OsDMI3‐mediated OsUXS3 phosphorylation improves oxidative stress tolerance by modulating OsCATB protein abundance in rice

Abstract

Calcium (Ca 2+ )/calmodulin (CaM)-dependent protein kinase (CCaMK) is an important positive regulator of antioxidant defenses and tolerance against oxidative stress. However, the underlying molecular mechanisms are largely unknown. Here, we report that the rice (Oryza sativa) CCaMK (OsDMI3) physically interacts with and phosphorylates OsUXS3, a cytosol-localized UDP-xylose synthase. Genetic and biochemical evidence demonstrated that OsUXS3 acts downstream of OsDMI3 to enhance the oxidative stress tolerance conferred by higher catalase (CAT) activity. Indeed, OsUXS3 interacted with CAT isozyme B (OsCATB), and this interaction was required to increase OsCATB protein abundance under oxidative stress conditions. Furthermore, we showed that OsDMI3 phosphorylates OsUXS3 on residue Ser-245, thereby further promoting the interaction between OsUXS3 and OsCATB. Our results indicate that OsDMI3 promotes the association of OsUXS3 with OsCATB to enhance CAT activity under oxidative stress. These findings reveal OsUXS3 as a direct target of OsDMI3 and demonstrate its involvement in antioxidant defense.

SlMPK1‐ and SlMPK2‐mediated SlBBX17 phosphorylation positively regulates CBF‐dependent cold tolerance in tomato

“…For instance, AtOST1 phosphorylates AtBTF3 and AtBTF3L and facilitates their interaction with AtCBFs to positively regulate plant cold tolerance (Y. L. Ding et al ., 2018). In another case, OsDMI3‐mediated phosphorylation of OsUXS3 enhances its interaction with OsCATB, thereby improving oxidative stress tolerance in rice (Ni et al ., 2022). These results showed that kinases could affect the interaction between the protein substrates and their interactive partners, thereby modulating a set of downstream pathway components, which is consistent with our results.…”

The Class III peroxidase OsPrx20 is a key regulator of stress response and growth in rice

“…Coincidentally, unlike OsDMI3 phosphorylation of OsRbohB that promotes H 2 O 2 production to amplify ROS signaling, phosphorylation of OsPrx20 directly enhanced its activity to promote the scavenging of intracellular ROS (Fig. 5H) , which was somewhat analogous to the phosphorylation of OsUXS3 by activated-OsDMI3 to enhance OsCATB activity and thereby scavenging ROS (Ni et al, 2022) , but more directly. Remarkably, ABA produced under stress conditions enhanced response to abiotic stress, but it also inhibits growth and development.…”

“…Previous studies have shown that OsDMI3 can phosphorylate multiple substrates, including OsMKK1, OsUXS3, and OsRbohB (Chen et al, 2021; Ni et al, 2022; Wang et al, 2023) . To determine whether OsPrx20 is a phosphorylated substrate of OsDMI3, recombinant OsPrx20-His fragment was incubated with OsDMI3-GST.…”

“…On the other hand, activated-OsDMI3 activates the OsMKK1-OsMPK1 cascade pathway by phosphorylating OsMKK1, which transmits signals downstream to scavenge the excess ROS by activating the antioxidant defense system under stress (Chen et al, 2021) . Moreover, activated-OsDMI3 indirectly promotes the interaction between OsUXS3 and OsCATB to scavenge H 2 O 2 by mediating the phosphorylation of OsUXS3, enhancing the CAT activity and thereby scavenging H 2 O 2 to improve oxidative stress tolerance in rice (Ni et al, 2022) . However, redox is a dynamic equilibrium process.…”

Allelic variation of TaWD40-4B.1 contributes to drought tolerance by modulating catalase activity in wheat

“…The transcriptional regulation of the activities of scavenging enzymes during the response to abiotic stress has been widely investigated [20][21][22][23] , but the modulatory scenario at the post-transcriptional level is still not well addressed in plants. It has been found that catalase, the important H 2 O 2 scavenger, can be regulated by interacting with chaperones such as AtNCA1, AtLSD1, small heat shock protein AtHsp17.6CII, natriuretic peptide AtPNP-A in Arabidopsis, and ROD1, NCA1 isoforms, UDPxylose synthase OsUXS3 and SRL10 in rice, and Alpha-momorcharin (αMMC) in Momordica charantia [24][25][26][27][28][29][30][31][32] , and through post-translational modifications such as phosphorylation by OsSTRK1, AtCPK8 and AtSOS2 and ubiquitination by OsAPIP6 [33][34][35][36] in the response to abiotic and biotic stresses. The activity of catalase can also be directly modulated by the effectors such as AvrPiz-t, CMV2b, and triple gene block protein 1 (TGBp1) from pathogens 24,[37][38][39] .…”