CAS Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China.
College of Advanced Agricultural Sciences, University of Chinese Academy of Sciences, Beijing 100049, China.
FEMS Microbiol Ecol. 2023 May 31;99(6). doi: 10.1093/femsec/fiad053.
The patterns of biogeographic distribution and assembly processes of microbiota are of vital importance for understanding ecological adaptation and functioning maintenance. However, the role of morphological characteristics in microbial assembly is still poorly ascertained. Here, by integrating high-throughput sequencing and robust extrapolation of traits, we investigated taxonomic and phylogenetic turnovers of various cyanobacterial morphotypes in biocrusts to evaluate the contributions of deterministic and stochastic processes across a large scale of drylands in northwestern China. The results showed that the non-heterocystous filamentous category dominated biocrusts in the arid ecosystem and exhibited strong tolerance against environmental fluctuations. Despite the significant distance-decay relationship of β-diversity detected in all categories, both species composition and phylogenetic turnover rates of coccoid cyanobacteria were higher than non-heterocystous filamentous and heterocystous morphotypes. Moreover, the assembly of cyanobacteria was driven by different ecological processes that the entire community and non-heterocystous filamentous morphotype were governed by deterministic processes, while stochasticity prevailed in heterocystous and coccoid cyanobacteria. Nonetheless, aridity can modulate the balance between determinism and stochasticity and prompt a shifting threshold among morphotypes. Our findings provide a unique perspective to understanding the critical role of microbial morphology in community assembly and facilitate the prediction of biodiversity loss under climate change.
微生物区系的生物地理分布模式和组装过程对于理解生态适应和功能维持至关重要。然而，形态特征在微生物组装中的作用仍未得到充分证实。在这里，我们通过整合高通量测序和特征的稳健外推，研究了生物结皮中各种蓝细菌形态的分类和系统发育周转率，以评估确定性和随机性过程在中国西北干旱地区大范围内的贡献。结果表明，非异形丝状体类别在干旱生态系统中主导着生物结皮，表现出对环境波动的强烈耐受性。尽管在所有类别中都检测到显著的β多样性距离衰减关系，但球形蓝细菌的物种组成和系统发育周转率均高于非异形丝状体和异形丝状体形态。此外，蓝细菌的组装受不同的生态过程驱动，整个群落和非异形丝状体形态由确定性过程控制，而随机性在异形丝状体和球形蓝细菌中占主导地位。然而，干旱可以调节确定性和随机性之间的平衡，并促使形态之间的转换阈值发生变化。我们的研究结果提供了一个独特的视角来理解微生物形态在群落组装中的关键作用，并有助于预测气候变化下生物多样性的丧失。
