  We present and analyze a hybrid quantum system that interfaces a
Majorana-hosted semiconductor nanowire with a single nitrogen-vacancy (NV)
center via a magnetized torsional cantilever. We show that, the torsional mode
of the mechanical resonator can strongly couple to the Majorana qubit and the
spin qubit simultaneously, which allows to interface them for quantum state
conversion through a dark state protocol. This work provides a promising
interface between the topological qubit and the conventional spin qubit, and
can find interesting applications in quantum information and computation.
