Tal2c Activates the Expression of to Promote Infection as a Redundant TALE of Tal2b in pv. .

delivers transcription activator-like effectors (TALEs) into plant cells to facilitate infection. Following economic principles, the redundant TALEs are rarely identified in Xanthomonas. Previously, we identified the Tal2b, which activates the expression of the rice 2-oxoglutarate-dependent dioxygenase gene to promote infection in the highly virulent strain of pv. HGA4. Here, we reveal that another clustered TALE, Tal2c, also functioned as a virulence factor to target rice , a homologue of . Transferring Tal2c into RS105 induced expression of to coincide with increased susceptibility in rice. Overexpressing caused higher susceptibility and less salicylic acid (SA) production compared to wild-type plants. Moreover, CRISPR-Cas9 system-mediated editing of the effector-binding element in the promoters of or was found to specifically enhance resistance to Tal2b- or Tal2c-transferring strains, but had no effect on resistance to either RS105 or HGA4. Furthermore, transcriptome analysis revealed that several reported SA-related and defense-related genes commonly altered expression in overexpression line compared with those identified in overexpression line. Overall, our results reveal a functional redundancy mechanism of pathogenic virulence in Xoc in which tandem Tal2b and Tal2c specifically target homologues of host genes to interfere with rice immunity by reducing SA.