Yan Bingfa, Liu Ning, Liu Minghao, Du Xueyuan, Shang Fei, Huang Ying
State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China.
College of Life Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China.
Environ Microbiol. 2021 Aug;23(8):4126-4140. doi: 10.1111/1462-2920.15483. Epub 2021 Jul 3.
Actinobacteria produce a variety of secondary metabolites that can influence the survival or behaviour of other organisms. The understanding of the ecological roles of actinobacteria has significantly improved in the past decades, but a systematic insight into the interactions between actinobacteria and other microbes in nature is warranted. Here, we studied the pairwise effects of actinobacteria on other microbes isolated from red soils under different nutritional conditions. We found that neutral effects dominated the interactions, accounting for 68.1% of the interactions in eutrophic conditions and for a significantly higher proportion (86.2%) in oligotrophic conditions. High nutrient levels boosted active metabolism of actinobacteria and generally made them more aggressive, supporting the stress gradient hypothesis. The secondary metabolites produced by actinobacteria played a pivotal role in interference competition with other microbes, of which the role of desferrioxamine siderophores could not be ignored. Niche overlap seemed to be another cause of competition, notably under oligotrophic conditions. Moreover, the large-scale phylogeny had a much greater impact on the interaction than the location origin of the microbes. These results provide an understanding of the coexistence of actinobacteria with other microbes in nature and suggest neutrality as a key mechanism for maintaining microbial diversity in soils.
放线菌产生多种次生代谢产物，这些产物会影响其他生物体的生存或行为。在过去几十年中，人们对放线菌生态作用的理解有了显著提升，但仍有必要对放线菌与自然界中其他微生物之间的相互作用进行系统深入的了解。在此，我们研究了在不同营养条件下，放线菌对从红壤中分离出的其他微生物的成对效应。我们发现中性效应在相互作用中占主导地位，在富营养条件下占相互作用的68.1%，在贫营养条件下占比显著更高（86.2%）。高营养水平促进了放线菌的活跃代谢，总体上使它们更具攻击性，这支持了胁迫梯度假说。放线菌产生的次生代谢产物在与其他微生物的干扰竞争中起关键作用，其中去铁胺铁载体的作用不可忽视。生态位重叠似乎是竞争的另一个原因，特别是在贫营养条件下。此外，大规模系统发育对相互作用的影响比微生物的地理位置起源大得多。这些结果有助于理解放线菌与自然界中其他微生物的共存，并表明中性是维持土壤微生物多样性的关键机制。
