  A cosmological model has been constructed in the framework of Brans-Dicke
(BD) gravity, based on an inter-conversion between matter and dark energy, for
a spatially flat universe in the era of pressureless dust. To account for the
non-conservartion of the matter content, a function of time f(t) has been
arbitrarily put into the expression of the density of matter. By definition,
f(t) is proportional to the matter content of the universe. Using suitable
ansazes for scale factor and scalar field, the functional form of f(t) has been
determined from the BD field equations. The scale factor has been so chosen
that it would cause a signature flip of the deceleration parameter with time.
The function f(t) decreases monotonically with time, indicating a
transformation of matter into dark energy. Time dependence of the proportions
of matter and dark energy of the universe has been determined. The effect of
non-conservation of the matter content upon various cosmological parameters has
been explored in the present study. Two models of matter-energy interaction
have been proposed and f(t) has been expressed as a function of their
interaction term. The dark energy equation-of-state (EoS) parameter has been
expressed and analyzed in terms of f(t).
