Skip to main content
. 2021 May 11;12:2661. doi: 10.1038/s41467-021-22917-3

Fig. 7. FgRbp1 is essential for the formation of fungal penetration structures on wheat.

Fig. 7

a Deletion of FgRbp1 leads to significantly reduced virulence on wheat heads (left panel) and corn silks (right panel). Flowering wheat heads were point-inoculated with the PH-1, ΔFgRbp1, ΔFgRbp1::FgRbp1ΔN-GFP, ΔFgRbp1::FgRbp1ΔRRM-GFP and ΔFgRbp1::FgRbp1-GFP. The infected wheat heads were photographed 14 days post-inoculation (dpi). Infected corn silks were examined 5 dpi. b Cross-sections of inoculated and adjacent wheat spikelets. Spikelets were infected with PH-1 or ΔFgRbp1, each strain bearing FgActin-RFP. The samples were taken at 7 dpi. Inoculated spikelets were indicated with black arrows. BF, bright field; RFP, red fluorescent protein. Bar = 200 µm. c Penetration of the wild type PH-1 and ΔFgRbp1 into cellophane membrane. After removing colonies of PH-1 and ΔFgRbp1 grown over cellophane membranes on MM (Before) for 3d, the plates were incubated for three additional days to examine for hyphal growth (After). d Electronic scanning microscope examination of the penetration structures on wheat glumes. Wheat head spikelets were inoculated with conidia of the wild-type PH-1 or ΔFgRbp1, and sampled after 7 dpi. Penetration structures are marked with yellow arrows. Bar = 5 µm. e Introns of FgSTE12 showed significantly reduced splicing ratio (left panel) in ΔFgRbp1 compared with those in the wild-type PH-1. f Verification of FgRbp1 binding on the mRNA of FgSTE12 by RIP-qPCR. ACTIN served as a control. Error bars represent means ± SD of three repeated experiments. The schematic of FgSTE12 is shown at the top. The black solid line denotes the binding peak identified in RIP-seq. g EMSA confirmation of the direct binding of FgRbp1 to the in vitro transcribed mRNAs containing the peak sequence of FgSTE12. The in vitro transcribed mRNA sequence is identical to f. h The deletion of the CAAGA motif in the peak fragment resulted in the decreased intron splicing ratio of two introns in FgSTE12. The strain FgSTE12-WT contains the CAAGA motif in the peak fragment, while the strain FgSTE12-Mu was deleted with the CAAGA motif. In e and h, bars represent means ± SD (n = 3 biologically independent replicates). Different letters indicate a significant difference (P < 0.05) according to the two-tailed unpaired Student’s t test.