Prof Ari Sadanandom Seminar: Understanding the SUMO code for adaptive responses in plants

He highlighted experimental and computational approaches for studying SUMO-dependent signalling, including tools for detecting SUMOylated proteins, predicting candidate SUMOylation sites, and identifying proteins that interact through SUMO-interacting motifs. He also discussed the expansion and diversification of SUMO proteases in plants, consistent with increasing complexity in SUMO-dependent regulation. A key example was the SUMOylation of ARF7, which regulates root hydropatterning by controlling auxin-response activity and recruitment of the Aux/IAA repressor IAA3, thereby helping position lateral root formation in response to local water availability. The SUMO proteases OTS1/2 are also relevant to this pathway. Ari also described newer work showing that reactive oxygen species/redox signalling can regulate IAA3/SHY2 multimerisation, linking water-stress responses to auxin signalling and lateral root development. Overall, the seminar emphasised how SUMO protease expression, localisation and activity help determine where and when SUMO-dependent regulatory events occur.