Fig. 4.

Targeted mutation of the Xa13 promoter to enhance resistance to bacterial blight. a Homozygous mutagenesis in the Xa13 promoter of four T1 lines selected for resistance evaluation. b Leaves of WT and mutant lines at heading stage showing resistance or susceptibility to bacterial blight at the heading stage. Leaves were detached from the inoculated plants at 14 dpi for photography. c Lesion area of wild type and mutant lines 14 days after inoculation. WT, wild type; Mock, without pathogen. The asterisk (**) indicates that a significant difference (P < 0.01, Student’s t test) was detected between mutant lines and wild-type plants. d Expression of the Xa13 (DQ421395.1) gene determined by RT-PCR in the leaves of wild-type and mutant lines 72 h after PXO99 infection. The OsActin gene (AY212324) was used as an internal control. e Morphology of wild-type and mutant lines. The gel images in (d) were cropped; the original gel images are shown in Supplementary Fig. 1