Bacterial Community Assemblages Associated with the Phyllosphere, Dermosphere, and Rhizosphere of Tree Species of the Atlantic Forest are Host Taxon Dependent

Abstract

Bacterial communities associated with tree canopies have been shown to be specific to their plant hosts, suggesting that plant species-specific traits may drive the selection of microbial species that comprise their microbiomes. To further examine the degree to which the plant taxa drive the assemblage of bacterial communities in specific plant microenvironments, we evaluated bacterial community structures associated with the phyllosphere, dermosphere, and rhizosphere of seven tree species representing three orders, four families and four genera of plants from a pristine Dense Ombrophilous Atlantic forest in Brazil, using a combination of PCR-DGGE of 16S rRNA genes and clone library sequencing. Results indicated that each plant species selected for distinct bacterial communities in the phyllosphere, dermosphere, and rhizosphere, and that the bacterial community structures are significantly related to the plant taxa, at the species, family, and order levels. Further characterization of the bacterial communities of the phyllosphere and dermosphere of the tree species showed that they were inhabited predominantly by species of Gammaproteobacteria, mostly related to Pseudomonas. In contrast, the rhizosphere bacterial communities showed greater species richness and evenness, and higher frequencies of Alphaproteobacteria and Acidobacteria Gp1. With individual tree species each selecting for their specific microbiomes, these findings greatly increase our estimates of the bacterial species richness in tropical forests and provoke questions concerning the ecological functions of the microbial communities that exist on different plant parts.

Promoting fruit seedling growth by encapsulated microorganisms

“…Lower growth of untreated (control) seedlings when compared to growth in the other treatments was also observed ( Table 2), suggesting that the use of microorganisms promoted the development of caimito seedlings. Thus, it could be inferred that the associations of bacterial communities associated with the rhizosphere of fruit species are hosts dependent on the taxon, that is, on the species itself, as concluded by Lambais et al (2014), who studied the rhizosphere of arboreal species of the Atlantic Forest and showed that the bacterial communities associated to trees were specific to the hosts of plants.…”

Physical Conditions Regulate the Fungal to Bacterial Ratios of a Tropical Suspended Soil

“…The inhabitants of canopy soils depend on the tight cycling of limited resources, facilitated by a decomposer community adapted to the extremes in climate that characterise canopy habitats [6][7][8]. In terrestrial soils, microorganisms are known to drive decomposition [9], yet little is known about the abundance of microorganisms or their role in canopy soils [10][11][12][13]. Recent advances in canopy access have improved our understanding of tropical rain forests but information on canopy microbial communities is lacking [14,15].…”

Redes ecológicas em comunidades bacterianas da filosfera, dermosfera e rizosfera de espécies arbóreas da Mata Atlântica

“…Esses dados sugerem uma associação entre a história evolutiva das árvores e a comunidade microbiana sobre a filosfera (REDFORD et al, 2010;LAMBAIS et al, 2014). Embora a comunidade bacteriana associada à filosfera de diferentes espécies arbóreas seja altamente diversa, no nível de proteoma elas compartilham processos metabólicos essenciais para a colonização e crescimento sobre a superfície da folha, sugerindo alta redundância funcional (LAMBAIS et al, 2016-submetido para publicação).…”

“…Diversos trabalhos desenvolvidos na Mata Atlântica têm avaliado e descrito a composição e estrutura das comunidades microbianas associadas ao solo e filosfera de algumas espécies arbóreas (MONTENEGRO, 2012;LAMBAIS et al, 2014;LIMA-PERIM et al, 2016). No entanto, abordagens que permitam avaliar associações entre micro-organismos e sua importância para a estruturação das comunidades, como redes de co-ocorrência (BARBERAN et al, 2012;BATES et al, 2012) Os resultados mostraram que, nas filosferas das duas espécies de plantas nas diferentes florestas, Gammaproteobacteria e Alphaproteobacteria foram os grupos com maior número de conexões, sugerindo que podem estar associadas com funções centrais na filosfera, como descrito anteriormente por Remus-Emsermann e Vorholt (2015).…”

“…Pouca informação existe sobre a microbiota associada a plantas na floresta, como filosfera e dermosfera, por exemplo. A superfície das plantas abriga uma grande diversidade microbiana, a maior parte ainda não caracterizada (LAMBAIS et al, 2006;ANDRADE, 2007;MONTENEGRO, 2012;BRAGINA 2012;LAMBAIS et al, 2014). Em estudos na Mata Atlântica, tem sido estimado que a filosfera de diferentes espécies arbóreas pode abrigar de 100 e 670 espécies bacterianas, sendo 97% delas não descritas, e que a filosfera coletiva da Mata Atlântica pode conter de 2 a 13 milhões de espécies bacterianas, a maioria ainda não descritas .…”