Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, PR China.
Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, PR China.
Sci Total Environ. 2022 Aug 25;836:155665. doi: 10.1016/j.scitotenv.2022.155665. Epub 2022 May 3.
Epiphytic microbes on the surfaces of leaves and roots can bring substantial benefits or damages to their plant hosts. Although various factors have been proposed for shaping the epiphytic microbial composition, the contributions of environment factors, endogenous microbial taxa interactions, host plant traits, and their interactive effects are poorly understood. Here, we conducted a field investigation along a precipitation gradient and collected leaf and root surface microbes of two alpine plant species for 16S rRNA sequencing. We found that epiphytic bacterial community composition significantly changed along the precipitation gradient through ordination analyses and permutational multivariate analysis of variance. Beneficial bacterial taxa from Caulobacteraceae, Sphingomonadaceae, Comamonadaceae and Rhizobiales were enriched in the high precipitation zones. The stress-tolerant Hymenobacteraceae, Micrococcaceae, and Geodermatophilaceae occurred more frequently in the phyllosphere, and the Thermoleophilia, Thermomicrobiales and Bacillales were enriched in the rhizosphere at the drier sites. Mean annual precipitation was the most important factor regulating the epiphytic bacterial community composition. The direct effect of climate on bacterial community composition was higher in the phyllosphere than in the rhizosphere where joint effects of climate, plant traits and soil properties predominated. Distinct leaf trichome cover and plant height clearly explained the host effect on the phyllosphere bacterial community composition while belowground traits did not explain the host effect well on the rhizosphere bacterial community composition. We detected a significant role of bacterial taxa interactions in shaping microbial communities, where greater negative taxa interactions led to lesser composition changes. Structural equation modeling showed that environmental factors and bacterial interactions substantially contributed to the variation in epiphytic community composition, followed by host plant traits. This study advances our understanding of complex factors affecting alpine epiphytic community assembly and further confirms the role of biotic interactions.
叶片和根系表面的附生微生物可以给植物宿主带来实质性的益处或损害。尽管已经提出了各种因素来塑造附生微生物的组成，但环境因素、内生微生物类群相互作用、宿主植物特性及其相互作用的影响仍知之甚少。在这里，我们沿着降水梯度进行了实地调查，并收集了两种高山植物的叶片和根表面微生物进行 16S rRNA 测序。我们发现，通过排序分析和置换方差多元分析，附生细菌群落组成沿降水梯度显著变化。根瘤菌科、鞘氨醇单胞菌科、贪噬菌科和根瘤菌目的有益细菌类群在高降水区富集。耐应激的节杆菌科、微球菌科和地衣杆菌科在叶片中更频繁出现，而嗜热菌科、嗜热微菌目和芽孢杆菌目在较干燥的地方在根际中富集。年平均降水量是调节附生细菌群落组成的最重要因素。气候对细菌群落组成的直接影响在叶片中高于根际，其中气候、植物特性和土壤特性的联合效应占主导地位。明显的叶片毛状体覆盖和植物高度清楚地解释了宿主对叶片细菌群落组成的影响，而地下特性并不能很好地解释宿主对根际细菌群落组成的影响。我们检测到细菌类群相互作用在塑造微生物群落方面起着显著作用，其中较大的负向类群相互作用导致群落组成变化较小。结构方程模型表明，环境因素和细菌相互作用对附生群落组成的变异有很大贡献，其次是宿主植物特性。本研究增进了我们对影响高山附生群落组装的复杂因素的理解，并进一步证实了生物相互作用的作用。
