Chen Liying, Bao Han, Yang Jie, Huo Yan, Zhang Jiabin, Fang Rongxiang, Zhang Lili
State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China.
University of the Chinese Academy of Sciences, Beijing, 100049, China.
Microbiome. 2024 Dec 3;12(1):253. doi: 10.1186/s40168-024-01978-8.
Rice cultivation relies on planting grains harboring beneficial microbiota. However, the origination, distribution, and transmission dynamics of grain-borne bacteria remain unclear.
Using rice grain as a model system, this study investigates the primary sources, major niches in seeds, and the dynamics of community acquisition, maintenance, and transmission between generations of grain-borne bacteria. Quantitative PCR and 16S rRNA gene sequencing demonstrate rice grains acquiring bacteria primarily from the external environment during panicle heading and flowering. These bacteria concentrate between the caryopsis and glumes, establishing sizable communities in developing seeds. The dominant taxa included Pantoea, Pseudomonas, and Sphingomonas. Throughout seed development and storage, community structure remains consistent while abundance fluctuates within one order of magnitude. Upon germination under axenic conditions, seed bacteria successfully colonize shoots and roots of offspring seedlings. However, bacteria transmitted solely through internal routes fail to form comparably large communities. Analysis of taxonomic composition uncovers dramatic reshaping from seeds to seedlings, potentially reflecting functional adaptation.
We clarify seed-borne bacterial origination, acquisition timing, seed colonization, intergenerational transmission, and seedling diversification. Our findings provide novel insights into rice seed bacterial dynamics critical for microbiome management. Video Abstract.
水稻种植依赖于播种带有有益微生物群的谷粒。然而，谷粒携带细菌的起源、分布和传播动态仍不清楚。
本研究以水稻谷粒为模型系统，调查了谷粒携带细菌的主要来源、种子中的主要生态位以及群落获得、维持和代际传播的动态。定量PCR和16S rRNA基因测序表明，水稻谷粒在抽穗和开花期间主要从外部环境中获取细菌。这些细菌集中在颖果和颖片之间，在发育中的种子中建立了相当大的群落。优势类群包括泛菌属、假单胞菌属和鞘氨醇单胞菌属。在种子发育和储存过程中，群落结构保持一致，而丰度在一个数量级内波动。在无菌条件下萌发时，种子细菌成功定殖于后代幼苗的地上部和根部。然而，仅通过内部途径传播的细菌未能形成相当大的群落。分类组成分析揭示了从种子到幼苗的显著重塑，这可能反映了功能适应性。
我们阐明了种子携带细菌的起源、获取时间、种子定殖、代际传播和幼苗多样化。我们的研究结果为微生物组管理至关重要的水稻种子细菌动态提供了新的见解。视频摘要。
