Despite the rapid development of microbial inoculants use, their effectiveness still lacks robustness, partly due to our limited understanding of the factors influencing their establishment in soil. Recurrent inoculation can temporarily increase their abundance, but the effect of this inoculation strategy on plant growth and on the resident microbial community is still poorly studied. Here, we investigated maize growth and soil bacterial community responses under recurrent inoculation of the plant-beneficial bacterium Pseudomonas fluorescens B177. We further assessed how the effect of recurrent inoculation was modulated by the inoculant dose, the application timing and the soil type. Recurrent inoculation at high dose transiently increased the abundance of P. fluorescens B177 and resulted in larger shifts in the resident bacterial community compared to a single inoculation event. Moreover, recurrent inoculation prior to sowing had the strongest effect on maize growth, with increased shoot dry weight by 47.4%, likely due to an indirect effect of the inoculant through early changes in the resident community. Altogether these findings highlight the significance of recurrent pre-sowing inoculations as an alternative strategy for promoting plant growth.

尽管微生物接种剂的使用迅速发展，但它们的有效性仍然缺乏稳健性，部分原因是我们对影响它们在土壤中建立的因素的了解有限。反复接种可以暂时增加它们的丰度，但这种接种策略对植物生长和常驻微生物群落的影响仍然研究不足。在这里，我们研究了植物有益细菌荧光假单胞菌 B177 反复接种下的玉米生长和土壤细菌群落反应。我们进一步评估了接种剂剂量、施用时间和土壤类型如何调节循环接种的效果。与单次接种事件相比，高剂量的反复接种瞬时增加了荧光假单胞菌 B177 的丰度，并导致常驻细菌群落发生更大的变化。此外，播种前反复接种对玉米生长的影响最强，芽干重增加了 47.4%，这可能是由于接种剂通过常驻群落的早期变化产生的间接影响。总而言之，这些发现强调了反复播种前接种作为促进植物生长的替代策略的重要性。