  Based on the most general principles of reality, gauge and reparametrization
invariance, a problem of constructing the action describing dynamics of a
classical color-charged particle interacting with background non-Abelian gauge
and fermion fields is considered. The cases of the linear and quadratic
dependence of a Lagrangian on a background fermion field are discussed. It is
shown that in both cases in general there exists an infinite number of
interaction terms, which should be included in the Lagrangian in question. From
a simple iteration scheme, examples of the construction of the first few
gauge-covariant currents and sources induced by a moving particle with
non-Abelian charge are given. It is shown that these quantities, by a suitable
choice of parameters, exactly reproduce additional currents and sources
previously obtained in [Yu.A. Markov, M.A. Markova, Nucl. Phys. A 784 (2007)
443] on the basis of heuristic considerations.
