Department of Agroecology, Faculty of Technical Sciences, Aarhus University, 4200 Slagelse, Denmark.
Department of Terrestrial Ecology, University of Copenhagen, 2100 Copenhagen Ø, Denmark.
FEMS Microbiol Ecol. 2023 Aug 22;99(9). doi: 10.1093/femsec/fiad091.
We investigated if activity of the pre-infective juveniles (J2s) of root-knot nematodes is linked to the recruitment of a specific microbiome on the nematode surface and/or to the composition of the surrounding microbiota. For this, we determined the J2 activity (active vs. non-motile, which referred to dead and immobile J2s) upon a 3-day incubation in soil suspensions and studied the composition of bacteria, protists, and fungi present on the nematode surface and in the suspensions using amplicon sequencing of the 16S/18S rRNA genes, and ITS region. We also amended suspensions with Pseudomonas protegens strain CHA0 to study its effects on J2 activity and microbial composition. The J2 activity was suppressed in soil suspensions, but increased when suspensions were amended with P. protegens CHA0. The active and non-motile J2s differed in the composition of surface-attached bacteria, which was altered by the presence of P. protegens CHA0 in the soil suspensions. The bacterial genera Algoriphagus, Pedobacter, and Bdellovibrio were enriched on active J2s and may have protected the J2s against antagonists. The incubation time appeared short for attachment of fungi and protists. Altogether, our study is a step forward in disentangling the complex nematode-microbe interactions in soil for more successful nematode control.
我们研究了根结线虫的预感染幼虫（J2）的活性是否与线虫表面特定微生物组的招募以及/或周围微生物组的组成有关。为此，我们在土壤悬浮液中孵育 3 天后确定了 J2 的活性（活跃与非运动性，即指死亡和不动的 J2），并使用细菌、原生动物和真菌的 16S/18S rRNA 基因和 ITS 区的扩增子测序研究了线虫表面和悬浮液中存在的细菌、原生动物和真菌的组成。我们还向悬浮液中添加了恶臭假单胞菌 CHA0 菌株，以研究其对 J2 活性和微生物组成的影响。J2 在土壤悬浮液中的活性受到抑制，但当用 P. protegens CHA0 处理悬浮液时，活性增加。活跃和非运动性 J2 的表面附着细菌组成不同，而 P. protegens CHA0 的存在改变了这种组成。Algoriphagus、Pedobacter 和 Bdellovibrio 等细菌属在活跃的 J2 上富集，可能保护了 J2 免受拮抗剂的侵害。孵育时间似乎很短，不足以附着真菌和原生动物。总的来说，我们的研究在阐明土壤中复杂的线虫-微生物相互作用方面迈出了一步，有助于更有效地控制线虫。
