Understanding the dynamics of plant-associated microbial communities within agriculture is well documented. However, the ecological processes that assemble the plant microbiome are not well understood. This study elucidates the relative dominance of assembly processes across plant compartments (root, stem, and leaves) and developmental stages (emergence, growth, flowering, and maturation). Bacterial community composition and assembly processes were assessed using 16S rRNA gene amplicon sequencing. Null models that couple phylogenetic community composition and species distribution models were used to evaluate ecological assembly processes of bacterial communities. All models highlighted that the balance between the assembly process was modulated by compartments and developmental stages. Dispersal limitation dominated amongst the epiphytic communities and at the maturation stage. Homogeneous selection dominated assembly across plant compartments and development stages. Overall, both sets of models were mostly in agreement in predicting the prevailing assembly processes. Our results show, for the first time, that even though niche-based processes dominate in the plant environment, the relative influence of dispersal limitation in community assembly is important.

了解农业中与植物相关的微生物群落的动态已有充分记录。然而，组装植物微生物组的生态过程尚不清楚。这项研究阐明了植物区室（根、茎和叶）和发育阶段（出苗、生长、开花和成熟）组装过程的相对主导地位。使用 16S rRNA 基因扩增子测序评估细菌群落组成和组装过程。使用将系统发育群落组成和物种分布模型耦合的零模型来评估细菌群落的生态组装过程。所有模型都强调组装过程之间的平衡是由隔室和发育阶段调节的。扩散限制在附生群落和成熟阶段占主导地位。同质选择主导了植物区室和发育阶段的组装。总体而言，两组模型在预测流行的装配过程方面基本一致。我们的结果首次表明，尽管基于生态位的过程在植物环境中占主导地位，但群落组装中分散限制的相对影响也很重要。