  We consider a mirror dual of the Berkovits-Vafa A-model for the BPS
superstring on $AdS_5\times S^5$ in the form of a deformed superconifold. Via
geometric transition, the theory has a dual description as the hermitian
gaussian one-matrix model. We show that the A-model amplitudes of generic
$AdS_2\times S^4$ branes, breaking the superconformal symmetry as $U(2,2|4)\to
OSp(4^*|4)$, are evaluated in terms of observables in the matrix model. As
such, upon the usual identification $g_{YM}^2=g_s$, these can be expanded as
Drukker-Gross circular 1/2-BPS Wilson loops in the perturbative regime of
${\cal N}=4$ SYM.
