Addendum to: Nature online 8 June 2022

By analyses of potato pan-genome and transcriptome, we discovered a TCP transcription factor, Soltu.DM.06G025210, determining tuber identity, on the basis of which we named this gene Identity of Tuber 1 (IT1).

After our manuscript was accepted in principle, a study by Nicolas et al.1 showed that BRANCHED1b acts as a tuberization repressor in aerial axillary buds in tetraploid potato. We note that IT1 and BRANCHED1b are the same gene. The name BRANCHED1b represents the A. thaliana nomenclature system2. We chose the name IT1 because the function of Soltu.DM.06G025210 in potato had not been reported before and our study suggests that it acts as a key regulator in potato tuberization, a new function that is different from its orthologue in tomato and Arabidopsis where it represses branching. Considering the difference in the function, we proposed the new name IT1 for Soltu.DM.06G025210.

Both studies confirmed that IT1/BRANCHED1b interacts with the mobile tuberization inductive signal SP6A and plays an essential role in tuberization. Further investigation is awaited into how the same gene promotes tuberization in underground shoots (stolons) and represses tuberization in aerial axillary buds