Quantitative Phosphoproteomics Reveals Targets of Protein Kinase SnRK1 in Arabidopsis under Submergence

ABSTRACT: SNF1 RELATED PROTEIN KINASE 1 (SnRK1) is proposed as a central integrator of regulatory pathways in plant stress and energy starvation signaling. We observed in this study that the Arabidopsis SnRK1.1 dominant negative mutant (SnRK1.1K48M) had lower tolerance to submergence than the wild-type, suggesting that SnRK1.1-dependent phosphorylation of target proteins is important in energy starvation signaling triggered by submergence. To gain further insight into submergence signaling mechanisms, we determined the temporal response to energy starvation through AMP/ATP quantification and used quantitative phosphoproteomics to compare the global changes in phosphopeptides in Col-0 and SnRK1.1K48M. We found that the phosphorylation levels of 59 peptides increased and the levels of 96 peptides decreased in Col-0 within 0.5–3 h of submergence. Among the 59 peptides with increased phosphorylation in Col-0, 49 did not show increased phosphorylation levels in SnRK1.1K48M under submergence. These proteins are involved in sugar synthesis, glycolysis, osmotic regulation, ABA signaling, protein synthesis and ROS signaling. In particular, the phosphorylation of MAPK6, which is involved in regulating ROS responses under different abiotic stresses, was disrupted in the SnRK1.1K48M mutant. In addition, PTP1, a negative regulator of MAPK6 activity that directly dephosphorylates MAPK6, was also regulated by SnRK1.1. These results reveal insights into the function of SnRK1 and the downstream signaling factors of submergence.

INSTRUMENT(S): LTQ Orbitrap Elite

ORGANISM(S): Arabidopsis Thaliana (mouse-ear Cress)

TISSUE(S): Plant Cell, Whole Body

SUBMITTER: Hsing Yi Cho  

LAB HEAD: Ming Che Shih

PROVIDER: PXD001815 | Pride | 2016-04-07

REPOSITORIES: Pride