  Generalized matter couplings to four-dimensional supersymmetric sigma models
on general Kaehler manifolds are presented, preserving all holomorphic
symmetries. Our generalization allows assignment of arbitrary U(1) charges to
additional matter fermions, in all representations of (the holomorphic part of)
the isometry group. This can be used to eliminate unwanted gamma_5 anomalies,
in particular for the U(1) symmetry arising from the complex structure of the
target space. A consistent gauging of this isometry group, or any of its
subgroups, then becomes possible. When gauged in the presence of a chiral
scalar multiplet, the U(1) symmetry is broken spontaneously, generating a mass
for the U(1) vector multiplet via the supersymmetric Higgs effect. As an
example we discuss the case of the homogeneous coset space E6/SO(10) x U(1).
