence due to the rhizosphere effect. Secondly, the rhizoplane bacteria exhibited a geographic distribution pattern, with significant differences observed in different climatic regions. Notably, there were significant variations in α- and β-diversity, with Xishuangbanna displaying significantly higher diversity compared to Hainan. Moreover, significant differences were observed at the phylum level in terms of composition. Temperature, soil organic matter, soil total nitrogen, and total phosphorus were identified as the primary factors contributing to these differences. In conclusion, although some convergence was observed in the rhizoplane bacteria, the influence of geographic differences weakened this effect.