FIG 5.

Bacterium-plant cocultivation assays and VOC tests on Arabidopsis thaliana Col-0 seedlings. (A) P. luminescens 1° and 2° cells as well as P. simiae WCS417 were spotted at a 5-cm distance from 4-day-old A. thaliana Col-0 seedlings on MS agar plates and cultivated for 8 days at 24°C (plates are shown in panel B, top). The root lengths were measured using ImageJ. Error bars represent standard deviation of at least three independently performed experiments. For the split agar assays (B, bottom), the left side of the MS agar plates contained only the seedlings, while on the right side, the respective bacteria were spotted at the bottom of the plate to test whether VOCs produced by bacteria have an influence on plant root length and development. (C) Phase contrast microscopy of A. thaliana roots colonized with P. luminescens 1° and 2° cells as well as P. simiae WCS417 (positive control). (D) Fluorescence microscopy of A. thaliana roots with attached P. luminescens 1° cells tagged with mTFP and P. luminescens 2° cells tagged with mCherry. All pictures show one representative of at least three independently performed experiments.