Root and rhizosphere microbiome of Saskatchewan crops

Root associated bacteria are an important component of the plant-microbiome and influence growth and productivity of crops in agricultural ecosystems. Because of the potential benefits of bacteria for sustainable agriculture, it is important to investigate their diversity in different plant species and how edaphic factors influence this relationship. This study assessed bacterial communities associated with the rhizosphere and root interior of canola (Brassica napus L.), wheat (Triticum aestivum L.), lentil (Lens culinaris L.) and field pea (Pisum sativum L.) grown at four agricultural fields in Saskatchewan. High throughput sequencing of 16S rRNA amplicons from bacterial communities suggested a selection of root endophytic bacteriafrom the rhizosphere. Proteobacteria, Actinobacteria and Bacteroidetes were the dominant phyla in the root interior, whereas Gemmatimonadetes and Firmicutes were only present in the rhizosphere soil. The genera Pseudomonas and Stenotrophomonas were predominant in the rhizosphere and root interior of all crops, suggesting a generalist distribution of these bacteria. However, other genera including Xanthomonas, Arthrobacter, Streptomyces, Acinetobacter, Variovorax and Rhizobium were dominant in the root interior of specific crops.

根系相关细菌是植物微生物组（plant-microbiome）的重要组成部分，可显著影响农业生态系统中作物的生长与生产性能。鉴于细菌对可持续农业的潜在应用价值，探究不同植物物种中根系相关细菌的多样性，以及土壤因子如何调控该菌群与植物的互作关系，具有重要的研究意义。本研究针对萨斯喀彻温省4处农田种植的油菜（Brassica napus L.）、普通小麦（Triticum aestivum L.）、小扁豆（Lens culinaris L.）及大田豌豆（Pisum sativum L.）的根际与根内细菌群落展开分析。通过对细菌群落的16S rRNA扩增子进行高通量测序（high-throughput sequencing），结果表明根内生细菌（root endophytic bacteria）主要由根际菌群筛选而来。变形菌门（Proteobacteria）、放线菌门（Actinobacteria）与拟杆菌门（Bacteroidetes）为根内的优势菌门，而芽单胞菌门（Gemmatimonadetes）和厚壁菌门（Firmicutes）仅存在于根际土壤中。假单胞菌属（Pseudomonas）与寡养单胞菌属（Stenotrophomonas）在所有供试作物的根际与根内均为优势菌属，提示这类细菌具有泛宿主分布的特性。然而，黄单胞菌属（Xanthomonas）、节杆菌属（Arthrobacter）、链霉菌属（Streptomyces）、不动杆菌属（Acinetobacter）、贪铜菌属（Variovorax）及根瘤菌属（Rhizobium）等其他菌属，仅在特定作物的根内占据优势地位。