The Bacterial Composition within the Sarracenia purpurea Model System: Local Scale Differences and the Relationship with the Other Members of the Food Web

Abstract

The leaves of the carnivorous pitcher plant, Sarracenia purpurea, contain a microscopic aquatic food web that is considered a model system in ecological research. The species identity of the intermediate and top trophic level of this food web, as well the detritivore midge, are highly similar across the native geographic range of S. purpurea and, in some cases, appear to have co-evolved with the plant. However, until recently, the identity, geographic variation, and diversity of the bacteria in the bottom trophic level of this food web have remained largely unknown. This study investigated bacterial community composition inside the leaves of S. purpurea to address: 1) variation in bacterial communities at the beginning of succession at the local scale in different areas of the plant’s native geographic range (southern and mid-regional sites) and 2) the impacts of bacterial consumers and other members of the aquatic food web (i.e., insects) on bacterial community structure. Communities from six leaves (one leaf per plant) from New York and Florida study sites were analyzed using 16S ribosomal RNA gene cloning. Each pitcher within each site had a distinct community; however, there was more overlap in bacterial composition within each site than when communities were compared across sites. In contrast, the identity of protozoans and metazoans in this community were similar in species identity both within a site and between the two sites, but abundances differed. Our results indicate that, at least during the beginning of succession, there is no strong selection for bacterial taxa and that there is no core group of bacteria required by the plant to start the decomposition of trapped insects. Co-evolution between the plant and bacteria appears to not have occurred as it has for other members of this community.

Aquitalea pelogenes sp. nov., isolated from mineral peloid

“…The culture-independent techniques allowed determination of members (or representatives, strains, isolates) of the genus Aquitalea sp. as the minor part of microbial communities associated with the traps and leaves of carnivorous plants (Caravieri et al, 2014;Gray et al, 2012). Members of the genus Aquitalea represent common resident bacterial flora of frog skin (Roth et al, 2013) and were isolated from freshwater lake sediments (Weber et al, 2009), activated sludge acquired from local municipal wastewater treatment plant (Adav et al, 2010) and from tropical forest soils as the most active cellulose degraders (Woo et al, 2014).…”

DNA metabarcoding reveals changes in the contents of carnivorous plants along an elevation gradient

“…A final possible source of Dipteran DNA could be from the pollinators of S. purpurea (Jürgens, Sciligo, Witt, El‐Sayed, & Suckling, ), as it is possible that our metabarcoding approach detects Dipteran DNA which has been transferred during these visits. Although the particular inquiline and prey species differ between native and allochthonous populations, invertebrate functional groups may be important biological predictors of pitcher plant range, as inquiline successional stages are thought to be similar in pattern (Gray, Akob, Green, & Kostka, ; Zander et al., ).…”

Predator trait evolution alters prey community composition

“…Initial work suggests that the abundance and composition of the bacterial community can vary greatly among and within sampling locations (Gray et al. ) and is driven largely by leaf age (Miller and terHorst ). The bacterial community composition is not correlated with that of bacterial communities from the surrounding soil (Koopman et al.…”

“…In contrast to the insect larvae and protists, the bacterial communities at the base of the inquiline food web in pitcher plants have been explored relatively little. Initial work suggests that the abundance and composition of the bacterial community can vary greatly among and within sampling locations (Gray et al 2012) and is driven largely by leaf age (Miller and terHorst 2012). The bacterial community composition is not correlated with that of bacterial communities from the surrounding soil (Koopman et al 2010) or adjacent pitchers (Peterson et al 2008).…”