TALE-triggered and iTALE-suppressed Xa1 resistance to bacterial blight is independent of OsTFIIAγ1 or OsTFIIAγ5 in rice.

Xa1-mediated resistance to rice bacterial blight, caused by Xanthomonas oryzae pv. oryzae (Xoo), is triggered by transcription activator-like effectors (TALEs) and suppressed by interfering TALEs (iTALEs). TALEs interact with the rice transcription factor OsTFIIAγ1 or OsTFIIAγ5 (Xa5) to transcriptionally activate expression of target resistance and/or susceptibility genes. However, it is not clear whether OsTFIIAγ is involved in TALE-triggered and iTALE-suppressed Xa1 resistance. In this study, genome-edited mutations in OsTFIIAγ5 or OsTFIIAγ1 of Xa1-containing rice IRBB1 and Xa1-transgenic plants of xa5-containing rice IRBB5 did not impair the activation or suppression of Xa1 resistance. Correspondingly, the expression pattern of Xa1 in mutated OsTFIIAγ5 and OsTFIIAγ1 rice lines and IRBB1 rice was similar. In contrast, the expression of OsSWEET11 was repressed in mutated OsTFIIAγ5 and OsTFIIAγ1 rice lines. Biomolecular fluorescence complementation (BiFC) and co-immunoprecipitation (Co-IP) showed that both the TALE PthXo1 and iTALE Tal3a interacted with OsTFIIAγ1 and OsTFIIAγ5 in plant nuclei. These results indicate that TALE-triggered and iTALE-suppressed Xa1 resistance to BB is independent of OsTFIIAγ1 or OsTFIIAγ5 in rice and suggest that an unknown factor is potentially involved in the interaction of Xa1, TALEs and iTALEs in rice.