Fig. 5
From: A mutualistic interaction between Streptomyces bacteria, strawberry plants and pollinating bees
S. globisporus SP6C4 dispersed from flower to flower, reduced insect mortality and incidence of gray mold. a Illustration of honeybee transport of SP6C4 from plant to plant. (a): SP6C4 untreated and honeybee access blocked by a cap, (b): flower stamens and carpels inoculated with a suspension (100 μL) of SP6C4 (106 cfu/mL), (c): SP6C4 untreated flower (n = 5, 3 independent experiments). b Population densities of SF7B6 and SP6C4 on flowers and honeybee bodies. Surface bacteria were detached by sonication for 30 mins at 35 kHz. Streptomyces strain was isolated on PDK media amended with hygromycin B (80 µg/mL). SF7B6 and SP6C4 treatments were analyzed by independent two sample t-test, *P < 0.05; inoculated flower: P = 0.9025, honeybee body: P = 0.0212, no inoculated flower: P = 0.7141. Bars represent standard deviation. c Mortality of Bombus impatiens. Entomopathogens (105 cfu/mL) were added with or without SP6C4 (106 cfu/mL) to pollen. Bars with different letters are significantly different according to Duncan’s test and ANOVA (Serratia marcescens: P = 2e−16; Paenibacillus larvae: P = 2e−16). Bars represent standard deviation. d Strain SP6C4 (107 cfu/mL with 0.1% methyl cellulose) was sprayed or e, not sprayed. The bacteria were sprayed by a sprayer (HP-2010, Korea; 1.5 L discharge capacity per min) and gray mold disease incidence was counted in three replicate plots. Length of each block was 15 meters (n = 450 plants per block). For analysis of the microbial community, flower samples were collected from January 2016 (0 week) to March 2016 (10 week). Taxonomy data were converted to Newick format on R (version 3.4.0) script. The converted taxonomic data were visualized with ggtree (version 3.4.11), ggplot2 (version 3.2.0), and agricolae (version 1.2–9) packages. f Botrytis cinerea spores in air collected by a spore trap every other week with BSTM media and the medium was incubated at 28 °C for 5 days to calculate the spore density. Bars represent standard error. b, c, d–f Source data are provided as a Source Data file
