Data_Sheet_1_Distinct Functions and Assembly Mechanisms of Soil Abundant and Rare Bacterial Taxa Under Increasing Pyrene Stresses.pdf

Elucidating the relative importance of species interactions and assembly mechanisms in regulating bacterial community structure and functions, especially the abundant and rare subcommunities, is crucial for understanding the influence of environmental disturbance in shaping ecological functions. However, little is known about how polycyclic aromatic hydrocarbon (PAH) stress alters the stability and functions of the abundant and rare taxa. Here, we performed soil microcosms with gradient pyrene stresses as a model ecosystem to explore the roles of community assembly in determining structures and functions of the abundant and rare subcommunities. The dose–effect of pyrene significantly altered compositions of abundant and rare subcommunities. With increasing pyrene stresses, diversity increased in abundant subcommunities, while it decreased in the rare. Importantly, the abundant taxa exhibited a much broader niche width and environmental adaptivity than the rare, contributing more to pyrene biodegradation, whereas rare taxa played a key role in improving subcommunity resistance to stress, potentially promoting community persistence and stability. Furthermore, subcommunity co-occurrence network analysis revealed that abundant taxa inclined to occupy the core and central position in adaptation to the pyrene stresses. Stochastic processes played key roles in the abundant subcommunity rather than the rare subcommunity. Overall, these findings extend our understanding of the ecological mechanisms and interactions of abundant and rare taxa in response to pollution stress, laying a leading theoretical basis that abundant taxa are core targets for biostimulation in soil remediation.

阐明物种相互作用与群落组装机制在调控细菌群落结构与功能——尤其是丰富类群与稀有类群亚群落——中的相对重要性，对于理解环境扰动塑造生态功能的机制至关重要。然而，目前对于多环芳烃（polycyclic aromatic hydrocarbon, PAH）胁迫如何改变丰富与稀有类群的稳定性及功能，仍知之甚少。本研究以施加梯度芘（pyrene）胁迫的土壤微宇宙（soil microcosms）作为模式生态系统，探究群落组装在决定丰富与稀有类群亚群落结构与功能中的作用。芘的剂量效应（dose–effect）显著改变了丰富与稀有亚群落的组成。随着芘胁迫强度升高，丰富亚群落的多样性呈上升趋势，而稀有亚群落的多样性则逐渐下降。值得注意的是，丰富类群的生态位宽度（niche width）与环境适应性远高于稀有类群，其对芘的生物降解（biodegradation）贡献更大；而稀有类群则在提升亚群落抗胁迫能力方面发挥关键作用，潜在促进群落的存续与稳定性。进一步的亚群落共现网络（co-occurrence network）分析显示，丰富类群在适应芘胁迫过程中倾向于占据核心枢纽位置。随机过程（stochastic processes）在丰富亚群落的组装中起到关键作用，而非稀有亚群落。综上，本研究结果拓展了我们对丰富与稀有类群响应污染胁迫的生态机制与相互作用的认知，为“丰富类群是土壤修复（soil remediation）中生物强化（biostimulation）的核心靶标”这一论断奠定了重要理论基础。