The protein modifier SUMO is critical for integrity of the Arabidopsis shoot apex at warm ambient temperatures.

SUMO is a protein modification whose conjugate levels peak during acute heat stress. We find that SUMO is also critical for plant longevity when Arabidopsis experiences a prolonged non-damaging period of only 28 degrees Celsius. Remarkably, this thermo-lethality at 28 degrees was not seen with any other mutant of the SUMO pathway tested.

The Arabidopsis SUMO E3 ligase SIZ1 mediates the temperature dependent trade-off between plant immunity and growth.

Increased ambient temperature is inhibitory to plant immunity including auto-immunity. SNC1-dependent auto-immunity is, for example, fully suppressed at 28°C. We found that the Arabidopsis sumoylation mutant siz1 displays SNC1-dependent auto-immunity at 22°C but also at 28°C, which was EDS1 dependent at both temperatures.

Arabidopsis TCP Transcription Factors Interact with the SUMO Conjugating Machinery in Nuclear Foci.

In Arabidopsis more than 400 proteins have been identified as SUMO targets, both and . Among others, transcription factors (TFs) are common targets for SUMO conjugation. Here we aimed to exhaustively screen for TFs that interact with the SUMO machinery using an arrayed yeast two-hybrid library containing more than 1,100 TFs.

Genetic characterization of T-DNA insertions in the genome of the Arabidopsis thaliana sumo1/2 knock-down line.

Sumoylation is an essential post-translational modification in Arabidopsis thaliana, which entails the conjugation of the SUMO protein onto lysine residues in target proteins. In Arabidopsis, 2 closely related genes, SUMO1 and SUMO2, act redundantly and are in combination essential for plant development, i.e.

Whole-genome duplications followed by tandem duplications drive diversification of the protein modifier SUMO in Angiosperms.

The ubiquitin-like modifier (UBL) SUMO (Small Ubiquitin-Like Modifier) regulates protein function. Structural rather than sequence homology typifies UBL families. However, individual UBL types, such as SUMO, show remarkable sequence conservation.