$U(1)$ $R$-Symmetry Topological Operators from Branes in Holography

We study $U(1)$ symmetry generators from wrapped branes in Type IIB string theory and M-theory. Specifically, we construct topological defects for the $R$-symmetry in 4d $\mathcal{N}=1$ and 3d $\mathcal{N}=2$ quantum field theories holographically dual to Sasaki-Einstein compactifications. These are studied using a universal consistent truncation to the gravity multiplet in the bulk theory. We furthermore check these constructions by identifying the objects charged under them, and understanding their origin in the bulk theory.