  In this paper we study aspects of geometries in Type IIA and Type IIB String
theory and elaborate on their field theory dual pairs. The backgrounds are
associated with reductions to Type IIA of solutions with $G_2$ holonomy in
eleven dimensions. We classify these backgrounds according to their
G-structure, perform a non-Abelian T-duality on them and find new Type IIB
configurations presenting {\it dynamical} $SU(2)$-structure. We study some
aspects of the associated field theories defined by these new backgrounds.
Various technical details are clearly spelled out.
