Fig. 5: BCG1 triggers plant immunity in wheat.
a Virulence of PH-1 and the indicated overexpression strains were evaluated on wheat heads. Representative images of infected wheat heads were photographed at 14 days post-inoculation (dpi). b Cross-sections of inoculated and adjacent wheat spikelets inoculated with PH-1 and the overexpression strains expressing FgActin-RFP. The samples were taken at 7 dpi. BF, bright field; RFP, red fluorescent protein. c DCFH-DA- (green fluorescent) and DAB- (dark brown color) staining showing ROS (H2O2) accumulation in wheat seedling leaves 48 h post-inoculation (hpi) with PH-1 and the indicated overexpression strains. Bar = 50 μm. d Quantification of H2O2 production in wheat seedling leaves at 48 h post-inoculation (hpi). e Disease resistance of wheat seedling leaves to F. graminearum wild-type PH-1 triggered by indicated proteins. Wheat seedling leaves were pretreated with 1 μM of indicated proteins 24 h before F. graminearum inoculation. Representative images of infected wheat seedling leaves were photographed at 3 dpi. f Comparative transcriptome analysis showing the BCG1-induced differentially expressed genes (DEGs) in wheat seeding leaves. DEGs were defined as log2(BCG1/mock fold change) ≥1.5 or ≤−1.5 and q value < 0.05. The defense-related genes, TaPR1, TaERF113, and TaWRKY28, are highlighted in yellow. g The top 21 gene ontology (GO) categories within biological processes enriched in BCG1-induced genes. Note that genes involved in defense responses and immune system processes were up-regulated upon BCG1 treatment. h Relative expression of defense-related genes in wheat leaves after treatment with 1 μM of indicated recombinant proteins was evaluated by RT-qPCR. TaGAPDH serves as an internal control. i Schematic representation of exogenous spray of indicated proteins on wheat heads in the field (upper panel). The disease index of Fusarium head blight after pretreatment with 1 μM of BCG1 and BCG1E118A proteins in field trials conducted in 2021 and 2022. 1 μM of His protein was used for the untreated control (Mock). In (d, h, i) data presented are the means ± standard deviation (n = 3, biologically independent samples). Statistical significance was assessed using a one-way ANOVA with Fisher’s LSD test (p value < 0.01). Source data are provided as a Source Data file.
