Rhizosphere microbial community of maize and summer annuals

Rhizosphere microbial communities are critically important for plant productivity. There is evidence that plant species and genotypes select distinct rhizosphere communities, however, knowledge of the drivers and extent of this variation remains limited. We grew 11 annual species and 11 maize (Zea mays) inbred lines in replicated monocultures to assess the influence of host phylogeny, growth and nitrogen economy on rhizosphere communities. Growth characteristics, bacterial community composition and potential activity of extracellular enzymes were assayed at anthesis. Microbial community composition and activity shifted markedly between bulk and rhizosphere soil and this effect was modulated by plant species and genotype. Across species rhizosphere beta-diversity was positively correlated with host phylogenetic distance and variation in plant growth characteristics. In particular, longer lifespan, high nitrogen use efficiency and larger seed size were associated with an increase in abundance of Actinobacteria and increased enzyme activity in the rhizosphere. These results indicate that plant evolutionary history and life history strategy influence rhizosphere community composition and activity. These findings can inform efforts to manage rhizosphere communities in agricultural systems via integration of plant phylogenetic and functional diversity.

根际微生物群落对于植物生产力具有至关重要的意义。已有研究表明，植物物种和基因型会选择性地构建独特的根际微生物群落，然而，关于这种变异的驱动因素及其范围的知识仍然有限。我们通过在重复的单一种植体系中培育了11种一年生植物和11个玉米（Zea mays）自交系，以评估宿主系统发育、生长和氮经济对根际微生物群落的影响。在花蕾期，我们对生长特性、细菌群落组成和胞外酶的潜在活性进行了测定。微生物群落组成和活性在土壤整体与根际土壤之间存在显著差异，而这种效应受植物物种和基因型的调节。在物种层面上，根际β多样性与宿主系统发育距离和植物生长特性的变异呈正相关。特别是，较长的生命周期、高氮利用效率和较大的种子尺寸与根际中放线菌丰度的增加和酶活性的提升相关联。这些结果表明，植物的进化历史和生命历史策略影响了根际微生物群落的结构与活性。这些发现可为通过整合植物系统发育和功能多样性来管理农业系统中的根际微生物群落提供指导。