Avirulence protein. Acts as a transcription factor in rice, inducing expression of a number of host genes including SWEET11 (Os8N3, XA13, AC Q6YZF3) in susceptible plants with the Xa13 allele. Plants with the xa13 allele, which has an altered promoter, are resistant to bacterial blight caused by this bacterial strain and do not induce SWEET11. The xa13 allele elicits an atypical hypersensitive response (HR). PthXo1 binds SWEET11 promoter DNA in a sequence-specific manner. Secreted via a type III secretions system (TTSS). Localizes to the plant cell nucleus. The central DNA-binding region is composed of 23.5 tandem core repeats with 1 base-specifying residue (BSR residue 13, also called the repeat variable diresidue, RVD, residues 12 and 13) each of which recognizes 1 base in the target DNA. The BSR is the only residue which contacts DNA in a sequence-specific manner. Reduced virulence in susceptible rice; its introduction into a deletion mutant restores virulence to the bacteria in rice plants. No longer induces SWEET11 (Os8N3, XA13, AC Q6YZF3). By combining the central DNA-binding domain with the catalytic domain of the restriction endonuclease FokI, TALE-nuclease (TALEN) enzymes able to target specific dsDNA sequences can be created that enable eukaryotic genome modification. Other potential uses as transcriptional repressors, for transposon targeting, DNA methylation or histone tail modifictions are also possible. Belongs to the transcription activator-like effector (TALE) family.