Université de Lorraine, INRAE, LSE, F-54000 Nancy, France.
Université de Lorraine, CNRS, LIEC, F-54000 Nancy, France.
Sci Total Environ. 2023 Aug 20;887:164131. doi: 10.1016/j.scitotenv.2023.164131. Epub 2023 May 13.
The seed microbiota is currently of great interest in the scientific community since seed germination is a critical stage in plant life cycle. Some seed endophytic bacteria could be commonly found in seeds of hyperaccumulating plants and may confer them an evolutionary advantage over non-hyperaccumulating plants when confronted to biotic or abiotic stress. This study focuses on the endophytic bacterial diversity of a wide diversity of metal hyperaccumulating and non-hyperaccumulating plants (93 seed samples from Mediterranean regions, Oceania, South-East Asia) to reveal the core endophyte communities specific of hyperaccumulating plants. The rather low richness of the seed bacterial communities found in all seeds suggest that a sub-population of specialized endophytic strains is able to colonize seeds and survive. The factor that shapes the diversity of those bacterial communities was first the botanical family and secondly the hyperaccumulation trait of the host plants. Based on the taxonomic affiliation, we revealed that the Brassicales had 1349 OTUs that were specific to them and the Asterales 204 OTUs, independently of their metal accumulation strategy. Nonetheless, a set of 12 OTUs were shared by the seeds of all the hyperaccumulators independently of the taxonomic order of the plants (among Asterales and Brassicales) and could be considered as a 'stable' core microbiome. Those OTUs identified as Luteibacter, Alphaproteobacteria unclassified, Sphingopyxis, Alishewanella, bacteria unclassified, Heliimonas, Aeromicrobium, Proteobacteria unclassified, Xanthomonadales unclassified and Micromonosporaceae unclassified may constitute an endophytic bacterial core with PGP traits. Further studies are needed to extend our knowledge of the possible role played by those bacteria.
种子微生物组目前在科学界引起了极大的兴趣，因为种子萌发是植物生命周期中的一个关键阶段。一些种子内生细菌通常可以在超积累植物的种子中发现，并且在面对生物或非生物胁迫时，它们可能会赋予超积累植物相对于非超积累植物的进化优势。本研究关注广泛的金属超积累和非超积累植物（来自地中海地区、大洋洲、东南亚的 93 个种子样本）的内生细菌多样性，以揭示超积累植物特有的核心内生菌群落。所有种子中发现的种子细菌群落的丰富度相当低，这表明能够定植和存活的专门内生菌株的亚种群。首先是植物科，其次是宿主植物的超积累特性，形成了这些细菌群落多样性的因素。基于分类学隶属关系，我们发现 Brassicales 有 1349 个 OTUs 是它们特有的，Asterales 有 204 个 OTUs 是它们特有的，与它们的金属积累策略无关。尽管如此，一组 12 个 OTUs 被所有超积累植物的种子共享，而与植物的分类顺序（在 Asterales 和 Brassicales 之间）无关，可以被认为是一个“稳定”的核心微生物组。被鉴定为黄杆菌属、未分类的α变形菌、鞘氨醇单胞菌属、Alishewanella 属、未分类的细菌、Heliimonas 属、气微菌属、未分类的变形菌门、未分类的黄单胞菌目和未分类的 Micromonosporaceae 的那些 OTUs 可能构成具有 PGP 特性的内生细菌核心。需要进一步的研究来扩展我们对这些细菌可能发挥的作用的认识。
