Euphorbia plant latex is inhabited by diverse microbial communities

Abstract

PREMISE OF THE STUDY: The antimicrobial properties and toxicity of Euphorbia plant latex should make it a hostile environment to microbes. However, when specimens from Euphorbia spp. were propagated in tissue culture, microbial growth was observed routinely, raising the question whether the latex of this diverse plant genus can be a niche for polymicrobial communities. M ETHODS: Latex from a phylogenetically diverse set of E uphorbia species was collected and genomic microbial DNA extracted. Deep sequencing of barcoded amplicons from taxonomically informative gene fragments was used to measure bacterial and fungal species richness, evenness, and composition. KEY RESULTS: Euphorbia latex was found to contain unexpectedly complex bacterial (mean: 44.0 species per sample; 9 plants analyzed) and fungal (mean: 20.9 species per sample; 22 plants analyzed) communities using culture-independent methods. Many of the identiFIed taxa are known plant endophytes, but have not been previously found in latex. C ONCLUSIONS: Our results suggest that E uphorbia plant latex, a putatively hostile antimicrobial environment, unexpectedly supports diverse bacterial and fungal communities. The ecological roles of these microorganisms and potential interactions with their host plants are unknown and warrant further research.