Drought consistently alters the composition of soil fungal and bacterial communities in grasslands from two continents
Drought consistently alters the composition of soil fungal and bacterial communities in grasslands from two continents
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DOI：
10.1111/gcb.14113
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发表时间：
2018-07
影响因子：
11.6
通讯作者：
R. Ochoa‐Hueso;S. Collins;M. Delgado‐Baquerizo;K. Hamonts;W. Pockman;R. Sinsabaugh;Melinda D. Smith
中科院分区：
文献类型：
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作者：
R. Ochoa‐Hueso;S. Collins;M. Delgado‐Baquerizo;K. Hamonts;W. Pockman;R. Sinsabaugh;Melinda D. Smith
短期干旱对土壤微生物群落的影响在很大程度上尚未探索，特别是在大规模和田间条件下。我们使用了来自两大洲（北美和澳大利亚）的七个实验地点，以评估极端干旱对土壤细菌和真菌群落的丰度，群落组成，丰富度和功能的影响。这些地点包括不同的草原生态系统，涵盖广泛的气候和土壤特性。干旱显着改变了土壤细菌的群落组成，并在较小程度上，真菌在草原从两大洲。真菌群落的变化幅度与降水梯度成正比。这种更大的真菌对干旱的敏感性，在更mesic网站与一般观察到的模式，更干旱的草原植物群落的干旱敏感性更大，这表明植物和微生物群落可能会作出不同的反应沿着降水梯度。放线菌，绿球藻，细菌门通常占主导地位，在干旱环境中，增加了它们的相对丰度响应干旱，而球囊菌，真菌类被认为是广泛的共生，相对丰度下降。衣原体和Tenericutes，两门的主要致病物种，响应下降和增加沿着降水梯度，分别。干旱条件下土壤酶活性持续增加，这种反应归因于干旱引起的微生物群落结构变化，而不是丰度和多样性的变化。我们的研究结果提供的证据表明，干旱对微生物群落的组装有广泛的影响，微生物群落是陆地生态系统土壤功能的主要驱动因素之一。这种反应可能对提供关键的生态系统服务（包括养分循环）产生重要影响，并可能导致植物-微生物相互作用减弱，某些土传疾病的发病率增加。
The effects of short‐term drought on soil microbial communities remain largely unexplored, particularly at large scales and under field conditions. We used seven experimental sites from two continents (North America and Australia) to evaluate the impacts of imposed extreme drought on the abundance, community composition, richness, and function of soil bacterial and fungal communities. The sites encompassed different grassland ecosystems spanning a wide range of climatic and soil properties. Drought significantly altered the community composition of soil bacteria and, to a lesser extent, fungi in grasslands from two continents. The magnitude of the fungal community change was directly proportional to the precipitation gradient. This greater fungal sensitivity to drought at more mesic sites contrasts with the generally observed pattern of greater drought sensitivity of plant communities in more arid grasslands, suggesting that plant and microbial communities may respond differently along precipitation gradients. Actinobateria, and Chloroflexi, bacterial phyla typically dominant in dry environments, increased their relative abundance in response to drought, whereas Glomeromycetes, a fungal class regarded as widely symbiotic, decreased in relative abundance. The response of Chlamydiae and Tenericutes, two phyla of mostly pathogenic species, decreased and increased along the precipitation gradient, respectively. Soil enzyme activity consistently increased under drought, a response that was attributed to drought‐induced changes in microbial community structure rather than to changes in abundance and diversity. Our results provide evidence that drought has a widespread effect on the assembly of microbial communities, one of the major drivers of soil function in terrestrial ecosystems. Such responses may have important implications for the provision of key ecosystem services, including nutrient cycling, and may result in the weakening of plant–microbial interactions and a greater incidence of certain soil‐borne diseases.