Responses of arbuscular mycorrhizal fungal communities to an experimental gradient of precipitation in the desert steppe of Northwest China

Climate change exerts profound effects on desert grassland ecosystems, influencing vital components such as plant and soil communities. Among these, Arbuscular mycorrhizal fungi (AMF) pivotal plant root symbionts, exhibit marked sensitivity to environmental fluctuations. Our study delves into how variations in precipitation impact AMF community diversity and composition within these ecosystems, aiming to identify the predominant influencing factors. Over three years, we simulated five precipitation regimes to investigate the responses of AMF communities: extreme drought (50% reduction), moderate drought (25% reduction), control (ambient precipitation), moderate wet (25% increase), and wet (50% increase). Utilizing Illumina high-throughput sequencing, we assessed the effects of precipitation changes on AMF richness and composition. Our findings reveal that AMF richness and composition are significantly responsive to precipitation alterations, with soil moisture and pH, along with plant biomass and plant cover, emerging as key drivers. Notably, soil properties exert a more pronounced influence on AMF community dynamics than plant community. These insights contribute to a nuanced understanding of AMF community responses to precipitation variability, offering implications for predicting and managing the impacts of climate change on Ningxia's desert steppe ecosystems.

气候变化对荒漠草原生态系统具有深远影响，可作用于植物群落与土壤群落等核心组成部分。其中，丛枝菌根真菌（Arbuscular mycorrhizal fungi，AMF）作为植物根系的关键共生体，对环境波动表现出显著敏感性。本研究聚焦降水变化如何影响该生态系统内丛枝菌根真菌群落的多样性与组成，旨在明确其主要调控因素。研究历时三年，设置五种降水处理模式以探究丛枝菌根真菌群落的响应特征，分别为极端干旱（降水减少50%）、中度干旱（降水减少25%）、对照组（自然降水）、中度增湿（降水增加25%）与重度增湿（降水增加50%）。本研究采用Illumina高通量测序技术，评估了降水变化对丛枝菌根真菌群落丰富度与组成的影响。研究结果显示，丛枝菌根真菌的群落丰富度与组成对降水变化具有显著响应，土壤含水量、pH值以及植物生物量、植物盖度均为其关键调控因子。值得注意的是，相较于植物群落，土壤属性对丛枝菌根真菌群落动态的影响更为显著。本研究结果有助于深入理解丛枝菌根真菌群落对降水变化的响应机制，可为预测与应对气候变化对宁夏荒漠草原生态系统的影响提供理论参考。