Fig. 6

The deletion of FoSSP17 reduced the virulence of Foc4 on banana and triggered host immune responses. a The ‘Cavendish’ bananas were inoculated with the conidia suspensions of different strains. Disease symptoms of plants, rhizomes, and corms infected with wild-type (WT), FoSSP17 mutant (ΔFoSSP17-4 and ΔFoSSP17-5), and complemented (ΔFoSSP17-C8) stains are shown. Photographs were taken 30 dpi. b The disease index was calculated from banana plants infected with indicated Foc strains (30 dpi). c qRT-PCR assay of transcript levels of PR genes (PR1, PR3, PR5 and PR 10). Total RNA was extracted 3 dpi from banana roots infected by WT and FoSSP17 deletion mutants. The banana Actin gene was used as the internal reference gene. Relative expression of PR genes in WT calibrated to the levels of Actin was arbitrarily set to 1. For b, c, data shown are means ± SD calculated from three biological replicates. Statistical analyses were performed with One-way analysis of variance (ANOVA), Tukey’s multiple comparisons test and Student’s t-test. Different letters indicate significant differences (P < 0.05). *P < 0.05; **P < 0.01