Table_1_Domestication Impacts the Wheat-Associated Microbiota and the Rhizosphere Colonization by Seed- and Soil-Originated Microbiomes, Across Different Fields.xlsx

The seed-transmitted microorganisms and the microbiome of the soil in which the plant grows are major drivers of the rhizosphere microbiome, a crucial component of the plant holobiont. The seed-borne microbiome can be even coevolved with the host plant as a result of adaptation and vertical transmission over generations. The reduced genome diversity and crossing events during domestication might have influenced plant traits that are important for root colonization by seed-borne microbes and also rhizosphere recruitment of microbes from the bulk soil. However, the impact of the breeding on seed-transmitted microbiome composition and the plant ability of microbiome selection from the soil remain unknown. Here, we analyzed both endorhiza and rhizosphere microbiome of two couples of genetically related wild and cultivated wheat species (Aegilops tauschii/Triticum aestivum and T. dicoccoides/T. durum) grown in three locations, using 16S rRNA gene and ITS2 metabarcoding, to assess the relative contribution of seed-borne and soil-derived microbes to the assemblage of the rhizosphere microbiome. We found that more bacterial and fungal ASVs are transmitted from seed to the endosphere of all species compared with the rhizosphere, and these transmitted ASVs were species-specific regardless of location. Only in one location, more microbial seed transmission occurred also in the rhizosphere of A. tauschii compared with other species. Concerning soil-derived microbiome, the most distinct microbial genera occurred in the rhizosphere of A. tauschii compared with other species in all locations. The rhizosphere of genetically connected wheat species was enriched with similar taxa, differently between locations. Our results demonstrate that host plant criteria for soil bank’s and seed-originated microbiome recruitment depend on both plants’ genotype and availability of microorganisms in a particular environment. This study also provides indications of coevolution between the host plant and its associated microbiome resulting from the vertical transmission of seed-originated taxa.

种子传播的微生物及其生长土壤的微生物群是根际微生物群的主要驱动力，而根际微生物群是植物全生物体的关键组成部分。由于适应性进化与代际垂直传播，种子携带的微生物群甚至可以与宿主植物共同进化。在驯化过程中基因组多样性的减少以及交配事件可能影响了植物特征，这些特征对于种子携带微生物在根系定殖以及从土壤中招募微生物至根际至关重要。然而，育种对种子传播微生物群组成及植物从土壤中选择微生物的能力的影响尚不清楚。本研究通过分析了两对基因相关的野生和栽培小麦物种（Aegilops tauschii/Triticum aestivum和T. dicoccoides/T. durum）在三个地点的内外根和根际微生物群，采用16S rRNA基因和ITS2宏条形码技术，以评估种子携带微生物和土壤来源微生物对根际微生物群组装的相对贡献。我们发现，与根际相比，更多细菌和真菌的OTU从种子传递到所有物种的根内，且这些传递的OTU在物种上是特定的，不受地理位置影响。仅在其中一个地点，与其它物种相比，A. tauschii的根际中微生物的种子传播更为显著。关于土壤来源的微生物群，与其它物种相比，在所有地点，A. tauschii的根际中出现了最独特的微生物属。不同地点之间，具有基因联系的小麦物种的根际富含相似的类群。我们的研究结果证明，土壤库和种子起源微生物群招募的宿主植物标准既依赖于植物的基因型，也取决于特定环境中微生物的可用性。此外，本研究还提供了宿主植物与其相关微生物群因种子起源类群的垂直传播而共同进化的迹象。