  Motivated by the LHCb's very recent observation of exotic $X_{0}(2900)$ in
the $B^{+}\rightarrow D^{+}D^{-}K^{+}$ process, for which could be a good open
charm $ud\bar{c}\bar{s}$ tetraquark candidate, we endeavor to investigate its
possibility by means of QCD sum rules. In technique, four configurations of
interpolating currents with $J^{P}=0^{+}$ are studied for the
$ud\bar{c}\bar{s}$ tetraquark state. In the end, mass values are calculated to
be $2.76^{+0.16}_{-0.23}~\mbox{GeV}$ for the axial vector diquark-axial vector
antidiquark configuration and $2.75^{+0.15}_{-0.24}~\mbox{GeV}$ for the scalar
diquark-scalar antidiquark configuration, both of which are consistent with the
experimental data $2.866\pm0.007\pm0.002~\mbox{GeV}$ of $X_{0}(2900)$ in view
of the uncertainty. These results support that $X_{0}(2900)$ could be a $0^{+}$
tetraquark state with open charm flavor.
