Hodgson Riley J, Cando-Dumancela Christian, Liddicoat Craig, Ramesh Sunita A, Edwards Robert A, Breed Martin F
College of Science and Engineering Flinders University Bedford Park South Australia Australia.
Ecol Evol. 2025 Jun 18;15(6):e71595. doi: 10.1002/ece3.71595. eCollection 2025 Jun.
Soil microbiota can colonise plant roots through a two-step selection process, involving recruitment of microbiota first from bulk soil into plant rhizospheres, then into root endospheres. This process is poorly understood in all but a few model species (e.g., ), which is surprising given its fundamental role in plant and soil ecology. Here, we examined the microbial community assembly processes across the rhizospheres and root endospheres in eight natural populations of the pan-palaeotropical C4 grass, , in southern Australia. Using a space-for-time substitution approach, we assessed whether bacterial root colonisation patterns conformed to the two-step model and tested whether community assembly was driven more by deterministic or stochastic processes. Our results show that the two-step selection process shaped bacterial recruitment dynamics across these natural populations, and we provide clear evidence that host plants influence microbial assembly via deterministic pressures that produce strong community convergence within endospheres. These findings highlight the central role of host filtering in shaping a conserved 'core' endosphere microbiome. However, limited understanding of these endosphere communities constrains efforts to harness these important relationships to, for example, improve plant propagation and revegetation practices.
土壤微生物群可以通过一个两步选择过程定殖于植物根系，该过程首先涉及将微生物群从土体土壤招募到植物根际，然后进入根内圈。除了少数模式物种（例如……）外，这个过程在其他物种中都了解甚少，鉴于其在植物和土壤生态学中的基础作用，这令人惊讶。在这里，我们研究了澳大利亚南部泛古热带C4禾本科植物……的八个自然种群根际和根内圈的微生物群落组装过程。使用时空替代方法，我们评估了细菌根系定殖模式是否符合两步模型，并测试了群落组装是更多地由确定性过程还是随机过程驱动。我们的结果表明，两步选择过程塑造了这些自然种群中细菌的招募动态，并且我们提供了明确的证据，即宿主植物通过确定性压力影响微生物组装，这些压力在根内圈产生强烈的群落趋同。这些发现突出了宿主筛选在塑造保守的“核心”根内圈微生物组中的核心作用。然而，对这些根内圈群落的有限了解限制了利用这些重要关系的努力，例如改善植物繁殖和植被恢复实践。
