title: Dry Season Constrains Bacterial Phylogenetic Diversity in a Semi-Arid Rhizosphere System.
abstract: The rhizosphere is viewed as a deterministic environment led by the interaction between plants and microorganisms. In the case of semi-arid plants, this interaction is strengthened by the harshness of the environment. We tested the hypothesis that dry season represents a constraint on the bacterial diversity of the rhizosphere from semi-arid plants. To accomplish this, we sampled two leguminous species at five locations during the dry and rainy seasons in the Caatinga biome and characterised bacterial community structures using qPCR and 16S rRNA sequencing. We found that the main differences between seasons were due to reduced phylogenetic diversity caused by dryness. Variation partitioning indicated that environmental characteristics significant impacts in β-diversity. Additionally, distance decay relationship and taxa area relationship indicate a higher spatial turnover at the rainy season. During the dry season, decreased bacterial abundance is likely due to the selection of resistant or resilient microorganisms; with the return of the rain, the sensitive populations start to colonise the rhizosphere by a process that is strongly influenced by environmental characteristics. Thus, we propose that the reduction of PD and strong influence of environmental parameters on the assemblage of these communities make them prone to functional losses caused by climatic disturbances.
authors: Laboratory of Environmental Microbiology, Embrapa Environment, Brazilian Agricultural Research Corporation-EMBRAPA, Rodovia SP-340 km 127,5, Jaguariúna, SP, 13820-000, Brazil. rgtaketani@gmail.com.
authors: Rodrigo Gouvêa
authors: RG
authors: Taketani
authors: Laboratory of Environmental Microbiology, Embrapa Environment, Brazilian Agricultural Research Corporation-EMBRAPA, Rodovia SP-340 km 127,5, Jaguariúna, SP, 13820-000, Brazil.
authors: Milena Duarte
authors: MD
authors: Lançoni
authors: Laboratory of Environmental Microbiology, Embrapa Environment, Brazilian Agricultural Research Corporation-EMBRAPA, Rodovia SP-340 km 127,5, Jaguariúna, SP, 13820-000, Brazil.
authors: Vanessa Nessner
authors: VN
authors: Kavamura
authors: Soil Science Department, Escola Superior de Agricultura "Luiz de Queiroz", University of São Paulo, Piracicaba, SP, Brazil.
authors: Ademir
authors: A
authors: Durrer
authors: Soil Science Department, Escola Superior de Agricultura "Luiz de Queiroz", University of São Paulo, Piracicaba, SP, Brazil.
authors: Fernando Dini
authors: FD
authors: Andreote
authors: Laboratory of Environmental Microbiology, Embrapa Environment, Brazilian Agricultural Research Corporation-EMBRAPA, Rodovia SP-340 km 127,5, Jaguariúna, SP, 13820-000, Brazil.
authors: Itamar Soares
authors: IS
authors: Melo
mesh_terms: D001419:Bacteria / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification*; D044822:Biodiversity; D001938:Brazil; D055864:Droughts; D007887:Fabaceae / Q000382:microbiology*; D064307:Microbiota / Q000235:genetics* / Q000502:physiology; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D011891:Rain; D058441:Rhizosphere; D012621:Seasons; D012988:Soil Microbiology
chemical_list: D012336:RNA, Ribosomal, 16S
keywords: 16S rRNA; Caatinga; Drought; Microbiome; Phylogenetic diversity; Rhizosphere; Semi-arid