Final Report Summary - SUMO (Study of the role of protein posttranslational modification by SUMO (Small Ubiquitin-like MOdifier) in abscisic acid signaling and stress responses in plants.)
Modulation of protein activity is crucial for all biological processes, and impairment of this control results in physiological defects that can compromise the viability of the organism. Protein modification by SUMO is a posttranslational regulatory mechanism that is essential and that is also involved in stress responses. In plants, SUMO modulates a wide array of biological processes, including seed development and stress responses, which have a vast agronomical interest. Our goal was to understand the molecular mechanisms of SUMO action that will eventually contribute to develop tools useful for crop improvement. For this purpose we have characterized the biochemical properties of SUMO conjugation machinery members and found key aspects that might regulate SUMO conjugation in vivo. This information could be useful to manipulate the SUMO conjugation capacity of the plant in order to generate plants more tolerant to adverse environmental conditions. In fact, based in this information we have developed a strategy to diminish the plant SUMOylation capacity, which is allowing us to perform more precise studies about SUMO biological role in plants.
We have found that, in addition to the essential function during early stages of seed development, SUMO conjugation has also a major role during seed maturation and early phases of seed germination, suggesting that SUMO could be a key regulator of plant developmental transitions.
Another important aspect that we have addressed is the identification of SUMO targets and SUMO interacting proteins, which are the molecular effectors of the SUMO biological role. We have used two complementary Omic approaches, the biochemical purification of endogenous SUMO conjugates and the combination of yeast two-hybrid screens with massive sequencing. Among the identified candidates, ABA signaling and seed specific proteins were identified, although, as in previous similar reports, a wide range of protein families are represented suggesting that SUMO potentially regulates any single cellular process.
We have found that, in addition to the essential function during early stages of seed development, SUMO conjugation has also a major role during seed maturation and early phases of seed germination, suggesting that SUMO could be a key regulator of plant developmental transitions.
Another important aspect that we have addressed is the identification of SUMO targets and SUMO interacting proteins, which are the molecular effectors of the SUMO biological role. We have used two complementary Omic approaches, the biochemical purification of endogenous SUMO conjugates and the combination of yeast two-hybrid screens with massive sequencing. Among the identified candidates, ABA signaling and seed specific proteins were identified, although, as in previous similar reports, a wide range of protein families are represented suggesting that SUMO potentially regulates any single cellular process.