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. 2017 Oct 18;7:13479. doi: 10.1038/s41598-017-14080-x

Figure 3.

Figure 3

Localization of endophyte 3F11 on the surface and inside root hairs of annual ryegrass along with evidence that 3F11 promotes root hair growth. (A–D) Localization of GFP-tagged endophyte 3F11 on the surface of root hairs of annual ryegrass following inoculation onto seeds at (A) 7 days after planting (DAP), (B) 9 DAP, (C) 15 DAP and (D) 16 DAP. Panels (C) and (D) show 3F11 cells colonizing in between layers of root hairs or in between the root hair to rhizosphere interface. (E) Colonies of GFP-3F11 cells on LB agar plates retrieved following surface sterilization and grinding of annual ryegrass roots from GFP-3F11 coated seeds confirming subsurface plant colonization of 3F11 inside roots (endophytic lifestyle). (F–H) Localization of GFP-tagged endophyte 3F11 cells inside annual ryegrass root hairs following germination of 3F11-inoculated seeds, where (G,H) are the corresponding higher magnification images showing (G) root hairs in cross section and (H) longitudinal section. Confocal microscopy was used in conjunction with propidium iodide (red). For panels (A–H), all seeds were germinated on medium containing insoluble rock P as the sole P source. (I–K) Effect of endophyte 3F11 on root hair length of annual ryegrass growing on media containing rock P as the sole P source. Representative pictures of root hairs of annual ryegrass following germination of seeds treated with (I) buffer (no endophyte control) or (J) endophyte 3F11. The scale bar is 0.2 mm. (K) Average root hair length. Thirty root hairs per plant were measured on the longest crown root (top, middle and bottom segments) from 5 plants per treatment. The error bars represent the standard error of the mean (SEM). The asterisk indicates that the mean is significantly different at p = 0.05 from the control. RH indicates root hairs.