(A and B) Knock down of TOR kinase expression abolishes alternative splicing changes induced by light in roots. RNAi TOR, transgenic line expressing an RNAi against TOR kinase mRNA. WT, wild-type seedlings. Splicing indexes for At-RS31 in response to light/dark are shown for leaves (A) and roots (B).
(C and D) TOR kinase activity is necessary for light-mediated alternative splicing response in roots. TOR kinase inhibitor, AZD-8055 (AZD), was used during the light/dark treatment. Splicing indexes for At-RS31 in response to light/dark are shown for leaves (C) and roots (D). Dimethyl sulfoxide was used as a vehicle (Ctrl).
(E and F) The TOR kinase pathway is activated by light and sugars. Upper panels, western blot images of RPS6 phosphorylation (RPS6-P) and total RPS6 levels in light/dark treated seedlings with exogenous sucrose (Suc, 100 mM) in leaves (E) and roots (F). Bottom graphs, splicing indexes in leaves (E) and roots (F) corresponding to the samples in the upper panels. Sorbitol (Sor, 100 mM) was used as osmotic control. (A-F) Lighter bars, light; darker bars, darkness. Graphs show means ± standard errors (n = 4). The same letters indicate means that are not statistically different (p > 0.05).