The microbiome of flowers (anthosphere) is an understudied compartment of the plant microbiome. Within the flower, petals represent a heterogeneous environment for microbes in terms of resources and environmental stress. Yet little is known of drivers of structure and function of the epiphytic microbial community at the within-petal scale. We characterized the petal microbiome in two co-flowering plants that differ in pattern of ultraviolet (UV) absorption along their petals. Bacterial communities were similar between plant hosts, with only rare phylogenetically distant species contributing to differences. The epiphyte community was highly culturable (75% of families) lending confidence to the spatially-explicit isolation and characterization of bacteria. In one host, petals were heterogeneous in UV absorption along their length and in these there was a negative relationship between growth rate and position on the petal, as well as lower UV tolerance in strains isolated from the UV absorbing base than from UV reflecting tip. A similar pattern was not seen in microbes isolated from a second host whose petals had uniform patterning along their length. Across strains, variation in carbon utilization and chemical tolerance followed common phylogenetic patterns. This work highlights the value of petals for spatially-explicit explorations of bacteria of the anthosphere.

For methodological details please consult the paper: Hayes et al. (2020). Spatially-explicit depiction of a floral epiphytic bacterial community reveals role for environmental filtering within petals. MicrobiologyOpen. If there are still doubts, please email Maria Rebolleda-Gomez at <mariarebolleda at gmail dot com>. 

This is a general index of the files in this folder. Each file contains metadata explaining the data contained in that file. If using this data, please cite the data set and the original paper. 

• Biolog Data.csv - This workbook contains data collected from Biolog Microbial Identification plates used in the analysis for Figures A4 and A5.
• Flowerhead_Age.csv - This workbook includes the raw data used to calculate the average longevity of entire flower head (days), number of disc flowers, and number of ray flowers for Helianthus tuberosus and Verbesina alternifolia in Table A1.
• LD50Assay_RawData.csv - The raw data collected from UV tolerance plate assays used in Figure 6. Data is from spot planting at different dilutions and exposing the plates to UV to estimate the surviving CFUs. 
• Raw Growth Curve Output.xlsx - The raw plate reader output for the growth curve assay used to produce Figure 5 (a .csv file formatted for easier analyses is available in https://github.com/mrebolleda/Paper_MicrobialCommunitySpacePetal).
• GC_fit_summary.csv - A summary of the fit of the bacterial strain growth curve data to various models used to produce Figure 5.
• TableS3 - These files contain information on the different bacterial isolates obtained for this study. The table contains the host, color of colonies in LB, resistance to UV (LD50), Vmax, and if it has previously been isolated from other plant organs. 
  • TableS3_Isolates.csv - List of all isolates and their associated data. 
  • TableS3_References.csv - List of references cited for TableS3.
• TableS4_ColonyTraits.csv - Table with colony descriptions of each isolate on LB.