Abstract:

In agroecosystems, microorganisms have rich, diverse, and complex ecological functions, so-called emergent properties, which refer to novel characteristics that emerge in complicated systems as their complexity increases. Interestingly, although emergent functions originate from the joint action of multiple species, the number of species required for triggering such a phenomenon is not so large, typically less than ten. This not only provides the possibility of using synthetic bacterial communities (SynComs) to explore the generation of emergent functions, but also makes it possible to use SynComs to modify the symbiotic microbiota of plant hosts. Seed microbiome, which consists of the earliest microbial residents of a plant, has much simpler community structures compared with either rhizosphere or phyllosphere microbiome. Considering the priority effect, however, it is believed that the seed microbiome plays an important role in the evolution and assembly of plant symbiotic microbial communities, which is currently overlooked. Under particular conditions, even if the members of the seed microbiome have become rare species or disappeared in the later stage, they may still affect the development of plant symbiotic microbiome with legacy effect. Notably, limited by the dry and oligotrophic microhabitat conditions, biofilms should be the main morphology for the microbes existing on the surface of and inside seeds. Applying functional synthetic microbial communities as the seed coatings or biofilms may be the most effective intervention strategy for plant microbiome manipulations, as it targets the most critical period of the early development of plant-associated microbiota. In the context of smart agriculture, the integration of seed chip technologies and drone intelligent platforms could facilitate the high-throughput field characterization and application of SynComs, enabling the discovery of functional SynComs with specific emergent properties that work with plant seeds. Therefore, the application of synthetic bacterial biofilms, or coatings, provides a feasible approach, and is expected to bring breakthrough for the development of microbe-crop breeding technology.

Key words: plant-microbiome interaction, seed microbiome, synthetic community, emergent property

摘要：

在农业生态系统中，微生物具有丰富多样的复杂生态学功能，这些功能的产生具有涌现性。所谓涌现性，指的是复杂系统中随着系统复杂性增加产生的新特性。有趣的是，虽然涌现性功能源于多物种的共同作用，但是所需物种数量通常较少。这不但为利用合成菌群探究涌现性功能的产生提供了可能，而且还为应用合成菌群改造植物菌群提供了抓手。种子菌群作为植物最早的微生物群落，其所包含的微生物具有多样性相对较低的特点。但是，其在植物共生菌群的演化过程中却具有重要作用。此外，受限于种子干燥、贫营养的微生境条件，生物膜是微生物在种子表面和内部存在的主要形式。因此，本文提出以有涌现性功能的合成微生物群落为种子包衣，或可成为在植物微生物组调控中最关键时间节点、最易于开展阶段的有效干预途径。在此基础上，分别从宿主和菌群角度介绍了调控种子菌群涌现性功能的潜在因素。在智慧农业的场景下，通过与种子芯片技术、无人智能化平台的结合，或可在农田中实现合成菌群的大规模施用和功能动态实时监测，为发掘具有特定功能的合成微生物群落、开展基于种子合成菌群生物膜包衣的应用提供可行途径，进而有望为微生物-作物联合育种技术的发展带来重大变革。

关键词: 植物-微生物互作, 种子菌群, 生物膜, 合成微生物群落, 涌现性