  We study the embedding of spacetime filling D7-branes in beta-deformed
backgrounds which, according to the AdS/CFT dictionary, corresponds to
flavoring beta-deformed N=4 super Yang-Mills. We consider supersymmetric and
more general non-supersymmetric three parameter deformations. The equations of
motion for quadratic fluctuations of a probe D7-brane wrapped on a deformed
three-sphere exhibit a non-trivial coupling between scalar and vector modes
induced by the deformation. Nevertheless, we manage to solve them analytically
and find that the mesonic mass spectrum is discrete, with a mass gap and a
Zeeman-like splitting occurs. Finally we propose the action for the dual field
theory as obtained by star-product deformation of super Yang-Mills with
fundamental matter.
