Llimós Miquel, Segarra Guillem, Sancho-Adamson Marc, Trillas M Isabel, Romanyà Joan
Section Environmental Health and Soil Science, Department of Biology, Health and Environment, Faculty of Pharmacy and Food Sciences, Universitat de Barcelona, Barcelona, Spain.
Section Plant Physiology, Department of Evolutionary Biology, Ecology and Environmental Sciences, Faculty of Biology, Universitat de Barcelona, Barcelona, Spain.
Front Microbiol. 2021 Jun 1;12:653027. doi: 10.3389/fmicb.2021.653027. eCollection 2021.
Plant communities and fertilization may have an impact on soil microbiome. Most commercial olive trees are minerally fertilized, while this practice is being replaced by the use of organic amendments. Organic amendments can both fertilize and promote plant growth-promoting organisms. Our aims were (i) to describe the changes in soil bacterial and fungal communities induced by the presence of young olive trees and their interaction with organic amendments and (ii) to compare the effects of mineral and organic fertilization. We set up two parallel experiments in pots using a previously homogenized soil collected from a commercial olive orchard: in the first one, we grew olive saplings in unamended and organically amended soils with two distinct composts and compared these two soils incubated without a plant, while in the second experiment, we comparatively tested the effects of organic and mineral fertilization. OTUs and the relative abundances of bacterial and fungal genera and phyla were analyzed by 16S rRNA and ITS1 gene amplicon using high-throughput sequencing. Basal respiration and substrate-induced respiration were measured by MicroResp. The effects of the different treatments were analyzed in all phyla and in the 100 most abundant genera. The presence of olive saplings increased substrate-induced respiration and bacterial and fungal richness and diversity. Organic amendments greatly affected both bacterial and fungal phyla and increased bacterial richness while not affecting fungal richness. Mineral fertilization increased the relative abundance of the less metabolically active bacterial phyla (Actinobacteria and Firmicutes), while it reduced the most metabolically active phylum, Bacteroidetes. Mineral fertilization increased the relative abundance of three N-fixing Actinobacteria genera, while organic fertilization only increased one genus of Proteobacteria. In organically and minerally fertilized soils, high basal respiration rates were associated with low fungal diversity. Basidiomycota and Chytridiomycota relative abundances positively correlated with basal respiration and substrate-induced respiration, while Ascomycota correlated negatively. Indeed, the Ascomycota phyla comprised most of the fungal genera decreased by organic amendments. The symbiotrophic phylum Glomeromycota did not correlate with any of the C sources. The relative abundance of this phylum was promoted by the presence of plants but decreased when amending soils with composts.
植物群落和施肥可能会对土壤微生物群落产生影响。大多数商业化橄榄树施用矿物肥料，而这种做法正逐渐被使用有机改良剂所取代。有机改良剂既能施肥又能促进植物促生长生物。我们的目标是：（i）描述幼龄橄榄树的存在及其与有机改良剂的相互作用所引起的土壤细菌和真菌群落变化；（ii）比较矿物施肥和有机施肥的效果。我们使用从商业橄榄园采集的预先均质化土壤在花盆中进行了两个平行实验：在第一个实验中，我们将橄榄树苗种植在未改良和用两种不同堆肥进行有机改良的土壤中，并将这两种土壤与无植物培养的土壤进行比较，而在第二个实验中，我们比较测试了有机施肥和矿物施肥的效果。使用高通量测序通过16S rRNA和ITS1基因扩增子分析OTU以及细菌和真菌属及门的相对丰度。通过MicroResp测量基础呼吸和底物诱导呼吸。在所有门和100个最丰富的属中分析了不同处理的效果。橄榄树苗的存在增加了底物诱导呼吸以及细菌和真菌的丰富度和多样性。有机改良剂对细菌和真菌门都有很大影响，增加了细菌丰富度但不影响真菌丰富度。矿物施肥增加了代谢活性较低的细菌门（放线菌门和厚壁菌门）的相对丰度，而降低了代谢活性最高的门——拟杆菌门的相对丰度。矿物施肥增加了三个固氮放线菌属的相对丰度，而有机施肥仅增加了一个变形菌属。在有机施肥和矿物施肥的土壤中，高基础呼吸速率与低真菌多样性相关。担子菌门和壶菌门的相对丰度与基础呼吸和底物诱导呼吸呈正相关，而子囊菌门呈负相关。实际上，子囊菌门包含了大多数因有机改良剂而减少的真菌属。共生营养门球囊菌门与任何碳源均无相关性。该门的相对丰度因植物的存在而增加，但在用堆肥改良土壤时会降低。
