Relationships between phyllosphere bacterial communities and plant functional traits in a neotropical forest

Abstract

The phyllosphere-the aerial surfaces of plants, including leavesis a ubiquitous global habitat that harbors diverse bacterial communities. Phyllosphere bacterial communities have the potential to influence plant biogeography and ecosystem function through their influence on the fitness and function of their hosts, but the host attributes that drive community assembly in the phyllosphere are poorly understood. In this study we used high-throughput sequencing to quantify bacterial community structure on the leaves of 57 tree species in a neotropical forest in Panama. We tested for relationships between bacterial communities on tree leaves and the functional traits, taxonomy, and phylogeny of their plant hosts. Bacterial communities on tropical tree leaves were diverse; leaves from individual trees were host to more than 400 bacterial taxa. Bacterial communities in the phyllosphere were dominated by a core microbiome of taxa including Actinobacteria, Alpha-, Beta-, and Gammaproteobacteria, and Sphingobacteria. Host attributes including plant taxonomic identity, phylogeny, growth and mortality rates, wood density, leaf mass per area, and leaf nitrogen and phosphorous concentrations were correlated with bacterial community structure on leaves. The relative abundances of several bacterial taxa were correlated with suites of host plant traits related to major axes of plant trait variation, including the leaf economics spectrum and the wood densitygrowth/mortality tradeoff. These correlations between phyllosphere bacterial diversity and host growth, mortality, and function suggest that incorporating information on plant-microbe associations will improve our ability to understand plant functional biogeography and the drivers of variation in plant and ecosystem function.tropical forests | host-microbe associations | plant microbiome | microbial ecology T he phyllosphere-the aerial surfaces of plants-is an important and ubiquitous habitat for bacteria (1). It is estimated that on a global scale, the phyllosphere spans more than 10 8 km 2 and is home to up to 10 26 bacterial cells (2). Bacteria are also important to their plant hosts. Leaf-associated bacteria represent a widespread and ancient symbiosis (3, 4) that can influence host growth and function in many ways, including the production of growth-promoting nutrients and hormones (5, 6) and protection of hosts against pathogen infection (7,8). Phyllosphere bacteria have the potential to influence plant biogeography and ecosystem function through their influence on plant performance under different environmental conditions (9-11), but the drivers of variation in leaf-associated bacterial biodiversity among host plants are not well understood.The ability to quantify microbial community structure in depth with environmental sequencing technologies has led to an increasing focus not only on the ecology of individual microbial taxa but on the entire genomic content of communities of microbes in different habitats, or "microbiomes" (12). Numerous studies of host-associated mi...

Backbones of evolutionary history test biodiversity theory for microbes

“…The relationship between the number of individuals sampled from a community and the expected phylogenetic diversity of this sample plays a crucial and practical role both in understanding how much diversity may be lost from a community as the number of Coarse graining an empirical phyllosphere phylogeny, sampled from leaves of angiosperm species Inga acuminata on Barro Colorado Island (25). Left shows the distribution of branch-length sizes in this tree, in the gray bars-each segment of branch length corresponds to the distance between two nodes in the tree.…”

“…In Fig. 1 we analyze microbial communities sampled from the human gut and skin microbiomes (24), phyllosphere communities sampled on Barro Colorado Island (25), and marine environments at various latitudes drawn from the International Census of Marine Microbes (26). We choose these habitats to provide a broad range of community similarities, so that we can compare communities from two human-associated habitats, nonhuman host-associated communities and a set of non-hostassociated communities.…”

Microbial and Functional Diversity within the Phyllosphere of Espeletia Species in an Andean High-Mountain Ecosystem

“…The Espeletia sp. microbial communities showed the dominance of few bacterial phyla, which also tend to dominate in phyllosphere microbiomes from Arabidopsis thaliana (13), Thlaspi geosingense (45), potato (46), soybean (47), almond drupes (48), and several tree species (18,49), among others (50). In addition to this similarity at the phylum level, Espeletia communities also contained taxa, such as Bacillus, Burkholderia, Methylobacterium, Pseudomonas, Sphingomonas, and Xanthomonas, that are an important fraction of the core community in several plants (7,13,50).…”

“…Microbial production of plant hormones has been reported to promote growth and development (80) and to prevent the entry of plant pathogens by modulating the plant's immune system (57,81). The relation between bacteria and host growth and mortality has been previously described (49), suggesting that microbial communities may indeed be important for plant development. The present study therefore represents a starting point for uncovering possible interactions between microbial communities and Espeletia sp.…”

Phylogenetic Evidence for Ancient and Persistent Environmental Symbiont Reacquisition in Largidae (Hemiptera: Heteroptera)

“…Gut tissue from a subset of 17 taxa was subjected to Illumina amplicon sequencing of an ϳ300-bp fragment of the bacterial 16S rRNA gene using 799F and 1115R primers with barcodes for multiplexing (44), intended to minimize amplification of chloroplast DNA (45); PCR was conducted in triplicate (35 cycles, with annealing at 52°C) with 5Prime HotMasterMix. Triplicate PCR products were pooled and cleaned with the Ultraclean PCR clean-up kit (MoBio, Carlsbad, CA).…”