Above- and belowground plant pathogens along elevational gradients: Patterns and potential mechanisms

Plant pathogens are important for community assembly and ecosystem functioning and respond to a variety of abiotic and biotic factors, which may change along elevational gradients. Thus, elevational gradients are a valuable model system for exploring how environmental, plant community and soil factors influence pathogen communities. Yet, how these factors influence pathogens in natural ecosystems remains poorly understood. We examined the dynamics of plant fungal pathogens along elevational gradients, as well as the mechanisms shaping these dynamics, by combining a field survey on the Tibetan Plateau with a global meta-analysis. In the field survey, increasing elevation was associated with a decrease in soil fungal pathogen richness but not in foliar fungal disease symptoms. Elevation was primarily related to soil fungal pathogen richness through abiotic factors, whereas no association was found between elevation and foliar fungal diseases. The meta-analysis confirmed the generality of our field survey results: elevation was associated with a decrease in soil fungal pathogen richness, but it had no consistent relationship with foliar fungal diseases or pathogens. Thus, above- and belowground plant pathogen communities showed distinct elevational patterns, providing new insights into underlying mechanisms.

植物病原体（Plant pathogens）在群落构建与生态系统功能维持中发挥关键作用，其可响应多种非生物与生物因子，而这些因子的组成与强度会随海拔梯度发生显著变化。因此，海拔梯度是探究环境、植物群落与土壤因子如何调控病原体群落的理想模型系统。然而，目前学界对于自然生态系统中这些因子如何作用于病原体群落仍缺乏深入认知。我们结合青藏高原野外调查与全球元分析（meta-analysis），探究了海拔梯度下植物真菌病原体的动态变化及其驱动机制。野外调查结果显示，海拔升高与土壤真菌病原体丰富度降低显著相关，但与叶部真菌病害症状无明显关联；海拔主要通过非生物因子影响土壤真菌病原体丰富度，而海拔与叶部真菌病害则未发现显著关联。元分析验证了本研究野外调查结果的普适性：海拔升高与土壤真菌病原体丰富度降低相关，但与叶部真菌病害或病原体并无稳定的关联。综上，植物地上与地下病原体群落呈现出截然不同的海拔分布格局，为解析其潜在驱动机制提供了新视角。